Chinese Xi-Gui tea is one ancient cultivated variety of Camellia sinensis var. assamica. At present, it is used for producing expensive and elite tea in China. Five new flavoalkaloids, (-)-6-(5''' S)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (ester-type catechins pyrrolidinone E, etc-pyrrolidinone E, 1), (-)-6-(5''' R)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone F, 2) (-)-8-(5''' S)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone G, 3a), (-)-8-(5''' S)- N-ethyl-2-pyrrolidinone-catechin-3- O-gallate (etc-pyrrolidinone I, 4a), (-)-8-(5''' R)- N-ethyl-2-pyrrolidinone-catechin-3- O-gallate (etc-pyrrolidinone J, 4b), and one new naturally occurring natural product (-)-8-(5''' R)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone H, 3b) together with the known flavoalkaloids etc-pyrrolidinones A-D (5, 6, 7a, and 7b) were detected and isolated from Xi-Gui green tea. Their structures were identified by comprehensive NMR spectroscopic analyses. Absolute configurations of 1-3 were established by comparison of the CD analyses with epicatechin-3- O-gallate (ECG). Compounds 1-4 were evaluated for their protection against high glucose induced cell senescence on human umbilical vein endothelia cells (HUVECs) and showed significant protection effects ( p < 0.01) at both 1.0 and 10 μM. A discussion on the possible evolution of tea plants divergent from related food plants on the basis of phytochemical view is also provided.

The sources and mechanism of action of coffee active ingredients are detailed and their joint roles in the prevention of common human diseases are summarized.

Black cohosh (Actaea racemosa L., syn. Cimicifuga racemosa L.) has become increasingly popular as a dietary supplement in the United States for the treatment of symptoms related to menopause, but the botanical authenticity of most products containing black cohosh has not been evaluated, nor is manufacturing highly regulated in the United States. In this study, 11 black cohosh products were analyzed for triterpene glycosides, phenolic constituents, and formononetin by high-performance liquid chromatography-photodiode array detection and a new selected ion monitoring liquid chromatography-mass spectrometry method. Three of the 11 products were found to contain the marker compound cimifugin and not cimiracemoside C, thereby indicating that these plants contain Asian Actaea instead of black cohosh. One product contained both black cohosh and an Asian Actaea species. For the products containing only black cohosh, there was significant product-to-product variability in the amounts of the selected triterpene glycosides and phenolic constituents, and as expected, no formononetin was detected.