In Vitro And In Vivo Anti-hepatitis B Virus Activities Of Lignans Isolated From Phyllanthus Niruri L. And Design,Synthesis,Biological Evaluation,Molecular Docking Studies Of Their Analogues

Hepatitis B virus(HBV)infection is a serious worldwide health problem while drugs(such as lamivudine and adefovir)for treating HBV are still unsatisfactory,due to high recurrence,drug resistance and inevitable side effects.Therefore,there exists a significant medical need to explore novel classes of drugs with different antiviral targets and mechanisms for anti-HBV purposes.The Chinese medicine have afforded a rich source of anti-HBV agents with mult-targeted and low toxicity.Hence,our study focused on the active constituents of Phyllanthus niruri L.,a traditional Chinese medicinal herb used in folk medicine for liver protection and antihepatitis B.Four lignans,namely niranthin,nirtetralin B,hypophyllanthin and phyllanthin were isolated from the petroleum ether extract of whole plants of Phyllanthus niruri L.HepG22.2.15 cells and duck hepatitis B virus(DHBV)infected ducks were used as in vitro and in vivo models to evaluate their anti-HBV activity.In the human HBV-transfected liver cell line HepG2 2.2.15,niranthin effectively suppressed the secretion of the HBV antigens in a dose-dependent manner with IC50 values for HBsAg of 15.6 μM,IC50 values for HBeAg of 25.1 μM,IC50 values for HBV DNA of 17.9 μM.Nirtetralin B effectively suppressed the secretion of the HBV antigens in a dose-dependent manner with IC50 values for HBsAg of 7.5 μM,IC50 values for HBeAg of 27.5 μM,IC50 values for HBV DNA of 27.2 μM.In the duck hepatitis B virus(DHBV)infected ducks,after niranthin and nirtetralin B were dosed intragastricly once a day for 14 days,the plasma DHBV DNA level was reduced,with the highest inhibition at 90.87%and 95.61%,respectively.In addition,the results also revealed that the effects of anti-HBsAg activity,anti-HBeAg activity,the positive expression of HBsAb,HBeAb,HBcAb,and the inhibition of ALT,AST,TBil on ducks were in a dose-dependent manner.Furthermore,analysis of the liver pathological changes confirmed the hepatoprotective effect of niranthin and nirtetralin B.In order to understand the anti-HBV mechanisms of niranthin and nirtetralin B at molecule level,the potential anti-HBV targets of niranthin and nirtetralin B were investigated with reverse docking approach.To increase the activity of niranthin and nirtetralin B,a series of analogues were designed and synthesized based on the reverse docking results and combination principle.HBcAg 30X8 and ASL-HBVES in pgRNA epsilon 2K5Z were used as molecular targets for anti-HBV activity of the analogues in a moe-docking technique.The structures of all the newly synthesized compounds were characterized by ’H NMR,13CNMR and MS data.The anti-HBV activity of all the synthesized compounds was evaluated in HepG2 2.2.15 cells.The results indicated that most of the synthesized compounds showed effective anti-HBV activity.In these compounds,compounds 4c-3 and 4d-7 showed the most potent anti-HBV activity,demonstrating potent inhibitory effect not only on the secretion of HBsAg(IC50 14.18 μM and 58.28 μM,respectively)and HBeAg(IC50=6.20 μM and 97.21 μM,respectively),but also on HBV DNA replication(IC50=23.43 μM and 42.28 μM,respectively).The structure-activity relationships(SARs)of phenylpropanoid derivatives had been discussed,which were useful for ligans analogues to be explored and developed as novel anti-HBV agents.This study identified a new class of potent anti-HBV agents...