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Polyphenolic compounds from chestnut astringent skin (CAS) were purified by dialysis, using Diaion HP-20 and Sephadex LH-20 columns. During purification, specific α-amylase inhibitory activities were increased about 3.4-fold, and the 50% inhibition value was 5.71 μg/mL in the Sephadex LH-20 fraction (SE-fraction). The SE-fraction contained about 67% of the total polyphenols, 57.3% of the flavanol-type tannins, and 51.3% of the procyanidins. Strong antioxidant activity was observed in the SE-fraction. Oral administration of the SE-fraction in rats fed corn starch significantly suppressed an increase in blood glucose levels. The SE-fraction contained gallic acid and ellagic acid. The MALDI-TOF spectrum showed a peak series exhibiting a mass increment of 288 Da, reflecting the variation in the number of catechin/epicatechin units. Our results suggest CAS contains polyphenols with strong α-amylase inhibitory activity. The data also suggest CAS polyphenols might be oligomeric proanthocyanidins with gallic acid and ellagic acid.

カンキツ類の未熟果，成熟果果皮及びじょうのう膜に含まれる脂肪分解活性を測定し，比較検討した．未熟果と成熟果の果皮及びじょうのう膜に脂肪分解活性が認められたが，果汁には認められなかった．未熟果の活性が最も高く，じょうのう膜は果皮の約30％であった．果皮ではフラベドがアルベドより約3倍高い活性が認められた．田中の分類によるダイダイ区（イヨカン，アマナツ等）やミカン区（ウンシュウミカン，ポンカン等）のカンキツには強い脂肪分解活性が認められたが，ライム区（タヒチライム等），シトロン区（レモン等）及びザボン区（土佐ブンタン，グレープフルーツ等）のカンキツには強い脂肪分解活性は認められなかった．以上のことより，カンキツの種類により脂肪分解活性は大きく異なり，未熟果，果皮及びじょうのう膜でもその傾向は同じであった．未熟果のシネフリン含量と脂肪分解活性の間には正の相関関係が認められた．以上のことより，カンキツジュース製造過程の廃棄物である搾汁粕（果皮やじょうのう膜）は，抗肥満作用やコレステロール低下作用を有する機能性食品素材としての利用が考えられる．

Chestnut astringent skin (CAS) extract inhibited pancreatic alpha-amylase and intestinal alpha-glucosidase in a concentration-dependent manner with the 50% inhibition concentration (IC50) for amylase, maltase and sucrase being 7.5, 650 and 390 microg/mL, respectively. We have investigated the effect of CAS extract on carbohydrate absorption in normal rats. Oral administration of CAS extract to rats fed cornstarch (2 g/kg body weight) significantly suppressed the increase of blood glucose levels and the area under the curve (AUC). Administration of CAS extract to rats fed maltose or sucrose delayed the increase of blood glucose level and slightly suppressed AUC, but not significantly. Administration of CAS extract to rats fed glucose did not affect the increase in blood glucose level or AUC. Similar results were observed with type-2 diabetic model rats (GK/jcl). To test the effect of CAS extract on diabetes, type 2 diabetic model mice (db/db mice) were fed a standard laboratory diet containing 1 or 2% CAS extract. CAS extract prevented increases in body weight and fasting blood glucose concentration. These data suggest that CAS extract has an anti-diabetic function in type 2 diabetic mice that mainly functions through inhibition of alpha-amylase.

Basic polysaccharide strongly inhibited the hydrolysis of trioleoylglycerol (TO) emulsified with phosphatidylcholine and taurocholate by either pancreatic lipase or carboxylester lipase. DEAE-Sephadex dose-dependently inhibited the hydrolysis of TO by pancreatic lipase and carboxylester lipase; however, carboxymethyl-Sephadex and Sephadex G-50 did not inhibit the hydrolysis. Polydextrose (PD), a soluble polysaccharide, was a very weak inhibitor of pancreatic lipase. However, when a basic group, a DEAE group, was attached to PD, lipase inhibition by DEAE-PD was increased, and this was dependent on the substitution ratio of DEAE groups. The number of positive charges per PD molecule is important in lipase inhibition. Similar substitution effects were observed with other basic groups, such as piperidinoethyl and 3-triethylamino-2-hydroxypropyl. The natural basic polysaccharide, chitosan, also inhibited pancreatic lipase activity. Gel-filtration experiments suggested that DEAE-PD did not bind strongly to pancreatic lipase. The effect of DEAE-PD on TO hydrolysis by pancreatic lipase was studied using various emulsifiers: DEAE-PD (50 microg/ml) did not inhibit the hydrolysis of TO emulsified with arabic gum, phosphatidylserine, or phosphatidic acid. In vivo, oral administration of DEAE-PD to rats reduced the peak plasma triacylglycerol concentration and increased fecal lipid excretion. These results suggest that basic polysaccharide is able to suppress dietary fat absorption from the small intestine by inhibiting pancreatic lipase activity.

