Antifungal and antibacterial activities of aqueous and methanolic root extracts of Carica papaya linn. (Caricaceae)

Full Length Research Paper

Antifungal and antibacterial activities of aqueous and methanolic root extracts of Carica papaya linn. (Caricaceae)

Adejuwon A.O¹, Agbaje E.O¹* And Idika N ²

¹Department of Pharmacology, College of Medicine, University of Lagos, P.M.B. 12003, Idi-Araba, Lagos, Nigeria.

²Department of Microbiology, Nigerian Institute of Medical Research (NIMR) Yaba-Lagos.

*Corresponding author E-mail: [email protected]; Tel: +2348023194340

Received 02 June, 2011; Accepted 08 August, 2011

The vast potentialities of plants as a source for anti-microbial drugs with reference to antibacterial agent, motivated the present  systematic investigation to screen the aqueous and methanolic root extracts of Carica papaya (CPY) for its antimicrobial activity. Eleven microorganism species consisting of seven bacteria and four fungi were tested for their sensitivity to the herbal preparations using the Agar Diffusion method. Ampicillin and tetracycline were used as standard drugs for investigating the bacterial species, while griseofulvin was selected for the fungi, while zones of inhibition were measured to determine the microbicidal property of the test agents.  Another set of plates was cultured to estimate the effect of combination therapy using the herbal drug together in varied concentrations with the standard drugs. The results obtained showed both extract to possess good antimicrobial activity against only four of the bacteria and three fungi.  However, the organic preparation produced a significant and better efficacy than the water preparation. Combination therapy revealed a synergistic effect between CPY and ampicillin, whereas, antagonism was observed with tetracycline.  A wide range of secondary metabolites were identified in both extract with methanolic extract containing a higher amount; Thin Layer Chromatography confirmed the presence of anthraquinones, cardiac glycosides and alkaloids. The study substantiates the folkloric use of CPY in microbial infections.  Furthermore, its spectrum of activity has been documented as well as the results of its combination therapy.

Keywords: Carica papaya, extract, antibacterial, antifungal, microorganisms.