In vitro and in vivo assessment of the antioxidant activity of melatonin and related indole derivatives

Effects of melatonin and some structurally related indole compounds were studied by in vitro methods such as (i) an inhibition of the hyaluronic acid degradation and (ii) a standard lipid peroxidation assay. In vivo approach was based on the alloxan model of hyperglycaemia. Reduction of the viscosity of a hyaluronic acid solution in the reaction mixture was inhibited by tryptamine (91% inhibition), as well as by indole-3-carboxylic acid and indomethacin (80% and 77% inhibition, respectively). Lipid peroxidation with tert-butyl hydroperoxide as a source of radicals was followed by the formation of thiobarbituric acid reactive substances. Tested drugs inhibited lipid peroxidation in the order: tryptamine (59%) > indole-2-carboxylic acid (38%) > indomethacin (26%) > melatonin and indole-3-carboxylic acid (13%). In vivo, alloxan-induced hyperglycaemia was reduced in mice pretreated with drugs tested. The highest protective effect was observed with indomethacin (52% inhibition), followed by tryptamine and melatonin (18% and 16% inhibition, respectively).     

Neuronal nitric oxide synthase in the rabbit spinal cord visualised by histochemical NADPH-diaphorase and immunohistochemical NOS methods

The NADPH-diaphorase (NADPH-d) staining method is widely used in the investigation of both the central and peripheral nervous systems. Neuronal nitric oxide synthase (nNOS) has previously been shown to be responsible for the NADPH-d activity in neurons. However, NADPH-d activity does not always fully represent the enzyme nNOS. We investigated the distribution of NADPH-d activity and nNOS protein in the rabbit spinal cord for all groups of neurons and Rexed's laminae. In most laminae the distribution of NADPH-d activity was identical to nNOS immunoreactivity. Both were present in the dorsal horn and in pericentral areas of the spinal cord, but some differences existed. The superficial part of the dorsal horn (laminae I-III) stained more intensely for NADPH-d than for nNOS. However, the most prominent difference was seen in the lateral part of the dorsal horn--the lateral collateral pathway (LCP). The LCP stained strongly for NADPH-d activity, while nNOS staining was absent. Although there is an excellent correlation between NADPH-d staining and nNOS immunohistochemical staining in the spinal cord in general, the presence of staining differences necessitates the use of immunohistochemistry for some specialized applications.     

Begging for milk: evolution of teat massaging in suckling pigs

We present a model that simulates the evolution of teat massaging (begging) by suckling piglets (Sus scrofa) and milk distribution among teats (provisioning) by their mothers. Contrary to previous begging models, this one incorporates an ontogenetic dimension in that the inherited begging and provisioning rules are repeatedly allowed to interact, and their consequences for milk intake, growth and death probability are assessed, during each nursing. We test the model under three selection regimes differing in the relative importance of the between-litter selection component. We show that the selection regime with the strongest between-litter selection component leads to lowest begging levels and most effective milk utilization, thus supporting the hypothesis that selection based on whole litters may attenuate sibling competition.     

An ectonucleotide ATP-diphosphohydrolase activity in Trichomonas vaginalis stimulated by galactose and its possible role in virulence

This work describes the ability of living Trichomonas vaginalis to hydrolyze extracellular ATP (164.0 +/- 13.9 nmol Pi/h x 10(7) cells). This ecto-enzyme was stimulated by ZnCl2, CaCl2 and MgCl2, was insensitive to several ATPase and phosphatase inhibitors and was able to hydrolyze several nucleotides besides ATP. The activity was linear with cell density and with time for at least 60 min. The optimum pH for the T. vaginalis ecto-ATPase lies in the alkaline range. D-galactose, known to be involved in adhesion of T. vaginalis to host cells, stimulated this enzyme by more than 90%. A comparison between two strains of T. vaginalis showed that the ecto-ATPase activity of a fresh isolate was twice as much as that of a strain axenically maintained in culture, through daily passages, for several years. The results suggest a possible role for this ecto-ATPase in adhesion of T. vaginalis to host cells and in its pathogenicity.     

Female sex pheromone of Cameraria ohridella Desch. and Dim. (Lepidoptera: Gracillariidae): structure confirmation,synthesis and biological activity of (8E,10Z)-8,10-tetradecadienal and some analogues

Mass spectrometric investigations confirmed the structure of the female produced sex pheromone of the horse-chestnut leafminer Cameraria ohridella Desch. and Dim. to be (8E,IOZ)-8,10-tetradecadienal. Pure samples, prepared in a straightforward synthesis, were highly attractive in field tests and proved to be suitable for monitoring of flight activities and population dynamics. In mixtures with the synthetic pheromone, analogues like 9-tridecynal and 7-dodecynyl formate were shown to reduce trap catches. In electroantennographic experiments, pheromone analogues were less active than the pheromone. 9-Tridecynal was the most EAG active analogue tested, followed by 7-dodecyn-1-yl formate and 7-undecyn-1-yl formate.     

