Biochemistry and Microbiology

Permanent URI for this collection

https://hdl.handle.net/10530/475

Browse

Now showing 1 - 20 of 101

Ameliorative effect of the methanolic Crude extracts of Inula glomerata and Salacia kraussii on erectile dysfunction in Sprague Dawley rats
(University of Zululand, 2020) Ojo, Michael Chukwuka
Erectile dysfunction (ED) is a common but multifaceted sexual disorder suffered by men with an adverse effect on their self-esteem and quality of life. Globally, the prevalence of ED has markedly increased as revealed by epidemiological studies. The use of conventional drugs has been reported to have side effects in addition to being unaffordable especially to rural dwellers. The leaves of Inula glomerata and roots of Salacia kraussii are among those herbal plants used by Zulu traditional healers to manage impotence. The study investigated the ameliorative effects of the methanolic crude extracts of the leaves of Inula glomerata and roots of Salacia kraussii on butanol induced erectile dysfunction. The plant materials were screened for their phytochemical’s composition. The crude extracts were prepared from the plant materials by maceration using methanol. The In vitro antioxidant efficacy of the crude extracts was tested against DPPH and ABTS radicals. For in vivo studies thirty-five male Sprague Dawley rats were divided into seven groups (with five rats per group). The normal group, n-butanol, n-butanol+ Inula glomerata (50 and 250 mg/kg body weight), n-butanol+ Salacia kraussii (50 and 250 mg/kg body weight) and n-butanol+ Cialis (5 mg/kg body weight). The extracts were administered to the male rats orally by cannula every day for 28 days. Some sexual behaviour were monitored. In addition, the effect of the extracts on antioxidant status, the level of nitric oxide, testosterone and uric acid as well as acetylcholinesterase, ACE, arginase activities were assessed. The crude extracts’ cytotoxicity was also determined using MTT assay. vii The result showed that both plants contain tannins, flavonoids, terpenoids, and alkaloids. At a varying degree of efficiency, the crude extracts scavenged ABTS and DPPH radicals with Salacia kraussii (IC50 6.58× 10−3 mg/ml) displaying a better scavenging activity than ascorbic acid (IC50 1.27× 10−2 mg/ml). Furthermore, the results indicated that the plants boosted catalase and SOD activities and concomitantly increased the level of glutathione. The extracts also attenuated arginase, ACE and acetylcholinesterase activities at the same time elevated nitric oxide and testosterone level. In conclusion, both plants exhibited libido-boosting capacity and anti-erectile dysfunction efficacy. Nonetheless, due to their cytotoxicity, they require strict medical supervision before ingestion.
An in silico approach to understanding the role of P450s involved in secondary metabolites production in mycobacterial species
(University of Zululand, 2022-09) Zondo, Ntokozo Minenhle
Cytochrome P450 monooxygenases (P450s/CYPs) are ubiquitous enzymes with unique regio- and stereo-selective oxidation activities. Due to these properties, P450s play a key role in the biosynthesis of natural metabolites. Mycobacterial species are well-known producers of complex metabolites that help them survive in diverse ecological niches, including in the host. In this study, a comprehensive analysis of P450s and their role in natural metabolite synthesis in 2666 mycobacterial species have been carried out. The study revealed the presence of 62815 P450s that can be grouped into 182 P450 families and 345 subfamilies. Blooming (presence of more than one copy of the same gene) and expansion (presence of the same gene in many species) were observed at the family and subfamily levels. CYP135 was the dominant family in mycobacterial species. The mycobacterial species have distinct P450 profiles, indicating lifestyle impacts P450 content in their genome vis a vis P450s play a key role in organisms' adaptation. Analysis of the P450 profile revealed a gradual loss of P450s from non-pathogenic to pathogenic mycobacteria. Pathogenic mycobacteria have more P450s in biosynthetic gene clusters that produce natural metabolites. This indicates that P450s are recruited for the biosynthesis of unique metabolites, thus helping these pathogens survive in their niches. This study is the first to analyze P450s and their role in natural metabolite synthesis in many mycobacterial species.
Analysis of the biophysical and in silico exploration of the interaction between small ribonucleoprotein G and the RING finger domain of retinoblastoma binding protein 6 for the identification of protein anti-cancer compounds
(University of Zululand, 2021) Mabonga, Lloyd
Cancer is the second leading cause of death globally after cardiovascular diseases, killing more people than HIV/AIDS, tuberculosis and malaria combined, which makes it a major public health concern. Increasing cancer morbidity and mortality rates has partly been due to the lack of specificity and side effects associated with most cancer drugs; hence over the years tremendous efforts have been linked to finding solutions to address these challenges. Novel techniques to design and develop cancer treatment methods using protein-protein interactions (PPIs) have become promising targets for therapeutic discovery. Suggestive evidence has proposed putative interactions between Small nuclear ribonucleoprotein polypeptide G (SNRPG) (also referred to as SmG in this study) and retinoblastoma binding protein 6 (RBBP6), which have been identified as potential diagnostic markers for cancer treatment. The broad focus of this study was to investigate the putative interactions between these two proteins. In-silico analysis and characterisation of the proteins using Autodock Vina revealed the binding and interaction patterns of SNRPG with the RBBP6 RING Finger domain with a docking score of 3.40kcal/mol. Using I-TASSER, a potential inhibitor known as (2R)-2-[(2-methyl-5-phenylpyrazol-3-yl) carbonyl amino]-3-napthalen-2-yl-propanoic acid) (4FI) was identified and MM/GBSA binding free energy analysis revealed a spontaneous reaction of SNRPG~RING Finger domain in complex with the inhibitor, due to a binding energy of -27.96kcal/mol. Some of the amino acid residues involved in the binding include Val222, Pro101 and Met194. Biophysical studies using MicroScale Thermophoresis (MST) confirmed the putative SNRPG~RING Finger domain interaction, and determined that the binding affinity was a Kdvalue of 3.1596 nM under aqueous buffer conditions. The overall results from this study suggest the potential druggability of the SNRPG~RING Finger domain PPI. These findings will enhance our understanding in selective identification of small molecule inhibitors or peptides, which could be developed as novel therapeutic candidates in the diagnosis and treatment of cancer.
Analysis of the effects of Gold nanoparticles on the functional integrity of select serum proteins and heat shock proteins of mammalian origin
(2012) Luthuli, Duncan Sifiso; Shonhai, A.; Revaprasadu, N.
