Turmerin, the antioxidant protein from turmeric (Curcuma longa) exhibits antihyperglycaemic effects.
Nat Prod Res. 2011 Oct 6. Epub 2011 Oct 6. PMID: 21972920
a Agroprocessing and Natural Products Division, National Institute for Interdisciplinary Science and Technology (CSIR) , Thiruvananthapuram , Kerala 695019 , India.
A wide range of proteinaceous inhibitors are present in plants to protect themselves from hydrolytic enzymes. In this study, turmerin, a water-soluble peptide in turmeric rhizomes, was evaluated for its inhibitory potential against glucosidase and its antioxidant (AO) capacity. Turmerin inhibited α-amylase and α-glucosidase activities with IC(50) values 31 and 192 µg mL(-1), respectively. Under the experimental conditions, those values for a standard glucosidase inhibitor, acarbose, were 81 and 296 µg mL(-1), respectively. The AO capacity of turmerin was evaluated using in vitro assay systems. Turmerin showed good DPPH (IC(50) = 29 µg mL(-1)) and superoxide (IC(50) = 48 µg mL(-1)) and moderate ABTS (IC(50) = 83 µg mL(-1)) radical scavenging and Fe(II) chelation (IC(50) = 101 µg mL(-1)) capacities. The inhibitory potential showed by turmerin against enzymes linked to type 2 diabetes, as well as its moderate AO capacity, could rationalise the traditional usage of turmeric rhizome preparations against diabetes.