Abstract

EVALUATION OF DIFFERENT METHODS FOR THE EXTRACTION OF ANTIOXIDANT PHENOLIC COMPOUNDS FROM GLYCYRRHIZA GLABRA ROOTS.

U. Vijayalakshmi and *Abhilasha Shourie

Abstract

Glycyrrhiza glabra is a medicinal herb of Fabaceae family that contains wide range of biologically active substances including phenols. Several medicinal properties of the plant such as antioxidant and anti inflammatory activity are due to the presence of phenolic compounds. The aim of the current research was to determine a suitable method for efficient extraction of antioxidant phenolic compounds from Glycyrrhiza glabra roots. Root extracts were prepared with 70% eathanol using four different extraction methods - Heated Stirred extraction (HSE), Microwave assisted extraction (MAE), Ultrasonication assisted extraction (UAE) and Reflux condensation (RFC). The extracts were tested for the free radical (DPPH˙) scavenging activity and reduction potential. Total phenolic contents of all the extracts were determined. Among the extracts obtained, HSE extracts exhibited highest anti radical activity (84%), highest reduction potential (OD=0.84) and maximum total phenolic content (127 mg gallic acid equivalent per gram dry weight). The GC-MS analysis of the extracts revealed the presence of pharmaceutically acive phenolic compounds like Licochalcone A, Licoisoflavone B, Liquirtigenin, Glabridin, and Hymechromone. Correlation analysis showed that there was a positive correlation between TPC and DPPH antiradical activity (Pearson’s coefficient R = 0.671), as well as TPC and reduction potential(R=0.641). The studies led to the conclusion that considerable quantity of wide array of phenolic compounds were obtained by extraction of G. glabra roots by Heated Stirred method and that these compounds contribute significantly to the antioxidant activity of the plant.

Keywords: Glycyrrhiza glabra; Extraction Methods; Total phenolic content; GC-MS; Reducing power.