Withanolides from leaves of cultivated Acnistus arborescens.

Seven withanolides, including four previously unknown, were isolated from the acetone and ethanol extracts of cultivated specimens of Acnistus arborescens. These four compounds were identified as rel-(18R,22R)-5β,6β:18β,20-diepoxy-3β,18α-dimethoxy-4β-hydroxy-1-oxowith-24-enolide, rel-(20R,22R)-5β,6β-epoxy-4β,16α,20-trihydroxy-1-oxowitha-2,24dienolide, rel-(20R,22R)-16α-acetoxy-6α-chloro-4β,5β,20-trihydroxy-1-oxowitha-2,24-dienolide and rel-(20R,22R)-16α-acetoxy-20-hydroxy-1-oxowitha-2,5,24-trienolide. Their structures were elucidated by interpretation of spectroscopic data (1D and 2D NMR), HRESIMS experiments and comparison with published data for similar compounds.