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Some bioactivity of triterpenes from stem bark of protorhus longifolia and their derivatives

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dc.contributor.advisor Opoku, A.R.
dc.contributor.author Mosa, Rebamang Anthony
dc.date.accessioned 2014-06-23T11:01:46Z
dc.date.available 2014-06-23T11:01:46Z
dc.date.issued 2014
dc.identifier.uri http://hdl.handle.net/10530/1321
dc.description A thesis submitted in fulfillment of the requirement for the Degree of Doctorate of Philosophy in the Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, South Africa, 2014. en_US
dc.description.abstract Despite availability of the current clinical drugs, metabolic disorders and microbial infections continue to be serious threats to human health. The diverse significant pharmacological effects possessed by plant-derived triterpenes have made these compounds new targets for drug development against an array of diseases resistant to conventional medicines. This work investigated some bioactivity of two lanostane triterpenes and their derivatives. Two lanostane triterpenes (ã..-hydroxylanosta-9,24-dien-21-oic acid, RA5 and methyl-ã..-hydroxylanosta-9,24-dien-21-oate, RA3) were isolated from stem bark of Protorhus longifolia (Benrh) Engl and their acetyl (ã..-acetyloxylanosta-9,24-dien-21- oic acid, R51, methyl-ã..-acetyloxylanosta-9,24-dien-21-oate, R31) and oxo (ã..- oxolanosta-9,24-dien-21-oic acid, R52, methyl-ã..-oxylanosta-9,24-dien-21-oate, R32) derivatives were prepared. Structures of the compounds were established based on spectroscopic (IR, NMR, HRMS) data analysis. The in vitro anti-hyperlipidemic activity of the compounds was evaluated on selected lipid and carbohydrate digestive enzymes. The effect of the compounds on glucose uptake in C2C12 muscle cells and 3T3-L1 adipocytes, and triglyceride accumulation in 3T3-L1 adipocytes was also investigated. The anticoagulant and anti-inflammatory activity was investigated using tail bleeding time assay and cotton pellet-induced granuloma model in Sprague-Dawley rats, respectively. The effect of the triterpenes on the expression of heat shock protein 70 (Hsp70) and their anti-protein aggregation activity using malate dehydrogenase (MDH) aggregation suppression assay were studied. The broth micro dilution assay was also used to determine the antimicrobial and antiplasmodial activity of the isolated compounds. The triterpenes effectively inhibited the activities of lipid digestive enzymes (pancreatic lipase, cholesterol esterase) and HSL with IC50 values ranging from 60.1 to 677.8 ìM; except for the weak activity of R52 on C2C12 cells, the other compounds (50 ìg/ml) effectively stimulated glucose uptake in both 3T3-L1 and C2C12 cells. A significant reduction (34.8%) of intracellular lipid accumulation was also observed following a 48 h exposure of the 3T3-L1 adipocytes to RA5 (â5 ìM). The compounds did not show any cytotoxic effects on the 3T3-L1 and C2C12 cells. The triterpenes exhibited anti-inflammatory activity and a reduction of granuloma formation by up to 40.3% after treatment with RA5 (250 mg/kg) was observed. Both triterpenes significantly (p < 0.05) increased bleeding time with up to 7.3 min recorded post treatment with RA3 (250 mg/kg). The triterpenes improved the activity of Hsp70 on MDH aggregation suppression. They also effectively stimulated expression of Hsp70 in E. coli cells and in the plasma of inflamed rats. While both compounds exhibited strong antibacterial activity against the tested bacteria with MIC and MBC values ranging from 0.16 to 5.00 mg/ml and 0.63 to 5.00 mg/ml, respectively, the compounds did not show any antifungal and antiplasmodial activity. The various bioactivity exhibited by the compounds suggest potential new approaches towards development of pharmacologically active agents with beneficial multiple effects. en_US
dc.description.sponsorship Medical Research Council and University of Zululand en_US
dc.language.iso en en_US
dc.publisher University of Zululand en_US
dc.title Some bioactivity of triterpenes from stem bark of protorhus longifolia and their derivatives en_US
dc.type Thesis en_US

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