Antioxidant and antimicrobial activities of solvent fractions of Vernonia  cinerea (L.) Less leaf extract.

Mubo A. Sonibare1 , Oluwafunmilola T. Aremu, Patricia N. Okorie
1. Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria.
2. Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria

Abstract
Background: Vernonia cinerea (L.) Less is used in folk medicine as a remedy for various diseases.

Objectives: The present study reports antioxidant and antimicrobial activities of solvent fractions of Vernonia cinerea.

Methods:The antioxidant properties of solvent fractions of V. cinereawere evaluated by determining radicals scavenging activity, total flavonoid and phenolic contents measured with the 2,2-diphenyl-1-picryl hydrazyl (DPPH) test, the aluminum chloride  and the Folin-ciocalteau methods, respectively. Antimicrobial activities were tested against human pathogenic microorganisms  using agar diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of  each active extract were determined.

Results:The ethyl acetate fraction having the IC 50 value of 6.50 µg/mL demonstrated comparable DPPH radical-scavenging  activity with standard antioxidants, gallic acid and quercetin included in the study. All fractions displayed moderate antimicrobial  potential against the tested pathogens with the zone of inhibition that ranged from 9.0 to 13.5 mm. The MIC (1.56 mg/mL) and  MBC (3.13 mg/mL) indicated highest susceptibility of Candida albicansin all fractions.

Conclusion: The results of this study showed that the solvent fractions of V. cinereapossess antioxidant and antimicrobial activities, hence justifying the folkloric use of the plant for the treatment of various ailments in traditional medicine.

Keywords: Vernonia cinerea, antioxidant activity, antimicrobial activity, total flavonoid content, total phenolic content