Effects of young barley leaf powder on gastrointestinal functions in rats and its efficacy-related physicochemical properties.

Young barley leaf is consumed as a popular green-colored drink, which is named "Aojiru" in Japan. In the present study, we examined effects of young barley leaf powder (BL) on gastrointestinal transit time (GTT) and fecal moisture and weight in comparison with wheat bran (WB) in male Sprague-Dawley rats. In addition, an attempt was made to identify BL components responsible for these effects by using various fractions of BL. Additionally, we examined the water-holding capacity and setting volume of BL in vitro. We also examined the granular structures of BL with a scanning electron microscope. As a result, BL supplementation in the diet increased the fecal weight and shortened GTT. Our results demonstrate that the active component responsible for the effect on increasing the fecal volume in BL is the water-insoluble dietary fiber fraction and that this effect is thought to be caused by stimulation of the gut tract by the pH lowering. Furthermore, the high laxative action of BL was thought to be ascribable to the high water-holding capacity due to the complicated structures of BL.

Insoluble fiber in young barley leaf suppresses the increment of postprandial blood glucose level by increasing the digesta viscosity.

Barley (Hordeum vulgare L.) is a well-known cereal plant. Young barley leaf is consumed as a popular green-colored drink, which is named "Aojiru" in Japan. We examined the effects of barley leaf powder (BLP) and insoluble fibers derived from BLP on postprandial blood glucose in rats and healthy Japanese volunteers. BLP and insoluble fibers derived from BLP suppressed the increment of postprandial blood glucose levels in rats (P < 0.01), and increased the viscosity of their digesta. The insoluble fibers present in BLP might play a role in controlling blood glucose level by increasing digesta viscosity. In human, BLP suppressed the increment of postprandial blood glucose level only in those which exhibited higher blood glucose levels after meals (P < 0.01). BLP might suppress the increment of postprandial blood glucose level by increasing digesta viscosity in both of rats and humans who require blood glucose monitoring.

Oral toxicological studies of pueraria flower extract: acute toxicity study in mice and subchronic toxicity study in rats.

Kudzu has been widely used as an herbal medicine in China. The root of the kudzu is also well known as an antipyretic and analgesic in treatment of the common cold, while its flower has been used to treat alcohol intoxication, alcohol abuse, and dysentery. Pueraria flower extract (PFE) is a hot water extract derived from the flower of the kudzu, Pueraria thomsonii Benth. (Fabaceae), oral intake of which exhibits anti-obesity properties in mice and humans. In this study, we conducted acute and subchronic toxicity studies for an evaluation of safety. In the acute study, PFE (5 g/kg body weight) was orally administered to ddY mice. For 14 d after administration, no deaths or abnormal changes were observed in general signs, body weight (BW), or food consumption, and no abnormal findings were observed in the major organs and tissues of either males or females at necropsy. The oral LD50 of PFE was therefore estimated to be higher than 5 g/kg BW. In the subchronic study, PFE was mixed into the diet in place of powdered CRF-1 and administered at concentrations of 0% (control), 0.5%, 1.5%, and 5.0% to male and female Sprague-Dawley rats for 90 d. No mortality or toxicological changes were observed during the experimental period. Blood biochemical, hematological, and urinary parameters revealed no toxicologically significant changes. Furthermore, no anatomical or histopathological changes due to PFE were observed. The no-observed adverse-effect-level of PFE was thus estimated to be 5.0% in the diet (male: 3.0 g/kg BW/d; female: 3.5 g/kg BW/d).

The isoflavone-rich fraction of the crude extract of the Puerariae flower increases oxygen consumption and BAT UCP1 expression in high-fat diet-fed mice.

