3143-37-1Relevant academic research and scientific papers
Potent and Nontoxic Chemosensitizer of P-Glycoprotein-Mediated Multidrug Resistance in Cancer: Synthesis and Evaluation of Methylated Epigallocatechin, Gallocatechin, and Dihydromyricetin Derivatives
Wong, Iris L.K.,Wang, Bao-Chao,Yuan, Jian,Duan, Liang-Xing,Liu, Zhen,Liu, Tao,Li, Xue-Min,Hu, Xuesen,Zhang, Xiao-Yu,Jiang, Tao,Wan, Sheng-Biao,Chow, Larry M.C.
, p. 4529 - 4549 (2015/06/25)
We are interested in developing novel natural product-derived P-gp inhibitors to reverse cancer drug resistance. Here, we have synthesized 55 novel derivatives of methylated epigallocatechin (EGC), gallocatechin (GC), and dihydromyricetin (DHM). Three EGC derivatives (23, 35, and 36) and three GC derivatives (50, 51, and 53) are significantly better than epigallocatechin gallate (EGCG) with a relative fold (RF) ranging from 31.4 to 53.6. The effective concentration (EC50) of 23 and 51 ranges from 102 to 195 nM. Compounds 23 and 51 are noncytotoxic to fibroblasts with IC50 > 100 μM. Compound 23 is specific for P-gp without modulating activity toward MRP1 or BCRP. Compounds 23 and 51 are non-P-gp substrates. Important pharmacophores for P-gp modulation were identified. In summary, methylated EGC and GC derivatives represent a new class of potent, specific, noncytotoxic, and nonsubstrate P-gp modulators.
Tannins and Related Compounds. XV. A New Class of Dimeric Flavan-3-ol Gallates, Theasinensins A and B, and Proanthocyanidin Gallates from Green Tea Leaf. (1)
Nonaka, Gen-Ichiro,Kawahara, Osamu,Nishioka, Itsuo
, p. 3906 - 3914 (2007/10/02)
Along with four dimeric proanthocyanidin gallates, viz. prodelphinidin B-2 3'-O-gallate (IV) and procyanidins B-2 3,3'-di-O-gallate (V), B-2 3'-O-gallate (VI) and B-4 3'-O-gallate (VII), two novel dimeric flavan-3-ol gallates (VIII and IX) named theasinensins A and B, in which two flavan units are linked at the B-ring, have been isolated from fresh green tea leaves, and their structures have been established on the basis of spectroscopic evidence in conjunction with enzymatic hydrolyses with tannase.Three new monomeric acylated flavan-3-ols have also been isolated, and their structures were similarly characterized as (-)-epigallocatechin 3-O-p-coumaroate (I), (-)-epigallocatechin 3,3'-di-O-gallate (II) and (-)-epigallocatechin 3,4'-di-O-gallate (III).In addition, the occurrence of the know (-)-epicatechin 3-O-gallate (X), (-)-epigallocatechin 3-O-gallate (XI), (+)-catechin (XII), (-)-epicatechin (XIII), (-)-epigallocatechin (XIV) and (-)-epicatechin 3-O-(3-O-methyl)-gallate (XV) in green tea leaves was confirmed.Keywords - green tea leaf; Thea sinensis; Theaceae; tannin; theasinensin; proanthocyanidin gallate; flavan-3-ol p-coumaroate; flavan-3-ol gallate
