Chemical composition, antimicrobial and antioxidant activity of Striga hermonthica extracts

Abstract

This study was conducted to evaluate the antioxidant and antimicrobial activity of different extracts of leaves of Striga hermonthica (Del.) Benth, and it includes extensive chemical study to identify the chemical composition of the active extract(s) by chromatographic and spectroscopic methods. Phytochemical screening of methanol and water extracts of S. hermonthica leaf revealed the presence of flavonoids tannins, terpenes, alkaloids, and saponins, coumarins, carbohydrates, reducing compounds, quinines, and proteins. The quantitative determination of chemical constituency showed that flavonoids represented (13.5%), tannins (6.57%), terpenes (5%), and alkaloids (2.12%). The fine powder of the S. hermonthica leaves was successively extracted with (petroleum-ether, chloroform, methanol) using soxhlet extractor. Methanol gave highest yield (22.6%). The methanolic extract of S. hermonthica showed a highest DPPH free radical scavenging activity (93.70%), petrolum ether (55.80%), chloroform (53.90%) at 100 μg/ml. Moreover, S. hermonthica methanol extract was exhibited moderate antifungial activity (inhibition zone: 15mm, at 100% concentration) against Candida albicans fungus. The active methanolic extract was further studied by intensive and extensive analytical investigations in order to isolate the extract components using analytical and preparative TLC chromatographic fractionation, an afforded nine pure fractions which were analyzed by spectroscopic methods (Infra-red and Ultra-violet).