Naturally occurring eugenin: Biosynthesis, distribution, bioactivity, and therapeutic potential

Introduction

Eugenin (5-hydroxy-7-methoxy-2-methyl-4H-chromen-4-one) is a bioactive phytoalexin mainly found as a bitter component in carrots (Daucus carota L.; Apiaceae) and cloves [Syzygium aromaticum (L.) Merr. & L. M. Perry; Myrtaceae].

Materials and methods

An extensive literature search was performed involving various established databases like Web of Science, PubMed, Science Direct, Dictionary of Natural Products and Google Scholar, using the keyword ‘eugenin’. The literature reports that describe various aspects of naturally occurring eugenin, e.g., isolation, structure elucidation, biosynthesis, bioactivity studies and therapeutic potential, have been included in this review, while the papers that present total synthesis or structural modifications of eugenin have been excluded.

Results

Eugenin, biosynthesized from the acetate-malonate pathway, has been reported from at least 22 plant species from 13 families. It has also been found in two fungal species, Aschersonia confluens and Chaetomium minutum. Dacaus carota and Syzygium aromaticum are two major sources of this chromone. Antimalarial, antimicrobial, antioxidant, antiplatelet aggregation, antiviral, cytotoxic, immunosuppressive/immunomodulatory, osteogenesis-inducing, pyrolyl endopeptidase (PEP)-inhibitory and blue-green algae growth inhibitory activities of eugenin have been reported in the literature. Among these bioactivities, antioxidant, antiplatelet aggregation, immunosuppressive/immunomodulatory activities of eugenin and its in silico prediction of antiviral property against severe-acute-respiratory-syndrome-related coronavirus-2 (SARS-CoV-2) activity may have some therapeutic potential.

Conclusion

The distribution of eugenin is rather limited to a few plant species and only a couple of fungal species. Based on the reported bioactivities, it could be concluded that this chromone might have some potential as a template for new drug development.