title: Synthesis of C-4-Substituted Steviol Derivatives and Their Inhibitory Effects against Hepatitis B Virus.
abstract: ent-13-Hydroxykaur-16-ene-19-N-butylureide (6) was one of 33 synthesized C-4-substituted steviol derivatives that were evaluated for their effects on hepatitis B virus (HBV) surface antigen (HBsAg) secretion. The IC50(16.9 μM) and SI (57.7) values for inhibiting HBV DNA replication of compound 6 were greater than those of the reference compound, lamivudine (3-TC; IC50: 107.5 μM; SI: 22.0). Thus, the anti-HBV mechanism of 6 was investigated, and it specifically inhibited viral gene expression and reduced viral DNA levels, as well as potently attenuated all of the viral promoter activity of HBV-expressing Huh7 cells. Examination of cellular signaling pathways found that 6 inhibited the activities of the nuclear factor (NF)-κB- and activator protein (AP)-1 element-containing promoters, but had no effects on AP-2 or interferon-stimulated response element (ISRE)-containing promoters in HBV-expressing cells. Meanwhile, it significantly eliminated NF-κB and extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling-related protein levels and inhibited their phosphorylation in HBV-transfected Huh7 cells. The inhibitory potency of 6 against HBV DNA replication was reversed by cotransfecting the NF-κB p65 expression plasmid. Using the MAPK-specific activator anisomycin also reversed the inhibitory effect of 6 on viral DNA replication. The present findings suggest that the anti-HBV mechanism of 6 is partly mediated through the NF-κB and MAPK signaling pathways.
authors.forename: Shwu-Jiuan
authors.initials: SJ
authors.lastname: Lin
authors.forename: Ta-Chi
authors.initials: TC
authors.lastname: Su
authors.forename: Chin-Nan
authors.initials: CN
authors.lastname: Chu
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, China Medical University , Taichung 404, Taiwan.
authors.forename: Yi-Chih
authors.initials: YC
authors.lastname: Chang
authors.affiliation: Division of Chinese Medicinal Chemistry, National Research Institute of Chinese Medicine, Ministry of Health and Welfare , Taipei 112, Taiwan.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Yang
authors.affiliation: Department of Radiation Oncology, Show Chwan Memorial Hospital , Changhua 500, Taiwan.
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Kuo
authors.affiliation: School of Medicine, China Medical University , Taichung 404, Taiwan.
authors.forename: Tsurng-Juhn
authors.identifier: http://orcid.org/0000-0002-2189-5486
authors.initials: TJ
authors.lastname: Huang
mesh_terms: D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000187:drug effects; D045786:Diterpenes, Kaurane / Q000138:chemical synthesis* / Q000145:classification / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006515:Hepatitis B virus / Q000187:drug effects*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D015394:Molecular Structure; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects
chemical_list: D004279:DNA, Viral; D045786:Diterpenes, Kaurane; D016328:NF-kappa B; D018808:Transcription Factor AP-1; C012042:steviol; D048049:Extracellular Signal-Regulated MAP Kinases