Antibacterial Activity of Organic and Aqueous Extracts of Hopea odorata Roxb. Leaves and their Total Flavonoid Content

Abstract

Objective: To examine the antibacterial effects of different extracts of Hopea odorata leaves against bacteria and to determine their total flavonoid content. Methods: Leaves of Hopea odorata was extracted with pure methanol (MEHO), ethanol (EEHO) and water (AEHO), which are tested for antibacterial activity on three Gram positive and three Gram negative bacteria by disk diffusion method. Total flavonoid content determined based on the method of Wang et al. Result: Among the all extracts, MEHO exhibited moderate antibacterial activity. It showed zone of inhibition in highest concentration of 2 mg/ml against Gram-positive bacteria Staphylococcus aureus (20.3±0.6 mm), Bacillus subtilis (18.3±0.6 mm), Bacillus megaterium (15.3±0.6 mm) and Gram-negative bacteria Salmonella typhi (18.7±1.2 mm), Escherichia coli (14.3±0.6 mm), Shigella dysenteriae (19±1 mm). The content of flavonoid was present at all extracts, but MEHO (85.98±0.76 mg quercetin/g) contained highest among them. Conclusion: Our results indicate that extracts have moderate antibacterial activity and flavonoid may one of such phytochemical, which exhibit antibacterial activity.