An ethnobotanical survey, antimicrobial activity and toxicity evaluation of plant species used for blood purification by rural communities in Northern Maputaland, South Africa
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Date
2021-06
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University of Zululand
Abstract
A blood purifier is defined as a substance that removes toxins from the bloodstream via a process known as detoxification. Blood purification (cleansing) is highly crucial for the entire body functioning as the body depends on healthy blood.In South Africaherbal remedies, herbal teas, spices and traditional medicine are all used forthe purification of blood. The use of different supplements to purify or strengthen the blood are available in pharmaciesand informaltrading centreswithout any prescription from adoctor.Medicinal plant speciesused for blood purification are a large component of rural peoples’Materia Medica. This can bea concernasvery few of these products and plant specieshave beenscientifically tested for safety and efficacy. Therefore,ethnobotanical survey was conducted on bloodpurification plant speciesused inrural areasofnorthern Maputaland. Furthermore,an investigation intolaypeoples’concept of bloodpurificationand the respective plant speciesused were investigated. A total of 55 key informantswere chosen purposively and interviewedusing a structured questionnaire. The information gathered during the interviewswas documented along with the plant voucher specimens. Available plant samples were collected for extraction. The study found that the laypeople in northern Maputaland use blood purification as a dual strategy for health care reasons. This technique is used for the prevention and treatment of diseases caused by variouspathogens (skin infections, oral infections, urinary tract infections)andspiritual complications. The study documented 65plant species with Bridelia cathartica, Catunaregam obovata, Cymbopogon marginatus, Sclerocarya birrea, Senecioserratuloidesand Terminalia sericeabeing the most frequentlycited plant specieswithin these communities. Twenty-two plantspecies and 32setsof plant species combinations were recorded for the first time as blood purifiers. There were five new vernacular (IsiZulu) names mentioned by the participants (isikwakwane, upata, umhlakuva, umbungwa anduvemvane) that were not found in literaturepreviously. Most blood purification remedies were prepared as decoctions,and taken orally before breakfast.Aqueous and organic (1:1 dichloromethane methanol) extracts were prepared from 58plant samples that were available for collection in northern Maputaland. Antimicrobial
viscreening using the minimum inhibitory concentration (MIC) assay was performed on selected bacterial pathogens involved in blood-related infections,i.e. Acinetobacter baumannii,Cutibacterium acnes,Listeria monocytogenes,Pseudomonas aeruginosa,Staphylococcus aureus, Streptococcus agalactiae and S. pyogenes. The most active aqueous extract came from Albertisia delagoensisroot with a noteworthy inhibition at0.13mg/ml MIC value against C. acnes.Whereasthe most active organic extract was Ozoroa engleriwith the MIC values of 0.004 mg/ml against C. acnes, 0.01mg/ml against S. agalactiaeand 0.02mg/ml against L. monocytogenes, S. aureusand S. pyogenesrespectively. Gymnosporia senegalensisand O. englerihad the broadest spectrum of antimicrobial activities with notableMIC values against four and five pathogens respectively. It was worth noting that the antimicrobial activity of A. delagoensis and Sapium integerrimum was evaluated for the first time and both have significant activities (MIC 0.16 mg/ml) against C. acnes. The antimicrobial activity of 308 plant combinations was evaluated using sum of the fractional inhibitory concentration index (ΣFIC). Once the ΣFIC of plant species combined in equal ratios was calculated, the combinations exhibited synergistic (61%), additive (16%), non-interactive (49%) and antagonistic (29%)effects. The broadest synergistic effect was displayed by Abrus precatorius + B. catharticaroot extracts, where the combination was synergistic against C. acnes, L. monocytogenes, S. aureus, A. baumannii and P. aeruginosa. The most synergistic effect was displayed by S. integerrimum + Strychnos spinosaroots having,the ΣFIC value of 0.33,against P.aeruginosa.The toxicity of the plant species was evaluated using the brine shrimp lethality assay (BSLA). When plant species were evaluated individually, the aqueous extracts had five plant speciesshowing potential toxicity (Dichapetalum cymosum, Ekebergia capensis, Gardenia volkensii, Trichilia emetica and Waltheria indica) and 12 organic extracts demonstrated toxicity. When dilutions of toxic extracts were made (1.00mg/ml, 0.50 mg/ml, 0.25 mg/ml, 0.13 mg/ml, 0.06 mg/ml and 0.03 mg/ml) it was observed that the toxicity of extracts decreased with lower concentrations. For the evaluation of the idifferent setsof combinationstested, two combinations(A. delagoensis + Pyrenacantha kaurabassana and D. cymosum+ Euclea natalensis)displayed consistent toxicity in both aqueous and organic extracts. Six combinations portrayed increased toxicity compared to when these plant species were tested individually. Overall, the results demonstrated that the use of medicinal plant species for infectious diseases related to blood purification is somewhat valid, since 35%of the plant extracts had noteworthy activity against some of the pathogens. The plant extracts displayed high antimicrobial activity against C. acnes, which for 80%of the time correlates with the traditional use reported by the participants. The results also demonstrated that the combination of plant species does not always guarantee increased efficacy, and that not all medicinal plant species are safe for use. This study served to provide an informative view to the concept of blood purification. It is clear that when looking into blood purification, ailments like acne and other skin disorders should not be disregarded. The role that blood purification play in lay peoples’ rituals emphasise thatholistic and spiritual healings of the laypeople should also be considered.
Description
A thesis submitted to the Faculty of Science, Agriculture and Engineering in fulfilment of the requirements for the Degree of Master of Science in the Department of Botany at the University of Zululand, South Africa, 2021.
Keywords
Ethnobotanical survey, Antimicrobial, blood purification, Plant species