Chemical Constituents Of Fuzhuan Brick Tea And Their Biological Activities

Fuzhuan brick tea is a unique post-fermented tea for the fermentation with Eurotium cristatum as one of the dominant fungi. The numerous health benefits of Fuzhuan brick tea, such as hypolipidemic, antioxidant, antibacterial activities and so on, had been studied extensively. But the chemical constituents were rarely reported. Our experiment was carried out in order to investigate the chemical compositions of Fuzhuan brick tea and their bio-activities.In this study, Fuzhuan brick tea was extracted and fractionated by organic solvents. Silica gel, polyamide, Sephadex LH-20, ODS and MCI column chromatographic methods were applied for isolation of chemical compositions. The structures of compounds were identified by spectral means such as1H-NMR,13C-NMR, HSQC and other nuclear magnetic resonance spectroscopy, as well as mass spectrometry, infrared (IR), ultraviolet (UV) spectra and so on. Finally the isolated compounds were tested by hole plate diffusion method to evaluated the antibacterial activity and compounds1-4were tested for cytotoxic activities by MTT method.Our phytochemical study on Fuzhuan brick tea have led to the isolation of three new compounds, twenty-four known compounds and two flavonoid anions. The three new compounds were named as fuzhuanin A (1), fuzhuanin B (2) and3R,9R-epoxy-megastigm-5-ene (29), respectively. The twenty four known compounds were three other flavan-3-ol derivatives: planchol A (3), xanthocerin (4) and (–)-epicatechin8-C-β-D-glucopyranoside (5) three flavone C-glycosides: chafuroside A (6), chafuroside B (7), vitexin-2″-α-L-rhamnopyranoside (8) eight flavonoid-O-glycosides: biorobin (10), quercetin-3-O-robinobioside (11), kaempferol-3-O-[β-D-glucopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→6)-O-β-D-galactopyranoside](12), nicotiflorin (13), rutin (14), myricetin-3-O-rutinoside (15), kaempferol-3-O-[β-D-glucopyranosyl-(1→3)--O-α-L-rhamnopyranosyl-(1→6)-O-β-D-glucopyranoside](16), quercetin-3-O-[β-D--glucopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→6)-O-β-D-glucopyranoside](17) five simple phenolic compounds:5,7-dihydroxycoumarin (19),(7R,8S)-dihydro--dehydrodiconiferyl alcohol9-O-β-D-glucopyranoside (20), p-coumaric acid (21),2,3-dihydroxy-1-(4-hydroxy-3-methoxy-phenyl)-propan-1-one (22), and benzyl2-neohesperidosyloxy-6-hydroxybenzoate (23) two norisoprenoid glycosides, roseoside (24) and icariside B5(25) two sesquiterpenoids, dihydrophaseic acid (26) and its isomer, 5-(3,8-dihydroxy-1,5-dimethyl-6-oxabicyclo[3.2.1]oct-8-yl)-3-methyl-2(E),4(E)-pentadien oic acid (27) as well as theobromine (28). The two flavonoid anions were identified as vitexin-2″-α-L-rhamnopyranoside-7-oxygen anion (9) and quercetin-3-O-[β-D--glucopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→6)-O-β-D-glucopyranoside]-7-oxyge n anion (18). Furthermore, compounds4,19,20,22–24,26and27were reported from tea for the first time.The preliminary biological activities of the isolated compounds were studied. All the isolated compounds were tested by hole plate diffusion method to evaluated the antibacterial activity. Five enteric pathogenic microbes, i.e., Escherichia coli, enteropathogenic E. coli, Staphyloccocus aureus, Salmonella typhi and Shigella dysenteriae were used for this study. As a result, none of the isolated29compounds showed any inhibition activity against the5tested enteric pathogenic microbes at800μg/mL. The cytotoxic activities of compounds1–4were evaluated against HeLa cells. Compound2(fuzhuanin B) showed significant inhibition activity in the cytotoxic assay. The IC50value of the cytotoxity of2(fuzhuanin B) on HeLa cells was calculated as4.48μM. Compound3(planchol A) showed moderate inhibition activity against the HeLa cells, but compound1(fuzhuanin A) and compound4(xanthocerin) showed no cytotoxity in the experiment.