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).

Theophrastus (372-287 BC), Cato (234-149 BC), and Xenophanes (44 BC), pointed out the importance of Traditional weed control practices in Mexico use legumes as cover legumes and grasses as mulches. Other common organic crops or manures. Legumes used in these practices play a dual role in agroecosystems by protecting the soil from erosion and by enriching fertilizers included dung of birds and bats (guano), it with organic matter and N through Rhizobium symbiosis. Farmers fish fertilizer, dry blood, and dry meat. The Maya people in the tropical regions of Mexico use Mucuna spp., Canavalia spp. fertilized their crops with dead leaves from the tropical and other legumes to control weeds in their fields. We conducted in forest, secondary and savanna plant communities, and vitro bioassays and greenhouse experiments to evaluate the toxic animal manures. All these organic compounds help imeffect of four legumes velvetbean [Mucuna deeringiana (Bort) Merr.], prove the soil by increasing water retention capacity, jackbean [Canavalia ensiformis (L.) DC.], jumbiebean [Leucaena

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