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ANTIFUNGAL ACTIVITY OF EXTRACTS OF THE WOODS Caesalpinia platyloba, Lysiloma latisiliquum, Metopium brownei AND Piscidia piscipula.
The objective of the study was to evaluate antifungal activity (AFA) of the heartwood extracts of the following Mexican tropical woods Caesalpinia platyloba S. Watson (Chakte-viga), Lysiloma latisiliquum (L.) Benth (Tzalam), Metopium brownei (Jacq.) Urban (Chechen) and Piscidia piscipula (Linn.) Sarg. (Jabin). Two heartwood zones were chosen, inner zone (next to pith) and outer zone (next to sapwood-heartwood boundary). From each zone, specimens were taken following the radial direction of the tree diameter. All wood specimens were ground in a Wiley Mill, particle size of mesh 40 (approximately 0.4 mm), then were sequentially extracted with cyclohexane, acetone, methanol and water in relation 1:10 (heartwood/solvent), laboratory temperature and 72 h constant shaking. The percentage of extractives obtained on either solvent was determined. Later, 0.5, 1, 2.5 y 5 mg/ml dilutions were prepared from either extractives obtained, and then tested to either fungus Gloeophyllum trabeum (Persoon ex Fries) Murrill and Trametes versicolor (Linnaeus ex Fries) Pilát to evaluated AFA. The method used was the dilution on agar with surface inoculation in Petri dish. The AFA of the heartwood extractives was determined using radial growth of mycelia fungus in Petri dishes. The total yield of wood extractives, based on dry wood weight, obtained in cyclohexane, acetone, methanol and water of the were: C. platyloba 12.5% and 11.2 %, L. latisiliquum 11.6% and 10.5%, M. brownei 23.0% and 20.6 and P. piscipula 26.8% and 24.4% for outer and inner zones respectively. Acetone soluble fraction obtained from the heartwood C. platyloba showed a high inhibitory effect, 100% and 96% on the growth of the fungi G. trabeum and T. versicolor respectively. The methanol soluble fraction of P. piscipula exhibited a 100% inhibitory effect when exposed to G. trabeum. Both soluble fractions could be classified as highly toxic.