Antibacterial activity of medicinal plants used in Ayurvedic medicine towards food and water borne pathogens

Abstract

Aim : In the emerging scenario of increasing multiple antibiotic resistance among pathogenic bacteria, plant based extracts having antibacterial activity are being explored as a means to check the emergence of drug resistant mutants. In the present study, aqueous extracts from various parts of twenty four different plants used in Ayurvedic medicine were evaluated for their antibacterial activity against water and food borne pathogens such as Salmonella, Escherichia coll, Vibrio, Aeromonas, Bacillus and Staphylococcus. Methodology: Antibacterial activity of plant extracts from various parts of twenty four different plants was evaluated by agarwell method. Antibiotic sensitivity testing was carried out by Kirby- Bauer method. The diameter of inhibition zones was measured in millimetres. Inhibition zone with diameter less than 12 mm were considered as having no antibacterial activity. Diameters between 12 and 16 mm were considered as moderately active, and greater than 16 mm were considered as highly active. Results : Out of 33 extracts prepared from various officinal parts, 23 extracts showed antibacterial activity ranging from narrow spectrum to broad spectrum. Tamarindus indica, Garcinia gummi-gutta and Allium sativum possessed excellent broad spectrum antibacterial activity. While inhibitory activity against Salmonella was widespread among many plants, some of the plant extracts showed specific activity towards Staphylococcus aureus. Interpretation: The study revealed that the Gram positive bacteria were more susceptible to crude plant extracts than Gram negative ones. Some of the plant extracts showed superior antibacterial activity when compared to antibiotics. Antibacterial properties of plants analysed might be helpful in discovery of new plant based bactericidal compounds to control drug resistant bacteria.