The Glycyrrhetin And Deoxy-Glycyrrhetin Derivate By Acetylneuraminic Acid And Its Anti-HBV Acticity

Type B hepatitis(HB) is a kind of serious infection disease caused by serum hepatitis virus(HBV) infected hepatic cell, and about three hundred million people(5% of the whole world population) were infected all over the world. So, it's important to study how to cure HB, and it has became a important direction to find new anti-virus drugs of high performance.We chose glycyrrhetin and acetylneuraminic acid as lead compounds, which both have anti-virus activity, and many of their derivates were used as anti-virus drugs on sale. The probable mechanism of anti-virus activity of glycyrrhetin is related to sialylation on the surface of HBV, by which way to decrease the secretion of HBsAg. Acetylneuraminic acid, the substrate of neuraminidase, which display a inhibitory effects on neuraminidase, has a close relationship with the infection and spread of many kinds of virus. A novel compound with a much higher anti-virus activity may be got by the conjunction of the two compounds without destroying the active domain.At first, zinc is activated by HgCl₂ which is used to take off 11-O of glycyrrhetin in the acid condition to get deoxy-glycyrrhetin. Then the carboxy groups of glycyrrhetin and deoxy-glycyrrhetin were protected. And hydroxyl groups of acetylneuraminic acid were protected by acetylation, then protecting groups were take off selectively to make chlorine take the place of 2-acetyl. After that, 2-C of acetylneuraminic acid was connected to 3-OH of glycyrrhetin and deoxy-glycyrrhetin. At last, four derivates, which were not reported yet, were got by taking off protecting groups. The four novel derivates K₁, K₂, K₃ and K₄ were confirmed by MS and H-NMR, and the structure were just as follows:After that, activity study was carried out on four concentrations. Cytotoxicity of target compounds was tested by MTT method in HepG2215 cell line, and ELISA was used to test anti-HBV activity. Cytotoxicity test demonstrated that all the novel compounds display unconspicuous cytotoxicity. And the anti-HBV activity test demonstrated that all the compounds display moderate activity. The inhibition ratio is above 26% even at the least concentration of 2.5μg/mL, which is better than the positive control glycyrrhetin. During all these compounds, K₁ displayed the strongest anti-HBV activity, when the concentration is 80μg/mL, the inhibition ratio on secretion of HBsAg was 60.9±6.5% in HepG2215 cell line.The results showed that, four target compounds, display moderate anti-HBV activity with low toxicity. In conclusion, we have tested the inhibitory activity of a new type of HBV inhibitors, which will provide a new type leading compound for anti-HBV drugs study in the future.