Seladoeflavones G-I, Three New flavonoids from Selaginella doederleinii Hieron.

Three new flavonoids, seladoeflavones G-I (1-3), together with six known flavonoids, involvenflavone E (4), involvenflavone F (5), unciflavone F (6), 3-[5,7-dihydroxy-2-(4-methoxy-phenyl)-4-oxo-4H-chromen-8-yl]-4-methoxy- benzoic acid (7), naringenin (8), and eriodictyol (9) were isolated from the petroleum ether and the ethyl acetate fractions of the whole herbs of Selaginella doederleinii. The structures of new flavonoids were established by 1D NMR (H-1, C-13 and DEPT), 2D NMR (HMBC, H-1-H-1 COSY and HSQC), HRMS and electronic circular dichroism (ECD). Compounds 1-7 are apigenin or naringin derivatives with aryl substituents at the C-8 or C-3 ' positions, in which the new compounds 1 and 2 were identified as S configuration. In addition, compounds 4 and 5 exhibited strong cytotoxicity against human laryngeal cancer cells (Hep-2 and Fadu) with IC50 values in the range of 1.41-3.22 mu g/mL. The results of this study could enrich the flavonoids diversity and be regarded as some further insight into the chemotaxonomic diversity of natural products in Selaginella.