Dietary polyphenols increase fecal mucin and immunoglobulin A and ameliorate the disturbance in gut microbiota caused by a high fat diet.

The effects of dietary polyphenols on human health have mainly been discussed in the context of preventing degenerative diseases, particularly cardiovascular diseases and cancer. The antioxidant properties of polyphenols have been widely studied, but it has become clear that the mechanism of action of polyphenols extends beyond the modulation of oxidative stress, as they are poorly absorbed from the digestive tract. The purpose of this study was to clarify the effects of polyphenols on the colonic environment, intestinal barrier function, and gut microbiota. We demonstrated that dietary polyphenols derived from aronia, haskap, and bilberry, markedly elevated the amount of fecal mucin and immunoglobulin A (IgA) as an intestinal barrier function and ameliorated the disturbance in gut microbiota caused by a high fat diet in rats. These results suggest that dietary polyphenols play a significant role in the prevention of degenerative diseases through improvement of the colonic environment without any absorption from the digestive tract.

Effects of various asparagus production methods on rutin and protodioscin contents in spears and cladophylls.

The purpose of this study was to clarify the relationship between various cultivation conditions and the amounts of the rutin (RT) and protodioscin (PD) in asparagus spears. Green and white spears were grown in open culture and under two different blanching conditions. Although RT was detected only in the green spears, PD was detected mainly in white spears produced by covering with soil. The RT and PD contents of cladophylls grown in an open field and in a closed cultivation system were also investigated, and the closed system resulted in cladophylls with low RT and high PD, unlike the open field.

Improvement of bone strength and dermal thickness due to dietary edible bird's nest extract in ovariectomized rats.

Oral administration of edible bird's nest extract (EBNE) improved bone strength and calcium concentration in the femur of ovariectomized rats. Dermal thickness was also increased by EBNE supplementation, whereas EBNE administration did not affect the serum estradiol concentration. These results suggest that EBNE is effective for the improvement of bone loss and skin aging in postmenopause all women.

Intestinal absorption of black chokeberry cyanidin 3-glycosides is promoted by capsaicin and capsiate in a rat ligated small intestinal loop model.

Recent studies have shown that aronia (black chokeberry) and haskap fruits (contain anthocyanins) have beneficial health effects in animals and humans. However, some reports have shown that anthocyanin is poorly absorbed in the small intestine. In this study, we compared the intestinal absorption of aronia and haskap anthocyanins by using rats with a ligated small intestinal loop and cannulated portal vein. Our results clearly showed that the intestinal absorption of aronia anthocyanins was significantly lower than that of haskap anthocyanins, suggesting that the intestinal absorption of anthocyanins is influenced by the glycoside type (galactoside or glucoside). In addition, we also examined the effects of capsaicin and capsiate on intestinal anthocyanin absorption. The amount of aronia anthocyanins in portal blood was much higher when they were co-administered with capsaicin or capsiate. Our study is the first to show that the intestinal absorption of aronia anthocyanins is promoted by capsaicin and capsiate.

Voluntary running exercise alters microbiota composition and increases n-butyrate concentration in the rat cecum.

The effects of voluntary wheel-running exercise on cecal microbiota and short-chain fatty acid production were investigated in rats. The microbiota composition was notably different between the exercised and sedentary rats. Furthermore, the exercised rats showed a significantly higher n-butyrate concentration than the sedentary rats. This alteration of the cecal microbial environment may contribute to the beneficial effect of exercise on gastrointestinal disorders.

Difructose anhydride III promotes absorption of the soluble flavonoid alphaG-rutin in rats.

