Antibacterial potency and synergistic effects of a few South Indian spices against antibiotic resistant bacteria

Abstract

Multi-antibiotic resistant strain of <i style="mso-bidi-font-style:normal">Xanthomonas campestris</i> affects large numbers of vegetable crops and causes severe damage. To control this harmful bacterium some south Indian spices were used herbal treatment in biocontrol method.<i style="mso-bidi-font-style:normal"> </i>The phyto-pathogen<i style="mso-bidi-font-style:normal"> </i>was tested against fifteen spices: Cardamom, Turmeric, Ginger, Cumin, Fennel, Clove, Poppy seed, Mustard, Garlic, Pepper, Fenugreek, Cinnamon, Mint, Asafoetida and Coriander. The antibacterial activities of the extracts, individually and in combination with them were determined using well diffusion method and the minimum inhibitory concentration (MIC) carried out by serial dilution technique. Synergistic activity of crude aqueous and crude methanolic extracts of the plant parts, in various combinations of two to six against the test organism ranged from 10-30 mm zone of growth inhibition. Relative Percentage of Inhibition (RPI) was also calculated using standard formula. The antibacterial efficacy of the mixture of extracts from spices increased considerably when compared to the low activities recorded with the extract of individual plant parts (<i style="mso-bidi-font-style:normal">P&lt;</i>0.05). Aqueous extracts of each plant material and mixture produced greater antimicrobial activity than the methanolic extracts. The plant materials possessed antimicrobial activity with greater efficacy when used synergistically on the test organism.