Anti-glycation properties of Illicium verum Hook. f. fruit in-vitro and in a diabetic rat model

BACKGROUND: Chronic hyperglycemic triggers the non-enzymatic glycation of biomolecules, resulting in the production of advanced glycation endproducts, that lead to several micro- and macrovascular complications. Therefore, the discovery of new, effective, and safe anti-glycation agents is an important need. One of the best choices for the management of diabetes is to use complementary and alternative medicinal therapies. Therefore, the present study was designed to evaluate the anti-glycation activity of ethanolic extract of Illicium verum Hook. f. (Star anise, a frequently used spice and medicinally important herb). METHODS: The anti-glycation activity of ethanolic extract of Illicium verum Hook. f. was determined by using both in-vitro and in-vivo assays. HSA-fructose glycation model was employed to assess the in-vitro inhibition of protein glycation, additionally cross-linked AGEs (formed by incubating lysozyme with fructose) were assessed by SDS polyacrylamide gel electrophoresis. Dual inhibitory mechanisms, i.e., antioxidant and metal chelating activities, were also evaluated by using DPPH, ABTS, and Fe (II)-chelation assays. Acute toxicity of I. verum extract was also performed (by administrating different doses i.e. 2,000, 1,500, 1,000, and 500 mg/kg of body weight). Finally, in-vivo anti-glycation potential was evaluated by 7 weeks of administration of I. verum extract in streptozotocin-induced diabetic rats. RESULTS: In HSA-fructose glycation model, extract of I. verum showed a good inhibitory activity with IC₅₀ value of 0.11±0.001 mg/mL, as compared to the standard inhibitor, rutin (IC₅₀ = 0.02±0.01 mg/mL). Extract of I. verum showed inhibitory activity in DPPH, and ABTS radical scavenging assays with IC₅₀ values of 130±1.0, and 57±2.0 μg/mL, respectively, while it was found to be inactive in the Fe⁺²-chelation assay. The extract was found to be non-toxic, and reduce the elevated blood glucose, urea, lipid, liver function parameters, and renal AGEs levels in streptozotocin-induced diabetic rats. CONCLUSIONS: These results suggest that I. verum supplementation might help to reduce the burden of AGEs, and may have potential in preventing diabetes-associated complications.