A highly soluble quercetin glycoside, alphaG-rutin, is a glucose adduct of insoluble rutin. We examined the effects of difructose anhydride III (DFAIII; di-D-fructofuranosyl 1,2':2,3'-dianhydride) on intestinal absorption of alphaG-rutin by rat experiments. alphaG-rutin, rutin, quercetin, and the quercetin conjugate appeared in the portal blood after an intubation of alphaG-rutin (100 micromol), DFAIII effected higher portal concentrations of alphaG-rutin in portal cannulated rats. In ligated jejunal and ileal loops of rats, alphaG-rutin, rutin, quercetin, and the quercetin conjugate appeared in the intestinal mesenteric blood at both 30 and 60 min in both loops; the concentration of alphaG-rutin was 1.5-3 times higher when absorbed in the presence DFAIII. In the isolated mucosae of the jejunum and ileum, mucosal-to-serosal passage of alphaG-rutin increased with the addition of 100 micromol of DFAIII. These results indicate that alphaG-rutin is absorbed as the intact form and that DFAIII stimulates its absorption in the small intestine.

Two-week feeding of difructose anhydride III enhances calcium absorptive activity with epithelial cell proliferation in isolated rat cecal mucosa.

OBJECTIVE: Ingestion of difructose anhydride III (DFAIII) enhances calcium (Ca) absorption in rats. The present study investigated the mechanism involved in increased Ca transport by DFAIII ingestion. The short-term and long-term effects of DFAIII feeding on Ca transport were determined by using isolated epithelium from the small and large intestine in rats. METHODS: Male Sprague-Dawley rats were fed an 8% cellulose or 5% cellulose plus 3% DFAIII diet for 14 d. Net epithelial Ca transport in the small intestine, cecum, and colon was compared between the two diet groups by using an Ussing chamber. The contents and epithelial tissues in the cecum were analyzed. RESULTS: There were no differences in basal and luminal DFAIII-induced Ca transport in the isolated small intestinal and colonic mucosa between the two diet groups. Basal and lumen DFAIII-induced Ca transport in the cecum in the DFAIII-fed group was higher than that in the control group. A decrease in pH and an increase in Ca pools, short-chain fatty acids, or organic acids in the cecal contents and in the depth and number of cells in crypts in cecal tissue were observed. CONCLUSIONS: The increase in Ca transport involved two mechanisms: the presence of DFAIII in the small intestine directly affected the epithelial tissue and caused increased Ca absorption as a short-term effect, and the degradation of DFAIII by microbial fermentation produced short-chain fatty acids and subsequently enhanced Ca absorption in the large intestine as a long-term effect.

Potato pulps lowered the serum cholesterol and triglyceride levels in rats.

In our previous study, we demonstrated that retrograded starch, a kind of resistant starch, of beans reduced serum lipid levels in rats. In this study, we examined whether retrograded starch in potato pulps could reduce serum lipid concentrations. Rats were given diets containing 15 g of retrograded starch in potato pulps from the Benimaru potato (BM) or Hokkaikogane potato (HK) in a 100 g diet for 4 wk. At the 4th week, the total cholesterol level in the serum in the BM group and serum triglyceride (TG) level in the HK group were significantly lower than those in the control group. In the BM group, the contents of fecal bile acids were significantly higher than those in the control group. On the other hand, in the HK group, the hepatic mRNA level of fatty acid synthase (FAS) was significantly lower than that in the control group. The FAS mRNA level correlated with the mRNA level of sterol regulatory element-binding protein-1c (SREBP-1c), a regulator of expression of FAS, positively. These results suggested that BM pulp promoted the excretion of bile acids, which resulted in a low concentration of serum cholesterol. On the other hand, HK pulp inhibited the synthesis of fatty acids at the mRNA levels of FAS and SREBP-1c, which might lead to a reduction of the serum TG level.

Protective Effect of Dietary Lily Bulb on Dextran Sulfate Sodium-Induced Colitis in Rats Fed a High-Fat Diet.

Lily bulb is traditionally consumed in East Asia and contains high amounts of glucomannan. This study investigated the effect of dietary lily bulb on dextran sulfate sodium (DSS)-induced colitis in rats fed a high-fat (HF) diet. Male Sprague-Dawley rats were fed a diet containing 30% beef tallow with or without 7% steamed lily bulb powder for 17 d. Experimental colitis was induced by replacing drinking water with DSS during the last 7 d. The disease activity index (DAI) was significantly lower in the lily bulb+DSS group than in the DSS group on day 17. The fecal abundance of Bifidobacterium was significantly reduced in the DSS group compared with that in the control group, but it was recovered by lily bulb intake. Cecal butyrate, fecal mucins, and alkaline phosphatase (ALP) activity were significantly higher in the DSS group than in the control group. Dietary lily bulb potentiated the increase in cecal butyrate, fecal mucins, and the ALP activity caused by DSS treatment. These results indicate that lily bulb attenuates DSS-induced colitis by modulating colonic microflora, organic acids, mucins, and ALP activity in HF diet-fed rats.

