Uncovering antioxidant and anti-breast cancer potential metabolite from streptomyces strain sp. VITAMB using integrated experimental and computational approaches.

Actinobacteria's are rich in bioactive compounds, showing antimicrobial, antiviral, antioxidative, anti-inflammatory, and anticancer activity. The increasing demand for these metabolites in the culinary, pharmaceutical, cosmetic, and nutraceutical industries emphasizes the latent potential of actinomycetes. Paddy field ecosystem provides unique physicochemical conditions that favor the growth of actinomycetes, making them a valuable reservoir of pigment-producing microorganisms. In the present study, a yellow pigment-producing strain identified as Streptomyces sp (GenBank ID: OR958670) was isolated from paddy field soil samples collected from Meghalaya. Scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GC-MS) analyses revealed that this strain produces various metabolites, including diethyl phthalate, which was highlighted following ADME/T (absorption-distribution-metabolism-excretion/toxicity) screening. Diethyl phthalate demonstrated strong antioxidant and cytotoxic activity. In silico studies using a multi-receptor approach assessed the binding energies of diethyl phthalate across several proteins. In silico molecular docking against key regulators of the PI3K/AKT/mTOR signalling axis revealed favourable binding affinities of DEP, with the strongest interactions recorded for PTEN (-7.1 kcal/mol) and AKT1 (-6.9 kcal/mol), both comparable to the positive control Everolimus (-7.2 and -6.6 kcal/mol, respectively), followed by mTOR (-5.2 kcal/mol) and PI3K (-4.8 kcal/mol). Accordingly, the obtained metabolite "diethyl phthalate" demonstrated notable antioxidant activity and moderate cytotoxic effects against MDA-MB-231 breast cancer cells, with an IC50 of ∼153 μg/mL. In addition, docking analysis revealed favourable binding affinities with key proteins associated with breast cancer progression; however, these findings should be regarded as exploratory at this stage, pending validation across a broader panel of cell lines and in vivo models. Despite the promising anticancer potential demonstrated in this study, the findings are limited to in vitro investigations, and further in vivo validation, toxicity assessment, and mechanistic studies are required to confirm the therapeutic applicability of the identified compounds. Future studies should also focus on purification, structural characterization, and clinical evaluation of the bioactive metabolites to facilitate their development as potential anticancer agents.