Antiviral Bioactive Compounds: Their Activities and Underlying Mechanisms Against Human Viral Infections

Viral infections continue to be a major global health issue, causing over five million fatalities and millions of hospitalizations every year. Existing vaccines and commonly used antiviral drugs often exhibit significant side effects and limited efficacy. In contrast, recent studies have shown that plant extracts and their bioactive compounds possess considerable antiviral activity, along with a favourable safety profile for long-term use. These findings have spurred increased interest in the discovery and development of novel plant-derived antiviral agents.

This review emphasizes the significance of plant-derived antiviral compounds and their corresponding therapeutic targets. It provides a comprehensive overview of recent research on phytochemicals with potential antiviral activity against a wide range of viruses. By consolidating current findings, this review serves as a unified and up-to-date resource on contemporary plant-based antiviral bioactive compounds used in the treatment of human viral infections.

The antiviral efficacy of selected phytoactive compounds was analysed through detailed molecular mechanism studies, supported by in vitro and/or in vivo experimental models. Key herbs were reviewed for their active compounds and antiviral activities against specific viruses like influenza, HIV, HBV, HCV, HSV SARS-CoV-2, and measles. The study also analyzed the results, comparing their mechanisms of action, such as immune modulation, inhibition of viral entry, or interference with replication, while also discussing limitations and gaps in current research.

Evidence from the literature suggests that the notable selectivity of herbal bioactive compounds toward viral target proteins may underlie their antiviral activity. Additionally, findings from in silico, in vitro, and in vivo studies indicate that these compounds exert their effects by binding to specific host cell components, thereby protecting the host from viral infection. This review identifies and summarizes over 150 plant-derived antiviral bioactive compounds, along with their respective mechanisms of action, that have demonstrated efficacy against various selected viruses.

Plant-derived compounds, such as alkaloids, flavonoids, phenolics, terpenoids, and coumarins, exhibit significant antiviral potential. Given the limited number of approved antiviral drugs, cellular and molecular evidence supports herbal bioactives as promising alternatives for developing effective antiviral therapies, offering a natural and safer approach to combating viral infections.