GC-MS-Based Phytochemical Profiling and Integrated Evaluation of Antioxidant, Antibacterial, and In Silico Studies of Kumaun Himalayan Strobilanthes Species.

Five Strobilanthes species indigenous to the Kumaun Himalayan region of Uttarakhand, India, have been historically employed in traditional medicine to treat bacterial infections, inflammatory conditions, and respiratory ailments, but remain largely unexplored for aquaculture disease management applications. Dichloromethane extracts of S. glutinosa (SGDE), S. pentastemonoides (SPDE), S. angustifrons (SADE), S. attenuata (SATDE) and S. tomentosa (STDE) were comprehensively analysed by GC-MS for phytochemical profiling, with antioxidant activity quantified using DPPH radical scavenging and ferrozine-based metal chelating assays, and antibacterial efficacy evaluated against Aeromonas salmonicida and Edwardsiella tarda using disc diffusion methodology. Pearson correlation analysis, molecular docking, and ADMET computational modelling were performed to elucidate structure-activity relationships and pharmacokinetic properties. GC-MS analysis identified 42-59 phytochemical constituents per species, with sterols and triterpenes constituting the predominant class. STDE demonstrated superior DPPH radical scavenging activity, while SATDE exhibited optimal metal chelating potential. SGDE and STDE displayed the good antibacterial activities against both pathogens. Pearson correlation analysis identified n-tritriacontane and sclareol associated with antimicrobial activity, while molecular docking revealed superior binding affinities for β-amirone to DNA topoisomerase I and β-amyrin. ADMET assessment identified sclareol, stigmasterol, and 24-epicampesterol as optimal candidates with favorable.