Advances in Life Science and Technology www.iiste.org ISSN 2224-7181 (Paper) ISSN 2225-062X (Online) Vol.29, 2015 5 The Antimicrobial Potential and Phytochemical Composition of Aristolochia ringens Vahl. *Taiye R. Fasola 1, 2 , M.E. Oluwole 1 , O. Obatayo 1 , and S. E. Obayagbo 1 1 Department of Microbiology, Lead City University, Ibadan, Nigeria 2 Department of Botany, University of Ibadan, Ibadan, Nigeria *Corresponding author’s e-mail: fasolatr@gmail.com Abstract Aristolochia ringens, a plant called Ako-igun in Yoruba, is widely distributed in southwestern Nigeria. Traditionally, it is used for the treatment of cancerous sore, lung inflammation, dysentery and dermatitis. The antimicrobial activity of A. ringens was tested on six pathogenic bacteria viz., Shigella sonnei, Salmonella typhii, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Proteus mirabilis and five fungi viz., Fusarium sp, Sporotrichum sp, Pichia sp, Penicillium camemberti and Aspergillus niger. Extracts from powdered stem and root barks of A. ringens were prepared using sterile water, ethanol, petroleum ether and acetone. The extracts were tested on each of the pathogens for their antimicrobial properties. The stem and the root barks were also screened for presence of secondary metabolites following standard procedures. The aqueous extracts of the stem and the root barks were not effective against all the bacteria and fungi tested except Shigella sonnei with Minimum Inhibitory Concentration (MIC) of 40mg/ml. Petroleum ether extracts of the stem and root barks were equally not active against all the bacteria isolates used but the root bark extracts reacted effectively against the fungal isolates, showing good potency at 40mg/ml. Ethanol extract of the stem bark was very potent against all the bacteria isolates at MIC of 33.3mg/ml except Shigella sonnei while the root bark ethanol extract only showed little effectiveness against the fungi. A similar result was obtained when acetone was used as solvent of extraction. Comparatively, ethanol and acetone stem and root bark extracts were less potent on the fungi isolates than the petroleum ether extract. The plant parts studied showed the presence of alkaloids, flavonoids, tannins, terpenoids and cardiac glycosides. Thus, the root and stem bark extracts from Aristolochia ringens may be broad based in their antimicrobial activities. The extracts, if purified and crystallized, may serve as alternatives to antimicrobial drugs. Keywords: Aristolochia ringens, Microorganisms, Ethnomedicine, Phytochemicals, Plant extracts Introduction Plants are known in ancient and modern civilizations for their healing properties. They remain the sole source of healing principle to man’s ailments until the 19 th century when development of chemistry, particularly organic compounds led to the experimental and clinical validation of their efficacy (Edeoga et al., 2005; Natarajan et al., 2011). Aristolochia ringens, a related local species, resembles over 500 species of Aristolochia (family Aristolochiaceae) that spread across tropical and sub-tropical regions of Asia and Africa, and used traditionally for cancerous sore, dysentery, lung inflammation, scorpion and snake bite (Kumar and Suryanarayana, 2008; Vermal et al., 2008; Abhijit and Jitendra, 2011; Thirumal et al., 2012). Aristolochia species are herbaceous vine with woody stock and widely distributed throughout the southwestern Nigeria (Kanjilal et al., 2009; Kumar et al., 2011). The leaves are variably glabrous, obovate - oblong with sub-pandurate entire and inflated pale green perianth up to 4cm long (Das et al., 2010). Like other species, Aristolochia ringens has been studied to contain essential oil, aristolochia acid and other phytochemicals that are of biological importance (Ashokkumar et al.,2010; Sinha and Choudhury, 2010; Tajkarimi et al., 2010; Abhijit and Jitendra, 2011; Samy et al., 2011). According to an ethnomedicobotanist’s oral interview conducted at Bode, a popular herbal market in Ibadan metropolis within Nigeria, A. ringens is used to treat various ailments such as wounds, dysentery, throat infections and skin problems of which are linked to microbial infestations. In Asian countries, especially India, over 2,500 plants have been studied to have provided alternative medicine and curative properties to the available synthetic drugs (Sarmiento et al., 2011; Thirumal et al., 2012). Extracts from Aristolochia sp, especially, phytochemicals and essential oil have been receiving earnest in-vitro investigations for their numerous activities. Among the documented activities traced to such phytochemical properties of A. ringens are antimicrobial, anti-inflammatory, anti-venom, antipyretic, antiseptic, abortifacient, emmenagogues, storage stability (preservative), foaming (lather), curative, taste, flavours and aroma on one hand and potent nephrotoxic, anti fertility and antispermatogenic on the other (AshokKumar et al., 2010; Sinha and Choudhury, 2010; Tajkarimi et al., 2010; Abhijit and Jitendra, 2011; Kumar et al., 2011). In recent years, the traditional application of natural compounds of plant origin has been receiving a lot of attention as an alternative source of remedy for the treatment of diseases coupled with the belief of their better safety nature and of less or non toxicity. This has led to the increase in laboratory (in-vitro) research into herbal medicine to establish their acclaimed efficacy and their therapeutic applications. This study aimed at ascertaining the acclaimed antimicrobial property possessed by A. ringens as an ingredient in the production of herbal medicine that serves as effective therapeutic agent against pathogenic microorganisms and their associated infections.