title: Cytotoxic oleanane-type saponins from Albizia inundata.
abstract: Bioassay-guided fractionation of a CH(2)Cl(2)-MeOH extract of the aerial parts of Albizia inundata resulted in the isolation of two new natural oleanane-type triterpene saponins {3-O-[α-L-arabinopyranosyl(1→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl oleanolic acid (1) and 3-O-[α-L-arabinopyranosyl(1→2)-α-L-arabinopyranosyl(1→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl acacic acid lactone (2)} along with seven known saponins {3-O-[α-L-arabinopyranosyl(1→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl echinocystic acid (3), 3-O-[β-D-xylopyranosyl (l→2)-α-L-arabinopyranosyl(l→6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl acacic acid lactone (concinnoside D) (4), 3-O-[β-D-glucopyranosyl(l→2)]-β-D-glucopyranosyl oleanolic acid (5), 3-O-[α-L-arabinopyranosyl(1→2)-α-L-arabinopyranosyl(l→6)]-β-D-glucopyranosyl oleanolic acid (6), 3-O-[β-D-xylopyranosyl(1→2)-α-L-arabinopyranosyl(l→6)]-β-D-glucopyranosyl oleanolic acid (7), 3-O-[α-L-arabinopyranosyl(l→2)-α-L-arabinopyranosyl(1→6)-[β-D-glucopyranosyl(l→2)]-β-D-glucopyranoside echinocystic acid (8), and 3-O-[β-D-xylopyranosyl(l→2)-α-L-arabinopyranosyl(1→6)-[β-D-glucopyranosyl(l→2)]-β-D-glucopyranoside echinocystic acid (9)}. The structures of 1 and 2 were established on the basis of extensive 2D NMR ((1)H-(1)H COSY or DQF-COSY, HSQC, HMBC, TOCSY, and HSQC-TOCSY) spectroscopic, ESIMS, and chemical methods. Saponins 1, 3, 6, and 7 showed cytotoxicity against human head and neck squamous cells (JMAR, MDA1986) and melanoma cells (B16F10, SKMEL28) with IC(50) values in the range 1.8-12.4 μM, using the MTS assay.
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, Kansas 66045, United States.
authors.forename: Huaping
authors.initials: H
authors.lastname: Zhang
authors.forename: Abbas K
authors.initials: AK
authors.lastname: Samadi
authors.forename: Karumanchi V
authors.initials: KV
authors.lastname: Rao
authors.forename: Mark S
authors.initials: MS
authors.lastname: Cohen
authors.forename: Barbara N
authors.initials: BN
authors.lastname: Timmermann
mesh_terms: D031289:Albizzia / Q000737:chemistry*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001118:Argentina; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: C558356:3-O-(alpha-L-arabinopyranosyl(1-2)-alpha-L-arabinopyranosyl(1-6))-2-acetamido-2-deoxy-beta-D-glucopyranosyl acacic acid lactone; C558355:3-O-(alpha-L-arabinopyranosyl(1-6))-2-acetamido-2-deoxy-beta-D-glucopyranosyl oleanolic acid; D000972:Antineoplastic Agents, Phytogenic; D012503:Saponins; D009828:Oleanolic Acid