Bioactivity and Secondary Metabolites Profiling of Kitasatospora sp. TC-ARCL7 Isolated from Curcuma longa L. Rhizosphere

Abstract

Actinomycetes are important sources of bioactive compounds with pharmaceutical potential. Kitasatospora sp. TC-ARCL7, isolated from the rhizosphere of Curcuma longa L., has previously shown anticancer activity against the T47D cell line, but its broader biological activities remain unexplored. This study evaluated the anticancer, antimicrobial, and antioxidant activities of its ethyl acetate extract. Cytotoxic activity was assessed against T47D, HepG2, HeLa, and Vero cell lines, while antimicrobial activity was determined against selected bacterial and fungal pathogens using minimum inhibitory concentration (MIC) analysis. Antioxidant activity was evaluated using the DPPH and FRAP assays. The extract exhibited potent cytotoxic activity, with IC50 values of 0.20 ± 0.04 (SI: 3883.03 ± 476.79), 2.64 ± 0.46 (SI: 301.28 ± 67.38), and 2.33 ± 0.39 (SI: 328.86 ± 23.37) μg/mL against T47D, HepG2, and HeLa cells, respectively. The Kitasatospora sp. TC-ARCL7 isolate inhibited the growth of Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Candida albicans. In contrast, the ethyl acetate extract showed no inhibitory zone against Pseudomonas aeruginosa and C. albicans. The extract exhibited antioxidant activity predominantly through electron-transfer mechanisms, as indicated by its strong FRAP response (118.70 ± 18.8 mM Fe(II)/g) despite weak DPPH scavenging activity (IC50 = 513.35 μg/mL). GC-MS analysis identified several compounds previously reported to possess anticancer, antimicrobial, and antioxidant activities. The high selectivity indices and potent cytotoxic activity against T47D cells suggest that the ethyl acetate extract of Kitasatospora sp. TC-ARCL7 is a promising source of bioactive compounds for further research into anticancer drug discovery.