Puerariae flower extract (PFE) is a crude extract of the Kudzu flower. Previous studies have shown that PFE supplementation exerts anti-obesity and anti-fatty liver effects in high-fat diet-fed mice. In this study, we aimed to identify the PFE components responsible for these effects and to determine their influence on energy expenditure and uncoupling protein 1 (UCP1) expression. Experiments were conducted on C57BL/6J male mice classified into 3 groups: (1) high-fat diet-fed (HFD), (2) high-fat diet-fed given PFE (HFD + PFE), and (3) high-fat diet-fed given the PFE isoflavone-rich fraction (HFD + ISOF). All groups were fed for 42 days. The HFD + PFE and HFD + ISOF groups showed significant resistance to increases in body weight, hepatic triglyceride level, and visceral fat compared to the HFD group. These groups also exhibited significant increases in oxygen consumption and UCP1-positive brown adipose tissue (BAT) area. Our results demonstrate that the active ingredients in PFE are present in the ISOF and that these compounds may increase energy expenditure by upregulation of BAT UCP1 expression. These findings provide valuable information regarding the anti-obesity effects of isoflavones.

Consumption of Pueraria flower extract reduces body mass index via a decrease in the visceral fat area in obese humans.

In Japan, kudzu is a familiar plant, well-known as an ingredient in the Japanese-style confections kudzu-kiri and kudzu-mochi. In this study, we focused on the flower of kudzu (Pueraria thomsonii) and conducted a clinical trial to investigate the effects of Pueraria thomsonii flower extract (PFE) on obesity using obese Japanese males and females (BMI ≥ 25 kg/m(2)). Eighty-one obese subjects were randomly divided into three groups and consumed test food containing 300 mg of PFE, 200 mg of PFE, and a placebo over 12 weeks. The results indicate that PFE intake reduces BMI and decreases, the visceral fat area, but not the subcutaneous fat area. In addition, the decrease in visceral fat area showed no sexual dimorphism. Consequently, we propose that PFE intake expresses its BMI reduction effects via a decrease in visceral fat area.

The crude extract from puerariae flower exerts antiobesity and antifatty liver effects in high-fat diet-induced obese mice.

Kudzu, a leguminous plant, has long been used in folk medicine. In particular, its flowers are used in Japanese and Chinese folk medicine for treating hangovers. We focused on the flower of Kudzu (Puerariae thomsonii), and we previously reported the antiobesity effect of Puerariae thomsonii flower extract (PFE) in humans. In this study, we conducted an animal study to investigate the effect of PFE on visceral fat and hepatic lipid levels in mice with diet-induced obesity. In addition, we focused on gene expression profiles to investigate the antiobesity mechanism of PFE. Male C57BL/6J mice were fed a high-fat diet (HFD) or an HFD supplemented with 5% PFE for 14 days. PFE supplementation significantly reduced body weight and white adipose tissue (WAT) weight. Moreover, in the histological analysis, PFE supplementation improved fatty liver. Hepatic reverse transcription-polymerase chain reaction revealed that PFE supplementation downregulated acetyl-CoA carboxylase expression. For adipose tissue, the expressions of hormone-sensitive lipase in WAT and uncoupling protein 1 in brown adipose tissue (BAT) were significantly upregulated. These results suggest that PFE exerts antiobesity and antifatty liver effects in high-fat diet-induced obese mice through suppressing lipogenesis in the liver, stimulating lipolysis in WAT, and promoting thermogenesis in BAT.

Direct assessment by electron spin resonance spectroscopy of the antioxidant effects of French maritime pine bark extract in the maxillofacial region of hairless mice.

Flavangenol, one of extract of French maritime pine bark, is a complex mixture of bioflavonoids with oligometric proanthocyanidins as the major constituents. These constituents, catechin and procyanidin B(1), are water-soluble derivatives of flavangenol. In this study, we investigated the antioxidant effects of flavangenol on reactive oxygen species such as hydroxyl radical, superoxide anion and singlet oxygen using electron spin resonance and spin trapping. The effect of flavangenol on oxidative stress in the skin from the maxillofacial region of hairless mice was investigated using an in vivo L-band electron spin resonance imaging system. Flavangenol attenuated oxidative stress in the maxillofacial skin by acting as a reactive oxygen species scavenger, as demonstrated by in vitro and in vivo electron spin resonance imaging analysis. The absorption and metabolism of flavangenol were also examined. After oral administration of flavangenol in human and rat, most of the catechin in plasma was in the conjugated form, while 45% to 78% of procyanidin B(1) was unconjugated, indicating that non-conjugated procyanidin B(1) would be active in the circulation. The ability of flavangenol to reduce reactive oxygen species levels in the circulation of the maxillofacial region suggests that this extract may be beneficial for skin protection from exposure to ultraviolet irradiation.

