Norihisa Nishida

Anti-Hyperlipidemic sesquiterpenes and new sesquiterpene glycosides from the leaves of artichoke (Cynara scolymus L.): structure requirement and mode of action

The methanolic extract from the leaves of artichoke (Cynara scolymus L.) was found to suppress serum triglyceride elevation in olive oil-loaded mice. Through bioassay-guided separation, sesquiterpenes (cynaropicrin, aguerin B, and grosheimin) were isolated as the active components together with new sesquiterpene glycosides (cynarascolosides A, B, and C). The oxygen functional groups at the 3- and 8-positions and exo-methylene moiety in alpha-methylene-gamma-butyrolactone ring were found to be essential for the anti-hyperlipidemic activity of guaiane-type sesquiterpene. In addition, inhibition of gastric emptying was shown to be partly involved in anti-hyperlipidemic activity.

Hepatoprotective, superoxide scavenging, and antioxidative activities of aromatic constituents from the bark of Betula platyphylla var. japonica

The 50% aqueous methanolic extract from the bark of Betula platyphylla SUKATCHEV var. japonica (MIQ). HARA was found to show potent inhibitory activity on the liver-injury induced by CCl4 or D-galactosamine (D-GalN)/lipopolysaccharide as well as O2- scavenging and antioxidative activities. From the 50% aqueous methanolic extract, two new diarylheptanoids named betulaplatosides Ia (1) and Ib (2) and a new arylbutanoid named betulaplatoside II (3) were isolated together with seventeen known aromatic constituents. 1, 2, and two known diarylheptanoids [(5S)-5-hydroxy-1,7-bis-(4-hydroxyphenyl)-3-heptanone 5-O-beta-D-apiofurano-syl-(1-->6)-beta-D-glucopyranoside (6) and aceroside VIII (7)] showed protective activity against D-GalN-induced cytotoxicity in primary cultured rat hepatocytes. Furthermore, several aromatic constituents exhibited potent O2- scavenging and antioxidative activities.

Hepatoprotective and nitric oxide production inhibitory activities of coumarin and polyacetylene constituents from the roots of Angelica furcijuga

The methanolic extract from the roots of Angelica furcijuga KITAGAWA was found to exhibit protective effects on liver injury induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). From the methanolic extract, seventeen coumarins, two phenylpropanoids, and two polyacetylenes were isolated and examined their in vitro and in vivo hepatoprotective effects and inhibitory activity of NO production in macrophages. A acylated khellactone, isoepoxypteryxin, showed protective activity against D-GalN-induced cytotoxicity in primary cultured rat hepatocytes. On the other hand, six acylated khellactones (hyuganins A, B, C, and D, anomalin, isopteryxin) and two polyacetylenes [(-)-falcarinol and falcarindiol] strongly inhibited NO production induced by LPS in cultured mouse peritoneal macrophages, and also other acylated khellactones (isoepoxypteryxin, pteryxin, and suksdorfin) and a coumarin glycosides (praeroside II) were found to show the activity. By comparison of the inhibitory activities for acylated khellactones with those for other coumarins, acyl groups were found to be essential to exerting potent activity.

Tiliroside, a glycosidic flavonoid, inhibits carbohydrate digestion and glucose absorption in the gastrointestinal tract.

SCOPE Recent studies have reported that tiliroside, a glycosidic flavonoid, possesses anti-diabetic activities. In the present study, we investigated the effects of tiliroside on carbohydrate digestion and absorption in the gastrointestinal tract. METHODS AND RESULTS This study showed that tiliroside inhibits pancreatic α-amylase (IC₅₀ = 0.28 mM) in vitro. Tiliroside was found as a noncompetitive inhibitor of α-amylase with K(i) values of 84.2 μM. In male ICR mice, the increase in postprandial plasma glucose levels was significantly suppressed in the tiliroside-administered group. Tiliroside treatment also suppressed hyperinsulinemia after starch administration. Tiliroside administration inhibited the increase of plasma glucose levels in an oral glucose tolerance test, but not in an intraperitoneal glucose tolerance test. In human intestinal Caco-2 cells, the addition of tiliroside caused a significant dose-dependent inhibition of glucose uptake. The inhibitory effects of both sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) inhibitors (phlorizin and phloretin, respectively) on glucose uptake were significantly inhibited in the presence of tiliroside, suggesting that tiliroside inhibited glucose uptake mediated by both SGLT1 and GLUT2. CONCLUSION These findings indicate that the anti-diabetic effects of tiliroside are at least partially mediated through inhibitory effects on carbohydrate digestion and glucose uptake in the gastrointestinal tract.

