ANTIOXIDANT, ANTIHYPERGLYCEMIC, AND RENAL PROTECTIVE EFFECTS OF HIBISCUS TILIACEUS L. LEAF EXTRACT ON STREPTOZOTOCIN-INDUCED HYPERGLYCEMIA

Tóm tắt

Hibiscus tiliaceus L. (Malvaceae) plays a significant role in traditional medicine for treating various diseases. This study aimed to quantify the total polyphenolic and flavonoid contents and evaluate the antihyperglycemic and renal protective effects of H. tiliaceus leaf extracts using in vitro assays (DPPH and α-glucosidase inhibitory activity) and a streptozotocin (STZ)-induced hyperglycemic mouse model. The results showed that the total phenolic and flavonoid contents in the aqueous extract (27.67 mg GAE/g and 11.01 mg QE/g) were lower than those in the 45% ethanol extract (31.67 mg GAE/g and 15.64 mg QE/g). Furthermore, the ethanol extract demonstrated superior antioxidant activity (IC₅₀ value of 5.75 μg/mL) and α-glucosidase inhibitory activity (IC₅₀ value of 2.69 μg/mL) compared to the aqueous extract (IC₅₀ value of 21.05 μg/mL and 7.71 μg/mL, respectively). Oral administration of the 45% ethanol extract at 1.33 g/kg for 14 days significantly reduced fasting plasma glucose and improved glucose tolerance in STZ-induced mice. This dose also attenuated the oxidative stress marker malondialdehyde (MDA) in the kidneys while significantly enhancing endogenous glutathione (GSH) levels. These findings suggest that the H. tiliaceus leaf 45% ethanol extract is a potential candidate for managing hyperglycemia and preventing diabetic kidney disease.