Phytochemical investigation and antimicrobial activity of leaves extract of Vernonia auriculifera Hiern

Context: The genus Vernonia is one of the largest groups in the family Compositae constituting more than 500 species distributed widely in tropical and sub-tropical regions of Africa, Asia, and America. Traditionally the genus is used for the treatment of schistosomiasis, amoebic dysentery, gastrointestinal problems, malaria, venereal diseases, wounds, hepatitis, and diabetes. Vernonia auriculifera Hiern is used for healing wounds as ointment around the injured areas. Aims: To investigate the phytochemical constituents and evaluate antimicrobial activity of leaves extract of Vernonia auriculifera Hiern. Methods: Phytochemical screening tests were conducted to identify the class of compounds present in the leaves extracts of V. auriculifera. Silica gel column chromatographic technique was applied to separate the constituents of the extracts. Various spectroscopic techniques (IR, 1H NMR, 13C NMR, DEPT-135, COSY, gHSQC, and gHMBC) were applied to determine the structures of isolated compounds. Results: Phytochemical screening of the methanol leaf extract revealed the presence of tannins, flavonoids, terpenoids, saponins and absence of anthraquinones, steroids, and alkaloids. Silica gel column chromatography of the methanol leaves extract yielded one compound. The hexane, chloroform, methanol and water extracts were tested against Staphylococcus aureus. The methanol and water extracts showed promising growth suppression at minimum inhibitory concentration of 200 mg/mL. Conclusions: The polar extracts of the leaves of Vernonia auriculifera Hiern possess antimicrobial activity.