[Gastroprotective and antidepressant-like effect of plum pectin (Prunus domestica L.) under water-immobilization stress in laboratory mice].

Stress effects activate the processes of free radical oxidation in the organism, lead to hyper production of reactive radicals and oxidative stress, provoking the development of an inflammatory process in various parts of the gastrointestinal tract. Pectin polysaccharides together with the enzyme components of the endogenous antioxidant system contribute to the elimination of the imbalance between prooxidants and antioxidants in the tissues of stressed animals and have a gastroprotective and antidepressant-like effect. The aim of the research was to evaluate the gastroprotective, antioxidant and antidepressant-like effect of plum pectin orally administered to white laboratory mice before stressful exposure. Material and methods. In the experiment on white BALB/c mice weighing 20-25 g (90 males, 10 in each group), pectin isolated from fresh plum fruits in an artificial gastric environment was used. It was administered orally to mice 24 h before the onset of stress exposure or behavioral activity asessment. 50 animals were subjected to 5 h of water immersion stress. After this corticosterone concentration in blood plasma, and the activity of superoxide dismutase, catalase and glutathione peroxidase in the tissue supernatants of the gastrointestinal tract were determined, and the condition of the gastric mucosa was also assessed. Behavioral activity of experimental mice (n=30) was assessed in the open field and forced swimming tests. Results. The stress effect was accompanied by an increase in plasma corticosterone concentration (more than 3 fold), in the activity of superoxide dismutase, glutathione peroxidase in the tissues of the stomach wall and small intestine (17.9-28.6%) and destructive damage in the gastric mucosa compared with the indices of intact animals. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight helped to reduce the level of corticosterone and the number of stress-induced hemorrhages on the gastric mucosa, normalized the activity of antioxidant enzymes and also decreased the immobility time of mice in the forced swimming test. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight prevented an increase in the activity of antioxidant enzymes, corticosterone in the blood and the development of stress-induced hemorrhages on the gastric mucosa, and reduced the time of immobility of mice in the forced swimming test. Conclusion. Plum fruit pectin pre-administered into mice before stress prevents stress-induced damage in the tissues of the gastrointestinal tract, contributing to an increase in the body's resistance to the stress factor. Plum pectin has an antioxidant, gastroprotective and antidepressant-like effect and can be used as an ingredient in functional foods that reduce the risk of inflammatory diseases of the gastrointestinal tract under stress.

Melatonin pretreatment does not modify extrasystolic burden in the rat ischemia-reperfusion model.

The mechanism of reentrant ventricular tachyarrhythmias complicating acute myocardial ischemia is largely based on the interaction between an arrhythmogenic substrate and triggers. Melatonin was proposed as an antiarrhythmic medication and was shown to ameliorate the arrhythmogenic substrate. Also, melatonin provides a sympatholytic effect in different settings and might attenuate ectopic activity, which provides reentry triggers. In the present study, we aimed at evaluating the melatonin effects on cardiac sympathetic activity and the incidence of premature ventricular beats during the episode of ischemia-reperfusion. Experiments were done in a total of 26 control and 28 melatonin-treated (10 mg/kg, daily, for 7 days) male rats. Sympathetic fibers density was assessed by glyoxylic acid-induced fluorescence. Continuous electrocardiograms recording was performed during ischemia-reperfusion episodes (5 min/5 min, respectively) induced by reversible coronary occlusion. Myocardial expression of tyrosine hydroxylase, a rate-limiting enzyme of catecholamine biosynthesis was assessed by Western blotting. No differences in the state of sympathetic innervation were observed in histochemical analysis. However, Western blotting analysis demonstrated that melatonin treatment suppressed tyrosine hydroxylase expression in the non-ischemic (p < 0.05 versus control) but not ischemic regions of myocardium. The melatonin-treated animals had longer RR-intervals in the baseline state than the control animals (264 ± 48 ms versus 237 ± 33 ms, p = 0.044, respectively), but this difference decayed during the period of ischemia due to the increase of heart rate in the treated group. The number of premature ventricular beats did not differ between the control and treated groups during the ischemic and reperfusion periods. One-week melatonin pretreatment caused a slight peripheral sympatholytic effect that attenuated during ischemia and completely disappeared by the onset of reperfusion. The slight expression of sympathetic downregulation was associated with the lack of any effect of melatonin on extrasystolic burden. Collectively, the data suggest that melatonin cannot target the triggers of reentrant arrhythmias.

