Biological activity and preliminary phytochemical screening of terminalia alata Heyne ex Roth

Abstract

Terminalia alata has been employed world widely in ethno-medicine including most of the Ayurvedic preparation for a treatment of ailments in Indian subcontinents. The present investigation was performed to study the in vitro antioxidant and antibacterial characteristics of hydro-alcoholic extracts of different parts (leaves, fruit, stem, and bark) of T. alata and to analyse the responsible phytochemical constituents. Phytochemical study documented the existence of carbohydrates, saponins, flavonoids, phenolics, tannins and terpenoids. Antioxidant activity was found to be highest in fruits as the lowest IC 50 was observed for the same. The total phenolic content was reported to be higher in leaf extract and lower in stem extract. Whereas, among the four extracts total flavonoid content was documented to be higher in the stem extract and lower in the bark extract. The antibacterial activity of each extract was tested against three standard bacteria strains viz. Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae. All parts of tested plant were found to have inhibitory activity against these pathogenic bacterial species. Therefore, presence of secondary metabolites (flavonoids, terpenoids and tannins) and allied antioxidative activity, could be answerable for antibacterial activity of these extracts. There are many reports on antibacterial and other biological activity of Terminalia species other than T. alata, hence plants parts of T. alata could provide new phytochemicals showing promising antibacterial activity.