Gold nanoparticles (AuNPs) are a natural starting point for understanding nanoparticle-protein interaction due to their possible applications in biomedical functions, such as disease diagnosis and drug delivery. This has driven interest to understand the effects of AuNPs on the functional and structural integrity of heat shock proteins (Hsp) and serum proteins. When AuNPs are used for medical purposes through the intravenous route, they may be modified by serum proteins and these modifications may give rise to pathologies, or alter the intended purpose of the nanoparticle. Furthermore, Hsp are ubiquitous proteins that occur in cells and are upregulated under stress. It is envisaged that Hsp may also interact with AuNPs delivered to cells and/or the blood circulatory system. In this study, I sought to analyse the interaction between AuNPs and bovine serum albumin (BSA), citrate synthase (CS), malate dehydrogenase (MDH) as well as human heat shock protein 70 (Hhsp70). AuNPs were synthesised by a citrate reduction method in the presence of cysteine as the capping agent, and analysed using UV/visible spectroscopy and transmission electron microscopy (TEM). The effects of AuNPs on the stability of BSA, MDH, Hhsp70 and CS to heat stress were assessed spectroscopically, both in the presence and absence of AuNPs. I further investigated the effects of AuNPs on the function of Hhsp70 in suppressing the aggregation of MDH. Data observed in this study suggested that, the interaction between AuNPs and proteins (BSA and Hhsp70) may be facilitated by sulfhydryl (SH) groups present in them. It was also observed that AuNPs have capabilities of suppressing heat induced aggregation of MDH and CS. Thus AuNPs have chaperone activity as they are capable of maintaining proteins in their soluble, functional forms during heat stress.
Angiotensin converting enzyme (ACE), Actinin (ACTN3), Tumour necrosis factor (TNF) gene polymorphism associated with biomarkers and physical characteristics in young African cricket players of Zulu origin
(2012) Ramakoaba, Abigail; Djarova, T.; Grace, J.; Watson, G.
Current research in biochemistry and genetics focuses on finding a relationship between genes and biomarkers that are playing a fundamental role in physical performance. A possible link between these genes, molecular adaptation to exercise training and various markers of physical performance has been established in the past decade. A handful of genes have been studied by scientists, among them are the Angiotensin Converting Enzyme (ACE), ACTN3 (Actinin) and the Tumor Necrosis Factor (TNF). The ACE gene which encodes the angiotensin converting enzyme has been studied in detail and is known for influencing human physical performance and trainability. ACTN3 gene encodes the actinin-3 protein, that is known to form part of the sarcomeric Z-line, anchoring the actin filaments together and maintaining the mechanical integrity of the muscles. The TNF gene is among less studied genes, it encodes the Tumor Necrosis Factor protein which initiates the production of interleukins and that results in the production of the inflammatory biomarker C- reactive protein (CRP). Cricket is like any other sport in whereby there are energy requirements, physical characteristics that have been accepted as indicators of good performance in the game (body mass index, hand grip, quadriceps and hamstring strength) which are assessed for the purpose of the study. This study therefore sought to explore the ACE I/D, ACTN3 R/X and TNF G/A gene polymorphism, biomarkers (uric acid (UA) lactate (LA) and CRP) changes and the association with physical tests in a previously unexplored cohort of African Zulu cricketers. The participants were 31 Africans males aged 20-27 years (n=14 cricketers and n=17 controls). The genotyping (blood spots) was performed by PCR amplification followed by restriction digestion. After ANOVA the association was examined using Chi2 maximum likelihood test and Fisher’s exact test. ACE genotyping for the whole group displayed a complete absence of II genotype, 67.7% DD and 32.3% ID genotypes. The frequency of D allele was 83.8% and I allele 16.2%. In cricketers DD and ID genotypes were 50% each compared to controls-83% DD and 17% ID. The D allele is associated with power/sprint performance and the I allele with endurance. ACTN3 genotype frequencies for the cohort were 90.3% RR and 9.7% RX. The XX genotype was absent. The R allele is linked to sports that require power/sprint and the X allele is related to endurance. No differences in genotype frequencies between the two groups were noted. R allele at extremely high frequency (100%) was associated with CRP (<3.0 mg/L) in cricketers (p=0.0001) and controls (p=0.0140). TNF genotyping displayed 42% GG, 45% GA and 13% AA for the whole cohort, but no differences between both groups. CRP (<3.0 mg/L) was associated (p=0.0001) with low A allele frequency (18% in controls and 40% in cricketers). Interestingly, a null homozygosis of both the ACE II and the ACTN3 XX genotypes was found for the first time in the cohort of Zulu cricketers. This research demonstrates high ACE D allele frequency and a strong ACTN3 R allele association with low CRP, UA and LA levels. This study provides evidence about the genotype distribution of previously unexamined cohort of African athletes.
Annotation and comparative analysis of P450s, their redox partners and secondary metabolite gene clusters in the bacterial phylum Bacteroidetes
(2022-09) Nkosi, Bridget Valeria Zinhle
Species belonging to the bacterial phyla Bacteroidetes and Firmicutes represent over 90% of the gastrointestinal microbiota. Changes in the ratio of these two bacterial groups were found to have contrasting health effects, including obesity and inflammatory diseases. Despite the availability of many bacterial genomes, comparative genomic studies on the gene pools of these two bacterial groups concerning cytochrome P450 monooxygenases (P450s), ferredoxins, and secondary metabolite biosynthetic gene clusters (smBGCs) are not reported. Recently, an analysis of P450s, ferredoxins, and smBGCs in Firmicutesspecies has been reported. However, such studies on Bacteroidetes species have not been performed. This study is aimed to address this research gap. In this study, a thorough comparative analysis of P450s in the phylum Bacteroidetes has been carried out. P450 data mining and annotation of P450s in this phylum displayed 98 P450s in 77 species. It consisted of 130 genera, the Hymenobacter genus having the most P450s. Twenty-one P450 families were discovered, with CYP1103 dominating. Cluster analysis revealed 1298 smBGCs, with terpene being the most dominant. Out of the 98 P450s found in 334 Bacteroidetes species, only eight P450s (8.2 %) of seven Bacteroidetes species were found as part of the secondary metabolite BGCs. Genome data mining and annotation of ferredoxins in 104 Bacteroidetes species revealed the presence of 269 ferredoxins in their genomes. Among the Bacteroidetes species, Tenacibaculum jejuense had the highest number of ferredoxins (six). The 269 ferredoxins found in Bacteroidetes species can be grouped into five iron-sulfur (Fe-S) cluster types: 2Fe-2S, 3Fe-4S, 4Fe-4S, 2[4Fe-4S], and 2[4Fe-4S]Alv. The 7Fe-8S cluster-type ferredoxins were not found in the Bacteroidetesspecies analyzed in this study. Based on the amino acid spacing pattern analysis between the cysteine amino acids of the Fe-S cluster binding motif, 136 2Fe-2S ferredoxins of Bacteroidetes can be grouped into five subtypes. Eleven 4Fe-4S ferredoxins found in Bacteroidetes species can be grouped into three subtypes. The study revealed the presence of diverse sets of P450s, ferredoxins, and smBGCs in Bacteroidetes species genomes. Bacteroidetes species have the highest number of P450 families, ferredoxin cluster-types, and smBGCs compared to Firmicutes species. Only four P450 families, three ferredoxin cluster types, and five smBGCs are commonly shared between these two bacterial groups. Considering the above facts, we propose that the contrasting effects of these two bacterial groups on the host are partly due to the distinct nature of secondary metabolites produced by these organisms. Thus, the cause of the contrasting health effects of these two bacterial groups lies in their gene pools.
Anti-aging potential of some freshwater microalgae extracts
(University of Zululand, 2023) Sithole, Siphesihle Zamajobe.; Opoku, A.R. Mosa, R.A. & Osunsanmi, F.O.
