Antibacterial, antifungal and antioxidant activity of the roots and leaves of Pelargonium reniforme Curtis (Geraniaceae)

Abstract

Pathogens such as bacteria and fungi and oxidative stress induce the progression of alcoholic liver disease. The antimicrobial and antioxidant activity of extracts from the roots and leaves of Pelargonium reniforme Curtis (Geraniaceae) were assessed in an effort to validate the traditional use of the plant in the treatment of liver diseases. Methanol, acetone and water extracts of the plant were investigated for antimicrobial activity against ten bacterial and five fungal species using the dilution method on solid agar medium. With the exception of Streptococcus faecalis, the extracts showed significant activity against all the gram-positive and three of the gram-negative bacteria tested in this study. Although not completely fungicidal, these extracts showed significant growth inhibition against all the fungi tested. The concentrations of the different classes of phenolic compounds were higher in the methanol extracts when compared with the water extracts. Antioxidant activities of the methanol and water extracts as assessed by three established in vitro methods, namely, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric ion reducing power showed that the extract possessed strong scavenging activity and moderate reducing power. Results obtained in this study show that P. reniforme has good antimicrobial and antioxidant activity and this validates its traditional use in the treatment of liver diseases. Also, a comparative study of the antioxidant and antimicrobial activities of both the leaves and root showed that both parts had similar activity. The choice of the root by the traditional healers over the leaves may be arbitrary or due to easy collection. The leaves of P. reniforme may, as well, substitute for its roots in medicinal formulations. © 2009 Academic Journals.