Chemical analysis, antimicrobial and antioxidant activities of eight extracts from <i>Schrankia leptocarpa</i> L.

Abstract

Schrankia leptocarpa DC. (Mimosaceae) is an African medicinal plant, traditionally used by plants practitioners in Benin to cure malaria, diarrhea and stomach ache. There is little ethnobotanical and almost no chemical information available for this species. Eight extracts from the entire plant of Schrankia leptocarpa were prepared using diethyl ether, acetone, cyclohexane, methylene chloride, ethyl acetate, methanol, butanol and ethanol/water (20:80). Phytochemical analysis were performed and antibacterial was evaluated against four reference bacteria, Staphylococcus aureus, Enteroccocus feacalis, Escherichia coli and Pseudomonas aeruginosa, and four patient isolated bacteria using iodonitrotetrazolium microtest. The antioxidant properties were investigated using 2,2-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radical scavenging activity. All extracts showed antimicrobial activity ranging from 0.078 to 5 mg/ml against one or more bacteria. The most potent extract was the diethyl ether extract with a minimum inhibitory concentration value of 75 μg/ml on E. faecalis. Phytochemical screening showed a wide variety of phytoconstituents such as steroids, terpenes, phenolic acid, flavonoids, tannins and alkaloids. The DPPH radical scavenging activity indicated that the radical scavenging activity ranged from 1.35 to 3.47 μg/ml. The superoxide anion radical scavenging showed inhibitory percentage ranging from 32.04 to 86%. Higher activity was observed with ethyl acetate extract. The results provide an evidence for the traditional use of S. leptocarpa for the treatment of infective diseases.

Keywords: Schrankia leptocarpa, antibacterial, antioxidant, 2,2-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion