New Flavan-3-ol Dimer from Green Tea Produced from Camellia taliensis in the Ai-Lao Mountains of Southwest China

Abstract

Camellia taliensis (W. W. Smith) Melchior, belonging to the genus Camellia sect. Thea (Theaceae), is an endemic species distributed from the west and southwest of Yunnan province, China, to the north of Myanmar. Known as a wild tea tree, its leaves have been used commonly for producing tea beverages by the local people of its growing area. One new flavan-3-ol dimer, talienbisflavan A (1), was isolated from green tea prepared from the leaves of C. taliensis collected from the east side of the Ai-Lao mountains, Yuanjiang county of Yunnan province, China. In addition, five hydrolyzable tannins (2-6), five flavonols and flavonol glycosides (9-13), three flavan-3-ols (14-16), nine simple phenolic compounds and glycosides (7, 8, and 17-23), and caffeine (24) were identified. Their structures were determined by detailed spectroscopic analysis. All of the isolated phenolic compounds were tested for their antioxidant activities by DPPH and ABTS(+) radical scavenging assays. The contents of its main chemical compositions were also compared with those collected from the Lincang area of Yunnan province by high-performance liquid chromatography analysis.

Isolation of antioxidant phenolics from Schinopsis brasiliensis based on a preliminary LC-MS profiling

“…The (6) (Saijo et al, 1989), 3,4-di-O-galloyl-quinic acid (7) (Zhu et al, 2012), catechin (9) (Benavides et al, 2006), 4,9-dihydroxypropiophenone-9-O-b-D-glucopyranoside (13) (Meng et al, 2010), 4-hydroxy-2-methoxyphenol-1-O-b-D-glucopyranoside (15) (Shi et al, 2010) and schizandriside (16) (Kim et al, 2012).…”

Chemo-Enzymatic Synthesis of Silybin and 2,3-Dehydrosilybin Dimers

“…Analogous dimers were prepared from ascorbic acid (and dehydroascorbic acid) but only the physico-chemical properties of the dimers were described [22]. Recently, a natural flavan-3-ol dimer was isolated from green tea from Camellia taliensis having DPPH- and ABTS + -scavenging activities superior to all other compounds from the tea, but unfortunately without testing the parent monomer [30]. Natural epicatechin dimer (procyanidin B2) exhibited, when the results were expressed based on a unit molar concentration of epicatechin, comparable DPPH and superoxide radical scavenging activities [31].…”

Synthesis of Triazole Schiff’s Base Derivatives and Their Inhibitory Kinetics on Tyrosinase Activity

“…ABTS free-radical scavenging assay was used to test the antioxidant capacity of compounds Y 1 to Y 4 . The method can be found in many articles [ 38 , 39 ]. 7 mM ABTS and 2.45 mM ammonium persulfate were blended and stored in a dark place 16 hours, and then diluted by 80% ethanol to obtain the working solution which gave an absorbance of 0.69 at 734 nm.…”