Antidiabetic Activity and Safety Evaluation of Methanolic Leaf Extract of Psidium guajava in Alloxan-Induced Diabetic Wistar Rats: A Focus on IL-6 Cytokine

Abstract

Background: Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia, insulin resistance, and inflammation, mediated by cytokines like interleukin-6 (IL-6). Psidium guajava (guava) is widely used in African traditional medicine for diabetes management, though its immunomodulatory effects remain poorly defined.

Aim: This study To evaluate the anti-diabetic, immunomodulatory, and safety profiles of methanolic Psidium guajava leaf extract in alloxan-induced diabetic Wistar rats, focusing on IL-6 modulation.

Methods: Thirty Wistar rats were randomized into six groups (n = 5): negative control, diabetic control, glibenclamide-treated, and three extract-treated groups (250, 500, 1000 mg/kg). Diabetes was induced with alloxan (160 mg/kg). Glucose, IL-6, liver and kidney function markers were assessed after 14 days. Phytochemical screening and acute toxicity tests were performed. ELISA kits with known sensitivity and specificity were used for cytokine quantification.

Results: Glucose levels decreased dose-dependently, with the 1000 mg/kg.bwt extract showing a significant reduction (p < 0.05), though not surpassing glibenclamide. IL-6 levels varied among groups but showed no statistically significant change (p > 0.05). Liver enzymes (AST, ALT) increased significantly in the 250 mg/kg.bwt group, while other markers remained within normal limits. The extract was well-tolerated with an LD50 > 5000 mg/kg.

Conclusion: Psidium guajava leaf extract demonstrated anti-diabetic effects and short-term safety but did not significantly modulate IL-6 levels, possibly due to the short treatment duration and the diabetes model used. Further studies using chronic models and longer exposure are recommended.