Antibacterial Activity of Curcuma longa (Turmeric) Plant Extracts Against Bacterial Wilt of Tomato Caused by Ralstonia solanacearum

Bacterial wilt caused by Ralstonia solanacearum is a major constraint for production of tomatoes (Solanum lycopersicon). It affects large varieties of solanaceous plants worldwide. Control of bacterial wilt is very tricky as there are no effective curative chemicals. Plants are considered as one of the most important source of medicine and drugs and they have been used for treating different ailments in humans worldwide from the beginning of the civilization. Turmeric (Curcuma longa) belongs to Family Zingiberaceae and Curcuma longa is known to be an important medicinal plant from initial period in India. With an aim to develop effective antibacterial agent without any residual effect, the present study was conducted to analyze the in vitro antibacterial potential of turmeric plant against ten highly virulent isolates of R. solanacearum. The antibacterial activity of the extracts was assayed by agar well diffusion method on Tryptone Soya agar. The results revealed that the average zone of inhibition of the rhizome extract was ranging at 20-26mm against R. solanacearum. Various concentrations of the extracts were prepared by dissolving extracts in DMSO. The means and standard error of triplicate tests were recorded. The minimum inhibitory concentration (MIC) was determined by two-fold micro broth dilution method for the tested pathogens. The MIC of the turmeric extract was 2-20g ml-1. The activities of the solvent extract are remarkable when compared with the water extracts. Hence, solvent extract will enhance the efficacy of turmeric in the activity of R. solanacearum infections.