Sweet potato (Ipomoea batatas L.) leaves suppressed oxidation of low density lipoprotein (LDL) in vitro and in human subjects.

Sweet potato (Ipomoea batatas L.) leaves are consumed as vegetables around the world, especially in Southeast Asia. The aim of this study was to investigate the inhibitory effect of sweet potato leaves on low-density lipoprotein oxidation in vitro and in human subjects. We compared the antioxidant activity of 8 kinds of sweet potato leaves. Every sweet potato leaf had high radical scavenging activity and prolonged a lag time for starting low-density lipoprotein oxidation in vitro. We found that sweet potato leaves contained abundant polyphenol compounds and the radical scavenging activity and prolongation rate of lag time were highly correlated with total polyphenol content. We also confirmed that thiobarbituric acid reactive substances production was increased in endothelial cell-mediated low-density lipoprotein oxidation, which was decreased by treatment with sweet potato leaves. We further measured the low-density lipoprotein oxidizability in 13 healthy volunteers after their intake of 18 g of "Suioh", raw sweet potato leaves. "Suioh" prolonged a lag time for starting low-density lipoprotein oxidation and decreased low-density lipoprotein mobility. These results suggest that sweet potato leaves have antioxidant activity leading to the suppression of low-density lipoprotein oxidation.

Metabolism of Isoflavones Found in the Pueraria thomsonii Flower by Human Intestinal Microbiota.

Isoflavones contained in the root and flower of Kudzu (Pueraria lobata and related species) are suggested to be the critical component for its effects. Although metabolism of soy isoflavones has been well studied, the composition of isoflavones found in Kudzu is completely different from that of soy isoflavones. In the present study, we investigated whether isoflavones found in the flower of Pueraria thomsonii, a species of Kudzu, were metabolized by human fecal microbiota and murine small intestinal enzymes. Among 5 glycosidic isoflavones of the Pueraria thomsonii flower, tectorigenin 7-O-xylosylglucoside, tectoridin, genistin and glycitin were completely hydrolyzed by a homogenate of germfree mouse small intestine without contribution of bacteria. Released aglycones were not further metabolized, except that up to half of glycitein disappeared. Mouse small intestinal enzymes did not metabolize 6-hydroxygenistein 6,7-di-O-glucoside. Isoflavone aglycones as well as 6-hydroxygenistein 6,7-di-O-glucoside were highly metabolized by most of the human fecal suspensions. Metabolites were not detected with the present analytical methods in most cases. Although further investigations of the pharmacokinetics of Pueraria thomsonii flower isoflavones are needed, the results of the present study indicate active metabolism of Pueraria thomsonii flower isoflavones in the human intestine.

Dietary pine bark extract reduces atherosclerotic lesion development in male ApoE-deficient mice by lowering the serum cholesterol level.

Pine bark extract (PBE) mainly contains proanthocyanidin in oligomers. It has many physiological effects, including antioxidant, anti-inflammatory, and so on. In this study, we investigated whether PBE has an anti-atherogenic effect on apoE-deficient mice. Male and female mice were fed a diet based on an AIN-76 formula (control diet), and that diet supplemented with 2% PBE (the PBF diet). The PBE diet, compared with the control diet, resulted in lowering the body weight gain and the adipose tissue weight in both male and female mice. The lesion area of the valve and the levels of serum and liver cholesterol in the male mice decreased on the PBE diet. The PBE diet had no significant effect on the levels of urinary isoprostanes or serum thiobarbituric acid reactive substances. These results indicate that dietary PBE can have beneficial effects on atherosclerosis development in male apoE-deficient mice by lowering the serum cholesterol level.