New Triterpenoids and Other Constituents from a Special Microbial-Fermented Tea—Fuzhuan Brick Tea

Fuzhuan brick tea, a special microbial-fermented tea prepared from the leaves of Camellia sinensis var. sinensis, is a traditional beverage used in China throughout history. Phytochemical investigation of this material led to the identification of three new triterpenoids, 3β,6α,13β-trihydroxyolean-7-one (1), 3β-acetoxy-6α,13β-dihydroxyolean-7-one (2), and 3β-O-(8-hydroxyoctanoyl)-12-oleanene (3), together with 11 known compounds, friedelin (4), β-amyrone (5), β-amyrin (6), α-spinasterone (7), α-spinasterol (8), 22,23-dihydro-α-spinasterone (9), 22,23-dihydro-α-spinasterol (10), α-phytol (11), α-tocopherol (12), α-tocoquinone (13), and caffeine (14). The structures of 1−13 were determined by spectroscopic and chemical methods. Compounds 1 and 2 are the first two examples of triterpenoids possessing a 6-hydroxy-7-one function. All of the compounds, except 6, 8, 10, 11, and 14, were isolated from tea and Camellia spp. for the first time. The antibacterial activities of 1 were assessed against some enteric pathogenic microbes. Compound 1 showed no cytotoxic activity against A-549, Bel-7402, and HCT-8 cell lines.