Antioxidant and anticancer activity of active secondary metabolites produced by Streptomyces griseorubens

Abstract

Natural products offer a great potential to advance the discovery of novel therapeutic agents for a variety of human diseases, particularly in cases like cancer where chemical, surgical, or hormonal treatments often come with substantial side effects. The study aimed to evaluate the bioactive potential of various Streptomyces isolates for antioxidant and anticancer activities. A total of 20 isolates of Streptomyces species were recovered from eight rhizosphere soil samples obtained in this study. Among, the isolate 506 exhibited superior antioxidant properties and substantial anticancer activity. Ethyl acetate was used to extract bioactive compounds and then were tested for free radical (DPPH) scavenging and antioxidative properties. The antioxidant activity, specifically targeting the scavenging of DPPH free radicals, for the selected Streptomyces extracts codes 1001, 1002, 1003, 1004, 506 and ascorbic acid as positive control were 15.5% ± 0.2, 21% ± 0.28, 22% ± 0.29, 21.5% ± 0.26, 28.9% ± 0.35, 47.4 ± 0.36 respectively. The sample which has shown maximum antioxidant potential was further evaluated for its anticancer activity against HepG-2 cells via MTT assay. The selected active Streptomyces strain was identified as S. griseorubens based on morphological characterization and 16S-rRNA gene sequencing, the sequence was submitted to the GenBank database under accession number OR144194. S. griseorubens 506 showed an IC50 value of 307.5 µg/mL in the anticancer assays, indicating moderate inhibitory effects on cancer cell growth. These findings highlight S. griseorubens 506 as a promising candidate for further development in therapeutic applications.