Bazı Astragalus taksonlarından Saponinlerin izolasyonu ve karakterizasyonu

Astragalus aureus, saponin, cycloartane, cyclocephalogenin, cyclocanthogenin, Astragalus angustifolius, Astragalus tauricolus, HPLC-ESIMSn profiling, oleanane saponins.;Eight new cycloartane-type triterpene glycosides (1-8) were isolated from Astragalus aureus Willd along with ten known cycloartane-type glycosides (9-18). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Compounds 1-5 are cyclocanthogenin glycosides, whereas compounds 6-8 are based on cyclocephalogenin as aglycon, more unusual in the plant kingdom, so far reported only from Astragalus spp. Moreover, for the first time monoglycosides of cyclocanthogenin (5) and cyclocephalogenin (7, 8) are reported. Six new cycloartane-type triterpene glycosides (19-24) and four new oleananetype triterpene glycosides (25-28) were isolated from Astragalus angustifolius Lam. subsp. angustifolius var. angustifolius along with three known cycloartane-type triterpene glycosides and two known oleanane-type triterpene glycosides. Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Compounds 19-21 are cicloastragenol glycosides derivatives, while compounds 22-24 possess the C-24 epimer of cycloastragenol as the aglycone moiety and so far this is the first report of a 20,24-epoxycycloartanes with 20(R),24(R) configuration. As a part of our ongoing research for new bioactive compounds from Turkish Astragalus species, the investigation of Astragalus tauricolus has been carried out. An approach based on HPLC-ESIMSn experiments has been used to profile the triterpene glycosides occurring in the butanol extract of the whole plant. On the basis of the results of the online screening by HPLC-ESIMSn, twenty-two oleanane-type triterpene glycosides, including ten compounds never reported before (29-38), were isolated, and their structures were unambiguously elucidated by NMR spectroscopic data. Noteworthy, cycloartane-type triterpene glycoside, the main constituents of Astragalus spp., were not found. This peculiar feature characterizes a very limited group of Astragalus spp.