The aging of the skin is a progressive, multi- faceted phenomenon that alters skin tissue and is impacted by both intrinsic and external causes. Age and genetics contribute to intrinsic aging, whereas ultraviolet radiation (UVR) contributes to extrinsic aging. Intrinsic aging is a predetermined process that produces fine wrinkles, whereas long-term UVR exposure (classified as photo-aging) causes patchy hyperpigmentation, dilated blood vessels, epidermal hyper proliferation, and sunburn. Existing skincare products for anti-aging are known to include hazardous substances associated with an elevated skin cancer risk. As a result, there is a need to look for natural alternative cosmetic items. Thus, this study aimed to assess the anti- aging potential of freshwater microalgal extracts. Freshwater samples collected from the University of Zululand environment were enriched with BG-11 and cultured under UV illumination. Out of the ten (10) pure colonies isolated from the culture and characterised through 16s RNA, Cylindrospermum alatosporum (NR125682.1) and Loriellopsis cavernicola (NR117881.1) were cultivated for biomass. Dried biomass was sequentially extracted with solvents with varying polarities namely hexane, dichloromethane (DCM) and ethanol. The phytochemical screening of the extract was conducted using GC-MS and FTIR. The antioxidant activities of the microalgal extracts were estimated by various in vitro assays including the scavenging of 1.1-Diphenyl-2-picryl hydrazil (DPPH), 2.2- Azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS), hydroxyl (·OH) radicals and metal ion chelating, In vitro experiments were conducted to explore the inhibition of aging enzymes, namely collagenase, elastase, hyaluronidase, and tyrosinase. UVB and UVA photoprotective activity of the microalgal extracts was also investigated. Antibacterial susceptibility testing was conducted on commensals, Propionibacterium acnes and Staphylococcus aureus. The results obtained indicate that the extracts contained phenols and sulfhydryl groupcontaining compounds that could be responsible for certain biological activities of importance to this study. The extracts were average scavengers of synthetic radicals (IC50 values in the range from 6.5 – 48.6 μg/ml) but were potent metal ion chelators (44.3- 75.7 μg/ml). All extracts inhibited (in vitro) tyrosinase (≈ 47.87%), hyaluronidase (≈ 89.51%), and collagenase (≈ 76.67%) activities, but were poor inhibitors of elastase (≈16.43%). UVA and UVB photoprotective activity were exhibited by the extracts with L cavernicola exhibiting better UVB photoprotective activity (SPF 14.67 – 78.96). besides, this is observed for antimicrobial activity against strains of Staphylococcus aureus (ATCC 25923 and APO25177.1) and Propionibacterium acnes Kwik-stikTM. In conclusion, C alatosporum (NR125682.1) and L cavernicola (NR117881.1) possess the potential to be exploited as anti-aging agents.
Anti-asthmatic and anti-cough activities of the essential oil Of Eucalyptus Grandis W. Hill Ex Maiden
(University of Zululand, 2015) Soyingbe, Oluwagbemiga Sewanu; Opoku, A.R.
Asthma is a chronic inflammatory disorder of the airways. It is characterized by an inflammation of the airways causing airway dysfunction. Asthma is associated with widespread airflow obstruction, with an associated increase in airway responsiveness to a variety of stimuli. An asthma attack is accompanied by wheezing, shortness of breath, chest tightness and coughing. This project aims to investigate the essential oil of Eucalyptus grandis, a medicinal plant used by Zulu traditional healers for its antiasthmatic and anti-cough activities in the treatment of respiratory tract infections. The anti-asthmatic and anti-cough activities of the essential oils and 1, 8-cineole on rats were assessed. These activities were induced and challenged with histamine and acetylcholine using an ultrasonic nebulizer for asthma and exposure to ammonia for coughs. The assessment of the chemical composition of the essential oils hydrodistilled from the fresh and dry leaves of Eucalyptus grandis was carried out using a GC and GC-MS analysis. Column chromatography was used to isolate 1,8-cineole and terpinen- 4-ol components of the essential oils. Agar well diffusion was used to access antibacterial (Klebsiella pneumoniae, Staphylococcus aureus and Moraxella catarrhalis) susceptibility to the essential oil. Cytosolic LDH was released and efflux pump inhibition activity was monitored to determine the apparent bactericidal mechanism of the essential oils. Antioxidant activity (free radical scavenging of nitric oxide, hydroxyl radical, superoxide anion, and also the sulfhydryl, NADH as well as the malondialdehyde (MDA)—TBARS contents) was determined. vi Anti-inflammatory activities of the essential oils and 1,8-cineole were determined using the cotton pellet granuloma test. Biochemical estimates were carried out on the catalase activity, superoxide dismutase, in vitro COX-1 and COX-2 inhibition assay and the acetylcholinesterase inhibitory activity. Muscle contraction studies where carried out using the vascular reactivity on aortic smooth muscle, and cytotoxicity assay done using the MTT assay on human embryonic kidney cells (HEK293) and human hepatocellular carcinoma cells (HepG2). The percentage yield of the essential oils from the fresh and dry leave was 0.19% and 0.40% respectively. The identified main components of the essential oil of the fresh leaves constituted 99.25% and the major constituents were: α- pinene (29.69%), p-cymene (19.89%), 1,8-cineole (12.80%), α-terpineol (6.48%), borneol (3.48%) and d-limonene (3.14%). The identified main components of the essential oil of the dry leaves was 92.63%, with the major constituents being: 1,8- cineole (47.44%), d- limonene (13.34%), α-pinene (7.49%), (-)-spathulenol (7.13%) and benzene,1-methyl-4-(1-methylethyl)-(5.42%). The oils exhibited concentration dependent anti-asthma and anti-cough activities. Significantly, 1,8-cineole isolated and purified from the essential oil showed a concentration dependent anti-inflammatory, anti-cough and anti-asthma activity. The oils inhibited the growth of the microorganisms studied. The minimum inhibitory concentration (MIC) ranged from 0.3125 mg/ml to 1.25 mg/ml, and the minimum bactericidal concentration (MBC) ranged from 0.625 mg/ml to >5 mg/ml. The LDH release assay (membrane damage) revealed bacterial membrane damage ranging from 1% to 11% in comparison with the standard tritonX-100. Accumulation of rhodamine 6G in bacterial cells, which was used to determine the activity of the essential oils as drug efflux pump inhibitors (EPIs), showed that the vii essential oils were effective as EPIs; the essential oils were also seen to be concentration dependent in inhibiting the activity of COX 2, with no significant effect on COX 1. The essential oils showed weak antioxidant activity in scavenging free radicals (IC50 for nitric oxide scavenging of 4.34 µg/ml and 3.65 µg/ml for the fresh and dry respectively, and >5 µg/ml for hydroxyl radical). Sulfhydryl contents were 9.00 µg/g(w/w) and 13.14 µg/g(w/w) for the oils from the fresh and dry leaves respectively. The essential oils showed vasorelaxant activity; cytotoxicity levels of the oils indicated that the oils were not toxic on cell lines, with IC50 of 2291, 2189 on HEK 293 cell, HEPG2 for the essential oils from the fresh leaves and 1875 and 1942 for the essential oils from the dry leaves on HEK293 and HEPG2 respectively. It is concluded that the essential oils have the potential to be used as an anti-asthma and anti-cough therapy. This study also justifies its use by traditional healers in the treatment of asthma and coughs in Zulu folklore medicine.
