Eight new triterpenoid saponins from the leaves of Astragalus membranaceus (Fisch.) Bunge and their neuroprotective effects.

Eight new triterpenoid saponins, named huangqiyesaponin IV to XI (1-8), along with three previously identified compounds (9-11), were isolated from the 70 % ethanol solution of the leaves of Astragalus membranaceus (Fisch.) Bunge. These compounds were isolated through various column chromatography techniques, including those using silica gel, ODS, and preparative liquid chromatography. Their structures were elucidated based on comprehensive spectral analyses, including 1D and 2D-NMR, HRESIMS, and IR, as well as comparisons with existing literature. Additionally, HT22 cells stimulated with D-galactose were employed to assess the neuroprotective potential of all isolated compounds. The findings revealed that compounds 3 and 7-9 demonstrated notable neuroprotective effects.