Meroterpenoids Produced by Fungi: Occurrence, Structural Diversity, and Biological Activity (An Update: February 2020 to December 2025)

Meroterpenoids are a class of hybrid natural products, biosynthesized from terpenoid fragments and non-terpenoid precursors, exhibiting a wide range of biological activities, that provide an important source of compounds for new drug development. This review firstly summarizes the update of meroterpenoids from February 2020 to December 2025 by applying a new classification method based on twelve key non-terpene precursors. A total of 906 new meroterpenoids were reported from 214 studies, while recent synthetic and biosynthetic investigations have further expanded both the accessible chemical space and our mechanistic understanding of this compound class. Among them, biosynthetic pathways originating from 4-hydroxybenzoic acid and 3,5-dimethylorsellinic acid were found to be the highest proportion. Statistical analysis shows that over 40% of the cataloged compounds exhibit broad biological activities, with anti-cancer, anti-inflammatory, and antimicrobial effects being the top three. The significant structural variety and potent bioactivity of fungal meroterpenoids serve as a sustainable source for novel drug lead compounds.