Impact of flavonol extracts derived from green tea or targeted flavonols as secondary ingredients on intestinal glucose transport

Yeong-Eun Lee; So-Hee Yoo; Jin-Oh Chung; Chan-Su Rha; Mi-Young Park; Hyun-Jeong Lee; Jeong-Ho Oh; Yong-Deog Hong; Soon-Mi Shim

doi:10.1007/s13197-021-05140-2

Impact of flavonol extracts derived from green tea or targeted flavonols as secondary ingredients on intestinal glucose transport

J Food Sci Technol. 2022 Apr;59(4):1317-1325. doi: 10.1007/s13197-021-05140-2. Epub 2021 May 26.

Authors

Yeong-Eun Lee¹, So-Hee Yoo¹, Jin-Oh Chung², Chan-Su Rha², Mi-Young Park², Hyun-Jeong Lee¹, Jeong-Ho Oh¹, Yong-Deog Hong², Soon-Mi Shim¹

Affiliations

¹ Department of Food Science and Technology, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 05006 Republic of Korea.
² AMOREPACIFIC R&D Center, 1920, Yonggu-daero, Giheung-gu, Yongin-si, Gyeonggi-do Republic of Korea.

Abstract

The purpose of the current study was to examine the effect of adding secondary ingredients such as green tea derived water-soluble polysaccharides (GTP) and flavonol aglycone rich fractions derived from cellulase treated green tea extract (FVN) into catechin rich green tea extracts (GTE) on wheat starch digestion and intestinal glucose transport using in vitro digestion with Caco-2 cells. Co-digestion of wheat starch with GTE (16.88 g L^-1) or GTE + GTP + FVN (16.69 g L^-1) appeared to promote starch hydrolysis compared to control (15.49 g L^-1). In case of major flavonoids, addition of epigallocatechin gallate (EGCG), EGCG + myricetin (M) into wheat starch significantly increased the digestion of starch into glucose. Glucose transport rate decreased by 22.35% in wheat starch + GTE + GTP + FVN (1.39%), while the least amount of glucose (1.70%) was transported in EGCG mixed with M (1% of EGCG) as secondary ingredients among individual flavonoids formulation. It indicated that inhibitory effect on glucose transport was higher in addition of GTE, GTP, and FVN as excipients ingredients rather than targeted major flavonoids. Results from the current study suggest that whole green tea including flavonoid rich fractions could enhance hypoglycemic potential of GTE.

Supplementary information: The online version contains supplementary material available at 10.1007/s13197-021-05140-2.

Keywords: Flavonol aglycone; Glucose; Green tea extracts; Hydrolysis; Intestinal transport; Kaempferol; Myricetin; Polysaccharides; Quercetin; Wheat starch.