Plant Pathogenic Fungi: A Treasure Trove of Bioactive γ-Pyrones

Plant pathogenic fungi are among the primary causes of plant diseases, which reduce worldwide crop yield. Regardless of their pathogenicity, they substantially contribute to medicine, agriculture, and other fields through their ability to generate bioactive natural substances. Particularly, they can produce γ-pyrones, the main scaffold in various biologically active metabolites. Numerous pharmacologists and natural product chemists are intrigued by natural compounds with γ-pyrone scaffolds due to their potential use as antibacterial, antifungal, anticancer, antiinflammatory, antidiabetes, antioxidant, and antiviral agents. Despite the extensive applications and increasing reports of γ-pyrones, their systematic chemistry, manufacturing, and therapeutic significance, especially in plant pathogenic fungi, remain inadequately understood. This review, covering up to December 2024, addresses this gap by compiling 316 γ-pyrones from plant-pathogenic fungi. The γ-pyrones are categorized into chromones (35%), xanthones (28%), naphtho-γ-pyrones (25%), hybrid pyrones (6%), monocyclic pyrones (4%), flavonoids/isoflavonoids (1%), and others (1%). This review elucidates the natural origins of γ-pyrones, their biosynthesis, pharmacological properties, activity mechanisms, structure-activity relationships, and biological activity. It also discusses the present evolutionary status, problems, future directions, and potential of γ-pyrones to assist scientists in their discovery. Furthermore, it seeks to underscore the significance of γ-pyrones as promising natural products for agriculture and pharmaceutical development.