Streptomyces griseoincarnatus AR2 from the cold desert as a biofactory for secondary metabolites with multifaceted bioactivities, confirmed by in vitro and in silico approaches.

Exploring natural pigments and multifunctional metabolites from the genus Streptomyces is experiencing global escalation, especially for health-related applications. The current study reports bioactive potential of deep yellow pigment and other metabolites from Streptomyces griseoincarnatus AR2, previously recovered from Katpana Cold Desert, Gilgit-Baltistan, Pakistan. Peptone glycerol (PG) medium supported extracellular pigment release and yielded a crude pigment at 20.64 g/L. The pigment was purified through chromatography, demonstrated Rf value of 0.65. The purified yellow pigment was further characterized and structurally elucidated as highly putative alloxanthin compound through UV-visible spectrophotometry (λmax 458 nm), Fourier Transform Infrared (FT-IR) spectroscopy and Mass Spectrometry (ESI-MS/MS) with m/z 375.4, 564 and 311.2, respectively. Antibacterial activity of crude yellow pigment at 50 mg/mL demonstrated highest antibacterial action against Gram Positive Bacillus subtilis (30 mm). The yellow pigment exhibited effective antifungal potential against Aspergillus niger (13.5 mm), along with antioxidant activity of 38.75% through DPPH assay. The effect of pigment treatment on human cervical cancer cell lines was evaluated through MTT cytotoxicity assay and cytotoxicity was observed with a minimum IC50 value of 1.64 µg/ml. In addition, molecular docking approach revealed that the analyzed molecules exhibited high binding affinities toward target sites e.g. alloxanthin showed binding affinity (-10.4 kcal/mol) against KEAP1 (antioxidant target site) and Resistomycin affinity was (-9.1 kcal/mol) toward Tyrosyl-tRNA synthetase (anticancer site). Hence, S. griseoincarnatus AR2 yellow pigment and other metabolites might be recognized as promising candidate for wide range of therapeutical relevance, manifesting complementation of multiple bioactive compounds.