Antiviral Activity and Therapeutic Potential of Medicinal Plants and their Bioactive Constituents: A Review of Experimental Evidence, Mechanistic Insights, and Molecular Docking Studies

Abstract

This review estimated the antiviral potential of plant‑derived natural products, focusing on phenolic compounds (flavonoids, phenolic acids), alkaloids, essential oils and terpenoids, based on a comprehensive literature analysis including molecular docking, molecular dynamics, and pharmacokinetic studies including absorption, distribution, metabolism, excretion, and toxicity studies. Our theoretical results show that plants synthesize and accumulate a wide range of secondary metabolites that interact with key viral targets such as the main protease, papain‑like protease, RNA‑dependent RNA polymerase, spike glycoprotein and host ACE2 receptor. Phenolic acids (caffeic acid, gallic acid, ellagic acid), flavonoids (quercetin, kaempferol, naringenin, epigallocatechin gallate), alkaloids (emetine, lycorine, michellamine B) and essential oil constituents (eucalyptol, thymol, carvacrol) all showed strong binding affinities and stable interactions with conserved viral proteins, preventing viral entry, replication, and assembly while regulating inflammatory reactions. The majority of natural antivirals have pharmacokinetic constraints, such as low oral bioavailability, rapid phase II metabolism and high polarity, despite their positive drug-likeness. These drawbacks may be addressed by sophisticated formulation techniques. In summary, this work demonstrates that aromatic and medicinal plants are abundant sources of broad-spectrum antiviral secondary metabolites and offers a theoretical foundation for their logical selection and development as reasonably priced antiviral treatments.