Huangqiyenins G - J, Four New 9,10-Secocycloartane (=9,19-Cyclo-9,10-secolanostane) Triterpenoidal Saponins from Astragalus membranaceusBunge Leaves

Four new 9,10-secocycloartane (=9,19-cyclo-9,10-secolanostane) triterpenoidal saponins, named huangqiyenins G–J (1–4, resp.), were isolated from Astragalus membranaceusBunge leaves. The acid hydrolysis of 1–4 with 1M aqueous HCl yielded D-glucose, which was identified by GC analysis after treatment with L-cysteine methyl ester hydrochloride. The structures of 1–4 were established by detailed spectroscopic analysis as (3β,6α,10α,16β,24E)-3,6-bis(acetyloxy)-10,16-dihydroxy-12-oxo-9,19-cyclo-9,10-secolanosta-9(11),24-dien-26-yl β-D-glucopyranoside (1), (3β,6a,10α,24E)-3,6-bis(acetyloxy)-10-hydroxy-12,16-dioxo-9,19-cyclo-9,10-secolanosta-9(11),24-dien-26-yl β-D-glucopyranoside (2), (3β,6α,9α,10α,16β,24E)-3,6-bis(acetyloxy)-9,10,16-trihydroxy-9,19-cyclo-9,10-secolanosta-11,24-dien-26-yl β-D-glucopyranoside (3), and (3β,6α,10α,24E)-3,6-bis(acetyloxy)-10-hydroxy-16-oxo-9,19-cyclo-9,10-secolanosta-9(11),24-dien-26-yl β-D-glucopyranoside (4).