title: Novel cytotoxic acylated oligorhamnosides from Mezzettia leptopoda.
abstract: Activity-guided fractionation of a stem extract of Mezzettia leptopoda using human oral epidermoid carcinoma (KB) cells led to the isolation of seven highly acylated oligorhamnosides. Four of these constituents are novel, namely, n-octyl 2-O-acetyl-alpha-L-rhamnopyranosyl-(1-->3)-2, 4-di-O-acetyl-alpha-L-rhamnopyranosyl-(1-->3)-4-O-hexanoyl-alpha-L-rh amnopyranoside (mezzettiaside 8) (1); n-octyl 2, 3-di-O-acetyl-alpha-L-rhamnopyranosyl-(1-->3)-4-O-hexanoyl-alpha-L-rh amnopyranoside (mezzettiaside 9) (2); n-octyl 2, 4-di-O-acetyl-alpha-L-rhamnopyranosyl-(1-->3)-4-O-hexanoyl-alpha-L-rh amnopyranoside (mezzettiaside 10) (3); and n-octyl 2,3, 4-tri-O-acetyl-alpha-L-rhamnopyranosyl-(1-->3)-4-O-hexanoyl-alpha-L-r hamnopyranoside (mezzettiaside 11) (4). Three known compounds were identified as mezzettiasides 2 (5), 3 (6), and 4 (7), respectively, previously isolated from this same plant. The structures of novel compounds 1-4 were determined by spectroscopic methods. All the isolates were evaluated against a panel of human cancer cell lines in this study, and compounds 1-2 and 4-7 were found to be weakly cytotoxic toward KB and/or human colon and lung cancer cell lines.
authors.affiliation: Program for Collaborative Research in the Pharmaceutical Sciences and Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
authors.forename: B
authors.initials: B
authors.lastname: Cui
authors.forename: H
authors.initials: H
authors.lastname: Chai
authors.forename: T
authors.initials: T
authors.lastname: Santisuk
authors.forename: V
authors.initials: V
authors.lastname: Reutrakul
authors.forename: N R
authors.initials: NR
authors.lastname: Farnsworth
authors.forename: G A
authors.initials: GA
authors.lastname: Cordell
authors.forename: J M
authors.initials: JM
authors.lastname: Pezzuto
authors.forename: A D
authors.initials: AD
authors.lastname: Kinghorn
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic; D002240:Carbohydrate Sequence; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D013785:Thailand; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D009844:Oligosaccharides