Two new phenanthrene derivatives from Pholidota chinensis

Abstract Two new phenanthrene derivatives, 2,3,7-trihydroxy-5H-phenanthro[4,5-bcd] pyran (1) and 2,3-dihydroxy-7-methoxy-5H-phenanthro[4,5-bcd] pyran (2) together with four known phenanthrenes derivatives (3–6) were isolated from the aerial parts of Pholidota chinensis Lindl. The structure of the new compounds 1 and 2 was determined by 1D and 2D NMR, as well as HRESIMS. The inhibitory activities of all compounds against four cancer cell lines were evaluated. Compounds 1 and 3 showed the highest cytotoxicity against the MCF-7 cell lines (IC50 = 8.1 and 7.5 μM). The other compounds showed modest activities or were inactive.