Protective Effects of Isolated Curcumin From <i>Curcuma longa</i> on Key Enzymes Involved in the Insulin Signaling Pathway and Digestive and Metabolic Enzymes Associated With Obesity, Type 2 Diabetes, and Hypertension
Munirah Sulaiman Othman Alhar, Walaa I. El-Sofany, Ayshah Aysh ALrashidi, Khaled Hamden
Abstract
This study explores the potential of curcumin (CUR), extracted from Curcuma longa , in combating obesity and Type 2 diabetes. Obesity and Type 2 diabetes were induced in rats through a high‐fat and high‐fructose diet (HFFD), and CUR, after purification and characterization by Fourier transform infrared spectroscopy (FTIR) and ultraviolet (UV) spectroscopy, was administered for 3 months via gastric gavage. The results show that CUR supplementation activates the insulin signaling pathway in a dose‐dependent manner, leading to improved insulin sensitivity. Specifically, administering CUR at a daily dose of 100 mg/kg significantly reduces the activities of protein tyrosine phosphatase (PTP1B) and dipeptidyl peptidase‐4 (DPP‐4) by 43% and 45%, respectively, in obese and Type 2 diabetic rats compared to untreated obese rats. Furthermore, CUR effectively inhibits lipase and α ‐amylase activities at both the serum and intestinal levels. In obese rats, CUR administration reduces glycogen phosphorylase (GP) activity by 35% and enhances glycogen synthase (GS) activity by 78%, leading to a substantial increase in hepatic glycogen content. Additionally, CUR also led to a 21% reduction in food intake and a 12% decrease in water consumption. These changes contributed to significant reductions in the blood sugar and glycosylated hemoglobin (HbA1c) levels, with decreases of 59% and 53%, respectively. Additionally, administering CUR at a dose of 100 mg/kg body weight reduced thiobarbituric acid reactive substances (TBARSs), hydrogen peroxide (H 2 O 2 ), and total oxidant status (TOS) in obese and diabetic rats, with reductions of 49%, 59%, and 58%, respectively. Furthermore, CUR demonstrates a strong regulatory effect on the levels of low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), and total cholesterol (TC). Overall, these results underscore the CUR potential for treating and preventing diabetes and obesity.