1.Effect of Thyme Herbal Tea on Proliferation of Human Coronavirus OC43 in vitro and in vivo
Jixiang TIAN ; Tongtong ZHANG ; Yuning CHANG ; Peifang XIE ; Shuwei DONG ; Xiaoang ZHAO ; Yun WANG ; Chunhui ZHAO ; Hongwei WU ; Amei ZHANG ; Haizhou LI ; Xueshan XIA ; Huamin ZHANG
Chinese Journal of Experimental Traditional Medical Formulae 2024;30(23):81-89
ObjectiveTo investigate the effects of thyme herbal tea (BLX) on the proliferation of human coronavirus OC43 (HCoV-OC43) in vitro and in vivo. MethodThe chemical composition of BLX was analyzed by UPLC-MS. The cytotoxicity of BLX in HRT-18 cells and the effect of BLX treatment on the proliferation of HCoV-OC43 in cells were analyzed. Copies of viral gene were detected by real-time PCR. The effect of BLX treatment on the life cycle of HCoV-OC43 was detected by time-of-addition assay. The maximum tolerated dose of BLX and the influences of BLX on the body weight and survival time of suckling mice infected with HCoV-OC43 were determined. The expression of viral protein in the brain and lung tissue was analyzed by immunohistochemistry. ResultThere were 11 chemical components identified in BLX by UPLC-MS. BLX showed the 50% cytotoxic concentration (CC50) of (13 859.56±319) mg·L-1, the median inhibitory concentration (IC50) of (1 439.09±200) mg·L-1, and the selection index of 8.26-11.44 for HCoV-OC43 in HRT-18 cells. Compared with the cells infected with HCoV-OC43, BLX at the concentrations of 1 500, 1 000, 500 mg·L-1 inhibited the proliferation of this virus (P<0.05, P<0.01). BLX exhibited antiviral effect in the early stage of virus infection, and the inhibition role in the attachment stage was more significant than that in the entry stage (P<0.05). In the suckling mice infected with HCoV-OC43, BLX at 1200 and 600 mg·kg-1·d-1 alleviated the symptoms, prolonged the survival period, reduced the death rate, and down-regulated the mRNA level of nucleocapsid protein in the mice. Moreover, BLX at 1 200 mg·kg-1·d-1 down-regulated the expression of nucleocapsid protein in the brain (P<0.01) and the lung (P<0.01). ConclusionBLX contained multiple antiviral ingredients. It inhibited the proliferation of HCoV-OC43 both in vitro and in vivo by interference with viral attachment. This study provides theoretical reference for the treatment of acute respiratory tract infection with HCoV-OC43 and for further development and application of BLX.