Anti-diabetic properties of GUH
(2006) Gabuza, Kwazi B.; Opoku, A.R.; Louw, J.; Woodroof, C.
Objective: To investigate anti-diabetic properties of the plant extract known as GUH in comparison to commercially available drugs metformin and rosiglitazone. Methods: Male Wistar rats were fed a maintenance diet (MD) with tap water or a high fat diet (HFD) with sucrose solution for a period of twelve weeks. Thereafter a separate groups of animals were then treated with GUH at 5 different dose levels, metformin or rosiglitazone for twelve weeks. Food intake, liquid intake, weights, blood glucose, and insulin were monitored throughout the treatment period. An intravenous glucose tolerance test (IVGTT) was performed on representative animals from each treatment group prior to termination. At termination blood was taken and total cholesterol, tri-acylglycerol (TAG), low density lipoproteins LDL, and high density lipoproteins (HDL) were measured. Results: The effect of GUH in MD fed rats was not marked. However, food intake and weight gain and total cholesterol were lower than in control animals. In HFD fed animals GUH, metformin and rosiglitazone had a significant effect The extract reduced blood glucose and increased circulating insulin levels when compared to controls but results were not significantly different to metformin and rosiglitazone treated animals. As with metformin and rosiglitazone, GUH increased food intake with a concomitant weight increase. This weight increase was, nevertheless, less than with the other 2 treatments. In HFD fed animals GUH at the highest dose level increased the glucose clearance rate to a greater extent than metformin and rosiglitazone. Conclusion: The results conclusively show that the extract GUH was at least as effective, and in some instances more effective, than currently used diabetes treatments. Although further work is required to investigate the mode of action, it is evident that extracts of indigenous South African plants can be cost effective and efficacious treatments.
Anti-nutritional constituent of Colocasia Esculenta (Amadumbe) : a traditional crop food in Kwazulu-Natal
(2008) McEwan, Ronalda; Opoku, A.R.; Djarova, T.; Oyedeji, O.A.
Colocasia esculenta L. Schott belongs to the family Aracea and is grown for its edible corms as a staple food throughout subtropical and tropical regions of the world. Amadumbe (the Zulu name for Colocasia esculenta) is consumed by and holds an important place in the diet of local rural people in Kwazulu-Natal, South Africa. Three Amadumbe phenotypes were evaluated for their nutritional qualities. Like all known tubers, the locally grown Amadume contained high carbohydrate levels, adequate protein and low lipid content. Essential fatty acids (linoleic and linolenic) were identified as components of the Amadumbe lipids. Amadumbe was generally low in mineral content, apart from potassium and magnesium levels that were relatively high. Some anti-nutrients (protease inhibitors, lectin, phenolic compounds, alkaloids, oxalates, phytates, cyanogens and saponin) present in Amadumbe were also identified and quantified. The anti-nutrient levels were generally low and thus may not pose an immediate effect on the health of consumers. Reduction of the anti-nutrients through processing (cooking, frying, roasting) was observed to enhance the nutritional value of these tubers. However, their presence suggests that a steady consumption may lead to toxic levels. Two proteins (Al and B2) with a-amylase inhibitor activity, and a steroidal saponin (gamma-sitosterol) were extracted and partially characterised. The a-amylase inhibitors were extracted and partially purified through ammonium sulphate precipitation and chromatographic fractionation on diethylaminoethyl (DEAE)-Sephacel and Sephadex G-100. The molecular weights of the two inhibitors were estimated to be 17 000 and 19 000 dalton, respectively. The inhibitors were fairly heat-stable, with optimum activity at 40° C? pH 6.0. Both inhibitors showed activity against mammalian a-amylases, but were devoid of activity against fungal amylases. Inhibitor A also showed activity against plant amylases. The steroidal saponin extracted from Amadumbe was characterized through TLC, HPLC, GC-MS, IR and NMR spectroscopic analysis and identified to be gamma- sitosterol, an isomer of beta-sitosterol which is known to have a variety of high biological activity. Studies of the effect of beta-sitosterol on absorptive and digestive enzymes in Sprague-Dawley rats revealed that oral administration of beta-sitosterol had no apparent gross or microscopic lesions in the liver, kidney or small intestine. The administered p-sitosterol significantly decreased serum aspartate aminotransferase (ALT) and alanine aminotransferase (AST) levels. Na+/K -ATPase and intestinal disaccharidases activities were also significantly reduced in beta-sitosterol fed rats. These results do suggest that even though Amadumbe is a neglected crop in South Africa, it is a highly nutritional crop; the consumption of it could be beneficial to diabetic and hypertensive patients.
Anti-platelet aggregation activity of melaleuca bracteata var.revolution gold derived betulinic acid and its derivatives
(University of Zululand, 2015) Oluwagbemiga, Osunsanmi Foluso; Opoku, A.R.
Abnormal Platelet aggregations are implicated in the onset of cardiovascular diseases which are the leading cause of death and disability globally. Management of pathological platelet aggregation with medicinal plants is a promising approach in treatment of cardiovascular diseases. In this study, betulic acid (BA) and a mixture of betulinic acid and oleanolic acid (BA/OA) isolated from Melaleuca bracteata leaf extract and their acetyl derivatives (3-β acetylbetulinic acid) (BAA), (3-β acetylbetulinic acid and 3-β acetyloleanolic acid mixture) (BAA/OAA) were investigated for their antiplatelet aggregation, anti-inflammatory, anticoagulant, anti-oxidant and cytotoxicity activity. The compound structures were confirmed through spectral nuclear magnetic resonance (NMR), mass (MS) and infrared (IR) spectroscopy data analysis. The antiplatelet aggregation activities of the compounds were evaluated against four agonists (thrombin, collagen, adenosine diphosphate and epinephrine) used separately to induce platelet aggregation. The ability of the compounds to separately inhibit the hydrolysis of chromogenic substrate was used for antithrombin activity of the triterpenoids. The release of ATP and calcium mobilization from the cytosol, as platelets aggregate, was investigated using a commercial kit and Fura 2/AM respectively. The anti-acetylcholinesterase activity of the triterpenes was also investigated using a commercial kit. The compounds were fed to rats and the tail bleeding time was used to determine the ex vivo anticoagulation activity of the triterpenoids. The anti-inflammatory activity of the triterpenes was investigated using the cotton pellet-induced granuloma model in rats. The homogenates from the granuloma tissues were used to determine the effect of the test compounds on catalase (CAT) and superoxide dismutase (SOD) activities. The in vitro effect of the triterpenes on cyclooxygenase COX-1 and COX-2 activity was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay was used to investigate the cytotoxic effect of the triterpenoids against carcinoma (HEPG2) and human embryonic (HEK293) cell lines. All the test compounds exhibited significant anti-platelet aggregation activity, albeit to different degrees of efficacy. BAA showed the highest antiplatelet aggregation activity regardless of the agonists. Coupled with its anti-platelet aggregation activity, BAA also exhibited significant anti-inflammatory, antithrombin, acetylcholinesterase inhibition, phosphodiesterase inhibition, calcium mobilization inhibition, inhibition of the release of ATP from dense granules, anticoagulant, cyclooxgensase (COX-2) activity inhibition, and iron chelating activities. BAA also significiantly stimulates SOD and CAT activity. In addition to the efficacy, the weak cytotoxicity of triterpenoids indicated their safety as an antiplatelet agent. It was concluded that BAA could be served as a template for the synthesis of safer anti-platelet agent.
