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The antioxidative activity of two plant growth promoters, ambiol and phonk, in a model system of photo-induced glycyltriptophane oxidation was measured. It was shown that ambiol has a significant antioxidative activity, whereas phonk is a weak antioxidant. The effects of these compounds on DNA conformation were studied in vitro and in vivo (on wheat seed shoots). In vitro ambiol had a stronger effect as compared with phonk, whereas in vivo the latter produced a more essential effect than ambiol. The assumption was done that both compounds affect indirectly the genome expression activity. Possible mechanisms of biological activity of each compound are discussed.

Photosensitizing effect of antimicrobial drug nitrofuran derivative--furagin N-(5-nitro-2-furil)-allylidencamino-hydantoin) under irradiation with light longer than 280 nm was found. The method of investigation is based on photochemiluminescence of Gly-Trp peptide in aqueous solution. Maximum photosensitizing efficiency was observed at the furagin concentration 0.08 mM when chemiluminescence yield was 33 times greater than photochemiluminescence of Gly-Trp peptide in absence of drug. It was shown that photochemiluminescence sensitized by furagin occurred via free radical way. Life time of the triplet state of furagin determined by flash photolysis was 40 microseconds. A comparison of experimental data with kinetic calculation allowed us to estimate the rate constant of triplet quenching by oxygen ((2.2 +/- 0.3)10(8) M-1.s-1) and the total rate constants of physical quenching and chemical reaction with Gly-Trp peptide ((2.0 +/- 0.4)10(8) M-1.s-1). It was also found in experiments with photochemiluminescence of Gly-Trp peptide sensitized by riboflavin (irradiation with monochromatic light 436 nm) that furagin possesses antioxidant properties twice reducing the intensity of chemiluminescence at the drug concentration 0.029 mM.

The effect of about 30 medicines and some other compounds on the yield of the riboflavin sensitized glycyltryptophan photochemiluminescence occurring at the participation of superoxide and glycyltryptophan peroxide free radicals in solution has been studied. Some of the investigated compounds decrease the chemiluminescence yield as a result of their reactions with superoxide and gly-try peroxide radicals. The concentrations of compounds decreasing the chemiluminescence yield by 2 times were obtained. The estimation of the rate constants for a few compounds is given. It is shown that rutin, quercetin, ascorbic acid, aethamzilat, analgin, paracetamol, serotonin and butadione are most effective among the investigated medicines.