Phytochemistry and biosynthesis of δ-lactone withanolides

Withanolides are highly oxygenated natural products. these c28 steroids with ergostane-based skeletons functionalized at c-22 and c-26 form six-membered δ-lactone rings. withanolides containing a δ-lactone side chain often occur in solanaceae and have a variety of biological activities because of their complicated structures. characteristic spectroscopic behaviors and biosynthesis of withanolides are conducive to their structural elucidation and “biomimetic synthesis”, respectively. however, the last review to summarize their spectroscopic features and biosynthesis was in 1996. since then, many withanolides with novel structures have been described by their spectra with biosynthesis investigated with many bioassays. this review surveys δ-lactone withanolides and emphasizes their spectral features, configurations and biosynthetic genes. the period reviewed includes through 2014. we also include phytochemical species.