The anti-platelet aggregation activity of Rapanea melanophloeos -A Zulu medicinal plant
(2011) Gwala, Phiwamandla Emmanuel; Opoku, A.R.; Oyedeji, A.O.
Rapanea melanophloeos (L.) Mez is a medicinal plant that is used by Zulu traditional healers to manage blood-clot related diseases.Various extracts (methanol, nhexane, chloroform, ethyl acetate and water) prepared from the bark of R. melanophloeos were screened for phytochemicals, antioxidant, and anti-platelet aggregation activity. Phytochemical screening of the plant showed the presence of tannins, terpenoids, alkaloids, saponins, cardiac glycosides, flavonoids and phlobatannins. Steroids and anthraquinone were however not detected. The extracts strongly (>70%) scavenged 1, 1 -diphenyl-2-picryhydrazyl and 2, 2-azinobis 3-ethyl-benzothiazoline-6-sulfonic acid free radicals. The extracts had 91% chelating effect on Fe2+ ions and exhibited concentration dependent reducing power. The extracts showed varying degrees of inhibition (21% to 97%) of rat platelet aggregation induced separately by thrombin, adenosine diphosphate (ADP) and epinephrine. The extracts further exhibited antiplatelets aggregation activity on enzymes (trypsin, papain and bromelain) treated platelets. The lethality of the extracts was tested on brine shrimps larvae. Hexane and chloroform extracts had LC50 values of 1068.731 mg/ml and 3648, 349mg/ml respectively. A triterpene (3β-Hydroxylanosta-9, 24-dien-21-oic acid) wasisolated and characterized (through various chromatographic techniques, extensive 1D and 2D NMR spectroscopy) from the ethyl acetate extract. The triterpene exhibited antiplatelet aggregation, and inhibition of acetylcholinesterase activity. The cytotoxicity of the triterpene on two cell lines (HEK293 and HEPG2) gave LC50 values of 851.5 μg/ ml and 796.0 μg/ ml respectively. The results suggested that the extracts of Rapanea melanophloeos could be considered as herbal treatment for disease associated with blood clotting.
The antidiabetic properties of four plants grown in India and KwaZulu-Natal, South Africa, suitable for diabetic management
(University of Zululand, 2015) Georgekutty, Raymol; Opoku, A.R.
Over the years, it has been suggested that various medicinal plants have anti-glycaemic properties which could help in the management of diabetes mellitus, a complex metabolic disorder. We aimed to evaluate the nutritional content (proximate and mineral) of four ayurvedic plants: Abelmoschus esculentus (L.) Moench, Momordica charantia L, Moringa oleifera Lam, Solanum melongena L. to identify nutritional differences between the Indian and South African varieties. An assessment of the anti-glycaemic activity of the aqueous and boiled extracts of the samples from South Africa was carried out by monitoring glucose, triglyceride and cholesterol levels as well as body weight in alloxan-induced diabetic rats and their control group over a 15 day period. Ninety-two Sprague-Dawley rats were separated into 7 groups (see table 3.3). Diabetes was induced in 48 rats by a single intraperitoneal injection of alloxan, 150mg/kg body weight. The apparent mechanism of anti-glycaemia was also investigated using the inverted intestine test, the glycogen content within the liver, the activity of Na/K ATPase and by assessing glucokinase and hexokinase activity by analysing liver and gastrocnemius muscle tissue. Results revealed that all four plants were reported to have protein, fats, glucose and starch, with the South African varieties showing higher protein content than the Indian varieties. According to mineral analysis by the varian inductively coupled plasma (ICP), all the four plants are rich in minerals. The in vivo studies revealed that all the plant extracts showed hypoglycaemic effects within the two week study period except the A.esculentus boiled extract. Preliminary experiments demonstrated that aqueous extracts of M.charantia and A.esculentus had maximum antidiabetic potential compared to the other plant extracts. The aqueous extract of M.charantia and A.esculentus fruits, at a dose of 300 mg/kg body weight, showed a statistically significant lowering of the glucose level of alloxan induced diabetic rats compared to the control group from 22.78 mmol/L to 8.1 mmol/L and 22.2 mmol/L to13.3 mmol/L respectively, after 15 days of treatment. The enteral use of M.charantia and A.esculentus extract resulted in an increase in body weight in diabetic rats and a reduction in body weight in the diabetic control rats. M.charantia and A.esculentus extracts lowered the entry of glucose into the intestine. Treatment with M.charantia and A.esculentus increased the glycogen content by 47.3% (M.charantia aqueous) 59.2% (M.charantia boiled), 55% (A.esculentus aqueous) compared to the diabetic control group. The evaluation of Na+/K+-ATPase activity revealed a more statistically significant inhibitory activity (25%) with the use of A.esculentus compared to M.charantia (12.5%). Hexokinase and glucokinase activity was reduced in the diabetic control rats as compared to the non-diabetic rats, with respective percentage decreases in activity of 66.7% and 83.3%. Treatment with Momordica charantia and Abelmoschus esculentus significantly increases the activity of these enzymes (P<0.001 as compared to diabetic controls). On the other hand, there was no change in glucokinase activity in non-diabetic treated groups. Histological analysis of diabetic control livers showed slight degenerative changes, which was within normal histological limits. Analysis of groups treated with extract showed mild diffuse sinusoidal congestion with mild hydropic degeneration which was within normal histological limits. Gastrocnemius muscle analysis of diabetic control, diabetic and non-diabetic treated groups appeared within normal histological limits. This revealed that the plant extracts of M.charantia and A.esculentus were non-toxic and thus advisable for safe consumption. The inclusion of these vegetables on a regular basis in the daily diet, together with medication and exercise would improve general health and blood glucose control in diabetic patients.
Antimalarial activity of hypoxis colchicifolia, bak, mimusops caffra, E. Mey. ex A.DC and mimusops obtusifolia, lam from South Africa
(University of Zululand, 2014) Simelane, Mthokozisi Blessing Cedric; Opoku, A.R.; Shonhai, A.; Shode, O.O.O.
