Antistress Properties of Physiologically Active Compounds and Lipid Peroxidation.
Institute of Biochemical Physics, Russian Academy of Sciences ul. Kosygina 4, Moscow, Russia1 pp. (accepted)
Any one of strong environmental impacts induces stress reactions in living organisms. As a result, a prooxidant–antioxidant balance in cells is shifted towards activation of lipid peroxidation (LPO) processes (L.N. Kurganova, 2001). Supposedly, preparations that can affect the structural parameters of biological membranes by reducing the LPO products content will exhibit antistress properties. Since, a major part of AFK is formed in mitochondria (V.P. Skulachev, 2001), we studied the effect of a plant growth regulator – melaphen (a melamine salt of bis(oxymethyl)-phosphine acid) on the LPO products level in plant mitochondria membranes and related the obtained data with the plant resistance to stresses. We used long storage of mitochondria and simulation of inadequate watering as stress situations.
The preparation taken in the concentrations 2×10-7 and 4×10-12 M has no effect on the level of fluorescence of LPO products in membranes of freshly isolated sugar beetroot mitochondria and decreases in half the fluorescence of LPO products in membranes of “aged” mitochondria (after a 5 h storage at 10°C). An inadequate watering results in a 40% decrease in maximum oxidation rates of NAD-dependent substrates and in a decrease in efficiency of oxidative phosphorilation in the respiratory chain of mitochondria isolated from Pisum sativum germs. A preliminary treatment of seeds with a 10-7% melaphen solution prevents from changes in the energy of mitochonria induced by inadequate watering. Moreover, a pretreatment of pea seeds with melaphen stimulated growth of shoots (by 18 to 24%) both of control plants and of plant under conditions of inadequate watering; the germination of treated and non-treated seeds differs significantly. In particular, under conditions of inadequate watering, the germination of seeds of control plants decreases by 46%; whereas the germination of melaphen-treated seeds varies but slightly. Melaphen stimulates growth of germ roots under drought conditions; the effect is an adaptive one.
The obtained data may be evidence for the relation between the antistress properties of physiologically active compounds and the antioxidant activity thereof. This conclusion is supported by data obtained in a study on antistress properties of a compound of the class of hindered phenols – potassium phenozan (potassium salt of 2,6-di-tert-butyl-4-hydroxyphenyl-propionic acid). An intraperitoneal introduction of the preparation in the concentration 10-14 M to mice enhances 3.5-fold the survival rate thereof under conditions of hypoxia and 4-fold under conditions of a cold stress.