title: Carboxymethyl- and carboxyl-catechins from ripe Pu-er tea.
abstract: Ripe Pu-er tea, a special microbial postfermented tea originated from Yunnan Province, China, since ancient times, is made from green Pu-er tea prepared from the leaves of Camellia sinensis var. assamica (Theaceae). Chemical investigation on thearubigin (n-BuOH-soluble) fraction of the commercial ripe Pu-er tea, led to the identification of four new flavan-3-ol derivatives, 8-carboxymethyl-(+)-catechin (1), 8-carboxymethyl-(+)-catechin methyl ester (2), 6-carboxymethyl-(+)-catechin (3), and 6-carboxyl-(-)-gallocatechin (4), together with 18 known compounds, including other three flavan-3-ol derivatives (5-7), 10 flavonoid glycosides (8-17), two hydrolyzable tannins (18 and 19), two quinic acid derivatives (20-21), and a purine alkaloid (22). Flavonoid glycosides 8-11 are reported from tea plants for the first time. The thearubigin fraction of ripe Pu-er tea was qualitatively analyzed by HPLC, and gallic acid was found to be the major component. Compounds 4, 6-17, 21 and 22 were tested for their acute activities on insulin sensitivity in differentiated 3T3-L1 adipocytes, but none of them showed significant bioactivity at a concentration of 10 μM.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201, P. R. China.
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Tian
authors.forename: Mu-Ke
authors.initials: MK
authors.lastname: Tao
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.forename: Jing
authors.initials: J
authors.lastname: Hu
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Zhu
authors.forename: Wen-Yong
authors.initials: WY
authors.lastname: Xiong
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Chong-Ren
authors.initials: CR
authors.lastname: Yang
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: Zhang
mesh_terms: D028244:Camellia / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D002681:China; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D010936:Plant Extracts; D002392:Catechin
keywords: carboxylcatechins; carboxymethyl-catechins; insulin sensitivity activity; ripe Pu-er tea