Department of Food Science and Biotechnology , Sejong University , 98 Gunja-dong , Gwangjin-gu, Seoul 143-747 , Republic of Korea.
Vital Beautie Research Institute , AmorePacific R&D Center , Yongin 17074 , Republic of Korea.
J Agric Food Chem. 2019 Feb 27;67(8):2331-2339. doi: 10.1021/acs.jafc.8b05733. Epub 2019 Feb 15.
Two bioconversions were applied to green tea extracts (GTE) and flavonol glycoside rich fraction (FVNg) derived from insoluble green tea extract by tannase and cellulase treatment in order to obtain gallated catechins (EnzGTE) and flavonol aglycone rich fraction (FVNa), respectively. The bioaccessibility of epicatechins from GTE increased with the addition of FVNg, FVNa, and flavonol aglycone rich fraction of commercial production (FVNap). Epigallocatechin-gallate (EGCG) and epicatechin-gallate (ECG) were highly recovered 4- and 125-fold, respectively, by adding FVNap. They were mostly affected by the radical scavenging activity provided from FVNap, showing remarkable 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (10769.3 μg/g) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (8341.5 μg/g) values. The intestinal cellular uptake of epicatechins in GTE increased with the FVNap addition as follows: EGCG (332.46 ± 136.18%) > ECG (273.92 ± 97.92%) > epicatechin (EC) (150.22 ± 12.59%) > epigallocatechin (EGC) (131.21 ± 8.51%). EnzGTE and EnzGTE + FVNa were revealed to have a significant downregulation on the expression of P-glycoprotein (P-gp), up to 0.06- and 0.6-fold, respectively. The gene expression of multidrug resistance associated proteins 2 (MRP2) was reduced in EnzGTE + FVNap. The results suggest that coconsumption GTE or EnzGTE with GTE-derived flavonols could improve the bioavailability of epicatechins.
采用单宁酶和纤维素酶处理不溶性绿茶提取物，分别得到富含没食子酰基儿茶素的绿茶提取物（EnzGTE）和富含黄酮醇糖苷配基的绿茶提取物（FVNg）。通过添加 FVNg、FVNa 和商业生产的富含黄酮醇糖苷配基的提取物（FVNap），可提高 GTE 中表儿茶素的生物利用度。添加 FVNap 后，表没食子儿茶素没食子酸酯（EGCG）和表儿茶素没食子酸酯（ECG）的回收率分别高达 4 倍和 125 倍。它们主要受 FVNap 提供的清除自由基活性的影响，表现出显著的 2,2'- 联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）（10769.3 μg/g）和 2,2-二苯基-1-苦基肼（DPPH）（8341.5 μg/g）值。GTE 中表儿茶素的肠道细胞摄取随着 FVNap 添加量的增加而增加：EGCG（332.46 ± 136.18%）> ECG（273.92 ± 97.92%）>表儿茶素（EC）（150.22 ± 12.59%）>表没食子儿茶素（EGC）（131.21 ± 8.51%）。EnzGTE 和 EnzGTE+FVNa 被证明对 P 糖蛋白（P-gp）的表达有显著下调作用，分别为 0.06-和 0.6 倍。EnzGTE+FVNap 中多药耐药相关蛋白 2（MRP2）的基因表达减少。结果表明，与 GTE 或 GTE 衍生的类黄酮同时消费 GTE 或 EnzGTE 可提高表儿茶素的生物利用度。
