EVALUATION OF THE ANTIBACTERIAL EFFICACY OF Curcuma longa LEAF EXTRACTS AGAINST SOME ENTERIC PATHOGENS
The rising prevalence of antibiotic-resistant enteric pathogens necessitates alternative antimicrobial solutions derived from medicinal plants. Curcuma longa (turmeric) is widely recognized for its traditional therapeutic uses, yet its antibacterial efficacy against clinically relevant bacteria remains underexplored. This study evaluated the antibacterial activity of aqueous extracts of Curcuma longa rhizomes against selected enteric bacterial pathogens and determined their minimum inhibitory and bactericidal concentrations. Stock cultures of Salmonella typhi, Shigella dysenteriae, Escherichia coli, and Klebsiella pneumoniae were confirmed by standard biochemical tests. Fresh turmeric rhizomes were cleaned, dried, and extracted in distilled water; phytochemical screening confirmed the presence of alkaloids, tannins, flavonoids, saponins, and cardiac glycosides. The cup-plate agar diffusion method assessed antibacterial activity, while macro-broth dilution determined MIC and MBC values. The extract demonstrated dose-dependent inhibition, producing zones ranging from 0 mm to 30 mm across concentrations. MIC values ranged from 0.16 to 0.63 mg/mL, while MBC values varied between 0.31 and 1.25 mg/mL. Salmonella typhi exhibited the highest susceptibility (MIC 0.16 mg/mL, MBC 0.63 mg/mL). Shigella dysenteriae and E. coli required higher MICs and MBCs, suggesting lower extract potency against these strains. Chi-square analysis indicated no significant difference in MIC and MBC values among isolates (χ² = 0.5915, df = 3, P = 0.8984). The aqueous extract of Curcuma longa shows promising broad-spectrum antibacterial activity, supporting its ethnomedicinal use. Future research should focus on optimizing extraction protocols, isolating active compounds, investigating synergistic effects with standard antibiotics, and conducting clinical trials to validate its therapeutic potential against multidrug-resistant bacteria.
Keywords: Antibacterial Activity, Curcuma longa, Enteric Pathogens, Minimum Inhibitory Concentration, Phytochemicals
