Fuzhuanins A and B: The B-ring Fission Lactones of Flavan-3-ols from Fuzhuan Brick-Tea

Abstract

Fuzhuan brick-tea is a special dark tea prepared from the leaves of Camellia sinensis var. sinensis. Its production involves a fungal fermentation stage, which forms the unique flavors and functions by a series of biochemical reactions. Our phytochemical research of the material led to the isolation of two new B-ring fission lactones of flavan-3-ols, fuzhuanins A (1) and B (2). In addition, three other flavan-3-ol derivatives (3-5), three flavone C-glycosides (6-8), eight flavonoid O-glycosides (10-17), five simple phenolics (19-23), two norisoprenoid glycosides (24, 25), two sesquiterpenoids (26, 27), and theobromine (28), as well as two flavonoid anions (9 and 18), were also identified. The structures of these compounds were determined by spectroscopic methods. Compounds 4, 19, 20, 22-24, 26, and 27 were reported for the first time in Camellia spp. and tea. Furthermore, HPLC analysis method was performed to compare the chemical constituents of the before/after fungal fermentation Fuzhuan brick-teas. Compound 1 was indicated as one of the major characteristic constituents generated in the fungal fermentation process. The IC50 value of the antiproliferative activity of 2 on HeLa cells was assayed as 4.48 μM. None of the isolated compounds showed any inhibition activity against the enteric pathogenic microbes at 800 μg/mL by the hole plate diffusion method.

Investigation on biochemical compositional changes during the microbial fermentation process of Fu brick tea by LC–MS based metabolomics

“…Then variable importance plots were generated to perform the most important variations or metabolites to the sore plot model of PLS-DA (Luo, Du, et al, 2013;Luo, Lu, et al, 2013).…”

“…In addition, it was reported that the activities increased with the course of MFP, which indicated that this process produced new varieties of functional metabolites (Mo et al, 2008). Furthermore, new metabolites such as three triterpenoids (Ling et al, 2010), one norisoprenoid (Luo et al, 2012), seven new B ring fission catechins (flavan-3-ols) derivatives (Jiang et al, 2011;Luo, Du, et al, 2013;Zhu et al, 2015) were reported from a few phytochemical investigations on FBT. Especially these B ring fission catechins have not been identified in other tea products, which suggested that the biochemical profiles of FBT were influenced significantly by MFP.…”

“…as the dominant fungi. At the end of the fermentation, the tea brick is predominant by yellow fungi, called ''golden flora'', which indicates massive production of complex metabolites by fungi (Luo, Du, et al, 2013;Mo, Zhu, & Chen, 2008;Xu et al, 2011;Zhu et al, 2015;Yue et al, 2014). The complex biochemical profiles are considered as the critical element to form the special flavors and a spectrum of health benefits of FBT, such as antihyperlipidemia, antiobesity, antihyperglycemia, and antidysentery activities (Fu et al, 2011;Luo et al, 2012).…”

“…The PCA, as a kind of unsupervised analysis exhibiting the original variation of samples, can undoubtedly show reliable multivariable consequences in metabolomics, but clear separation of each group cannot be well achieved especially when the variation of samples within groups is more significant than those of different groups in the PCA. As a result, supervised methods are supposed to exhibit the systematic metabolic differences between groups ignoring some variation within groups, and screen out key metabolites responsible for these systematic differences (Luo, Du, et al, 2013;Luo, Lu, et al, 2013). Therefore, a kind of supervised method named partial least squares discriminate analysis (PLS-DA) was applied to analyze the complex manufacture process of FBT.…”

“…The production involved in B ring fission catechins such as teadenol A, teadenol B, teasperin, teasperol, xanthocerin, fuzhuanins A-F and alkaloids such as puerins I-VIII. These compounds were identified as potential proliferative inhibitors on human cell (Luo, Du, et al, 2013;Luo, Lu, et al, 2013) and potential protective effects on the HMEC from injury induced by H 2 O 2 . These suggested that other active substances derived from catechins had been produced by microorganisms grown during the MFP of FBT, which needed to be further investigated and identified.…”