Overview of harziane diterpenoids: discovery, bioactivity, total synthesis and biosynthesis

Harziane diterpenoids constitute a unique class of diterpenoids distinguished by their intricate 6/5/7/4 carbocyclic scaffold, presenting notable structural complexity. Since the first harziane diterpenoid, harziandione, was isolated from <i>Trichoderma harzianum</i> in 1992, a plethora of harziane diterpenoids have been predominantly isolated from the genus <i>Trichoderma</i>. Owing to their complex structural diversity and potential biological properties, these substances have attracted considerable interest from chemists and pharmacologists. This review provides, for the first time, a comprehensive summary of the structures, biological properties, total synthesis, and biosynthetic study of harziane diterpenoids reported to date, and discusses the potential roles of harziane diterpenoids in fungal-host interactions.