Efficient discovery of active isolates from Dioscorea spongiosa by the combination of bioassay‐guided macroporous resin column chromatography and high‐speed counter‐current chromatography

Abstract

In the present study, twelve compounds from Dioscorea spongiosa were successfully purified by an efficient technique combined bioassay‐guided fractionation macroporous resin column chromatography (MRCC) pretreatment and high‐speed counter‐current chromatography (HSCCC) separation for the first time. Then, D101 MRCC was used to fractionate the crude extract into five parts, which further applied the bioassay‐guided fractionation strategy to screen the active fractions of 2 and 4. As for the separation, 200 mg Fr.2 was purified by HSCCC using EtOAc/n‐BuOH/H2O (2:2:3, v/v), leading to annulatomarin (1), dioscoresides C (2), diosniponol C (3), methyl protodioscin (4), pseudoprotodioscin (5), protogracillin (6), as well as 200 mg Fr.4 yielding montroumarin (7), dioscorone A (8), diosniponol D (9), protodioscin (10), gracillin (11), and dioscin (12) using CH2Cl2/MeOH/H2O (3:3:2, v/v) with the purities over 95.0%. Finally, the isolates were assayed for their anti‐inflammatory, urico‐lowering, and anti‐diabetic activities in vitro, which indicated that the steroidal saponins of 5, 6, and 11 showed all these three activities.