A total of 98 compounds including 20 aldehydes, eight arenes, six acids, 17 alcohols, 13 ketones, nine esters, nine methoxyphenolics, three alkenes, seven alkanes, and six other components were tentatively identified in six Chinese dark teas (CDTs) using gas chromatography-mass spectrometry. Multivariate statistical analysis revealed that dark teas from Yunnan and Guangxi provinces could be classified into one group, and other CDTs belonged to the other cluster. The diagnostic volatile compounds being responsible for CDTs' discrimination were observed as (E,E)-2,4-decadienal, methoxyphenolics, geraniol, α-terpineol, 2,4-heptadienal, cis-jasmone, linalool oxides, and 2-nonenal. Furthermore, mature tea leaves were separately fermented using Eurotium cristatum and Aspergillus niger. The results showed that E. cristatum increased the contents of cis-jasmone, α-terpineol, ß-ionone, nonanal, and 2-pentylfuran, whereas A. niger advanced the levels of geraniol, linalool oxides, 9,12-octadecadienoic acid, and ß-ionone after short-term fermentation. Fungus species may contribute to forming the flavor of Chinese dark teas by affecting the volatile compounds during postfermentation.

Traditional Chinese medicine (TCM) are becoming more and more popular all over the world. However, quality issues of TCM may lead to medical incidents in practice and therefore quality control is essential to TCM. In this review, the state of TCM in European Pharmacopoeia are compared with that in Chinese Pharmacopoeia, and herbal drugs that are not considered as TCM and not elaborated by TCM working party at European Directorate for the Quality of Medicines & Health Care (EDQM) but present in both European Pharmacopoeia and Chinese Pharmacopoeias are also discussed. Different aspects in quality control of TCM including origins, identification, tests and assays, as well as sample preparation, marker selection and TCM processing are covered to address the importance of establishing comprehensive quality standard of TCM. Furthermore, advanced analytical techniques for quality control and standard establishment of TCM are also reviewed.

Astragaloside IV (AIV) is the most abundant saponin and a marker compound in Astragali Radix, a Chinese herb notable for its anti-aging and immune-enhancing effects. The present study investigated the role of intestinal bacterial conversion in the in vivo fate of AIV administered through a traditional oral route for the first time. When incubated anaerobically with rat intestinal bacteria, AIV generated five metabolites with three [monoglycosides brachyoside B and cyclogaleginoside B, the aglycone cycloastragenol (CA)] via stepwise deglycosylation and two from further epimerization (CA-iso) and dehydrogenation (CA-2H). Hydrolytic removal of C-6 glucose was a rate-limiting step for formations of CA and its derivatives. When AIV was orally administered to the rat, CA and CA-iso presented as the main components in plasma following AIV, and the AUC(0-∞) were 88.60 ± 9.66 (CA), 179.06 ± 28.53 (CA-iso) and 452.28 ± 43.33 nM·h (AIV). CA-2H was the predominant form in feces but was not detected in urine or plasma. This agreed well with in vitro data including rapid hepatic metabolism of CA-2H to form CA and CA-iso and reversible conversions between CA-2H and CA/CA-iso by intestinal bacteria. These findings support a crucial role of gut bacterial conversion of AIV in the traditional application of Astragali herb and warrant further investigational emphasis on CA and CA-iso.