Consumption of lily bulb modulates fecal ratios of firmicutes and bacteroidetes phyla in rats fed a high-fat diet.

It has been recently suggested a high ratio of fecal Firmicutes and reduction in the Bacteroidetes in obese animals. This study investigated the effect of dietary lily bulb (LB) on fecal Firmicutes and Bacteroidetes in rats fed a high-fat (HF) diet. In experiment 1, rats were fed an HF diet with or without 7% raw (R) or steamed (S) LB. In experiment 2, rats were fed the HF diet with or without 7% RLB, 0.9% ethanol extract of LB, or 6.1% ethanol extract residue of LB. In experiment 1, fecal Firmicutes was reduced and Bacteroidetes was increased in both the RLB and SLB groups. In experiment 2, the fecal Firmicutes/Bacteroidetes ratio was not affected by the ethanol extract or ethanol extract residue of LB. These results suggest that LB in its entirety modulates colonic microflora, regardless of heat treatment.

Intestinal absorption and metabolism of a soluble flavonoid, alphaG-rutin, in portal cannulated rats.

A highly soluble quercetin glycoside, alphaG-rutin, is a glucose adduct of insoluble rutin, and intestinal absorption and metabolism of alphaG-rutin has not been known. We investigated the intestinal absorption and metabolism of alphaG-rutin by using portal and duodenal cannulated rats and the isolated rat intestinal mucosa. After a duodenal instillation of alphaG-rutin (150 mumol), intact alphaG-rutin, rutin and quercetin were appeared in the portal blood and these concentrations were similarly increased at 15 min. Portal quercetin reached a peak value at 60 min, and the value was higher than those of alphaG-rutin and rutin at that time. Quercetin-conjugates were also increased 30 min after the instillation. The remaining of alphaG-rutin metabolites, mainly rutin, in the intestine were 58% of instilled alphaG-rutin after 150 min. In the experiment by using the isolated mucosa of the jejunum, ileum and cecum, alphaG-rutin and rutin, but not quercetin, appeared in the serosal sides of all segments, and they were increased linearly from 10 to 100 mmol/l of mucosal alphaG-rutin. We also showed portal injected alphaG-rutin was very rapidly cleared from the blood, and appeared a large amount of conjugates. In conclusion, a soluble flavonoid-glycoside, alphaG-rutin, was absorbed as glycosides into the portal blood. A part of alphaG-rutin was hydrolyzed to rutin, but not to aglycone, through the intestine.

Amylomyces rouxii strain CBS 438.76 affects cholesterol metabolism in cholesterol-fed rats.

We examined the effects of Amylomyces rouxii, which is a mold found in some fermented foods in Indonesia, on serum cholesterol and hepatic LDL receptor mRNA in rats. Rats were fed a 0.5% cholesterol-enriched diet with (A. rouxii group) or without (control group) 30 g/kg A. rouxii for 4 wk. There were no significant differences in the body weight, food intake or liver weight among the groups. However, the weight of the cecum in the A. rouxii-fed group was significantly higher than that in the control group. The cecal pH in the A. rouxii-fed group was significantly lower than that in the control group. Cecal acetic acid, propionic acid and total SCFA concentrations in the A. rouxii-fed group were significantly higher than those in the control group. The serum total cholesterol and VLDL+intermediate density lipoprotein (IDL)+LDL-cholesterol concentrations in the control group were significantly higher than those in the A. rouxii-fed group at the end of the 4-wk feeding period. There were no significant differences in the HDL-cholesterol or triglyceride concentrations between the groups. The hepatic LDL receptor and cholesterol 7alpha-hydroxylase mRNA levels in the A. rouxii-fed group were significantly higher than those in the control group. The results of this study demonstrate that feeding of A. rouxii lowers the serum total cholesterol level by enhancement of the cecal SCFA concentration and the hepatic LDL receptor mRNA.

