Functional Characterization of Epitheaflagallin 3-O-Gallate Generated in Laccase-Treated Green Tea Extracts in the Presence of Gallic Acid.

Epitheaflagallin (ETFG) and epitheaflagallin 3-O-gallate (ETFGg) are minor polyphenols in black tea extract that are enzymatically synthesized from epigallocatechin (EGC) and epigallocatechin gallate (EGCg), respectively, in green tea extract via laccase oxidation in the presence of gallic acid. The constituents of laccase-treated green tea extract in the presence of gallic acid are thus quite different from those of nonlaccase-treated green tea extract: EGC and EGCg are present in lower concentrations, and ETFG and ETFGg are present in higher concentrations. Additionally, laccase-treated green tea extract contains further polymerized catechin derivatives, comparable with naturally fermented teas such as oolong tea and black tea. We found that ETFGg and laccase-treated green tea extracts exhibit versatile physiological functions in vivo and in vitro, including antioxidative activity, pancreatic lipase inhibition, Streptococcus sorbinus glycosyltransferase inhibition, and an inhibiting effect on the activity of matrix metalloprotease-1 and -3 and their synthesis by human gingival fibroblasts. We confirmed that these inhibitory effects of ETFGg in vitro match well with the results obtained by docking simulations of the compounds with their target enzymes or noncatalytic protein. Thus, ETFGg and laccase-treated green tea extracts containing ETFGg are promising functional food materials with potential antiobesity and antiperiodontal disease activities.

Isoliquiritigenin is a potent inhibitor of NLRP3 inflammasome activation and diet-induced adipose tissue inflammation.

Inflammasome activation initiates the development of many inflammatory diseases, including obesity and type 2 diabetes. Therefore, agents that target discrete activation steps could represent very important drugs. We reported previously that ILG, a chalcone from Glycyrrhiza uralensis, inhibits LPS-induced NF-κB activation. Here, we show that ILG potently inhibits the activation of NLRP3 inflammasome, and the effect is independent of its inhibitory potency on TLR4. The inhibitory effect of ILG was stronger than that of parthenolide, a known inhibitor of the NLRP3 inflammasome. GL, a triterpenoid from G. uralensis, had similar inhibitory effects on NLRP3 activity, but high concentrations of GL were required. In contrast, activation of the AIM2 inflammasome was inhibited by GL but not by ILG. Moreover, GL inhibited NLRP3- and AIM2-activated ASC oligomerization, whereas ILG inhibited NLRP3-activated ASC oligomerization. Low concentrations of ILG were highly effective in IAPP-induced IL-1ß production compared with the sulfonylurea drug glyburide. In vivo analyses revealed that ILG potently attenuated HFD-induced obesity, hypercholesterolemia, and insulin resistance. Furthermore, ILG treatment improved HFD-induced macrovesicular steatosis in the liver. Finally, ILG markedly inhibited diet-induced adipose tissue inflammation and IL-1ß and caspase-1 production in white adipose tissue in ex vivo culture. These results suggest that ILG is a potential drug target for treatment of NLRP3 inflammasome-associated inflammatory diseases.

Inhibitory activity on lipid peroxidation of extracts from marine brown alga.

Several extracts from marine brown alga Sargassum micracanthum (Kuetzing) Endlicher were screened for their inhibitory activity on lipid peroxidation. In an in vitro study, methanol extract (Sm-M), chloroform/ methanol (3:1) extract and ethyl acetate fraction of Sm-M inhibited lipid peroxidation in rat liver homogenates. The IC(50) values were 0.70, 0.70 and 0.37 micro g/mL, respectively. These inhibitions were stronger than vitamin C and E. These extracts showed reductive activity on DPPH, the IC(50) values were 34, 37 and 11 micro g/mL, respectively. In an in vivo study, Sm-M had the effect on CCl4 induced liver injury in rats and Sm-M (120-1200 mg/kg, p.o.) lowered dose-dependently the level of lipid peroxidation in liver.

Anti-invasive and metastatic activities of evodiamine.

We have recently reported that evodiamine can suppress in vitro invasion and lung metastasis by colon 26-L5 carcinoma cells. To extend our study, we examine here the anti-invasive and metastatic effects of evodiamine on Lewis lung carcinoma (LLC) and B16-F10 melanoma in addition to colon 26-L5 carcinoma. Critical structures of evodiamine for the activities were also evaluated by comparison with compounds possessing structures similar to that of evodiamine. Evodiamine concentration-dependently inhibited the invasion of B16-F10, LLC and colon 26-L5 cells with IC(50) values of 2.4 micro M, 4.8 micro M and 3.7 micro M, respectively. Pre-treatment of colon 26-L5 cells with evodiamine before inoculation into mice caused significant suppression of the liver metastasis as well as the lung metastasis. Lung metastasis by LLC is also inhibited significantly by pre-exposure to evodiamine. When the anti-migratory activity of evodiamine was compared with that of evodiamine-like compounds, rutaecarpine lacking a methyl group at N-14 and a hydrogen at C-13 b exhibited much less effect than evodiamine. In addition, reserpine, having beta-configurated hydrogen at C-13 b, inhibited tumor cell migration more potently than yohimbine, having alpha-configurated hydrogen at the same position. These results suggest that evodiamine may be useful as a leading compound for agents in tumor metastasis therapy. Also, the presence of a methyl group at N-14 and the configuration of hydrogen at C-13 b may be responsible for the inhibitory activities of evodiamine.