Malaria is one of the major health problems of today, more so since the parasite has become resistant to the currently used drugs. There is a need for research into new drugs from medicinal plant species which are used by local traditional healers for the treatment of malaria. Mimusops caffra, E.Mey. ex A.DC, Mimusops obtusifolia, Lam (both members of Sapotaceae family) and Hypoxis colchicifolia, Bak are used by traditional healers in Zululand to manage malaria. In this study, the plants were separately extracted exhaustively with methanol, ethyl acetate, hexane and dichloromethane (DCM). The crude extracts were screened for antioxidant, antipyretic, and antimalarial activity. The antioxidant activity of the methanol extracts was determined by measuring the decrease in the colour of an oxidative system in the presence and absence of the extract. The various antioxidant activities tested include free radical scavenging, Fe2+ chelating, reducing power, and total antioxidant capacity. Yeast induced pyrexia was used to evaluate the antipyretic activity of the plant extracts. In vitro antimalarial activity of the extracts was investigated against the chloroquine sensitive (CQS) strain of Plasmodium falciparum (D10) and the in vivo antiplasmodial activity was done against Plasmodium berghei. The most active in vitro antiplasmodial crude extracts were subjected to isolation, purification and characterization of the active components using column chromatographic techniques. The triterpenes isolated were confirmed using Nuclear Magnetic Resonance (NMR) techniques with the application of 2D-NMR (1H-1H, 13C, DEPT, COSY, HMQC, HMBC and NOESY) and infrared (IR). The preliminary phytochemical analysis of plants’ extracts revealed the presence mainly of saponins, tannins, alkaloids and flavonoids. Methanol extracts of the plants exhibited strong scavenging of 2,2-Diphenyl-1-picryl-hydrazyl (DPPH) and 3- ethylbenzothiazoline-6-sulfonate (ABTS) radicals, but showed poor (< 50%) radical scavenging of nitric oxide, superoxide and hydroxyl radicals. The DCM extract of the leaves of M. caffra and the ethyl acetate extract of the bark of M. obtusifolia exhibited antimalarial activity against the chloroquine sensitive (CQS) strain of Plasmodium falciparum (D10). The leaf extracts of M. caffra exhibited higher activity (IC50=2.14 μg/ml) compared to the extracts of M. obtusifolia (IC50=32.5 μg/ml). The pentacyclic tritepenoid (PTCs) ursolic acid isolated from the leaves of M. caffra was most active (IC50 = 6.8 μg/mL) in comparison to taraxerol and Sawamilletin isolated from the stem bark of M. obtusifolia with IC50 of > 100. Chemical modification of the ursolic acid to 3β-acetylursolic acid greatly enhanced (72%) its anti-plasmodial activity. The 3β-acetylursolic acid reduced parasitaemia against Plasmodium berghei by 94.01% in in vivo studies in mice. An attempt to elucidate the possible mechanism of action for the active compound was carried out. 3β-acetylursolic acid prevented the aggregation of MDH in vitro but did not prevent the expression of PfHsp 70 in E.coli XL1 blue cells. However, it showed PfHsp 70 ATPase activity with the specific activity of 65 (amount of phosphate released 73.83 nmolPi/min/mg). The cytotoxicity of 3β-acetylursolic acid (IC50) to two human cell lines (HEK293 and HepG2) was 366.00 μg/ml and 566.09 μg/mL, respectively. The results validate the use of these plants in folk medicine.
The antimicrobial activity of five food spices when tested against various gram-positive –and gram-negative microorganisms
(2008) Seepersad, Kashimee; Basson, A.K.; Djarova, T.; Shandu, J.S.
The discovery of antibiotics by Alexander Fleming in the early nineteen hundreds not only created an enormous breakthrough in medical treatment but along with it introduced the emergence of new and now what is considered an ever increasing number of multi-drug resistant pathogens. Like antibiotics, herbs and spices have been used traditionally by many, for the treatment of various aliments ranging from stomach indigestion, lesions of the skin to beauty therapy. At present it is estimated that about 80% of the world population rely on botanical preparations as medicines to meet their health needs as opposed to treatment by conventional medicine with spices creating a shelf of its own in the global medical cabinet. In this study, the antimicrobial potential of five spices (commonly known as ginger, cinnamon, turmeric, nutmeg and chilli) was analysed against various Gram positive- and Gram negative microorganisms namely, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Salmonella spp, Shigella spp and Staphylococcus aureus. Analysis of the results of sensitivity tests (disc and agar well diffusion assays) indicated each of the microorganisms to be completely inhibited, intermediately inhibited or completely resistant towards a particular spice extract. The formation of zones of inhibition present where inhibition had occurred indicated that the spice tested was effective as an antimicrobial agent when screened. Zones of absolute inhibition (greater than fifteen millimetres in diameter) were obtained during positive agar well and disc diffusion assaying with neomycin used as the antimicrobial agent of choice. Inhibition zones observed to be in the upper limit range (pertaining to the study) of 20 mm – 27 mm in diameter. Comparative studies using the test spices indicated that chilli, turmeric, nutmeg, cinnamon and ginger each demonstrated zones of inhibition within this limit at one or more laboratory testing. Chilli was the most active antimicrobial agent when tested and in some instances demonstrated antimicrobial effectiveness greater than that exhibited by the positive control neomycin. Turmeric, nutmeg, cinnamon and ginger however each demonstrated inhibition within the same range as that of neomycin. The observations of such inhibition amongst the spices were comparatively significant and demonstrated the potential use of these spices as antimicrobial agents with an efficacy that can be compared to that of the already recognized and widely used antibiotic, neomycin. The minimum inhibitory concentration (MIC) was successfully determined for each of the spice extracts. The reactions observed during MIC determination were confirmatory of the antimicrobial activity present in the extracts of each spice. Analyses of the results conclude that the active compounds present in the selected spices were effective against certain microbial species. This observation demonstrated that spice can and may be used in the treatment of bacterial infections. This could in the future be an alternative treatment to antibiotics for one or all of the microbial species investigated and in so doing allow the healing powers of spices to be acknowledged.
Antimicrobial activity testing of traditionally used plants for treating wounds and sores at Ongoye area KwaZulu-Natal, South Africa
(2009) Mthethwa, Ntombeziningi Shirley; de Wet, H.; Basson, A.K.
This study focused on the investigation of plants used for the treatment of wounds and sores by local people living around the Ongoye forest, KwaZulu-Natal. An ethnobotanical survey was conducted in eighty homesteads in this area. The ethnobotanical data revealed that 33 plant species were used in treating sores and wounds, but only 15 plant species were collected from the wild and homesteads and three plant species were bought from a muthi market. According to the ethnobotanical information Hypericum aethiopicum (unsukumbili) was the most used plant for treating sores and wounds in this area. The survey showed that women (62.5%) possessed more knowledge than the men (37.5%) who were interviewed at the homesteads regarding the medicinal uses of plants. Acetone, methanol, cold and hot water extracts from the different plant parts (bark, leaves, stems and the whole plant) were done on 18 species. These plants species are: Acanthospermum australe, Acorus calamus, Albizia adianthifolia, Baccharoides adoensis, Clerodendrum hirsutum, Combretum erythrophyllum, Faurea saligna, Gerbera ambigua, Gunnera perpensa, Hypericum aethiopicum, Hypoxis hemerocallidea, Lippia javanica, Pentanisia prunelloides, Sclerocarya birrea, Solanum aculeastrum, Trichilia dregeana, Warburgia salutaris, Ziziphus mucronata. The above-mentioned plants were screened for antibacterial activity against the following bacteria strains: Bacillus subtilis (6051), Escherichia coli (7751, U1405s, U16406, U16403), Klebsiella pneumoniae (13883), Staphylococcus aureus (12600, P5020, P4790, T1266), ‘Salmonella spp., Shigella flexneri and Shigella sonnei’. The antibacterial activities were determined by disk-diffusion, agar-well diffusion, minimum inhibitory concentrations (MIC) and bio-autographic methods. The plant extracts were also screened for the following phytochemicals: alkaloids, flavonoids, saponins, anthraquinones, cardiac glycosides and tannins. The following plants were the most effective against the micro-organisms tested: Gunnera perpensa, Hypericum aethiopicum, Hypoxis hemerocallidea, Lippia javanica, Pentanisia prunelloides, Trichilia dregeana and Warburgia salutaris. The bio-autographic results showed several compounds separated on the TLC with activity against the test organism, Staphylococcus aureus (ATCC2600). This study thus lends some support to traditional knowledge and may serve as a basis for selecting the most active medicinal plants to use in traditional medicine practices in the future.
