No abstract

No abstract

The lignan otobaphenol, (8R,8'R,7R)-4'-hydroxy-5'-methoxy-3,4-methylenedioxy-2',7,8,8'-neolignan, extracted from Virola Aff. Pavonis leaves, completely inhibits at a concentration of 2.5 micro M the Fe(3+)-ascorbate-induced lipoperoxidation of rat liver mitochondria that was determined by oxygen consumption and accumulation of thiobarbituric acid-reactive species. At 25 micro M, it delays the mitochondrial permeability transition induced by tert-butyl hydroperoxide or Ca(2+), substantially inhibits the state 3 respiration, does not affect the state 4 respiration and the ADP/O ratio (with succinate), diminishes the rate of Ca(2+) uptake by mitochondria, and delays the ruthenium red-insensitive uncoupler-induced release of the loaded Ca(2+). Dose-dependent delaying of the calcium-induced swelling of mitochondria in the presence of otobaphenol nonlinearly correlates with its 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity. At 75 micro M and higher, this lignan causes mitochondrial aggregation and is able to aggregate itself, without mitochondria. The formed aggregates of otobaphenol do not cause an aggregation of subsequently added mitochondria. Thus, otobaphenol seems to be a promising target to prevent the oxidative stress death of cells.

Con el objeto de evaluar el efecto de Trichoderma harzianum, E.M. (Microorganismos Eficaces) y de AGROPLUX sobre el desarrollo de hongos Rhizoctonia solani y Sclerotinia sclerotiorum, fue realizada la presente investigación en condiciones de laboratorio y se determinaron los efectos sobre el crecimiento micelial de los patógenos en cajas de Potril, con el PDA. Los resultados indican que T. harzianum presentó una acción de parasitismo con R. solani y S.sclerotiorum; en cambio con E.M. y AGROPLUX se observó la presencia de antibiosis representada en un halo alrededor del anillo de vidrio que contenía los productos mencionados, los cuales impidieron el crecimiento de los patógenos.