Antiviral activity and active components of the leaves from Sabia parviflora Wall. ex Roxb

Sabia parviflora (, "xiao hua qing feng teng" in Chinese) was recorded as an important ethnic medicine to be used for treating viral hepatitis. The antiviral activity of four extracts and potent antiviral compounds evaluated with cathepsin L protease (Cat L PR) and HIV-1 protease (HIV-1 PR). UPLC-HRMS was used for identifying the bioactive components. In addition, the possible inhibitory mechanism of the identified compounds on viral protease was further discussed by molecular docking. As a result, four extracts of exhibited inhibitory activity of HIV-1 PR and Cat L PR with IC₅₀ range from 0.015 to 0.80 mg/mL. Meanwhile, six compounds inhibited HIV-1 PR with IC₅₀ range from 0.032 to 0.80 mg/mL. Moreover, procyanidin B2 had good affinity for HIV-1 PR and CatL PR protein, respectively. These findings suggest S. parviflora leaves can be used for treating HIV and procyanidin B2 may play a role in antiviral protease.