QUANTIFICATION OF PHYTOCHEMICALS AND ANTIBACTERIAL ACTIVITY OF FRUIT EXTRACT OF AVICENNIA OFFICINALIS

Avicennia officinalis (AO) is an evergreen mangrove tree that finds a prominent place in folk medicine. In this study, we have quantified 2 significant phytochemicals viz., phenols and flavonoids and studied the antibacterial activity of extracts of AO fruits in ethyl acetate, acetone, methanol and ethanol against 8 pathogenic bacterial species E. coli, En. aerogenes, K. pneumoniae, P. aeruginosa, B. subtilis, L. delbrueckii,  S. aureus and  Strep. pyogens. Phenols and flavonoids were quantified Spectrophotometrically. Total phenolic content (TPC) ranged from 125-350mg of GAE/g of crude extract and the flavonoid levels were in the range of 60-192 mg of rutin equivalent/g of dry sample. The methanol and ethanol extracts showed highest levels of TPC, while acetone extract was identified to contain comparatively elevated amounts of flavonoids. Antibacterial activity of all the extracts was screened against the selected strains by agar well diffusion method. All the extracts exhibited different degrees of inhibition against the bacterial strains tested.  Their MIC values ranged between 1.25-5.0mg/100µl. Methanol and Ethanol extracts showed strong inhibitory activities against both Gram negative and Gram positive bacterial strains compared to those of other extracts. However, ethyl acetate infusion restricted its activity only against the Gram positive bacterial strains tested. Strains of E. coli, En. aerogenes (Gram negative) S. aureus and  Strep. pyogens (Gram positive) were inhibited by acetone extract. This study provides the necessary data for isolation and characterization of individual broad spectrum antibacterial compounds from different extracts of AO fruits. The study also supports the potentiality of AO in folk medicine.   Keywords:  Avicennia officinalis, Phenols, Flavonoids, Antibacteria