Anthocyanin-rich Phytochemicals from Aronia Fruits Inhibit Visceral Fat Accumulation and Hyperglycemia in High-fat Diet-induced Dietary Obese Rats.

Aronia fruits (chokeberry: Aronia melanocarpa E.) containing phenolic phytochemicals, such as cyanidin 3-glycosides and chlorogenic acid, have attracted considerable attention because of their potential human health benefits in humans including antioxidant activities and ability to improved vision. In the present study, the effects of anthocyanin-rich phytochemicals from aronia fruits (aronia phytochemicals) on visceral fat accumulation and fasting hyperglycemia were examined in rats fed a high-fat diet (Experiment 1). Total visceral fat mass was significantly lower in rats fed aronia phytochemicals than that in both the control group and bilberry phytochemicals-supplemented rats (p < 0.05). Moreover, perirenal and epididymal adipose tissue mass in rats fed aronia phytochemicals was significantly lower than that in both the control and bilberry phytochemicals group. Additionally, the mesenteric adipose tissue mass in aronia phytochemicals-fed rats was significantly low (p < 0.05). Furthermore, the fasting blood glucose levels significantly decreased in rats fed aronia phytochemicals for 4 weeks compared to that in the control rats (p < 0.05). Therefore, we investigated the effects of phytochemicals on postprandial hyperlipidemia after corn oil loading in rats, pancreatic lipase activity in vitro, and the plasma glycemic response after sucrose loading in order to elucidate the preventive factor of aronia phytochemical on visceral fat accumulation. In the oral corn oil tolerance tests (Experiment 2), aronia phytochemicals significantly inhibited the increases in plasma triglyceride levels, with a half-maximal inhibitory concentration (IC(50)) of 1.50 mg/mL. However, the inhibitory activity was similar to that of bilberry and tea catechins. In the sucrose tolerance tests (Experiment 3), aronia phytochemicals also significantly inhibited the increases in blood glucose levels that were observed in the control animals (p < 0.05). These results suggest that anthocyanin-rich phytochemicals in aronia fruits suppress visceral fat accumulation and hyperglycemia by inhibiting pancreatic lipase activity and/or intestinal lipid absorption.

Gastroprotective effect of red pigments in black chokeberry fruit (Aronia melanocarpa Elliot) on acute gastric hemorrhagic lesions in rats.

It has been reported that the fruits and leaves of berries such as the blackberry, raspberry, and strawberry contain a high level of scavenging activity for chemically generated active oxygen species. This study investigated the antioxidative activities of black chokeberry fruit (Aronia melanocarpa Elliot) both in vitro and in vivo using the DPPH stable radical and rats with ethanol-induced gastric injury, respectively. The red pigment fraction of the black chokeberry contained three main components, one of which was identified as cyanidin 3-O-beta-glucoside by HPLC analysis and (1)H NMR. The black chokeberry red pigment fraction scavenged >44% of DPPH radicals at a concentration of 25 microg/mL compared to the control solution. The black chokeberry extract and its hydrolysate administrated at 2 g/kg of body weight each had nearly the same protective effect as quercetin administrated at 100 mg/kg of body weight in suppressing the area of gastric mucosal damage caused by the subsequent application of ethanol to <30% compared to the control group. The black chokeberry red pigment fraction had a similarly significant protective effect on gastric mucosa in a dose-dependent manner when administered at 30-300 mg/kg of body weight, and the administration of 30 mg/kg of body weight could suppress ethanol-induced gastric mucosal damage by approximately 50% (ID(50) = 30 mg/kg of body weight).

Cholesterol metabolism in rat is affected by protocatechuic acid.