Rosehip Extract Inhibits Lipid Accumulation in White Adipose Tissue by Suppressing the Expression of Peroxisome Proliferator-activated Receptor Gamma

Recent studies have shown that Rosa canina L. and tiliroside, the principal constituent of its seeds, exhibit anti-obesity and anti-diabetic activities via enhancement of fatty acid oxidation in the liver and skeletal muscle. However, the effects of rosehip, the fruit of this plant, extract (RHE), or tiliroside on lipid accumulation in adipocytes have not been analyzed. We investigated the effects of RHE and tiliroside on lipid accumulation and protein expression of key transcription factors in both in vitro and in vivo models. RHE and tiliroside inhibited lipid accumulation in a dose-dependent manner in 3T3-L1 cells. We also analyzed the inhibitory effect of RHE on white adipose tissue (WAT) in high-fat diet (HFD)-induced obesity mice model. Male C57BL/6J mice were fed HFD or HFD supplemented with 1% RHE (HFDRH) for 8 weeks. The HFDRH-fed group gained less body weight and had less visceral fat than the HFD-fed group. Liver weight was significantly lower in the HFDRH-fed group and total hepatic lipid and triglyceride (TG) content was also reduced. A significant reduction in the expression of peroxisome proliferator-activated receptor gamma (PPARγ) was observed in epididymal fat in the HFDRH-fed group, in comparison with controls, through Western blotting. These results suggest that downregulation of PPARγ expression is involved, at least in part, in the suppressive effect of RHE on lipid accumulation in WAT.

Absolute stereostructures of acylated khellactone-type coumarins from Angelica furcijuga

Two new acylated khellactone-type coumarin hyuganoside I (1) and hyuganin F (2) were isolated from the leaves of Angelica furcijuga. Their absolute stereostructures were determined on the basis of chemical and physicochemical evidence. Furthermore, the absolute stereostructures of the acyl moieties in hyuganins A (3) and C (4) and isoepoxypteryxin (5) were elucidated.

Anti-Glycation Effects of Pomegranate (Punica granatum L.) Fruit Extract and Its Components in Vivo and in Vitro

Accumulation of advanced glycation end products (AGEs) leads to various diseases such as diabetic complications and arteriosclerosis. In this study, we examined the effect of pomegranate fruit extract (PFE) and its constituent polyphenols on AGE formation in vivo and in vitro. PFE, fed with a high-fat and high-sucrose (HFS) diet to KK-A(y) mice, significantly reduced glycation products such as glycoalbumin (22.0 ± 2.4%), hemoglobin A1c (5.84 ± 0.23%), and serum AGEs (8.22 ± 0.17 μg/mL), as compared to a control HFS group (30.6 ± 2.6%, 7.45 ± 0.12%, and 9.55 ± 0.17 μg/mL, respectively, P < 0.05). In antiglycation assays, PFE, punicalin, punicalagin, ellagic acid, and gallic acid suppressed the formation of AGEs from bovine serum albumin and sugars. In this study, we discuss the mechanism of the antiglycation effects of PFE and its components in vivo and in vitro.

