From ancient remedy to modern COVID-19 adjunct: a narrative review of mechanistic, in vitro, and clinical evidence on propolis.

INTRODUCTION

Despite the global rollout of COVID-19 vaccines, limited access, vaccine hesitancy, and the emergence of viral variants continue to underscore the need for complementary antiviral strategies. Propolis, a resinous bee product widely used in traditional medicine, has attracted scientific interest due to its reported antiviral, anti-inflammatory, immunomodulatory, and antioxidant properties.

CONTENT: This narrative review examines the therapeutic potential of propolis as a candidate adjunctive treatment for COVID-19, focusing on mechanistic, in vitro, and clinical evidence. A comprehensive review was conducted using PubMed, Scopus, and Europe PMC (January 2020 to May 2025), covering molecular docking reports, in vitro assays, and human clinical studies evaluating propolis or its key constituents against SARS-CoV-2. In silico reports describe interactions of more than forty propolis constituents with key host and viral targets, providing mechanistic context. In vitro evidence demonstrates inhibition at entry and replication targets alongside attenuation of inflammatory signaling. Limited clinical data, spanning seven studies and two case reports, suggest milder symptoms and shorter hospital stays, with no serious adverse events observed.

SUMMARY AND OUTLOOK: Preclinical and early clinical evidence suggest propolis may be a useful adjunct in COVID-19 therapy. Large, placebo-controlled trials with well characterized and standardized extracts are needed to confirm efficacy and safety.