The effects of protocatechuic acid on serum cholesterol and gene expression related to cholesterol metabolism in rats were investigated. Rats were fed a cholesterol-free diet with or without 5 g protocatechuic acid/kg diet for 4 wk. There were no significant differences in body weight and food intake among groups through the experimental period. The liver weight in the protocatechuic acid group was significantly lower than that in the control group. The serum total cholesterol, high-density lipoprotein (HDL)-cholesterol and very low-density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low-density lipoprotein (LDL)-cholesterol concentrations in the protocatechuic acid group were significantly lower than those in the control group through the feeding period. The hepatic cholesterol concentration in the protocatechuic acid group was significantly higher than in the control group at the end of the 4-wk feeding period. The relative hepatic LDL receptor, apo B, apo E, lecithin-cholesterol acyltransferase (LCAT) and hepatic triglyceride lipase (HTGL) mRNA levels in the protocatechuic acid group were significantly higher than those in the control group. The results of this study suggest the possibility that the increase in the hepatic LDL receptor, apo E, LCAT and HTGL guessed by these mRNAs increase in the protocatechuic acid group lowers the serum total cholesterol level.

Hepatoprotective effects of the water extract from adzuki bean hulls on acetaminophen-induced damage in rat liver.

We examined the hepatoprotective effect of water-extract from adzuki bean (Vigna angularis) hulls on acetaminophen (AAP)-induced damage in rat liver. F344/DuCrj rats of 8 weeks of age were fed diets without and with 0.5% AAP or besides it 5% adzuki extract (lyophilized) on a daily basis over a period of 4 wk. At that time, serum aspartate aminotransferase activity in only AAP-treated group was higher than in both control and AAP plus adzuki extract (AAPA)-treated groups, while hepatic glutathione content and hepatic glutathione reductase and catalase activities in the AAP-treated group were lower than in the control group in contrast to the reverse in the AAPA-treated group. Hepatic phosphatidylcholine hydroperoxide and phosphatidylethanolamine hydroperoxide concentrations were higher in the AAP-treated group than in the control group, and were lower in the AAPA-treated group than in the AAP-treated group. Hepatic glutathione peroxidase activity was higher in the AAP-treated group than in the control group, although there was no significant difference between both AAP- and AAPA-treated groups in this respect. These findings suggest that the adzuki extract will serve as a prophylactic against oxidative damage to the liver.

Dietary anthocyanin-rich Haskap phytochemicals inhibit postprandial hyperlipidemia and hyperglycemia in rats.

Haskap (Lonicera caerulea L.) fruit contains some bioactive phenolic phytochemicals, mainly cyanidin-3-glucoside (cy3-glc) and chlorogenic acid. The purpose of this study was to investigate the effects of anthocyanin-rich phenolic phytochemical (containing 13.2% anthocyanin) purified from a Haskap fruit (named Haskap phytochemical) on postprandial serum triglyceride and blood glucose levels. The Haskap phytochemical (containing cy 3-glc at 300 mg/kg of body weight) was administered orally to rats fasted for 24 h and 30 min later, a corn oil emulsion was administered to these rats. After the administration, serum triglyceride concentration was measured. An increase in serum triglyceride concentration and the AUC significantly lowered in the Haskap phytochemical-administered group than in the saline-administered group. To evaluate the effect of serum glucose levels, the Haskap phytochemical was orally administered to rats fasted for 24 h and sucrose solution (2 g/kg of body weight) was administered to these rats after 30 min. After the administration, blood glucose level was measured. The Haskap phytochemical significantly reduced the increase in blood glucose levels and AUC in the Haskap phytochemical-administered group than in the saline-administered group. Furthermore, to investigate the long-term effects of Haskap phytochemical intake, high-fat diet (HF diet) with 1.5% or 3.0% Haskap phytochemical was administered to rats for four weeks. The investigation of chronological changes in the serum components of the rats fed HF diets in addition to the administration of Haskap phytochemical showed that the increase in serum triglyceride concentrations, total cholesterol concentrations and blood glucose were significantly suppressed compared to the HF diet-fed control (HF-control). These results suggest that the decrease in postprandial blood lipids and blood glucose by short or long-term Haskap phytochemical ingestion is due to anthocyanin and other polyphenols contained in the Haskap phytochemical.

