Bogusław Król

Composition and properties of purified phenolics preparations obtained from an extract of industrial blackcurrant (Ribes nigrum L.) pomace

Summary An extract obtained from industrial blackcurrant pomace was purified and fractionated on an RP C18 column, resulting in three phenolics preparations of different composition. The phenolics in the preparations were quantified by HPLC, their anti-oxidant capacity was determined, and the preparations were subjected to HPLC-MS analysis in order to identify the bioactive compounds present. The purified preparations selected for study were an anthocyanin-rich preparation, a myricetin and quercetin glycosides-containing preparation, and an aglycon-containing preparation. All three preparations were characterised by having a high content of polyphenols. The anthocyanin-rich preparation was the most concentrated in polyphenols [> 50% (w/w)], followed by the aglycon-containing preparation [> 20% (w/w)], and finally the glycosides-containing preparation [> 9% (w/w)]. The preparations were also characterised by their high anti-oxidant capacity, which was > 3,100 µM TEAC g−1 (TEAC = Trolox Equivalent Anti-oxidant Capacity) for all preparations. The HPLC-MS study confirmed that the anthocyanin-rich preparation was composed of the following anthocyanins: delphinidin-3-glucoside, delphinidin-3-rutinoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside. The aglycon preparation contained four aglycons, of which myricetin and quercetin were predominant, and kaempferol and isorhamnetin were present in lower amounts. The glycosides-containing preparation was found to be the most interesting, since it contained myricetin, quercetin, kaempferol, and isorhamnetin glycosides. Myricetin and quercetin galactosides were also detected in blackcurrant extract for the first time. Moreover, the presence of nitrile-containing compounds, two acylated anthocyanins, and one auron-type compound was detected.

Polyphenol-Rich Strawberry Pomace Reduces Serum and Liver Lipids and Alters Gastrointestinal Metabolite Formation in Fructose-Fed Rats

This study compared the effects of supplementation with a polyphenol-rich pomace from strawberry (US) and a strawberry pomace without most of these compounds (PS) on gastrointestinal, blood, and tissue biomarkers in rats fed diets differing in carbohydrate contents for 4 wk. The diets were: corn starch (group CS), high fructose (60% by weight; group F), starch with 7.7% of either US or PS (groups CS+US and CS+PS, respectively), and high fructose with 7.7% of either US or PS (groups F+US and F+PS, respectively). An interaction (P < 0.05) was observed between diet type and strawberry preparation, showing that upon fructose feeding, US had a greater effect than PS on lowering serum insulin, liver total cholesterol, and conjugated dienes. Additionally, the F+US group had lower serum FFA than the F+PS group (P < 0.05). The extraction of polyphenols diminished the physiological effect associated with strawberry intake, suggesting that the fiber component of the pomace was also active in reducing metabolic complications following fructose feeding to rats.

Physiological effects of lactulose and inulin in the caecum of rats

A model experiment was performed on rats to evaluate the effect of partial or total substitution of saccharose (S) and cellulose (C) by preparations of lactulose and inulin on the development and metabolism of the caecum. In the experimental diets given to rats for 4 weeks, the examined preparations were administered either with an equivalent amount of cellulose (each at 4% of the diet) or as sole source of dietary fibre at 8% of the diet. Compared to the saccharose group cellulose had no effect, and low doses of lactulose and inulin in the diet increased to a medium extent the weight of the caecum wall and caecal digesta. The addition of lactulose and inulin at 8% increased significantly the content of caecal digesta (4.62 and 4.11 g/100g BW, respectively) and the weight of the caecal wall (1.10 and 0.86 g/100g BW, respectively), compared to the groups with saccharose and cellulose (0.73, 0.90 and 0.24, 0.28 g/100g BW, respectively). Cellulose and cellulose partially-substituted with lactulose and inulin caused an increase in the dry matter content of caecal digesta (26.5–27.5%), compared to other groups (21.8–22.8%). The administration of lactulose and inulin preparations was accompanied by a significant drop in pH (5.47–5.81), compared to the groups with cellulose or saccharose (6.83–6.91), and a decrease in the ammonia concentration in the caecal digesta, compared to the cellulose control (0.27–0.40 and 0.62 mg/g, respectively). The group with 8% lactulose was characterized by the highest activities of microbiological α- and β-galactosidase and β-glucosidase in the caecal digesta. Cellulose and both preparations significantly decreased the activity of β-glucuronidase, compared to the saccharose group (0.39–0.89 and 1.52 U/g, respectively). The highest concentration of VFA in the caecal digesta was observed in the saccharose group (89.2 μmol/g), and the lowest concentration in the group where cellulose was totally substituted by lactulose and inulin (55.1 and 57.5 μmol/g, respectively). The total production of VFA in the caecum was fourfold higher with 8 % lactulose and inulin (254.7 and 236.4 μmol/100g BW, respectively) than in both controls groups (65.1 and 67.8 μmol/100g BW, respectively). The high dose of inulin and lactulose increased the share of propionic acid in the VFA profile (C2:C3:C4) compared to both control groups. When 4% inulin was added to the diet a significant increase of butyrate concentration in the caecum was observed.

