Diabetes and exposure to heavy metals like mercury chloride are known to induce oxidative stress-mediated neurodegeneration, particularly in vulnerable brain regions like the substantia nigra. Medicinal plants such as Chromolaena odorata extract possess antioxidant and neurorestorative properties that may mitigate such damage. This study investigated Neurorestorative and Antidiabetic Effects of Chromolaena odorata Extract on the Substantia Nigra of Diabetic Rats Exposed to Mercury. A Histopathological Study. The study was conducted in Ebonyi State University, Abakaliki and the study lasted for 35 days. Thirty-six (36) male Wistar rats weighing between 250g-300g used for the study were randomly divided into six groups (n = 6): Control (A), diabetic + Hgcl2 (B), diabetic + Hgcl2+ metformin (C) and diabetic + Hgcl2 treated with 200 (D), 400 (E) and 600mg/kg (F) of the extract. Diabetes was induced using a single dose of alloxan monohydrate (150mg/kg) intraperitoneally. 72 hours after diabetes confirmation (glucose ≥200 mg/dL), mercury chloride (3mg/kg), was administered orally daily for 14 days followed by treatment with the administration of the extract to the experimental groups. At the end of the experimental period, animals were humanely sacrificed, the substantia nigra excised and processed for histological evaluation using H&E staining. Data obtained were analyzed using ANOVA followed by Tukey’s post hoc test with P-value at (P = .05). Group B showed significant weight loss and hyperglycemia (370 ± 32 mg/dl) compared to Group A (95 ± 7mg/dl). Histologically, the nigral section revealed severe neurodegenerative changes, vacuolation, and pyknotic nuclei indicative of apoptosis. Treatment with Chromolaena. odorata extract significantly improved glycemic control and restored nigral histoarchitecture in a dose-dependent manner, with the 600 mg/kg showing near-normal morphology comparable to metformin. In conclusion, Chromolaena odorata extract exhibits significant neurorestorative and antidiabetic effects against combined diabetic and mercury neurotoxicity.
Ama et al. (2026) studied this question.