Abstract

TOXICITY PROFILING AND ASSESSMENT OF IN VITRO ANTIMICROBIAL ACTIVITY OF DIOSPYROS PHILIPPINENSIS A.D.C. (EBNACEAE) METHANOLIC LEAF EXTRACT

Estela P. De Vera and Librado A Santiago

Abstract

The aim of the study was to evaluate the potential antimicrobial and to have a profile on the toxicity of Diospyros philippinensis, an endemic medicinal plant in the Philippines. Methanolic extraction of the leaves yielded 23% crude extract. The MCE was non-lethal at a dose of 2000 mg/kg BW, however histopathological examination showed to be slightly hepatotoxic. Furthermore, MCE was partitioned using solvents with increasing polarity (hexane, chloroform, ethyl acetate, n-butanol and water). Each solvent partition crude extracts was subjected to Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). Ethyl acetate fraction (EF) gave the highest phenolic (31.92±0.001 mg GAE/g) and flavonoid content (8.66±0.001 mg QE/g). This was further subjected to silica gel column chromatography (hexane, hexane:ethyl acetate (1:1), ethyl acetate, ethyl acetate:n-butanol (1:1) and n-butanol). Antimicrobial activity of MCE, fractions and subfractions 1, 4 and 6 was carried out using Disc Diffusion method and found out that the 100% concentration of MCE, EF and ESF6 can inhibit the growth of gram positive-bacteria (14-19 mm zone of inhibiton). MCE, EF and ESF6 were subjected to HPLC where gallic acid and quercetin were identified in both MCE (18.86±0.08 mg gallic acid /g dry weight; 0.658±1.03 mg quercetin/ g dry weight) and EF (10.10±0.08 mg gallic acid /g dry weight; 0.059±1.03 mg quercetin/ g dry weight). ESF6 was identified with gallic acid (6.86±0.08 mg gallic acid /g dry weight), but no peak for quercetin. Data was expressed as mean standard error (SEM) and was analyzed using SPSS v.19.

Keywords: Ebenaceae, D. philippinensis, antimicrobial, toxicity.