Maebienne Anjelica Gapol, Beazl Lucenio (March 2009)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
A previous study of PSHS-WVC students showed that among the ten chosen mangrove species from Taklong Island, Guimaras, Xylocarpus granatum had the highest antibacterial activity against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.
Extracts from mangroves and mangrove-dependent species may have a great potential source of compounds of medicinal value and a new source of many already known biologically active compounds, but only limited investigations have been carried out to identify the metabolites responsible for their bioactivities.
In this study, methanol extracts of Xylocarpus granatum barks were subjected to liquid-liquid extraction using petrolium ether, dichloromethane and ethyl acetate and subjected to antibacterial assay using the standard Kirby-Bauer disc diffusion method to and determine the fraction that exhibited the highest antibacterial activity against Escherichia coli and Staphylococcus aureus.
Dichloromethane fractions exhibited the highest mean zones of inhibition against the selected pathogens. This indicated that the active compounds responsible for the bioactivity of Xylocarpus granatum barks were polar in nature.
Statistical Analysis (Fisher’s LSD, a=0.05) showed that the mean zones of inhibition exhibited by dichloromethane fractions were significantly greater than those of the other fractions for Staphylococcus aureus. The antibacterial activity of dichloromethane fractions is comparable to those of ethyl acetate fractions for Escherichia coli.
Dichloromethane fractions were subjected to High Performance Liquid Chromatography. The chromatogram showed three peaks, possibly those of the unknown compound, dichloromethane and methanol, but such data is insufficient and renders this study as inconclusive as to the identity of the compound.