Xylogalacturonan-enriched pectin from the fruit pulp of Adansonia digitata: Structural characterization and antidepressant-like effect.

The low methyl-esterified and acetylated xylogalacturonan (DM 20 %, DA 2 %, Mw ∼ 58 kDa) was isolated by water extraction for 4 h × 2 at 50 °C (yield 23 %) from the pulp of baobab fruit (Adansonia digitata L.). Subsequent tightening of the conditions for water extraction by mean increasing the temperature to 70 °C and time to 12 h led to the co-extraction of small amounts of starch components and RG I with xylogalacturonan. Structural analysis (DEAE-cellulose ion-exchange chromatography, HPSEC, monosaccharide analysis, NMR spectroscopy) revealed that about 12 mol. % of 1,4-linked α-GalpA residues were substituted by single ß-Xylp residues at the O-3 position. The xylogalacturonan was found to possess an antidepressant-like effect in mice. The study offers using the baobab fruit as a rich source of soluble dietary fiber - water-soluble pectin with beneficial physiological effect.

[The effect of agar-pectin gels on the eating behaviour of fasted and fed mice].

A diet rich in non-digestible plant polysaccharides (dietary fibers) leads to effective appetite suppression and reduces food intake. The mechanical properties of food contribute to the satiating effect of food. It is known that solid food satiates to a greater extent than liquid, as the duration of food processing in the oral cavity increases. The aim of the study was to assess the effect of mechanical properties of agar-pectin gels on the feeding behaviour of mice Material and methods. The gels were prepared by dissolving the corresponding weights of agar, pectin and sucrose in 100 ml of water: gel 1 contained 6 g of agar, 3 g of pectin, gel 2 - 20 g of agar, 1 g of pectin and 0.03 M CaCl2, gel 3 - 20 g of agar, 1 g of pectin (without the addition of calcium ions). All gels contained an equal amount of sucrose (15 g per 100 ml of water). The mechanical properties of the gels (strength, Young's modulus and elasticity) were determined on a texture analyzer. Mice with an initial body weight of 32.9±0.5 g (n=8 in each group) received gels once a day for four days. Each day, animals were individually placed in experimental cages for 60 minutes: in the first 30 min, they were given test gels and for the next 30 min standard rodent food. The first two days were training. Before the third gel presentation, the animals were previously completely restricted in food for 14 hr (fasted mice), and before the fourth gel presentation, the mice received food ad libitum (fed mice). The eating behaviour of the mice, the amount of gel eaten and standard feed eaten were determined. Mice that were not exposed to gels were used as control. Results and discussion. Gel 3 was the hardest (251±3 kPa) in comparison with gel 1 (44±1 kPa) and 2 (141±3 kPa). Fasted mice that received gel 3 ate 36% less food (p<0.05), and the total energy intake was 19% lower (p<0.05) compared to the control. Fasted mice that received gels 1 and 2 ate the same amount of food as the control animals. Gel 3 significantly reduced feeding time by 19% (p<0.05) in fasted mice. Gels 1 and 2 did not alter the eating behaviour of fasted mice. Fed mice that received gels ate as much food as in the control. Gels failed to affect the eating behaviour of fed mice. Conclusion. Overall, solid gel 3 reduced food intake and time spent on feeding after 14 h of complete food restriction. The effect of the gel on the feeding behaviour of animals and the amount of food eaten is determined by the hardness of the gel and does not depend on the ratio of the components of the gel and its resistance to in vitro simulated gastric and intestinal fluids.

