Potential Antimicrobial Plant Extract Based Therapeutics from Temnocalyx obovatus Roots

Abstract

Aims: The study was conducted to determine antimicrobial activity of Temnocalyx obovatus mature root extracts popularly used in folk medicine to treat diarrhoea in chickens, stomach disorders in turkeys, goats and cows, snakebites, asthma, ulcers and whooping cough in humans. Study Design: Agar disk diffusion method and determining MIC. Place and Duration of Study: Department of Chemistry (Natural product section) June 2011 and July 2011. Methodology: Two methods were employed for the determination of antimicrobial activities; an agar paper disc diffusion method and determination of minimal inhibitory concentration (MIC). Methanol and ethanol extracts were assayed for antimicrobial activities. The following bacterial strains were employed in the screening studies: Staphylococcus aureus, Escherichia coli, Clostridium perfringens and fungi: Aspergillus niger, Candida albicans all from stock cultures of Bindura University department. Results: Methanol extract exhibited the greatest extraction efficiency; 136,1g/Kg as compared to ethanol; 124,8 g/Kg. Both methanol and ethanol extracts showed significant antibacterial and antifungal activity. Sensitivity to the extracts was not similar for the chosen strains. The highest antibacterial activity of plant extract was 37,0 mm for methanol and 28,0 for ethanol extracts for diameter of zone inhibition found against Clostridium perfringens followed by 35,0 mm and 26,3 diameter of zone inhibition against Escherichia coli at a concentration of 100%. Antifungal activity was highest for Aspergillus niger at a concentration of 100%. The minimum inhibitory concentration (MIC) values against these bacteria ranged from 10 - 60 µg/ml. In comparison to reference standards Gentamicin, and miconazole, methanolic extracts showed significant antimicrobial activity, student t-test, p = 0,05. Conclusion: The present results support the use of aqueous extracts of Temnocalyx obovatus roots in folk medicine for the treatment of conditions such as diarrhoea and stomach disorders. These results encourage follow-ups through bioassay-directed isolation of the phytocompounds responsible for the potency.