Withania somnifera Seed Extract with Superior Metabolic Effects, Preserved Safety, and Strong DPP-4 Binding

Withania somnifera is increasingly used in nutraceutical formulations, yet plant part specific safety data remain limited particularly for the seeds, which have received comparatively little attention relative to the roots and leaves. This study evaluated the safety and metabolic effects of W. somnifera seed extract (WSS-E) and seed powder (WSS-P) following the 56 days of dietary supplementation in rats, alongside a molecular docking analysis examining the interaction of major seed phytochemicals with dipeptidyl peptidase-4 (DPP-4). Five experimental groups were assessed: the control group, 0.25% WSS-E, 0.5% WSS-E, 0.5% WSS-P, and 1% WSS-P. The 0.5% WSS-E group exhibited the most favorable metabolic response, with significant improvements across all measured lipid and glycemic parameters by day 56, glucose decreased from 105.69 to 85.73 mg/dL, triglycerides from 108.84 to 78.40 mg/dL, total cholesterol from 104.03 to 90.55 mg/dL,  LDL from 48.53 to 37.69 mg/dL, and VLDL from 21.78 to 15.70 mg/dL. HDL cholesterol increased from 33.76 to 37.19 mg/dL, and the atherogenic index declined from 3.24 to 2.13. Hepatic, renal, and hematological markers remained within normal ranges across all groups, indicating no evidence of toxicity. Molecular docking for the further revealed that withanone showed the strongest binding affinity for DPP-4 (−10.0 kcal/mol) among the phytochemicals tested, while the remaining compounds also displayed appreciable, though comparatively weaker, binding affinities.