Tricolorin A, major phytogrowth inhibitor from Ipomoea tricolor.
The allelopathic potential of Ipomoea tricolor (Convolvulaceae), used in Mexican traditional agriculture as a weed controller, has been demonstrated by measuring the inhibitory activity of organic extracts on seedling growth of Amaranthus leucocarpus and Echinochloa crus-galli. Bioactivity-directed fractionation of the active CHCl3 extract led to the isolation of the allelopathic principle, which turned out to be a mixture of the so-called "resin glycosides" of convolvulaceous plants. The structure of tricolorin A, the major phytogrowth inhibitor present in the active fraction, was elucidated as (11S)-hydroxyhexadecanoic acid 11-O-alpha-L-rhamnopyranosyl-(1-->3)-O-alpha-L-[2-O-(2S-methylbutyryl)-4 -O- (2S-methylbutyryl)] rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->2)-beta-D-fucopyran oside- (1,3"-lactone)[1], based on chemical methods and spectral analysis including 1H-1H COSY, 1H-13CHETCOR, long range 1H-13C COLOC, and selective INEPT experiments. Bioassays showed that radicle elongation of the two weed seedlings tested was inhibited by tricolorin A [1] with IC50 values ranging from 12 to 37 microM. Staphylococcus aureus was sensitive to compound 1 with an MIC value of 1.8 micrograms/ml. Significant cytotoxic activity against cultured P-388 and human breast cancer cells (ED50 2.2 micrograms/ml) was demonstrated for compound 1, and it also inhibited phorbol 12,13-dibutyrate binding using calf brain homogenate as a source of protein kinase C (IC50 43 microM).
Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, D.F.
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Pereda-Miranda
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Mata
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Anaya
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Wickramaratne
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JM
Pezzuto
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Kinghorn
D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification* / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D004354:Drug Screening Assays, Antitumor; D006027:Glycosides / Q000138:chemical synthesis* / Q000494:pharmacology; D006540:Herbicides / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D006027:Glycosides; D006540:Herbicides; D010936:Plant Extracts; C081262:tricolorin A; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C