Inhibitory Effects of Oolong Tea Polyphenols on Pancreatic Lipase in Vitro

Abstract

Fifty-four polyphenols isolated from tea leaves were evaluated for their inhibitory activities against pancreatic lipase, the key enzyme of lipid absorption in the gut. (-)-Epigallocatechin 3-O-gallate (EGCG), which is one of major polyphenols in green tea, showed lipase inhibition with an IC50 of 0.349 microM. Moreover, flavan-3-ol digallate esters, such as (-)-epigallocatechin-3,5-digallate, showed higher activities of inhibition on lipase with an IC50 of 0.098 microM. On the other hand, nonesterified flavan-3-ols, such as (+)-catechin, (-)-epicatechin, (+)-gallocatechin, and (-)-epigallocatechin, showed zero and/or the lowest activities against pancreatic lipase (IC50 > 20 microM). These data suggested that the presence of galloyl moieties within the structure was required for enhancement of pancreatic lipase inhibition. It is well-known that flavan-3-ols are polymerized by polyphenol oxidase and/or heating in a manufacturing process of oolong tea. Oolonghomobisflavans A and B and oolongtheanin 3'-O-gallate, which are typical in oolong tea leaves, showed strong inhibitory activities with IC50 values of 0.048, 0.108, and 0.068 microM, respectively, even higher than that of EGCG. The oolong tea polymerized polyphenols (OTPP) were prepared for the assay from oolong tea extract, from which the preparation effectively subtracted the zero and/or less-active monomeric flavan-3-ols by preparative high-performance liquid chromatography. The weight-average molecular weight (Mw) and number-average molecular-weight (Mn) values of OTPP were 2017 and 903, respectively, by using gel permeation choromatography. OTPP showed a 5-fold stronger inhibition against pancreatic lipase (IC50 = 0.28 microg/mL) by comparison with that of the tannase-treated OTPP (IC50 = 1.38 microg/mL). These data suggested that the presence of galloyl moieties within their chemical structures and/or the polymerization of flavan-3-ols were required for enhancement of pancreatic lipase inhibition.

Licorice Flavonoid Oil Effects Body Weight Loss by Reduction of Body Fat Mass in Overweight Subjects

“…Suppression of lipid absorption, 27) reduction in calorie intake, 28) reduction in biosynthesis of fatty acid, and enhancement of fatty acid oxidation 29) are possible mechanisms of the reduction in body fat. There was no appreciable change in calorie intake for any subject in the present study.…”

Anti-obesity and cardioprotective effects of cinnamic acid in high fat diet- induced obese rats

“…The method was modified from the assay reported by Nakai et al (2005). The pancreatic lipase activity was measured using 4-methylumbelliferyl oleate (4-MU oleate) as a substrate.…”

Characterization of Proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

“…The activities increase proportionally with the raise of the DP [23]. Proanthocyanidins is very important in human health protection and disease prevention; they have been reported to be strong antioxidants [24,25], anticancer [26], anti-ulcerogenic [27], antiprotozoal [28], cicatrizing [29], anti-inflammatory [30] agents and other beneficial properties that can suggest the application of species with tannins in pharmacologic studies, like anti-HIV and anti-HSV effects [31] and pancreatic lipase inhibition properties [32].…”