Pharmaco-toxicological study of Kageneckia oblonga, Rosaceae

The probable antipyretic, antiinflammatory, analgesic and antioxidant properties of Kageneckia oblonga, Rosaceae, were investigated and the major compounds of its active extracts were isolated. The study comprised the acute toxicity of the extracts of global methanol, hexane, dichloromethane and methanol. The cytotoxicity of global methanol extract was studied in three tumoral cell lines. All the extracts exhibited the pharmacological activities under study. Methanol and dichloromethane were the most toxic extracts. From the global methanol extract, isolations were performed of prunasin, 23,24- dihydro-cucurbitacin F, and a new cucurbitacin, 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycucurbita-5,24-diene-11-one. The cytotoxicity of both cucurbitacins on human neutrophils at the assayed concentrations was not statistically significant. In-vitro assays showed that both cucurbitacins can be partly responsible for the analgesic, antipyretic, and anti-inflammatory activities. Evaluation was done of the cytotoxicity of global methanol extract, 23, 24-dihydrocucurbitacin F, aqueous extracts and prunasin against P-388 murine leukaemia, A-549 human lung carcinoma and HT-29 colon carcinoma. Since global methanol extract presented a strong cytotoxicity against P-388 murine leukaemia, A-549 human lung carcinoma, and HT-29 cell lines, it is highly probable that this extract contain one or more cytotoxic compounds that could be investigated for their potential use as an agent against cancer.     

Hydroxylated 2-amino-3H-phenoxazin-3-one derivatives as products of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) biotransformation by Chaetosphaeria sp., an endophytic fungus from Aphelandra tetragona

The biotransformation of the phytoanticipin HBOA and its major degradation metabolites 2-hydroxy-N-(2-hydroxyphenyl)acetamide (7) and N-(2-hydroxyphenyl)acetamide (8) by Chaetosphaeria sp., an endophytic fungus isolated from Aphelandra tetragona, was studied. Three new metabolites could be identified as 2-amino-7-hydroxy-3H-phenoxazin-3-one (12), 2-acetylamino-7-hydroxy-3H-phenoxazin-3-one (13) and 7-hydroxy-2-(2-hydroxyacetyl)-amino-3H-phenoxazin-3-one (14). Structure elucidation of 12 and 13 was performed by MS, 1H, 13C NMR and 2D NMR techniques and confirmed by chemical transformation.     

Neuroactive steroids,their precursors and polar conjugates during parturition and postpartum in maternal and umbilical blood: 3.3beta-hydroxy-5-ene steroids

Five 3beta-hydroxy-5-ene steroids involved in the metabolic route from pregnenolone sulfate to dehydroepiandrosterone and its sulfate, of which three are known allosteric modulators of neurotransmitter receptors, were monitored in the serum of 20 women around parturition. In addition, their levels in maternal and umbilical serum were compared at delivery. On the basis of these data, a scheme of steroid biosynthesis in maternal organism during the critical stages around parturition is proposed.In maternal serum, all the steroids except dehydroepiandrosterone sulfate decreased during labor and even first day after delivery, although their changes were less distinct the more distant from pregnenolone sulfate (PregS) in the metabolic pathway. Calculation of product/immediate precursor ratios in maternal serum over all stages around parturition enabled identification of the respective changes in the activities of the relevant enzymes. The ratio of 17-hydroxypregnenolone/pregnenolone did not change significantly, while that of dehydroepiandrosterone/17-hydroxypregnenolone grew, indicating increased C17,20 side chain cleavage on the account of C17-hydroxylation both catalyzed by C17-hydroxylase-C17,20-lyase. As was shown by factor analysis, the changes in the maternal steroids were associated with a single common factor, which strongly correlated with all the steroids except dehydroepiandrosterone sulfate. The lack of change in the pregnenolone sulfate/pregnenolone ratio and a marked increase of the ratio dehydroepiandrosterone sulfate to unconjugated dehydroepiandrosterone indicate a different means of formation of both steroid sulfates. On the basis of these data, a scheme of steroid biosynthesis in maternal organism during the critical stages around parturition is proposed.