In vitro antidiabetic and inhibitory potential of turmeric (Curcuma longa L) rhizome against cellular and LDL oxidation and angiotensin converting enzyme.

Turmeric (Curcuma longa L) rhizome extracts were evaluated for their antidiabetic, antihypertensive and antioxidant potentials. α-Glucosidase (0.4 μg/mL) and α-amylase (0.4 μg/mL) inhibitory potential of turmeric ethyl acetate extract was significantly higher than those of the reference drug acarbose (17.1 μg/mL and 290.6 μg/mL respectively). Protein glycation inhibitory potential of ethyl acetate extract was 800 times higher than that of ascorbic acid. High potential of ethyl acetate extract to scavenge free radicals and to reduce LDL oxidation and cellular oxidative stress was also revealed. The positive correlation obtained between the free radical scavenging capacity of the extracts and their antiglycation potential further confirmed the role of antioxidants in controlling glycation reactions. Ethyl acetate extract was also found as effective in reducing hypertension by inhibiting angiotensin converting enzyme (ACE). Antidiabetic, ACE inhibitory and antioxidant capacities of the extracts were in the order of their curcumin contents.