Exploration of the mechanisms and active compounds of Scutellaria barbata D. Don against influenza A (H1N1) virus.

INTRODUCTION

Scutellaria barbata D. Don (S. barbata), a traditional Chinese medicinal herb widely used for its heat-clearing and detoxifying properties, has shown broad-spectrum antiviral potential. However, its anti-H1N1 activity and underlying mechanisms remain to be fully elucidated.

METHODS

In this study, the anti-H1N1 activity and underlying mechanisms of S. barbata extract were investigated using H1N1-infected MDCK cells and BALB/c mice. Transcriptomic analysis followed by mRNA and protein-level validation was performed to characterize its molecular effects, while UPLC-Q-Orbitrap-MS was used to identify blood-absorbed constituents. Potential active compounds were subsequently screened by integrating the absorbed constituents with network pharmacology and further validated in vitro and in vivo.

RESULTS

S. barbata extract markedly inhibited H1N1 replication in MDCK cells (IC50 = 42.87 μg/mL; CC50 > 500 μg/mL) and reduced viral burden and pulmonary inflammation in infected mice. Mechanistically, S. barbata treatment suppressed the Toll-like receptor, NF-κB, and chemokine signaling pathways, suggesting coordinated regulation of antiviral and inflammatory responses. Among the blood-absorbed constituents, baicalein and chrysoeriol were identified as key candidate active compounds and exhibited potent anti-H1N1 activity in vitro and in vivo (IC50 = 13.80 and 11.10 μM, respectively).

DISCUSSION: Collectively, these findings demonstrate that S. barbata exerts anti-H1N1 effects through a combination of direct inhibition of viral replication and modulation of excessive inflammatory responses, with baicalein and chrysoeriol representing important contributors to its antiviral activity.