Evaluation of withacoagulin from Withania coagulans for glycemic improvement and β-cell preservation in a type 2 diabetic model

Type 2 diabetes mellitus remains a global health emergency, with existing therapies often failing to achieve durable glycemic control or preserve pancreatic β-cell function. In this study, we isolated and purified withacoagulin, a novel withanolide from Withania coagulans , confirmed by NMR, MS, FTIR, and HPLC (>98% purity). A total of 72 male Wistar rats were randomized into six groups (n=12 per group): normal control, diabetic control (streptozotocin–nicotinamide), metformin (100 mg/kg), insulin (4 U/kg), and withacoagulin at 10, and 20 mg/kg. Twelve weeks of oral withacoagulin administration resulted in significant improvements in glycemic control, including a 62% reduction in fasting blood glucose and a 65% decrease in HbA1c relative to diabetic controls (p < 0.001 These effects were accompanied by marked improvements in insulin sensitivity, evidenced by reduced HOMA-IR and increased QUICKI indices. Histological and immunohistochemical analyses demonstrated preservation of pancreatic islet morphology and enhanced insulin immunoreactivity in treated animals. Dyslipidemia was corrected, oxidative stress markers were improved (↑SOD, ↑CAT, ↑GPx; ↓MDA), and pro-inflammatory cytokines (TNF-α, IL-6) were significantly lowered. Mechanistic analyses demonstrated reactivation of IRS-1/PI3K/Akt signaling, increased GLUT4 translocation, and upregulation of AMPK phosphorylation, highlighting a multi-targeted mechanism of action. A 28-day subacute toxicity study conducted in accordance with OECD guidelines indicated no observable hepatic, renal, hematological, or histopathological abnormalities at doses up to 500 mg/kg, establishing a favorable preliminary safety profile. Collectively, these findings provide support for withacoagulin’s potential as a mechanistically active natural lead compound for further preclinical development in metabolic disease research. • Withacoagulin was isolated from Withania coagulans and structurally characterized with high purity (>98%). • Antidiabetic activity was evaluated in a well-established HFD plus nicotinamide–streptozotocin rat model with adequate group sizes (n = 12) and a 12-week treatment period. • Withacoagulin treatment significantly improved glycemic control, evidenced by reductions in fasting blood glucose and HbA1c, along with improved glucose and insulin tolerance. • Metabolic improvements were associated with modulation of key insulin-signaling pathways, including IRS-1/PI3K/Akt and AMPK activation, and enhanced GLUT4 translocation. • A 28-day OECD-407 subacute toxicity study indicated a favorable preliminary safety profile, with no observable hepato-renal toxicity at the tested doses.