Chemical Constituents And Biological Activities Of Garcinia Mangostana L. And Piper Betle

Young fruits of Garcinia mangostana L. from Guttiferae family and leaves of Piper betle from Piperaceae family were phytochemically studied and screened for their biological activities. The young fruits of Garcinia mangostana L. were collected from Negeri Sembilan while the leaves of Piper betle were collected from Sabah. The phytochemical works involved extraction of the plant materials with organic solvents of different polarity and chromatographic separation of the extracts with several techniques to obtain pure compounds. The structures of the compounds were determined by using spectroscopic techniques such as IR, MS, NMR and UV. The crude extracts from both plants were screened for antimicrobial (against four pathogenic bacteria and 3 pathogenic fungi), cytotoxic activities and antioxidant using disc diffusion method, Tetrazolium Salt (MTT) assays and 1,2-Diphenyl-2-picrylhydrayl (DPPH) respectively. Three isolated compounds, epicatechin (39), 4-hydroxybenzoic acid (114) (both from mangostana L.) and 2-allyl-3,4-dihydroxybenzaldehyde (115) (from P. betle) were tested for antioxidant by using DPPH.Separation of the extracts of young fruits of Garcinia mangostana L. afforded seven chemical compounds identified as methylparaben (110), methyl 3,4,5- trihydroxybenzoate (111), parvifoliol A1 (112), methyl 2,3-dihydroxybenzoate (113), 4- hydroxybenzoic acid (114), epicatechin (39) and a xanthone, mangostanin (20) after extensive various chromatographic techniques. Two compounds, methylparaben (110) and methyl 3,4,5-trihydroxybenzoate (111) have not been previously reported to occur in Garcinia mangostana. This is the first report on the occurrence of these compounds in Garcinia mangostana and the proper technical name for methylparaben (110) is methyl 4-hydroxybenzoate. On isolation and purification of the leaves extracts of Piper betle led to the isolation of four compounds chavibetol (77), 2-hydroxychavicol (80), β- sitosterol (47) and 2-allyl-3,4-dihydroxybenzaldehyde (115). The antimicrobial activity test for both plant extracts was carried out using seven microbes namely, methicilin resistant Staphylococcus aureus (MRSA), Bacillus substili, Salmonella typhimurium, Pseudomonas aeruginosa, Candida albicans, Aspergillus ochraceaus and Saccharomyces cerevisiae. However, no activity was observed in the crude extracts of both Garcinia mangostana L. and Piper betle. The same results were obtained for the cytotoxic activity using Tetrazolium Salt (MTT) assay. When tested for antioxidant by using 1,2-Diphenyl-2-picrylhydrayl (DPPH), all the crude extracts failed to exhibit any activity. However two of the isolated compounds, epicatechin (39) and 2- allyl-3,4-dihydroxybenzaldehyde (115) showed strong activity with IC50 < 7.81 μg/mL in comparison with the standard, ascorbic acid (IC50 < 11.70 μg/mL).

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