Kristine Joy D. Fernandez, Setzel Anne Marie V. Suresca, Angeline Veil C. Tiosayco (February 2008)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Although mangroves have been proven to possess medicinal properties, only few studies provide sufficient information regarding their antibacterial property and bioactive compounds. Mangrove studies focused mostly on community structure and the role of these plants in the marine ecosystem.
This study screened the antibacterial property of crude methanol extracts of ten mangrove species collected in Taklong Island, Guimaras against human pathogens Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus using the Kirby-Beuer disc diffusion method.
Statistical analysis (One-Way ANOVA and Fisher’s LSD, a=0.05) showed that the extract of Xylocarpus granatum exhibited the greatest antibacterial activity. Other species that showed significantly higher antibacterial activity were Ceriops decandra, Lumnitzera racemosa and Rhizophora x lamarckii.
The four species Ceriops decandra, Lumnitzera racemosa, Rhizophora x lamarckii and Xylocarpus granatum were subjected to liquid-liquid extraction using solvents of increasing polarity: petroleum ether, dichloromethane and ethel acetate. Fractions where subjected to antibacterial assay against Pseudomonas aeruginosa and Staphylococcus aureus. Among the four fractions, ethyl acetate and aqueous methanol fractions showed significant activity against the test organisms.
Phystochemical screening of the ethyl acetate and aqueous methanol fractions established the presence of bioactive compounds such as alkaloids, flavonoids (leucoanthocyanins and y-benzopyrone necleus) and tannins. Related studies showed that these secondary metabolites are responsible for the wide range of bioactivity reported on plant extracts.