Daily intake of rosehip extract decreases abdominal visceral fat in preobese subjects: a randomized, double-blind, placebo-controlled clinical trial

Background Obesity has become a great problem all over the world. We repeatedly screened to find an effective food to treat obesity and discovered that rosehip extract shows potent anti-obesity effects. Investigations in mice have demonstrated that rosehip extract inhibits body weight gain and decreases visceral fat. Thus, the present study examined the effect of rosehip extract on human body fat in preobese subjects. Methods We conducted a 12-week, single-center, double-blind, randomized, placebo-controlled study of 32 subjects who had a body mass index of ≥25 but <30. The subjects were assigned to two random groups, and they received one tablet of placebo or rosehip that contained 100 mg of rosehip extract once each day for 12 weeks with no dietary intervention. Abdominal fat area and body fat percent were measured as primary outcomes. The other outcomes were body weight and body mass index. Results Abdominal total fat area, abdominal visceral fat area, body weight, and body mass index decreased significantly in the rosehip group at week 12 compared with their baseline levels (P<0.01) after receiving the rosehip tablet intake, and the decreases in these parameters were significantly higher when compared with those in the placebo group. Additionally, body fat percent tended to decrease compared with the placebo group and their baseline level. Moreover, the abdominal subcutaneous fat area was significantly lower in the rosehip group than in the placebo group at week 12 after the initiation of intake (P<0.05). In addition, there were no abnormalities, subjective symptoms, and findings that may indicate clinical problems during the study period. Conclusion These results suggest that rosehip extract may be a good candidate food material for preventing obesity.

650. Development of Combination Therapy of Bifidobacterium-Based Oral Vaccine Displaying HCV-NS3 with Interferon-α

INTRODUCTION: Hepatitis C virus (HCV) is a major cause of chronic liver diseases, such as liver cirrhosis and hepatocellular carcinoma. The efficacy of the standard-of-care including interferon-α and ribavirin for chronic HCV infection is limited, especially in HCV genotype 1, the most prevalent genotype in Japan. It is considered that chronic HCV infection correlates strongly with failure of host immune response against HCV. Although HCV specific immune responses play an especially significant role in clearing virus, no effective vaccine against HCV was approved at present. We had successfully developed a recombinant Bifidobacterium based novel oral vaccine against HCV infection, displaying a HCV-nonstructural protein 3 (NS3) fusion peptide on the bacterial cell surface. We had found that this oral vaccine could induce HCV-NS3 specific CTL in mice. Then, in this study, to determine the therapeutic efficacy of this oral vaccine, the functional HCV specific cellular immune response was investigated by using HCV-NS3/4A antigen expressing tumor mouse model. Furthermore, to enhance the therapeutic efficacy, we combined interferon-α therapy with this oral vaccine in the mouse model. EXPERIMENTAL SUMMARY: Bifidobacterium longum (B. longum 2165) expressing NS3 fusion peptide derived HCV-genotype 1b was prepared and then heat inactivated for 5 min at 65 ° C for oral vaccination. For the tumor challenge, C57BL/6N mice were subcutaneously injected EL-4 lymphoma cells stably expressing HCV-NS3/4A, and then orally administered 2.4×108 CFU of inactivated B. longum 2165, active B. longum 2165, active B. longum transfected control vector (B. longum 2012), or PBS every other day for 4 weeks. In addition, for the combination therapy with interferon-α, inactivated B. longum 2165 and PBS groups were combined with 20,000 units of interferon-α subcutaneous injection every 4 days during vaccination. In the results, B. longum 2165 with interferon-α combination therapy significantly delayed tumor growth compared with the other treatments. For in vitro cytotoxicity assay, splenocytes were collected from immunized mice and restimulated with EL4-NS3/4A and IL-2. In the B. longum 2165 with interferon-α treated group, the cytotoxicity of splenocytes against EL4-NS3/4A was significantly higher than that of the other groups. CONCLUSION: This study demonstrated multiple oral vaccinations of B. longum 2165 could induce functional NS3 specific cellular immune responses in mice. Moreover, interferon-α combination therapy with the vaccine could strongly enhance the therapeutic efficacy of this vaccine. These findings support the feasibility of this therapeutic oral vaccine as additional agent of interferon based standard therapy against chronic HCV infection.