ABSTRACT
Diterpenoids represent a large and structurally diverse class of compounds derived from four isoprene units linked in a head-tail fashion. Diterpenes are also classified into different types such as linear or acyclic, bicyclic, tricyclic, tetracyclic, pentacyclic, and macrocyclic depending on the presence of their skeletal core. The evaluation of biological activities by in-vitro cell-based assays and in-vivo animal studies indicates the medicinal effects of diterpenes against a variety of diseases. Taxanes are the diterpenoids containing a taxadiene core. Taxadiene is produced from geranylgeranyl pyrophosphate by taxadiene synthase. Taxadiene is considered the intermediate for the synthesis of taxol. Halimane is a diterpenoid and its skeleton is formed by cyclization of geranylgeranyl diphosphate which is catalyzed by class-II diterpene cyclases. The mulinane class of diterpenoids is a set of tricyclic, biologically active natural products whose members exhibit a variety of oxidation states.
