ANTIOXIDANT AND ANTIHYPERGLYCEMIC EFFECTS OF JUSTICIA CARNEA LEAVES IN STREPTOZOTOCIN-INDUCED DIABETIC WISTAR RATS

Abstract

Diabetes mellitus (DM) is a chronic metabolic disorder characterised by persistent hyperglycemia arising from impaired insulin secretion, action, or both. The condition disrupts carbohydrate, lipid, and protein metabolism, resulting in widespread systemic complications. This study evaluated the proximate and phytochemical composition of Justicia carnea leaves as well as the antioxidant and antihyperglycemic effects of the methanol leaf extract in streptozotocin (STZ)-induced diabetic Wistar rats. Proximate and phytochemical analyses were conducted using standard procedures. For the in vivo study, thirty-six male Wistar rats (180–200 g) were randomly assigned to six groups. Group 1 served as the normal control, Group 2 was diabetic and untreated, Group 3 received metformin (50 mg/kg body weight (bw), while Groups 4 to 6 received 100, 200, and 500 mg/kg bw of the methanol extract, respectively. Diabetes was induced using a single intraperitoneal injection of STZ (50 mg/kg bw). After 21 days of treatment, animals were euthanised to measure antioxidant enzyme activity in the pancreas, liver, and kidney.  Phytochemical screening indicated the presence of flavonoids, tannins, steroids, phenols, and terpenoids. Proximate analysis revealed high carbohydrate (47.88%) and moisture (22.12%) contents, with low crude fat (0.23%) and protein (1.26%) levels. Untreated diabetic rats exhibited significantly elevated fasting blood glucose and reduced antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) (p < 0.05). Treatment with J. carnea extract produced a dose-dependent reduction in fasting blood glucose and significant restoration of antioxidant enzyme activities (p < 0.05). These findings demonstrate that Justicia carnea leaves possess valuable nutritional and bioactive constituents and exhibit strong antioxidant potential, supporting their traditional use and suggesting therapeutic relevance in managing oxidative stress–associated diabetic complications.