α-Glucosidase Inhibitory Profile of Catechins and Theaflavins

Abstract

To clarify the postprandial glucose suppression effect of flavonoids, the inhibitory effects of catechins and theaflavins against alpha-glucosidase (AGH) were examined in this study. It was initially demonstrated that theaflavins and catechins preferentially inhibited maltase rather than sucrase in an immobilized AGH inhibitory assay system. For the maltase inhibitory effects of theaflavins, the effects were observed in descending order of potency of theaflavin (TF)-3-O-gallate (Gal) > TF-3,3'-di-O-Gal > TF-3'-O-Gal > TF. This suggests that the AGH inhibition induced by theaflavins is closely associated with the presence of a free hydroxyl group at the 3'-position of TF as well as the esterification of TF with a mono-Gal group. In addition, the R-configuration at the 3'-position of TF-3-O-Gal showed a higher inhibitory activity than the S-configuration. As a result of a single oral administration of maltose (2 g/kg) in rats, a significant reduction in blood glucose level was observed at a dose of 10 mg/kg of TF-3-O-Gal, demonstrating for the first time that TF-3-O-Gal can suppress glucose production from maltose through inhibition of AGH in the gut.

Inhibitory Potency of Withania Somnifera Extracts Against DPP-4: An in Vitro Evaluation

“…Modern studies have found that catechin is responsible for antioxidant activity, antimicrobial activity, anti-ageing and antidiabetic properties (Lambert and Yang, 2003;Liu et al, 2014). The potent antioxidant property of catechin reduces free radical damage to cells and prevents the oxidation of LDL, cholesterol and blood glucose level (Cooper et al, 2005;Matsui et al, 2007).…”

In vitro antioxidant, anti-diabetic and antilipemic potentials of quercetagetin extracted from marigold (Tagetes erecta L.) inflorescence residues

“…Globally, it is estimated that 1.9 billion adults are overweight and 600 million are obese by 2014 (Hosseinpanah et al 2016). Meanwhile, metabolic syndrome can cause serious damage to body systems, such as blood vessels and nerves (Matsui et al 2007;Cohen and Goedert 2004). One of the major causes of the metabolic syndrome is excessive consumption of carbohydrates and triglycerides.…”

Antidiabetic activity of Plumeria rubra L. in normal and alloxan induced diabetic mice

“…1 It is a chronic disease caused by inherited or acquired deficiency in insulin secretion and by decreased responsiveness of the organs to secreted insulin. 2 Such a deficiency results in increased concentrations of glucose in the blood, which in turn damage many of the body systems, in particular the blood vessels and nerves. 3 It is currently growing at a rapid rate throughout the world, and it is the 16th leading cause of global mortality.…”