Novel Cytotoxic Acylated Oligorhamnosides from Mezzettia l eptopoda

• Published in: Journal of natural products (Washington, D.C.) D.C.), 1998-12, Vol.61 (12), p.1535-1538
• Main Authors: Cui, Baoliang, Chai, Heebyung, Santisuk, Thawatchai, Reutrakul, Vichai, Farnsworth, Norman R., Cordell, Geoffrey A., Pezzuto, John M., Kinghorn, A. Douglas
• Format: Article
• Language: English
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np980270j

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-α-l-rhamnopyranosyl-(1→3)-2,4-di-O-acetyl-α-l-rhamnopyranosyl-(1→3)-4-O-hexanoyl-α-l-rhamnopyranoside (mezzettiaside 8) (1); n-octyl 2,3-di-O-acetyl-α-l-rhamnopyranosyl-(1→3)-4-O-hexanoyl-α-l-rhamnopyranoside (mezzettiaside 9) (2); n-octyl 2,4-di-O-acetyl-α-l-rhamnopyranosyl-(1→3)-4-O-hexanoyl-α-l-rhamnopyranoside (mezzettiaside 10) (3); and n-octyl 2,3,4-tri-O-acetyl-α-l-rhamnopyranosyl-(1→3)-4-O-hexanoyl-α-l-rhamnopyranoside (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.