Effect of dietary Maitake (Grifola frondosa) mushrooms on plasma cholesterol and hepatic gene expression in cholesterol-fed mice.

To investigate the effects of dietary Grifola frondosa on cholesterol, normal mice were fed a diet containing 1% cholesterol (HC group) or 1% cholesterol and 10% freeze-dried G. frondosa powder (HC+G group) for 4 weeks and hepatic and plasma lipid levels were compared with those of a cholesterol-free diet-fed mice (N group). Hepatic total cholesterol (TC), triacylglycerol contents were considerably increased and plasma TC / phospholipid (PL) was also increased significantly in the HC group compared with the N group. However, plasma TC content decreased in the HC+G group compared with the HC group. To characterize the mechanisms responsible for lowered plasma cholesterol in G. frondosa-supplemented mice, hepatic gene expression was profiled using DNA microarray and gene ontology. Genome analyses revealed that de novo cholesterol synthesis genes were suppressed following cholesterol intake. However, expression of bile acid biosynthesis and low-density lipoprotein receptor genes showed little change. Scarb1, Abcg5, and Abcg8, involved in cholesterol transport and excretion, were slightly upregulated in the HC+G group compared with the HC group. These data indicate the plasma cholesterol-lowering effect of G. frondosa. Moreover, fatty acid (FA) ß-oxidation was promoted via adipocytokine signaling pathways, and Saa, encodes serum amyloid A related to arteriosclerosis, was suppressed in the HC+G group.

Ingestion of potato starch containing esterified phosphorus increases alkaline phosphatase activity in the small intestine in rats.

Alkaline phosphatase (ALP) hydrolyzes a variety of monophosphate esters and plays an important role in phosphorus (P) metabolism. Several nutrients in food have been reported to affect intestinal ALP activity in animal models. Previous reports indicated that high levels of P or phosphate in diets decreased intestinal ALP activity in rats. Because potato starch contains considerable amounts of esterified P, unlike other starch-derived plants, we hypothesized that the feeding of potato starch would decrease ALP activity in the intestinal tract. Male Sprague-Dawley rats (7 weeks old) were fed 3 different types of diet containing 60% corn starch or 1 of 2 types of potato starch with different esterified P content for 1 or 5 weeks. Body weight and food intake of each rat were measured every day throughout the experimental periods. At the end of the feeding periods, the small intestine was removed to determine ALP activity in the mucosal tissues. Significant differences were observed in ALP activity in the small intestine between the 2 feeding periods, among the 4 segments of the small intestine, and among the 3 diet groups. Significant positive linear correlations between the amount of P derived from the starch and mucosal ALP activity were obtained in the jejunum and jejunoileum in rats after feeding for 5 weeks. We concluded, contrary to our hypotheses, that the ingestion of potato starch adaptively increases ALP activity in the upper part of the small intestine of growing rats in an esterified P content-dependent manner.

Oligosaccharide promotes bioavailability of a water-soluble flavonoid glycoside, alpha G-rutin, in rats.

This study examined the effects of a nondigestible saccharide, difructose anhydride (DFA) III, and fructooligosaccharides (FOS) on the intestinal absorption and metabolism of alpha G-rutin, a quercetin glycoside in rats during a 2 week feeding period with diets containing 1% alpha G-rutin with or without 1.5 or 3% DFAIII and FOS. Blood concentrations and urinary excretion of quercetin derivatives were largely and dose-dependently increased during the test period with feeding DFA III and FOS. The amounts of quercetin derivatives in the cecal contents and feces were also much higher in both saccharide groups than in the control group. The degradation rate of aglycone, estimated by differences between ingestion and sum of fecal and urinary excretion, were suppressed in the both saccharide groups. Cecal fermentation was dose-dependently modified by the oligosaccharides. It was concluded that suppression of degrading quercetin aglycone in the large intestine has a major role for increasing alpha G-rutin bioavailability by DFA III and FOS feedings.