Purpose: The purpose of this study was to investigate the antiviral activities of herbal extracts against human norovirus surrogates including feline calicivirus (FCV) and murine norovirus (MNV).
Methods: Twenty-nine extracts of Z. latifolia, P. oleracea, S. chinensis, G. uralensis, C. longa, C. versicolor, I. obliquus, L. edodes, F. carica, C. aurantium, G. lucidum, C. militaris, C. sinensis, C. pinnatifida, A. annua, G. biloba, A.thumbergii, A. pilosa, C. sativum, V. vinifera, P. multiflorus, E. sessiliflorus, A. sativum, S. flavescens, A. fistulosum, C. officinalis, P. lactiflora, A. japonica, and E. ulmoides were used in this study. The effect of pre-, co-, and post-treatment of 29 medicinal plant extracts was investigated on virus-infected cells. Antiviral activity, cytotoxicity, and antioxidant activity was measured on Crandell-Reese Feline Kidney for FCV and RAW264.7 cells for MNV at 10, 20, 50, and 100 µg/ml concentration of medicinal plant extracts.
Results: Compared with antiviral drug and 29 herbal extracts, C. sinenesis, A. japonica, and C. pinnatifida showed the significant reduction of norovirus surrogates without cytotoxicity. The titer of FCV significantly reduced to 81.35 ± 9.48 and 65.00 ± 7.07% on CRFK cells pretreated with 100 µg/ml of C. sinensis and 20 µg/ml of A. japonica for 24 h, respectively. The titer of MNV was reduced to 53.71 ± 9.18 % on RAW264.7 cells pre-treated with 50 µg/ml of C. pinnatifida for 24 h.
Significance: Three herbal extracts of C. sinenesis, A. japonica, and C. pinnatifida could have potential to control norovirus without cytotoxicity.