Antimicrobial Activity of Juglans regia Root Bark Extracts

Background: Juglans regia tree is widely found in several parts of India, Europe and Central Asia. Different parts of J. regia are rich sources of alkaloids, flavonoids, glycosides, saponins, amino acids, and terpenoids. J. regiais has antiasthmatic, anti-atherosclerotic, antihypertensive, antioxidant, antidiabetic, antimicrobial, cardioprotective, hepatoprotective, hypolipidemic, osteoblastic, and wound healing activities. The bark and roots are used against tooth decay and ringworm infection. Purpose: In the present study we evaluated antibacterial and antifungal activities of J. regia root bark. Methods: Extracts of root bark of J. regia were prepared using methanol, water, and petroleum ether. Methanolic and aqueous extracts in concentrations 50, 100 and 200 mg/ml were tested against three Gram negative bacterial strains (S. typhi, P. vulgaris, and E. coli), one Gram positive strain (S. aureus) and fungi (S. cerevisiae, P. chrysogenum, and A. fumigatus). Results: The extracts effectively inhibited growth of cultured microorganisms. Methanolic extracts showed maximum zone of inhibition (ZOI) for all the microorganisms ranging from 12.8 – 17.0 mm. Aqueous extract disclosed maximum effectiveness against S. typhi. Conclusions: Quantification of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) revealed potent antibacterial activities of methanolic extracts (200 mg/ml) of J. regia root bark.