Triterpene saponins from the roots of Acacia albida Del. (Mimosaceae).

Seven previously undescribed bidesmosidic triterpenoid saponins named albidosides A - G, were isolated from a methanol extract of the roots of Acacia albida. Their structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry and determined to be bidesmosides of oleanolic acid and of 16α-hydroxyoleanolic acid. Albidosides B - G were assayed for their cytotoxicity against HeLa and HL60 cells using MTT method and microscopic observation.

Cycloartane and oleanane-type glycosides from Astragalus pennatulus.

Four new cycloartane and one new oleanane-type glycosides were isolated from Astragalus pennatulus along with five known cycloartane-type glycosides. The structures of the new compounds were established as 3-O-ß-D-xylopyranosyl-6-O-ß-D-glucopyranosyl-3ß,6α,16ß-trihydroxy-24-oxo-20(R),25-epoxycycloartane (1), 3-O-[ß-D-glucuronopyranosyl-(1 → 2)-ß-D-xylopyranosyl]-3ß,16ß,24α-trihydroxy-20(R),25-epoxycycloartane (2), 3-O-[ß-D-glucuronopyranosyl-(1 → 2)-ß-D-xylopyranosyl]-3ß,16ß,25-trihydroxy-20(R),24(S)-epoxycycloartane (3), 3,25-di-O-ß-D-glucopyranosyl-6-O-ß-D-xylopyranosyl-3ß,6α,16ß,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), 29-O-α-L-rhamnopyranosyl-abrisapogenol B (5) by 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. The aglycone of compound 1, 3ß,6α,16ß-trihydroxy-24-oxo-20(R),25-epoxycycloartane, is reported for the first time. The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. None of the tested compounds caused a significant reduction of the cell number.

Secondary Metabolites from Astragalus lycius and Their Cytotoxic Activities.

Eight known secondary metabolites were isolated from the methanolic extract of the whole plant of Astragalus lycius Boiss. They were identified as 5,5'-dihydoxy-3'-methoxy-isoflavone-7-0-ß-D-glucoside (1), genistin (2), sissotrin (3), 5,4'-dimethoxy-isoflavone-7-0-ß-D-glucopyranoside (4), (7S,8R)-5-methoxydehydrodiconiferyl alcohol-4-0-ß-D-glucopyranoside (5), 4-0-lariciresinol-glucoside (6), 2-phenylethyl-ß-D-glucopyranoside (7) and ß-sitosterol-3-O-ß-D-glucopyranoside (8) by spectroscopic methods including (1)H- and (13)C-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1-7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 µM concentration.

Cycloartane glycosides from Astragalus plumosus var. krugianus and evaluation of their antioxidant potential.

The methanol extracts of Astragalus plumosus var. krugianus Chamb. & Matthews afforded sixteen cycloartane glycosides among which krugianoside A, was never reported before. All compounds were evaluated for their cytotoxic activity in human skin fibroblast WS1 cells. For compounds exhibiting no significant effect on WS1 viability, the antioxidant potential was examined. Compounds 1 and 8 prevented elevation of ROS induced by t-BOOH, suggesting the potential activity of these compounds to protect fibroblasts from oxidative stress.

Saponins from Astragalus hareftae (NAB.) SIRJ.

Four cycloartane- (hareftosides A-D) and oleanane-type triterpenoids (hareftoside E) were isolated from Astragalus hareftae along with fifteen known compounds. Structures of the compounds were established as 3,6-di-O-ß-D-xylopyranosyl-3ß,6α,16ß,24(S),25-pentahydroxycycloartane, 3,6,24-tri-O-ß-D-xylopyranosyl-3ß,6α,16ß,24(S),25-pentahydroxycycloartane, 3-O-ß-D-xylopyranosyl-3ß,6α,16ß,25-tetrahydroxy-20(R),25(S)-epoxycycloartane, 16-O-ß-D-glucopyranosyl-3ß,6α,16ß,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[ß-D-xylopyranosyl-(1→2)-O-ß-D-glucopyranosyl-(1→2)-O-ß-D-glucuronopyranosyl]-soyasapogenol B by the extensive use of 1D- and 2D-NMR experiments along with ESI-MS and HR-MS analyses.

Triterpene glycosides from Astragalus icmadophilus.

Six cycloartane-type triterpene glycosides were isolated from Astragalus icmadophilus along with two known cycloartane-type glycosides, five known oleanane-type triterpene glycosides and one known flavonol glycoside. The structures of the six compounds were established as 3-O-[alpha-L-arabinopyranosyl-(1-->2)-O-3-acetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-alpha-L-arabinopyranosyl-(1-->2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxy cycloartane, 3-O-[alpha-L-arabinopyranosyl-(1-->2)-O-3,4-diacetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, 3-O-[alpha-L-arabinopyranosyl-(1-->2)-O-3-acetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[alpha-L-arabinopyranosyl-(1-->2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,24alpha-tetrahydroxy-20(R),25-epoxycycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-alpha-L-arabinopyranosyl-(1-->2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta,24alpha-tetrahydroxy-20(R),25-epoxycycloartane by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis. The first four compounds are cyclocanthogenin and cycloastragenol glycosides, whereas the last two are based on cyclocephalogenin as aglycone, more unusual in the plant kingdom, so far reported only from Astragalus spp.