Front Cover: Alashanoids O–S, seco‐Humulane and Eremophilane Sesquiterpenoids from Syringa pinnatifolia (Chem. Biodiversity 2/2022)

Abstract

Front Cover. Syringa pinnatifolia (SP) is a species endemic to China belonging to the Oleaceae family. It is limitedly distributed in the Helan Mountain between Ningxia and Inner Mongolia provinces of China. Its peeled stems and roots have been used as a folk herbal medicine for the treatment of chest tightness, shortness of breath, and coronary diseases for hundreds of years. Previously, our group reported a series of sesquiterpenoids with diverse types from SP, such as humulane, caryophyllane, eremophilane, and recent discovered syringane and pinnatane, and found that many sesquiterpenoids from SP exit as racemates, which provided inspiration for the potential unusual biosynthesis of sesquiterpenoids within this species. Five new sesquiterpenoids were isolated from the peeled stems of SP, namely alashanoids O−S (1–5), including two seco-humulanes with a rare 13-membered oxygen heterocycle framework as reported by C.-X. Liu et al. in their research article at 10.1002/cbdv.202100917.