Evaluation of the antiviral activity of naringenin, a major constituent of Typha angustifolia, against white spot syndrome virus in crayfish Procambarus clarkii

White spot syndrome virus (WSSV) is a serious pathogen threatening global crustacean aquaculture with no commercially available drugs. Herbal medicines widely used in antiviral research offer a rich reserve for drug discovery. Here, we investigated the inhibitory activity of 13 herbal medicines against WSSV in crayfish Procambarus clarkii and discovered that naringenin (NAR) has potent anti-WSSV activity. In the preliminary screening, the extracts of Typha angustifolia displayed the highest inhibitory activity on WSSV replication (84.62%, 100 mg/kg). Further, NAR, the main active compound of T. angustifolia, showed a much higher inhibition rate (92.85%, 50 mg/kg). NAR repressed WSSV proliferation followed a dose-dependent manner and significantly improved the survival of WSSV-challenged crayfish. Moreover, pre- or post-treatment of NAR displayed a comparable inhibition on the viral loads. NAR decreased the transcriptional levels of vital genes in viral life cycle, particularly for the immediately early-stage gene ie1. Further results showed that NAR could decrease the STAT gene expression to block ie1 transcription. Besides, NAR modulated immune-related gene Hsp70, antioxidant (cMnSOD, mMnSOD, CAT, GST), anti-inflammatory (COX-1, COX-2) and pro-apoptosis-related factors (Bax and BI-1) to inhibit WSSV replication. Overall, these results suggest that NAR may have the potential to be developed as preventive or therapeutic agent against WSSV.

Automated summary

The study found that naringenin (NAR) has potential as a preventive or therapeutic agent against WSSV, inhibiting viral replication and improving survival rates in crayfish. NAR can reduce viral loads and inhibit WSSV replication by regulating key genes and immune-related factors.