Consumption of polyphenol concentrate with dietary fructo-oligosaccharides enhances cecal metabolism of quercetin glycosides in rats

OBJECTIVE We verified the hypothesis that the consumption of polyphenol concentrate (PC), rich in quercetin and its glycosides (36 g/100 g), in association with different dietary fiber matrices, that is, an easily fermentable fructo-oligosaccharides (FOS) or non-fermentable cellulose (CEL), causes a disparate adaptive response of the cecal microbial activity in rats. This in turn facilitates further utilization of biologically active polyphenolic compounds, which are not, as usual, digested in the foregut. METHODS Four-week experimental feeding of male Wistar rats consisted of diets containing 5% FOS or CEL, as a source of dietary fiber, with or without 0.3% addition of PC. RESULTS Positive changes in rat cecum were observed resulting from the ingestion of an FOS-containing diet, such as decreased pH and increased the production of short-chain fatty acids in the digesta, compared with a CEL-containing diet. The addition of PC to the FOS diet did not eliminate the positive effects of the latter, except for a slight increase in cecal pH and a decrease in microbial glycolytic activity. However, a simultaneous increase in the cecal butyrate pool was also observed. An adaptation process of the microflora enzymatic system to dieting with PC and FOS was proven in further enhanced susceptibility of rutin (quercetin 3-O-glucorhamnoside), hyperoside (quercetin 3-O-galactoside), and quercitrin (quercetin 3-O-rhamnoside) to hydrolysis by the cecal digesta solution. CONCLUSION Especially when consumed together, PC and FOS are important dietary factors affecting the susceptibility of quercetin glycosides to microbial metabolism in the cecum. The intensification of the hydrolysis of quercetin glycosides by dietary treatments leads also to the increased metabolism of quercetin itself.

Caffeoylquinic acid-rich extract from chicory seeds improves glycemia, atherogenic index, and antioxidant status in rats

OBJECTIVE Comparison of the effects of a high-fructose diet supplemented with rutin, a phenolic compound with well-recognized bioavailability and bioactivity, and a chicory (Cichorium intybus L.) seed extract rich in caffeoylquinic acids (CQA) on gut physiology and the development of disorders related to metabolic syndrome. METHODS A 28-d experiment was conducted on 32 young male Wistar rats. In comparison with control rats fed a standard corn starch diet (group C), the experimental group (group E) was fed a diet with an increased content of cholesterol and fructose (to 1% and 66% of the diet, respectively), as well as with oxidized soybean oil. Rats from the other two experimental groups were administered the same diet as group E during the first 2 wk of feeding, whereas at the beginning of the last 2 wk, the diet was enriched with rutin (group ER) or the CQA-rich ethanol extract from chicory seeds (9.6% of CQA, group EC), so the amount of added phenolics was equal in both dietary groups (0.15%). RESULTS The diet administered in group E caused hyperglycemia and increased blood serum atherogenicity in rats, but did not induce other manifestations of the metabolic syndrome, i.e., dyslipidemia and oxidative stress. Additionally, it affected gut physiology through increasing mucosal sucrase activity and disturbing fermentative processes in the cecum, such as the production of short-chain fatty acids and the activity of microbial enzymes. Similarly to rutin, the dietary addition of the chicory seed extract improved glycemia, which was comparable to that determined in group C. In addition, the extract was found to decrease the atherogenic index to the level observed in group C and to increase blood antioxidant status. Both dietary supplements reduced the content of thiobarbituric acid-reactive substances in kidney and heart tissue when compared with group E. CONCLUSION The potential efficacy of the CQA-rich extract from chicory seeds in improving diet-induced metabolic disturbances proved to be better than that of rutin; thus, the extract might be considered as a dietary supplement for carrying out clinical trials.

