Densely Functionalized Macrocyclic Sesquiterpene Pyridine Alkaloids from <i>Maytenus austroyunnanensis</i>

Eleven densely functionalized new dihydro-β-agarofuran sesquiterpenoid derivatives, named maytenoids A–K (1–11), as well as one known analog, were isolated and characterized from Maytenus austroyunnanensis. Their structures were assigned based on analysis of spectroscopic data and X-ray crystallography. Compounds 1–9 are macrocyclic sesquiterpene pyridine alkaloids generated by the respective acylation of the hydroxy groups at C-3 and C-13 of dihydro-β-agarofuran sesquiterpenoids via diverse pyridine dicarboxylic acids. Compounds 1, 2, 5–10, and 12 exhibited significant inhibitory effects on NO production at 10 μM in lipopolysaccharide (LPS)-stimulated BV2 cells.