Antiplasmodial/Antipyretic activity of some Zulu medicinal plants
(University of Zululand, 2011) Nethengwe, Mulalo Flexy; Opoku, A.R.; Shonhai, A.; Oyedeji, O.A.
Malaria is one of the major diseases that have partially paralysed the world‘s health presently. There is, therefore, an urgent need to identify new antimalarial drugs as the plasmodium species continues to gain resistance to presently used drugs. In developing communities where malaria is prevalent, people depend strongly on traditional medicine as a source of inexpensive treatment for this disease. Gardenia thunbergia T.A Sprague, Siphonochilus aethiopicus (Schweif.) B.L Burtt, Schotia brachypetala Sond., Acorus calamus L., Withania somnifera (L) Dunal in DC., Elaeodendron transvalense (Burtt Davy) R.H. Archer, Hypoxis hemerocallidea Fisch., C.A. Mey.&Ave-Lall., Vernonia adoensis Sch. Bip. Ex Walp. and Acanthospermum australe (Loefl.) Kuntze) are some of the medicinal plants commonly used by Zulu traditional healers in South Africa to treat malaria. Aim The study aims to determine the phytochemicals present in the plants, larvicidal, antioxidant, in vivo antipyretic and in vitro antiplasmodial activities as well as the cytotoxicity of the nine plants. The study also aims to isolate and purify the active compound in the most active plant extract. Material and methods Plants obtained from the muti market were botanically identified and were screened for phytochemicals; the appropriate portions of each plant were separately extracted v into dichloromethane, methanol and water solvents. Larvicidal activity against Culex quinquefascitus larvae was determined by incubating the larvae with the plant extracts for 24 hours, where after percentage mortality was calculated. The antioxidant activity of the methanol extracts of the plants was determined by measuring the decrease in the colour of an oxidative system in the presence of the plants extracts. The various antioxidant activities investigated included the free radical (DPPH, ABTS, super oxide, nitric oxide and hydroxyl) scavenging activity, Fe2+ chelating, reducing power, and total antioxidant capacity. Antipyretic activity was determined by treating different groups of pyretic rats with different concentrations of the plants extracts (100 mg/kg, 500 mg/kg and 1000 mg/kg). The pyretic condition was induced by subcutaneous injection of 12% brewer‘s yeast. Temperatures before and after treatment were also compared. The antimalarial activity of the plants extracts were also screened against the chloroquine sensitive plasmodium falciparum D10 strain. Tests were done in triplicate for three concentrations (20 μg/ml, 10 μg/ml and 5 μg/ml). The active extracts were screened for cytotoxicity using the MTT assay. The most active in vitro antiplasmodial extract was subjected to isolation, purification and characterization using chromatographic and spectrometric techniques-IR, GC-MS, 1H-NMR, and 13C-NMR. Results Phytochemical screening revealed the presence of saponins, terpernoids, flavonoids, anthroquenones, cardiac glycosides; alkaloids (the major active constituents of most antimalarial drugs) were also observed in A. australe which, amongst others, exhibited the most in vitro antiplasmodial activity. The plant extracts either killed or reduced spontaneous movement in Culex quinquefascitus larvae after 24 hours following treatment. Methanol extracts exhibited antioxidant (DPPH, ABTS scavenging, Fe2+ chelating) activity, albeit to varying degree of efficiency. The dichloromethane and methanol extracts significantly (p≤ 0.05) reduced pyrexia with activity increasing in a concentration dependent manner. The antiplasmodial activity against chloroquine sensitive strain of Plasmodium falciparum (D10) showed that the methanol extracts of G. thunbergia, V. adoensis and the dichloromethane extracts of E. transvalense, and W. somnifera were active (IC50 of 1.04-5.07μg/ml). Although A. australe exhibited high in vitro antiplasmodial activity, the major compounds (Sitosterol and Stigmasterol) present in the extract did not exhibit any observable antiplasmodial activity. Conclusion The results support the use of some of these plants in folk medicine and suggest that these plants contained constituents that could be developed as potent antimalarial drugs (mosquito larvicide, anti-fever and anti-plasmodial).
Antithrombotic and anti-inflammatory activity of ethyl acetate extract of Protorhus longifolia stem bark
(University of Zululand, 2019) Majola, Londiwe Cynthia
Blood clotting related disorders are the major underlying cause of cardiovascular diseases, which are the major cause of premature deaths globally. Despite great efforts made in the discovery of antithrombotic agents, ischemic events continue to claim more lives. Thus, there is a need to discover and develop new and more effective antithrombotic drugs, preferably from natural sources. The study is aimed at investigating the anti-thrombotic and anti-inflammatory activity of the ethyl acetate extract of Protorhus longifolia stem bark. The in vitro antioxidant activity of the crude ethyl acetate was evaluated against DPPH, ABTS and nitric oxide radicals. Its reducing power and metal ion chelating potential were also determined. A chromogenic substrate was used to determine the antithrombin activity of the extract. While the thrombolytic activity of the extract was determined in rat whole blood clot, the antiplatelet aggregation activity was evaluated on rat platelet rich plasma. The carrageenan induced rat paw edema and rat tail bleeding time models were used to investigate the anti-acute inflammatory and antithrombotic activity of the extract, respectively. The experimental rats were orally pre-treated with the extract at 100 and 350 mg/kg for 8 consecutive days. While the water displacement method was used to measure the rat paw edema, the time it took for the rat tail to stop bleeding following a 5 mm amputation was taken as the bleeding time of the rats. At the end of the experiments, all the rats were euthanized and blood and the hind paws of the rats were collected for biochemical analysis of some inflammation and oxidative stress biomarkers. The extract showed, to a varying degree of efficacy, concentration dependent scavenging activity on DPPH, ABTS and nitric oxide radicals. While the plant extract showed a strong reducing power, only a moderate metal ion (Fe2+) chelating activity was observed. The extract also exhibited concentration dependent antithrombin and antiplatelet aggregation activities. At the highest concentration of 10 mg/ml, the extract exhibited up to 35.7% thrombolytic activity. While a marked decrease in tail bleeding time (3.18 min) was observed in the untreated inflammation induced rats when compared to the normal control group, prior oral administration of the extract (at 100 and 350 mg/kg) to the rats seemed to prolong the bleeding time up to 8.8 min. The animals pre-treated with the extract also displayed anti-inflammatory activity as they effectively reduced the rat paw swelling. Even though no significant v changes were observed in the tissue levels of IL-6 and TNF-α on the extract treated groups, a marked decrease in COX-2 and TGF- β1 was observed. Increased tissue levels of superoxide dismutase and total antioxidant status were also observed in the inflammation induced rats pre-treated with the extract at both 100 and 350 mg/kg in comparison to the untreated control group. Even though lower serum levels of some kidney and liver function biomarkers (urea, creatinine, AST, ALT and ALP) were observed in the group treated with the extract at 100 mg/kg, relatively higher serum levels of BUN and AST were observed in the rat group administered with the extract at a higher concentration of 350 mg/kg. The results obtained suggest that the ethyl acetate extract of P. longifolia stem bark possess antithrombotic and anti-inflammatory activities. The observed increases in serum levels of BUN and AST at the higher dosage of the extract indicate its potential nephro-and hepatotoxicity and that it be used as a treatment with caution.
