Samarangenin B from Limonium sinense suppresses herpes simplex virus type 1 replication in Vero cells by regulation of viral macromolecular synthesis.
Inhibitory effects of ethanolic extracts from 10 Chinese herbs on herpes simplex virus type 1 (HSV-1) replication were investigated. By a bioassay-guided fractionation procedure, samarangenin B (Sam B) was isolated from Limonium sinense; Sam B significantly suppressed HSV-1 multiplication in Vero cells without apparent cytotoxicity. Time-of-addition experiments suggested that the inhibitory action of Sam B on HSV-1 replication was not due to the blocking of virus adsorption. In an attempt to further localize the point in the HSV-1 replication cycle where arrest occurred, a set of key regulatory events leading to viral multiplication was examined, including viral immediate-early (alpha), early (beta), and late (gamma) gene expression and DNA replication. Results indicated that levels of glycoprotein B (gB), gC, gD, gG, and infected-cell protein 5 (ICP5) expression and gB mRNA expression in Vero cells were impeded by Sam B. Data from PCR showed that replication of HSV-1 DNA in Vero cells was arrested by Sam B. Furthermore, Sam B decreased DNA polymerase, ICP0, and ICP4 gene expression in Vero cells. Results of an electrophoretic mobility shift assay demonstrated that Sam B interrupted the formation of an alpha-trans-induction factor/C1/Oct-1/GARAT multiprotein complex. The mechanisms of antiviral action of Sam B seem to be mediated, at least in part, by inhibiting HSV-1 alpha gene expression, including expression of the ICP0 and ICP4 genes, by blocking beta transcripts such as DNA polymerase mRNA, and by arresting HSV-1 DNA synthesis and structural protein expression in Vero cells. These results show that Sam B is an antiviral agent against HSV-1 replication.
Kuo
Yuh-Chi
YC
National Research Institute of Chinese Medicine,Taipei, Taiwan, Republic of China. kuo9111@cma23.nricm.edu.tw
Lin
Lie-Chwen
LC
Tsai
Wei-Jern
WJ
Chou
Cheng-Jen
CJ
Kung
Szu-Hao
SH
Ho
Yen-Hui
YH
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001578:Benzopyrans / Q000302:isolation & purification / Q000494:pharmacology*; D015152:Blotting, Northern; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D004261:DNA Replication / Q000187:drug effects; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004279:DNA, Viral / Q000096:biosynthesis*; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis / Q000235:genetics; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000378:metabolism*; D029606:Plumbaginaceae / Q000737:chemistry*; D012367:RNA, Viral / Q000096:biosynthesis / Q000235:genetics; D014709:Vero Cells; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects*
D000998:Antiviral Agents; D001578:Benzopyrans; D018076:DNA, Complementary; D004279:DNA, Viral; D004365:Drugs, Chinese Herbal; D012367:RNA, Viral; C471026:samarangenin B; D004259:DNA-Directed DNA Polymerase