An overview of grayanane diterpenoids and their biological activities from the Ericaceae family in the last seven years.

Grayanane diterpenoids, possessing a unique 5/7/6/5 tetracyclic system, exist exclusively in plants of the Ericaceae family. Owing to their various skeletons, complex structures, and diverse bioactivities, grayanoids have been the topic of research in many phytochemical and pharmacological laboratories, offering opportunities for the development of new drugs with analgesic, anti-inflammatory, and protein tyrosine phosphatase 1B (PTP1B) properties. Recently, a number of new grayanane diterpenoids with unprecedented carbon skeletons have been obtained from plants of the Ericaceae family, and they exhibit diverse biological properties, such as agalgesic, antinociceptive, anticancer, antiviral, antifeedant, insecticidal, toxicity, and PTP1B. In this review, 162 new grayanoids with 14 carbon skeletons from the Ericaceae family over the past seven years (2012-October 2018) are discussed, including their occurrence and distribution, skeleton types, structural features, biological activities, and structure-activity relationships (SARs). Also, strategies for the structural elucidation are summarized to provide useful information for medicinal chemists in developing potent anticancer, antiviral, analgesic, anti-inflammatory, and novel PTP1B agents.