Phytochemical and pharmacological investigations of <i>Garcinia volkensii</i> Engl.

Abstract

AIM: The aim of this study is to investigate the biological potential of extracts and isolated compounds from G. volkensii using three different bioassays, namely antibacterial, cytotoxicity and antioxidant. METHODS: The extracts and pure compounds were obtained from the stem bark of G. volkensii using standard procedures. Antibacterial activity of the extracts and morelloflavone (1), was determined against standard strains of Bacillus anthracis, Bacillus cereus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shigella flaxineri, Staphylococcus aereus, Streptococcus fecalis, Salmonela typhimirium and Vibrio cholera. The cytotoxicity potential of extracts and compound 1 was evaluated against brine shrimp larvae, whereas the antioxidant activity was determined using using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Oxygen Radical Absorbance Capacity (ORAC) assays. Furthermore, the anti-AGEs (Advanced Glycation Endproducts) activity was determined using an automated liquid handling workstation. The isolation of pure compounds was carried out using column chromatography with silica gel as a stationery phase and organic solvents of different polarities as mobile phases. RESULTS: The crude extract and morelloflavone (1) exhibited higher antibacterial activity having MIC values in the range of 0.049 - >2.50 mg/ml. The BST results indicate that all extracts and morelloflavone (1) exhibited LC50 value > 100 µg/ml. In the antioxidant assays, both extracts and morelloflavone (1) showed activities higher than that of standard drugs. CONCLUSION: These data suggests that G. volkensii could be a potential source of antibacterial and antioxidant agents. The result gives scientific support to its use by the indigenous people in managing conditions associated with HIV-related secondary infections.