Antioxidant activities and phenolic contents of the aqueous extracts of some Indian medicinal plants

Abstract

Antioxidants protect the body against oxidative stress by neutralizing free radicals. Plants contain rich amount of polyphenols which are very potent natural antioxidants. The present study was designed to evaluate the relative contribution of different polyphenols such as total phenolics, flavonoids and flavonol contents and their antioxidants activities. For this purpose the total phenolics, flavonoids and flavonol contents of some medicinal plants were determined in the aqueous extracts of leaves of Trichosenthes dioica, fruits ofMoringa olifera and Ficus bengalensis as well as seeds of Emblica officinalis. Total antioxidant activity of these extracts was monitored by Free Radical Absorbing Power (FRAP) assay. In this paper, those parts of the plants are used for the analysis of aforesaid parameters which are normally overlooked. The total phenolic content of T. dioica leaves was about two times more than that obtained from the fruits and seeds of M. olifera and E. officinalis, respectively.However, the aerial roots of F. bengalensis registered presence of least phenolic content. The aqueous preparation from E. officinalis exhibited total flavonoid content twice as high as that of the other three plants. The extract from seeds ofE. officinalis was found to contain highest antioxidant activity as compared to the preparations from other plants. The high antioxidant activity and flavonoids contents in E. officinalis seeds indicated that it could be exploited as an ingredient in developing a potential antioxidant supplement. Key words: Antioxidant, flavonoids, flavonols, phenolics, FRAP assay, Ficus bengalensis, Trichosanthes dioica, Emblica officinalis, Moringa oleifera.