Standardized Emblica Officinalis Fruit Extract Inhibited the Activities of α-amylase, α-glucosidase, and Dipeptidyl Peptidase-4 and Displayed Antioxidant Potential

Background: Emblica officinalis, known as amla in Ayurveda, has been used as a folk medicine to treat numerous pathological conditions, including diabetes. However, the novel extract of E. officinalis fruit extract (amla fruit extract, AFE, Saberry®) containing 100 g kg β-glucogallin along with hydrolyzable tannins has not yet been extensively studied for its antidiabetic potential.

Objective: The aim of this study was to investigate the antidiabetic and antioxidant activities of AFE and its stability during gastric stress as well as its thermostability.

Methods: The effect of AFE on the inhibition of pancreatic α-amylase and salivary α-amylase enzymes was studied using starch and yeast α-glucosidase enzyme using 4-nitrophenyl α-d-glucopyranoside as substrate. Further, 2,2-diphenyl-1-picrylhydrazyl radical scavenging and reactive oxygen species inhibition assay was performed against AFE.

Results: AFE potently inhibited the activities of α-amylase and α-glucosidase in a concentration-dependent manner with half maximal inhibitory concentration (IC ) values of 135.70 μg mL and 106.70 μg mL respectively. Furthermore, it also showed inhibition of α-glucosidase (IC 562.9 μg mL ) and dipeptidyl peptidase-4 (DPP-4; IC 3770 μg mL ) enzyme activities. AFE is a potent antioxidant showing a free radical scavenging activity (IC 2.37 μg mL ) and protecting against cellular reactive oxygen species (IC 1.77 μg mL ), and the effects elicited could be attributed to its phytoconstituents.

Conclusion: AFE showed significant gastric acid resistance and was also found to be thermostable against wet heat. Excellent α-amylase, α-glucosidase, and DPP-4 inhibitory activities of AFE, as well as antioxidant activities, strongly recommend its use for the management of type 2 diabetes mellitus. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.