Effect of dietary supplementation with unprocessed and ethanol-extracted apple pomaces on caecal fermentation, antioxidant and blood biomarkers in rats.

The present 4-week study on growing Wistar rats was aimed at assessing the potential advantages of dietary supplementation with apple pomace containing both fibre and polyphenols, which enables nutritional exploitation of the physiological traits of both compounds. A total of twenty-four rats, assigned to the control (C), group fed with a diet supplemented with 14% of processed apple pomace (A) and group fed with a diet supplemented with 15% unprocessed apple pomace (AP) groups, were fed the following iso-fibrous diets: control, ethanol-extracted and unprocessed apple pomaces (low and high level of dietary polyphenols, i.e. 0·002 and 0·018%, respectively). To measure the animal response, parameters describing the caecal fermentation, antioxidative status and lipoprotein profile of rats were assessed. Both dietary apple pomaces were found to significantly (P≤0·05) decrease caecal pH and ammonia concentration, microbial β-glucuronidase activity as well as to increase caecal SCFA concentration in comparison to the control diet. The unprocessed pomace did not suppress caecal fermentation. Unlike the extracted one, the dietary apple pomace rich in polyphenols significantly (P≤0·05 v. C group) increased erythrocyte superoxide dismutase activity and serum antioxidant capacity of lipid-soluble substances and significantly (P≤0·05 v. C group) decreased amounts of thiobarbituric acid-reactive substances in liver tissue. Moreover, the 4-week administration of the AP diet to rats evoked a significant decrease in serum glucose concentration (P≤0·05 v. C and A groups). In conclusion, the results demonstrated that the polyphenol-rich fibre complexes from apple pomace exerted positive effects on gastrointestinal physiology and antioxidant status of rats.

Gastrointestinal tract metabolism of young turkeys fed diets supplemented with pure nystose or a fructooligosaccharide mixture.

In a four-week experiment on 60 7-day-old BUT-9 male turkeys the effects of dietary fructooligosaccharides (pure nystose and a fructooligosaccharide mixture) supplemented at 1 and 2%, were studied on ileal and caecal metabolism. The control carbohydrate was cellulose, added also at 1 or 2%. Each dietary treatment consists of 10 birds kept individually. The average degree of polymerisation of the nystose and oligofructose preparation amounted to 2.9 and 4.1, respectively. The addition of nystose significantly decreased the pH value and viscosity in the ileal contents compared with the cellulose treatment. On the other hand, the oligofructose preparation increased the activity of sucrase and lactase in the ileal mucosal by 30–60% and 33–47%, respectively. Both fructan preparations similarly acidified the caecal and colonic digesta (by 0.2–0.4 pH units) as well as diminished the activity of bacterial harmful β-glucuronidase (by 24–40%), but only nystose caused an enlargement of the caeca and effectively reduced caecal ammonia concentration, especially at a higher dose. Oligofructose supplementation at 2% caused a 3.5-fold increase of bacterial activity of α- and β-galactosidase, while 2% nystose resulted in 1.7 and 3 times higher α- and β-glucosidases activities, respectively. Compared to oligofructose, dietary nystose increased propionic and decreased butyric fermentation in caeca. Nystose and oligofructose preparations added at 2% reduced the triacylglycerol concentration in the serum in comparison to the addition of 2% cellulose by 46 and 25%, respectively. Beside the fact that dietary levels of supplementation were of great importance, the results indicated that even small difference in the length of carbohydrate chain may cause different physiological responses.

