Abstract:In order to study the chemical constituents of Selaginella delicatula (Desv.) Alston, HP20 macroporous resin column chromatography (CC), normal-phase silica gel CC, Sephadex LH-20 gel CC, and semi-preparative liquid chromatography were used to separate and purify the ethyl acetate fraction of S. delicatula. Eighteen compounds isolated from the ethyl acetate fraction of S. delicatula were identified by modern spectroscopic methods ( NMR, MS, UV, IR ). They were identified as bilobetin (1), delicaflavone (2), 7-O-methyl-amentoflavone (3), 2,3,2″,3″-tetrahydrohinokiflavone (4), 2,3,2″,3″- tetrahydroamentoflavone (5), 2S,2″S-tetrahydrorobustaflavone (6), (2″S)-2″,3″-dihydrodelicaflavone (7), 2,3-dihydroamentoflavone (8), (2S)-2,3-dihydrorobustaflavone-4′-methyl ether (9), hinokiflavone (10), amentoflavone (11), (2″S)-2″,3″-dihydrorobustaflavone (12), 2,3-dihydro-robustaflavone (13), 2″,3″-dihydroisocryptomerin (14), robustaflavone-4′-methyl ether (15), osthol (16), 6-(5-acetyl-2-methoxyphenyl)-apigenin (17), apigenin (18), respectively. Among them, 16 compounds including 1-10, 12-14, and 16-18 were firstly isolated from this title plant, and compound 16 was firstly isolated from the Selaginella genus. Compound 10 and compound 13 were able to inhibit the growth of the Eca-109 cell line to a certain extent at a concentration of 55.35 μmol·L-1 and 75.89 μmol·L-1, respectively.