摘要：AbstractAstragalusL. species were reported for their important biological activities and they were used in the treatment of several diseases.Astragalus sieberiDC. is a wild plant belonging to family Fabaceae and is growing in the Egyptian deserts. The plant was subjected to extraction by 70% methanol to give the total aqueous methanol extract which was fractionated by organic solvent to give three fractions; petroleum ether (Pet.Ether), ethyl acetate (EtOAc) and methanol (MeOH). These fractions were screened for theirin vitrocytotoxic activity using colon (HCT-116) and breast (MCF-7) carcinoma cell lines as well asin vitroantioxidant activity by DPPH assay. The EtOAc fraction showed IC5032.2 and 69.6 (µg/ml) against HCT-116 and MCF-7, compared to doxorubicin with IC5037.6 and 26.3 (µg/ml), respectively. Moreover, the pet.ether fraction showed a moderate radical scavenging activity at 100 ug/ml with cell viability 57.6%. Phytochemical investigation of the EtOAc and MeOH fractions of the plant revealed isolation and identification of eight compounds. They were identified as 3-nitro-1-propanol (1), 3-nitro-1-propyl-β-D-glucopyranoside (2), kaempferol (3), rhamnocitrin (4), kaempferol 3-O-(2″-α-arabinopyranosyl)-β-glucopyranoside (5), kaempferol 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside (6), isorhamnetin 3-O-(2″-α-arabinopyranosyl)-β-glucopyranoside (7) and isorhamnetin 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside (8). GC–MS analysis of the Pet.Ether and EtOAc fractions led to identification of twelve compounds, where phtyol (11.55%), 9,12,15-octadecatrienoic acid methyl ester (10.3%) and 16-octadecenoic acid methyl ester (9.45%) are the major compounds detected in the EtOAc fraction as well as N,N-dimethyl-1-dodecanamine (42.36%) and butylated hydroxytoluene (35.96%) were the major compounds detected in the pet.ether fraction. Additionally, LC–ESI–MS analysis of the MeOH fraction was also performed and revealed the tentative identification of kaempferol and isorhamnetin nuclei with high grade of glycosylation for the first time.
