Traditional Chinese medicine herbal extracts of Cibotium barometz, Gentiana scabra, Dioscorea batatas, Cassia tora, and Taxillus chinensis inhibit SARS-CoV replication.
Development of anti-severe acute respiratory syndrome associated coronavirus (SARS-CoV) agents is pivotal to prevent the reemergence of the life-threatening disease, SARS. In this study, more than 200 extracts from Chinese medicinal herbs were evaluated for anti-SARS-CoV activities using a cell-based assay that measured SARS-CoV-induced cytopathogenic effect (CPE) in vitro on Vero E6 cells. Six herbal extracts, one each from Gentianae Radix ( lóng dǎn; the dried rhizome of Gentiana scabra), Dioscoreae Rhizoma ( shān yào; the tuber of Dioscorea batatas), Cassiae Semen ( jué míng zǐ; the dried seed of Cassia tora) and Loranthi Ramus ( sāng jì shēng; the dried stem, with leaf of Taxillus chinensis) (designated as GSH, DBM, CTH and TCH, respectively), and two from Rhizoma Cibotii ( gǒu jǐ; the dried rhizome of Cibotium barometz) (designated as CBE and CBM), were found to be potent inhibitors of SARS-CoV at concentrations between 25 and 200 μg/ml. The concentrations of the six extracts needed to inhibit 50% of Vero E6 cell proliferation (CC50) and 50% of viral replication (EC50) were determined. The resulting selective index values (SI = CC50/EC50) of the most effective extracts CBE, GSH, DBM, CTH and TCH were > 59.4, > 57.5, > 62.1, > 59.4, and > 92.9, respectively. Among these extracts, CBM and DBM also showed significant inhibition of SARS-CoV 3CL protease activity with IC50 values of 39 μg/ml and 44 μg/ml, respectively. Our findings suggest that these six herbal extracts may have potential as candidates for future development of anti-SARS therapeutics.AbbreviationsSARS,severe acute respiratory syndromeCoV,coronavirusCPE,cytopathogenic effectTCM,traditional Chinese medicine.
Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 404, Taiwan ; Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
Chih-Chun
CC
Wen
Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
Lie-Fen
LF
Shyur
Genomics Research Center, Academia Sinica, Taipei 115, Taiwan.
Jia-Tsrong
JT
Jan
Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.
Po-Huang
PH
Liang
Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan ; Department of Population Medicine and Diagnostic Science, Veterinary Medical Center, Cornell University, Ithaca, NY, 14853 USA.
Chih-Jung
CJ
Kuo
Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
Palanisamy
P
Arulselvan
Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 404, Taiwan.
Jin-Bin
JB
Wu
Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 404, Taiwan.
Sheng-Chu
SC
Kuo
Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
Ning-Sun
NS
Yang
Cibotium barometz; Cytopathogenic effect (CPE); SARS 3CL protease; Severe acute respiratory syndrome (SARS); Traditional Chinese medicine (TCM)