Antibacterial Activity of Extracts of Pericarp of Garcinia mangostana

Abstract

Pericarp of the fruit of Garcinia mangostana L is used for the treatment of skin infections, wounds and diarrhea in indigenous medicine of Thailand, India, Sri Lanka and Myanmar. In the present study, the inhibitory effect of extracts of pericarp ofGarcinia mangostana on bacterial growth was investigated. An inhibitory activity was exhibited by methanolic extract against Gram-positive bacteria tested (Bacillus subtilis., Staphylococcus aureus. and Streptococcus faecalis) whilst no inhibitory effect was observed against Gram -negative bacteria such as Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) was determined using serially diluted extract with methanol on nutrient agar. After 24 hours of incubation at room temperature, the lowest concentration of the extract which inhibited the visible bacterial growth was recorded as MIC. The MIC of the extract was 0.0005 glml against Bacillus subtilis and Staphylococcus aureus while 0.005g1ml against Streptococcus faecalis. Crude extract was fractionated with ether and ethyl acetate successively to obtain ether-soluble and ethy I acetate - soluble phenolics respectively. These two fractions were found to possess inhibitory effect on growth of Bacillus subtilis., Staphylococcus aureus. and Streptococcus faecalis. Chromatographic analysis of the two fractions showed the presence of several phenolic compounds.