Physiological effects of chicory root preparations with various levels of fructan and polyphenolic fractions in diets for rats

The experiment was aimed at studying the effects of easily fermentable oligosaccharides and phenolic compounds from chicory root meal (CRM) on the fermentative processes in the caecum, the antioxidative status and the lipoprotein profile of rats. Five different diets were fed ad libitum to 40 Wistar rats (eight animals per group, individually housed): a control group (C); group PCM (10% processed CRM, deprived of polyphenolic fraction); group PCMO (8% processed CRM and 1.6% oligofructose); group UCM (10% unprocessed CRM); and group FP (8.3% fructan-polyphenol concentrate from CRM). Diets PCM, PCMO, UCM and FP induced favourable metabolic changes in the caecum, blood lipid profile and the antioxidative status of the body. In the caecum, the experimental diets increased the production of volatile fatty acids (VFA) and acidification of digesta as well as a decrease in the ammonia concentration and bacterial β-glucuronidase activity. In blood serum, the total cholesterol concentration was reduced and, simultaneously, the proportion of HDL in the total cholesterol concentration was increased. The presence of the polyphenolic fraction in the unprocessed meal (diets UCM and FP) evoked a significant increase in the total antioxidative status in blood serum. Dietary fibre and the polyphenolic fraction present in diet UCM and the FOS-polyphenol concentrate in diet FP did not exhibit an antagonistic activity regarding the physiological parameters analysed, except for in the intensity of caecal fermentation. The results of the experiment point to the benefits of dietary supplementation with chicory preparations containing both prebiotic saccharides and polyphenolic compounds, which enable us to take advantage of the physiological traits of both components.

Characterisation of the chemical composition of scab-resistant apple pomaces.

Summary Pomaces obtained during the production of cloudy or clear juice from scab-resistant apple cultivars (28 harvested in 2006, and 23 harvested in 2007) were studied as a source of nutritionally important components. It was shown that the average yield of pomace during the production of cloudy juice was 6.4% (w/w), and 4.9% (w/w) for clear juice pressing. The average total dietary fibre (TDF) contents were 48.4% (w/w) and 52.4% (w/w) for cloudy and clear juice pomaces, respectively. Ten pomaces from cloudy apple juice production, and 12 obtained from clear juice production, contained ≥ 2,000 mg kg−1 of polyphenols.‘Ariwa’ and ‘Rajka’ are apple cultivars suitable for juice production and their pomaces are characterised by having high contents of TDF [50.9% (w/w) and 51.1% (w/w), respectively], with aboveaverage polyphenol and quercetin glycoside concentrations. The mean contents of quercetin glycosides for pomaces from all apple cultivars was 994 mg kg−1 after clear juice production, and 908.2 mg kg−1 after cloudy juice production. ‘Topaz’, which became a popular commercial apple cultivar in Europe, was the best source of health-promoting components. Its pomace was the richest source of polyphenols among all 28 cultivars studied. It contained ≥ 2,000 mg kg−1 quercetin glycosides in both its clear and cloudy juice pomaces.

Physiological Properties of Dietary Ellagitannin-Rich Preparations Obtained from Strawberry Pomace Using Different Extraction Methods

Abstract The objective of this study was to establish the composition of strawberry preparations rich in ellagitannins obtained using water or acetone extraction (EF and EP preparation, respectively). Then, biological effect of these extracts was assessed in 4-wk nutritional experiment on Wistar rats. The preparations were applied in cholesterol-containing diets that had equal content of ellagitannins (0.03%). To measure animals response, parameters describing the caecal fermentation (ammonia and short-chain fatty acid concentrations, bacterial enzymes activity), blood serum lipoprotein profile, and TBARS content in selected tissues (heart, liver, kidney) were assessed. Apart from polyphenols, including ellagitannins (7.8 and 7.1%, respectively), the EF preparation contained high quantities of soluble dietary fibre and other carbohydrates (33.3 and 38.9%, respectively), whereas the EP preparation was characterised by 58.9% content of ellagitannins, no dietary fibre and a high content of proanthocyanidins (16.9%). In comparison to EF group, the dietary treatment with EP had a stronger effect on caecal environment as manifested by decreased digesta bulk, β-glucuronidase activity and total short-chain fatty acid concentration (P<0.05 vs. group C without supplementation). Both preparations lowered lipaemia and glycaemia. It could be concluded that more efficient acetone extraction of strawberry pomace increased the content of both ellagitannins and proanthocyanidins in the polyphenolic preparation, which caused a stronger inhibiting effect on caecal fermentation processes and at the same time lowered blood triacylglycerols and glucose level. Considering the equal content of ellagitannins in both supplemented diets, it may be speculated that the above effects were due to the presence of proanthocyanidin fraction.