RESUMEN
Blood coagulation and platelet-dependent primary homeostasis are important defense mechanisms against bleeding and novel inhibitors have been researched to obtain pharmacological and clinical applications. In this work, the PpyLL, a lectin obtained from Phthirusa pyrifolia, was characterized in terms of its molecular structure and biological functions (anticoagulant, antiplatelet agreggation and hemagglutinating activities) in presence or absence of Gamma radiation exposure. Results revealed a lectin with secondary-structure content by approximately 49% of ß-sheet, 20% of ß-turn and 31% of disordered structure. Irradiation effect demonstrated possible different sites of function by lectin on anticoagulant and hemagglutinating activities, once a decrease about 80% was observed when compared the activities under 0.5kGy of exposition to gamma radiation. An emphatic discussion about the use of gamma radiation as a possible modulator of the lectin activity was made, and once the ionizing radiation affected differently the anticoagulation and hemagglutinating activities, we speculated that the results are determined by selective molecular damages in different binding sites. PpyLL biological activities and gamma radiation modulation could be considered for future researches in biomedical field aiming possible medical applications.
Asunto(s)
Anticoagulantes/farmacología , Rayos gamma , Hemaglutinación/efectos de los fármacos , Loranthaceae/química , Lectinas de Plantas/farmacología , Secuencia de Aminoácidos , Anticoagulantes/química , Humanos , Masculino , Lectinas de Plantas/química , Agregación Plaquetaria/efectos de los fármacosRESUMEN
Several plant-derived compounds have been screened by antioxidant assays, but many of these results are questionable, since they do not evaluate the pharmacologic parameters. In fact, the development of better antioxidants stills a great challenge. In vitro cell-based assays have been employed to assess the antioxidant effect of various compounds at subcellular level. Cell-based assays can also reveal compounds able to enhance the antioxidant pathways, but without direct radical scavenging action (which could not be detected by traditional assays). These methodologies are general of easy implementation and reproducible making them suitable for the early stages of drug discovery. Hydrogen peroxide, a nonradical derivative of oxygen, can be employed as an oxidative agent in these assays due its biochemical properties (presence of all biological systems, solubility) and capacity to induce cell death. Truthfully, if their limitations are understood (such as difference on cell metabolism when in in vitro conditions), these cell-based assays can provide useful information about the pathways involved in the protective effects of phytochemicals against cell death induced by oxidative stress, which can be exploited to develop new therapeutic approaches.