Digoniodiol, deoxygoniopypyrone A, and goniofupyrone A: three new styryllactones from Goniothalamus amuyon

Three new styrylpyrone analogues, digoniodiol (2), deoxygoniopypyrone A (3), and goniofupyrone A (4), along with ten known styryllactones, were isolated from the aerial parts of Goniothalamus amuyon. Among these compounds, 2 is the first example of a bis-styrylpyrone. Compound 4 represents a new skeleton for styryllactones. All structures were established on the basis of spectroscopic data. The stereochemistry of 2 and 4 was determined by X-ray crystallographic analysis. The absolute configuration of 3 and 4 was further confirmed by Mosher ester derivatives. All styryllactones were subjected to cytotoxicity assays. Among them, goniothalamin, goniothalamin epoxide, and 8-chlorogoniodiol showed significant cytotoxicity against the HepG2 cancer cell line with IC50 in the range of 0.19 - 0.64 microg/mL, and moderate activity toward Hep3B, MDA-MB-231, and MCF-7 cancer cell lines.