Antihyperglycemic and anti-inflammatory activities of polyphenolic-rich extract of Artocarpus heterophyllus lam stem bark in streptozotocin-induced diabetic rats

Context: Artocarpus heterophyllus Lam (Moraceae) stem bark has been used locally in managing diabetes mellitus with scanty scientific information. Objectives: This study investigates the in vitro antioxidants of polyphenolic-rich extract of Artocarpus heterophyllus stem bark as well as its antidiabetic activity in streptozotocin-induced diabetic rats. Materials and methods: Fifty male Wistar rats were used with induction of diabetes by a single intraperitoneal injection of streptozotocin (45 mg/kg body weight) and were orally administered with 400 mg/kg free and bound phenols of Artocarpus heterophyllus stem bark. Hence, cervical dislocation method was used to sacrifice the animals on 28th day of the experiment; antihyperglycemia and anti-inflammatory parameters were assessed. Results: Thfe polyphenolic extracts demonstrate antioxidant potential (IC₅₀ hydrogen peroxide = 112.49 and 128.50 µg/mL for bound and free phenols, respectively), and DPPH (IC₅₀ = 98.19 and 114.81 µg/mL for bound and free phenols, respectively) and strong inhibitory activity against amylase (IC₅₀ = 95.82 and 110.01 µg/mL for bound and free phenols, respectively) and glucosidase (IC₅₀ of 83.33 and 91.05 µg/mL for bound and free phenols, respectively). There was a significant (p < 0.05) increase in glycogen, insulin concentration, pancreatic β-cell scores (HOMA-β), antioxidant enzymes and hexokinase activities; and glucose transporter concentration in diabetic animals administered with the extracts and metformin. Also, a significant (p < 0.05) reduction in fasting blood glucose, lipid peroxidation, glucose-6-phosphatase and in all anti-inflammatory parameters were observed in diabetic rats administered with the extracts and metformin. Discussion and conclusion: The extracts demonstrate antidiabetic potential which may be useful in managing diabetes mellitus.