[The effect of pectin of tansy, Tanacetum vulgare L., on anxiety and overeating food rich in fats and sugars in mice in modelling binge eating].

Binge eating is repeated episodes of eating large amounts of sweet and fatty food in short periods. Dietary fibers, including pectin, significantly reduce the subjective ratings of hunger, and the amount of food eaten. However, studies showing the effect of dietary fibers on satiety use juices or yoghurts with added dietary fiber, or a kissel-like food. Thus, there is a lack of data on the effect of dietary fibres on binge eating of palatable food. The aim of the study was to assess the effect of tansy pectin on anxiety and the binge eating of palatable food in mice. Material and methods. 64 mice weighing 33.3±0.6 g were divided into two groups. Binge eating was induced in forty mice of the first group by consumption of sunflower halva (SH) in addition to regular chow for 24 h once a week. The total energy intake and separately the consumption of regular chow (RC) and SH were monitored. Tansy pectin in the form of an aqueous solution was administered to the mice using a gastric feeding tube (50 mg/kg body weight) before the last presentation of SH. Blood was obtained by cardiac puncture at the end of the last 24 h SH access period. The concentration of insulin and ghrelin in plasma samples were determined by the enzyme immunoassay. In animals of the second group, 24 hours after the administration of pectin, the level of anxiety and depression of mice was assayed with an open field test, a light-dark box test, an elevated plus-maze test, and a forced swim test. Throughout the study, water was used as a negative control, and imipramine at a dose of 20 mg/kg was used as a positive control. Results. Mice treated with tansy pectin ate 2.6 fold less SH within 3 h and 1.4 fold less within 24 h after oral administration of tansy pectin compared to control (water administration). Consumption of RC did not differ within 3 or 24 h. The total energy intake was 1.9 fold lower within 3 h in mice treated with tansy pectin. Within 24 h after pectin oral administration the total energy intake did not differ from control. Insulin plasma level was 2.5 fold lower and ghrelin plasma concentration was 25% higher in the mice that received pectin compared to control, at the end of the 24 h SH access period. The administration of tansy pectin was found to decrease anxietyrelated behaviour in mice. Its administration significantly increased the time spent in the central sector of the open field apparatus by 87%, the time spent in the light area of the light-dark box by 31%, and the time spent on the open arms of the elevated plus maze by 22% compared with the control. Conclusion. Overall, tansy pectin reduced the binge eating of SH representing highly palatable, sweet, and fatty food. Reduced intake SH lead to a decrease in insulin concentration. Blood level of ghrelin was increased in mice treated with tansy pectin at the end of the sweet and fatty food presentation period. Tansy pectin reduced the level of anxiety in mice.

Effect of Pectin Gel Particles on Endotoxemia Induced by Restraint Stress in Mice.

We studied the effect of pectin gel particles on endotoxemia in mice induced by restraint stress. It was shown that the concentration of LPS in mouse blood increased during restraint stress, which was associated with memory impairment. Pectin gel particles prevented the development of stress-induced endotoxemia and memory impairment in mice.

[Binding of human serum low-density lipoprotein cholesterol in vitro by sulfated pectin derivatives].

The ability to bind human serum LDL-C in vitro by the native pectins is lower than that of their sulfation derivatives. The number of sulfate groups and molecular weight of the sulfated derivatives are assumed to be crucial factors. The sulfated derivatives of pectin with molecular weight above 200 kDa containing 45 wt % sulfate groups possess the highest ability to bind atherogenic lipids, the lowest activity was estimated for the derivatives with molecular weight below 50 kDa containing 5 wt % of sulfate groups.

Effects of pectin polysaccharides on leukocyte migration into the oral cavity during exercise.

The effects of pectin polysaccharides on leukocyte migration into the oral cavity during exercise were studied. The migration and hence, counts of neutrophils in the oral cavity increased during exercise. Pectins reduced neutrophil migration into the oral cavity during exercise because of hyperstimulation of their functional activity.