Isolation, Characterization of Flavonoids fromTerminalia brownie, Ziziphus abyssinica, Cassia sieberiana Roots and Evaluation of Antimicrobial Activity

Abstract

This study aimed to investigate the major flavonoids of Terminalia brownie, Ziziphus abyssinica and Cassia sieberianaroots and to screen these plants for their antimicrobial activity. The flavonoids were extracted with aqueous ethanol and the crude extracts were purified by TLC. The structures of the isolated flavonoids have been partially characterized by some spectral tools (UV and 1HNMR). One flavonoid-compound I- was isolated from Terminalia brownie root another one-compound II- was isolated from Ziziphus abyssinica root while a third flavonoid-compound III- was isolated from Cassia sieberiana root.

Compound I

Compound II

Compound III

In the cup plate agar diffusion bioassay, the ethanol extract of Terminalia brownie showed significant activity against Pseudomonas aeruginosa and Staphylococcus aureus, while the ethanolic extract of Ziziphus abyssinica rootshowed moderate activity against Staphylococcusaureus and the yeast Candida albicans. Cassia sieberiana ethanolic extract exhibited partial activity againstall test microbes. The antioxidant capacity ofthe ethanol extracts of Terminalia brownieand Cassia sieberiana roots was carried out by measuring the capacity of the test sample against stable DPPH radical and significant activity was observed for both extracts.