GC-MS based metabolite profiling and angiotensin I-converting enzyme inhibitory property of black tea extracts

Abstract Angiotensin I-converting enzyme inhibitors are used as therapeutic agents for the treatment of hypertension. Regular consumption of black tea (Camellia sinensis (L.) Kuntze, Theaceae) has been reported to lower blood pressure. The aims of the present work were to compare chemical composition and angiotensin I-converting enzyme inhibitory properties of infusion and decoction of four samples of black tea. GC/MS based metabolomics approach helped in identification of fifty-one metabolites including ten organic acids, one inorganic acid, sixteen amino acids, two sugars, five sugar alcohols, fifteen phenols and flavonoids, two fatty acids from infusions and decoctions of four black tea samples. Partial least squares discriminant analysis and orthogonal partial least squares discriminant analysis models showed good classification among the two groups, diffusion and infusion, based on metabolites. Both infusion and decoction inhibited the enzyme. However, the activity differed with samples. Multivariate analysis also segregated extracts on the basis of activity. Thearubigin, theaflavin, catechin inhibited the enzyme. Epicatechin, epigallocatechin gallate, gallic acid, caffeine showed lower activity.

In silico investigation of black tea components on α-amylase, α-glucosidase and lipase.

Black tea is one of the most widely consumed beverages in the world and traditionally known for its antidiabetic and antiobesity property. However, the underlying mechanisms of these properties are not studied widely. In this work, we hypothesize that the reason could be because of the inhibition of gut enzymes by the tea derived phytochemicals. Molecular docking was used to explore the efficacy of tea components to inhibit the key enzymes related with Type II diabetes and obesity; α-glucosidase, α-amylase and lipase. Autodock4.2 molecular docking software that applies Lamarckian Genetic Algorithm was used. The ligand structures were retrieved from PubChem and KNApSAcK-3D database. PreADMET web server was used for Toxicity and ADME predictions. Based on this analysis, it has been found that 8-c-ascorbyl-(-)-epigallocatechin, rutin and orientin could be the putative molecules for amelioration of post-prandial hyperglycaemia whereas 8-c-ascorbyl-(-)-epigallocatechin,8-c-ascorbyl epigallocatechin 3-o-gallate and schaftoside could be used to reduce fat absorption in obese persons. It can be concluded that these phytochemicals or their derivatives can be used for further in-vitro and in-vivo studies to design valuable drugs.