Study on Antiviral Activity of Different Solvent Extracts of Houttuynia Cordata

OBJECTIVE To study the antiviral activity of different solvent extracts of Houttuynia cordata. These viruses include enterovirus type 71(EV71), herpes simplex virus type 1(HSV-1), respiratory syncytial virus(RSV), coxsackie virus type B3(CV-B3) and coxsackie virus type B5(CV-B5). METHODS A variety of virus infection models were established by in vitro culture technique, and different solvent extracts of Houttuynia cordata were used for treatment. Therapeutic index(TI) was determined by cytopathic effect observation and MTT staining to determine its antiviral activity. RESULTS The results of in vitro antiviral experiments showed that the different solvent extracts of Houttuynia cordata had better antiviral effect on HSV-1 and EV71, and had little or no effect on RSV, CV-B3 and CV-B5. The content of flavonoids in the alcohol extract of Houttuynia cordata was higher, and the antiviral activity was relatively higher. The TI values of HSV-1 for 30%, 50%, 75% ethanol extract and precipitation obtained by water extraction and alcohol precipitation treatment were 81.68, 67.23, 41.91 and 32.61, respectively, and were higher than the positive control acyclovir TI value 23.43. It showed that Houttuynia cordata extract had stronger anti-HSV-1 virus activity. The TI values of 75%, 50%, 30% ethanol extracts for EV71 were 19.58, 20.13 and 18.84, and the effect was significant. CONCLUSION This study confirms that the antiviral activity of Houttuynia cordata extract on HSV-1 and EV71 is higher by in vitro antiviral experiments, which can provide a reference for clinical treatment of diseases caused by these two viruses.