Potential mechanisms and material basis of Jinhua Qinggan Granules against Zika virus infection and associated inflammatory responses.

ETHNOPHARMACOLOGICAL RELEVANCE: Jinhua Qinggan Granules (JHQG) is a traditional Chinese medicine formulation widely used for the treatment of viral respiratory infections. Traditional herbal formulations contain multiple phytochemical constituents that may act individually or synergistically to produce therapeutic effects. Although its clinical applications have been reported, the bioactive constituents underlying its antiviral activity and their mechanisms of action remain to be clarified.

AIM OF THE STUDY: This study aimed to identify representative bioactive constituents of JHQG with antiviral activity against Zika virus (ZIKV) and to investigate their potential mechanisms of action.

MATERIALS AND METHODS: A panel of representative phytochemical constituents reported in JHQG was screened for antiviral activity against ZIKV in vitro. Antiviral efficacy and cytotoxicity were evaluated by determining EC50 and CC50 values. Viral replication was assessed using plaque assay, RT-qPCR, immunofluorescence, and Western blot analysis. Time-of-addition experiments were performed to explore stage-specific effects. Transcriptome analysis and quantitative PCR were conducted to examine host inflammatory gene expression. Intracellular reactive oxygen species (ROS) levels and NF-κB activation were evaluated in stimulated cells. In vivo antiviral efficacy was assessed in a ZIKV infection model using A129 mice. Molecular docking and molecular dynamics simulations were performed to explore potential interactions with the viral NS3 protease.

RESULTS: Among the screened compounds, chlorogenic acid (CGA) exhibited notable antiviral activity and was selected for further investigation. CGA treatment was associated with reduced ZIKV replication, decreased viral protein expression, and lower production of infectious viral particles under the tested conditions. Time-of-addition experiments indicated that CGA exerted inhibitory effects during early stages and throughout the infection period. ZIKV infection induced the expression of inflammatory genes including CXCL8, CXCL10, and TNFAIP3, whereas treatment with JHQG or CGA was associated with reduced expression of these genes. CGA treatment also corresponded with decreased intracellular ROS levels and attenuation of NF-κB activation. In A129 mice, CGA administration was associated with improved survival, reduced viral RNA levels in brain and liver tissues, and partial preservation of tissue morphology. Computational analyses suggested potential interactions between CGA and the NS3 protease.

CONCLUSION: These findings identify CGA as a representative bioactive constituent selected from the screened phytochemical components of JHQG that may contribute to its antiviral activity. The antiviral effects observed in this study, together with the modulation of host inflammatory responses, provide experimental evidence supporting further investigation of CGA as a candidate compound for the development of therapeutic strategies against ZIKV infection.