Assessing the microbial community structure’s diversity associated with nutrients concentration in the natural wetland systems
(University of Zululand, 2018) Buthelezi, Nondumiso, Petunia; Mthembu, M.S; Basson, A.K
Microbial communities play a major role in natural wetlands systems biogeochemical cycles. Therefore, understanding the association between their composition, diversity and environmental parameters is significant in order to understand soil microbial ecology associated with nutrients concentration. Such knowledge may enhance the improvement in the management and protection of wetland systems, as nutrients are essential for wetland plant growth. Despite their usefulness, they promote toxin-producing cyanobacteria and facilitates algal biomass growth that cause undesirable eutrophication and oxygen depletion when present in excess. Nutrient pollution therefore is one of the most widespread and challenging environmental problems in the water that usually result to serious environmental and health challenges. For this study, water and sediment samples were collected over a period of twelve months from Lake Icubhu, which is a fresh water wetland, and Nhlabane mouth Estuary. The physicochemical properties such as temperature, potential hydrogen (pH), chemical oxygen demand (COD), total suspended solids (TSS) and nutrients were analyzed in water samples. The InoLab_IDS multi 9310 was used for the analysis of temperature and pH, while the filter technique was used for the analysis of TSS concentrations, and spectrophotometric methods were used for the analysis of nutrients and COD concentrations, using respective kits.The pH ranged between 6.5 -7 in Lake Icubhu, and 6.9 – 7.3 in Nhlabane Estuary. Nitrate and nitrite were highest in the autumn (3.2 mg/l – 0.5 mg/l),and least in the summer (0.1 mg/l – 0.01 mg/l) for both wetlands, phosphorus and ammonium were also examined. The results of nutrients obtained in this study demonstrated a significant threat to the studied wetlands when compared to the South African standard for Water Quality Guidelines of Aquatic ecosystem throughout the study period. It has been observed and concluded from the values obtained in this study that seasonal variations contributed to nutrient cycling. Correlation coefficient of each wetland system were also analyzed in order to understand the pollution load, as well as the effect of physicochemical parameters on the nutrients. The correlation results revealed that all these parameters are interrelated with each other and should be considered together. Specifically, the Illumina Miseq Sequencing analysis method was used in this study to identify microbial community structures. After sequencing, the most represented bacterial community was Proteobacteria in both wetlands. Therefore, the core composition of these bacterial communities consisted of: Proteobacteria, Bacteroides, Actinobacteria, Firmicutes among others. While members of Actinobacteria, bacteroidetes and Acidobacteria were observed in Lake Icubhu, members of Firmicutes, Chloroflexi and Bacteroidetes were also dominant at Nhlabane Estuary. Finally, some representatives of Thermomicrobia, Fusobacteria, Verrucomicrobia and Fusobacteria were also retrieved from some samples. Based on the results of nutrients, microbial diversity and community structuresobtained in this study, it was concluded that seasonal variations and nutrient pollution loads were related to microbial community structures.
Assessment of chemical markers as surrogates for efficacy and safety of Rooibos extracts
(University of Zululand, 2017) Viraragavan, Amsha; Muller, C.J,F; Basson, A.K
Research interest in the bioactive polyphenols of rooibos. to which its health-promoting properties are attributed, has escalated. Defining the quality attributes for assessing the efficacy of rooibos health products forms part of a quality control system. The aim of this study was to identify chemical markers in green rooibos extract (GRE) that could predict bioactivity in cell-based assays, with particular focus drawn to the dihydrochalcone C-glucoside, aspalathin, which has displayed antidiabetic effects in vitro and in vivo. METHODS Two ethanol-based (80% and 60% ethanol) and aqueous extracts were prepared from ten randomly selected plant batches of green rooibos. HPLC-DAD analysis was performed to quantify aspalathin and other major flavonoids present in the extracts. A radioimmunoassay was used to measure 2-deoxy-[3H]-D-glucose absorption in C2C12 murine skeletal muscle and C3A human liver cells, exposed to 10 μg/mL of the extracts. The effect of the green rooibos extracts (GRE’s) and reference extracts ARC 2 and GRT on glucose uptake and lipid accumulation was also tested in 3T3-L1 adipocytes. GRE’s were also tested at concentrations ranging from 1 and 100 μg/mL for inhibitory activity against the protein tyrosine phosphatase 1B (PTP1B) enzyme. To investigate the possible mechanism of action of glucose uptake in C2C12 cells, protein expression studies were conducted. Multivariate statistical analysis was performed using principle component analysis (PCA), to elucidate the relationship of extract type, plant batch variation and bioactivity. RESULTS HPLC-DAD analysis of the different GRE’s demonstrated that extraction with 80% ethanol yielded the highest average phenolic compound enrichment (17.09 ± 2.66% aspalathin), compared to the 60% ethanol and aqueous GRE (12.54 ± 2.51% and 9.52 ± 1.85% aspalathin, respectively). In C2C12 cells glucose uptake was related to the phenolic content, as activity increased in the 80 and 60% ethanol extracts (by up to 182% and 142%, respectively. The glucose uptake was comparable to ARC 2 the reference extract. While in C3A cells the aqueous extract appeared to be more effective. Lipid accumulation was greatly enhanced in 3T3-L1 adipocytes by the ethanolic GRE’s. Furthermore, all extracts showed potent inhibitory activity on PTP1B with IC50 values ≤ 20 μg/mL. Principle component analysis demonstrated clustering between the 80% ethanol-based extracts and the reference extracts. For C2C12 glucose uptake and 3T3-L1 lipid accumulation, a positive correlation was demonstrated with aspalathin and nothofagin, isoorientin and orientin as well as isovitexin and vitexin. CONCLUSION The chemical complexity of these different extracts make it difficult to identify single active pharmaceutical ingredients, however activity was associated with aspalathin and the 3-deoxy-dihydrochalcone, nothofagin, and their flavone derivatives.

Browse

Browsing Biochemistry and Microbiology by Title

Results Per Page

Sort Options