[Identification of antiviral activity of Toddalia asiatica against influenza type A virus].
OBJECTIVE
To identify antiviral activity of Toddalia asiatica against influenza virus type A in vitro.


METHODS
More than two hundred Chinese medicinal herb extracts were screened for antiviral activities against influenza A/PR/8/34 (H1N1) virus using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for virus induced cytopathic effect (CPE) in a primary screening. Positive samples were picked up and were subjected to quantitative real-time polymerase chain reaction (PCR) to quantify reduction of H1N1 virus genomic RNA.


RESULTS
Toddalia asiatica showed potent antiviral activities against H1N1 virus, with 50% effective concentration (EC50) value of 4.7 mg x L(-1) in MTS assay and 0.9 mg x L(-1) in quantitative PCR assay respectively. The cytotoxicity test of Toddalia asiatica generated a CC50 value of 187.2 mg x L(-1) and a selective index (SI) larger than 206 in quantitative PCR. Although the best antiviral activity of Toddalia asiatica was observed with co-treatment of influenza virus infection, it remained effective even when administrated 24 h before and after the initiation of infection.


CONCLUSIONS
The results suggested that Toddalia asiatica compound extract could be a candidate for anti-H1N1 virus agent in the treatment of influenza.
Lu
Shi-you
SY
Beijing Genomics Institute, Chinese Academy of Sciences, Beijing 101300, China.
Qiao
Yan-jiang
YJ
Xiao
Pei-gen
PG
Tan
Xue-hai
XH
D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002478:Cells, Cultured; D004285:Dogs; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics; D007668:Kidney / Q000166:cytology; D010946:Plants, Medicinal / Q000737:chemistry*; D012367:RNA, Viral / Q000187:drug effects; D027821:Rutaceae / Q000737:chemistry*; D013997:Time Factors
D000998:Antiviral Agents; D004365:Drugs, Chinese Herbal; D012367:RNA, Viral