The phytochemical constituents of red (RR) and black (BR) rice extracts were determined using high-pressure liquid chromatography (HPLC). Phytochemical screening revealed the presence of catechin, rutin, isoquercetin, cyanidin 3-glucoside, cyanidin 3-O-rutinoside, peonidin and quercetin. The anti-diabetic activities of RR and BR extracts on diabetic complications were examined in a streptozotocin-induced diabetic rat model. Rats (n = 80) were divided into 10 groups (n = 8 rats per group). Healthy and diabetic RR or BR-treated groups received 10, 50, or 200 mg of RR or BR per kg of body weight daily for 45 days. The results demonstrated significantly improved glucose control in rats administered RR or BR, while triglyceride and cholesterol levels were reduced in the diabetic groups. Moreover, RR or BR treatment led to decreased levels of malondialdehyde, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine. Further, glutathione concentration was significantly increased in both serum and liver tissue from RR- and BR-treated diabetic rats.
Keywords: black rice; diabetic rats; hyperglycemia; phytochemical analysis; red rice.