eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2026-06-22 23 2 59136 article Sadhana Yashwant More 1 Saurav Somnath Gaikwad 2 Department of Microbiology, Shrimati Vimlaben Khimji Tejookaya Arts, Science and Commerce College, (Affiliated to S. P. Pune University, Pune), Nashik, India P.G. Department of Botany, K.S.K.W. Arts, Science and Commerce College, (Affiliated to S. P. Pune University, Pune) CIDCO Nashik, India The increasing emergence of antibiotic-resistant bacterial pathogens has intensified the search for effective natural antimicrobial agents. Curcuma caesia Roxb. (black turmeric) is a medicinal plant traditionally used in Indian ethnomedicine for the treatment of infectious diseases. The present study aimed to evaluate the antibacterial activity of C. caesia rhizome extracts prepared using different solvents. Rhizomes were shade-dried, powdered, and extracted using methanol, chloroform, petroleum ether, and distilled water. Antibacterial activity was assessed against Escherichia coli, Streptococcus pneumoniae, Bacillus sp., Pseudomonas aeruginosa, and Klebsiella pneumoniae using the agar well diffusion method. Among all extracts, the methanolic extract exhibited the highest antibacterial activity, with zones of inhibition ranging from 16.3 ± 0.5 mm to 21.4 ± 0.7 mm, followed by chloroform and aqueous extracts, while petroleum ether extract showed minimal activity. Gram-positive bacteria were more susceptible than Gram-negative bacteria. These findings suggest that Curcuma caesia may serve as a promising natural source for the development of antibacterial agents. https://www.biotech-asia.org/vol23no2/antibacterial-activity-of-curcuma-caesia-roxb-rhizome-extracts/ Antibacterial activity; Curcuma caesia; Phytochemicals; Rhizome extract; Turmeric