We previously found that ergosterol isolated from Agaricus blazei inhibited tumor growth through the inhibition of tumor-induced neovascularization. In the present study, we isolated further anti-angiogenic substances (A-1 and A-2) from this fungus using an assay system of angiogenesis induced by Matrigel supplemented with vascular endothelial growth factor, and A-1 was identified as sodium pyroglutamate. Next, we examined the antitumor and antimetastatic actions of A-1 using Lewis lung carcinoma (LLC)-bearing mice. A-1 (30, 100 and 300 mg/kg) inhibited tumor growth and metastasis to the lung. The reduction of the numbers of splenic lymphocytes, CD4+ and CD8+ T cells in LLC-bearing mice was inhibited by the oral administration of A-1 (30, 100 and 300 mg/kg). Further, A-1 increased the number of apoptotic cells of tumors and the numbers of CD8+ T and natural killer cells invading the tumors, and inhibited the increase of von Willebrand factor expression (a measure of angiogenesis) in the tumors. These results suggest that the antitumor and antimetastatic actions of A-1 (sodium pyroglutamate) may be associated with inhibition of the reduction of immune response caused by the tumor growth and tumor-induced neovascularization. This is the first report showing that sodium pyroglutamate isolated from A. blazei as an anti-angiogenic substance has potent antitumor and antimetastatic actions, as well as immune-modulatory activity, in tumor-bearing mice.

The effect of bittern on a mouse IgE-mediated dermatitis model was examined. Both the immediate- and delayed-type responses elicited by the IgE-antigen treatment were significantly suppressed in mice treated with bittern. On the other hand, MgCl2, the main component of bittern, failed to suppress either the immediate-or delayed-type response. Furthermore, bittern was found to inhibit IgE production in mice treated with ovalbumin. These results suggest that bittern may improve the pathological state of human atopic dermatitis.

Oral administration of epsilon-polylysine to rats reduced the peak plasma triacylglycerol concentration. In vitro, epsilon-polylysine and polylysine strongly inhibited the hydrolysis, by either pancreatic lipase or carboxylester lipase, of trioleoylglycerol (TO) emulsified with phosphatidylcholine (PC) and taurocholate. The epsilon-polylysine concentration required for complete inhibition of pancreatic lipase, 10 microg/ml, is 1,000 times lower than that of BSA required for the same effect. Inhibition requires the presence of bile salt and, unlike inhibition of lipase by other proteins, is not reversed by supramicellar concentrations of bile salt. Inhibition increases with the degree of polylysine polymerization, is independent of lipase concentration, is independent of pH between 5.0 and 9.5, and is accompanied by an inhibition of lipase binding to TO-PC emulsion particles. However, epsilon-polylysine did not inhibit the hydrolysis by pancreatic lipase of TO emulsions prepared using anionic surfactants, TO hydrolysis catalyzed by lingual lipase, or the hydrolysis of a water-soluble substrate. In the presence of taurocholate, epsilon-polylysine becomes surface active and adsorbs to TO-PC monomolecular films. These results are consistent with epsilon-polylysine and taurocholate forming a surface-active complex that binds to emulsion particles, thereby retarding lipase adsorption and triacylglycerol hydrolysis both in vivo and in vitro.

The Basidiomycete fungus Agaricus blazei Murill has traditionally been used as a health food for the prevention of cancer, diabetes, hyperlipidemia, arteriosclerosis and chronic hepatitis. In the present study, we examined the antitumor activities of various substances isolated from the lipid fraction of A. blazei. Tumor growth was retarded by the oral administration of the lipid fraction extracted from A. blazei with a chloroform/methanol mixture in sarcoma 180-bearing mice. The substance with the antitumor activity in the lipid fraction was isolated via silica gel column chromatography, eluted with an acetonitrile/methanol (3:2) mixture and identified as ergosterol by direct comparison of the (1)H NMR and mass spectrometry spectral data of an authentic sample. The oral administration of ergosterol to sarcoma 180-bearing mice significantly reduced tumor growth at doses of 400 and 800 mg/kg administered for 20 d without side effects, such as the decreases in body, epididymal adipose tissue, thymus, and spleen weights and leukocyte numbers induced by cancer chemotherapy drugs. Ergosterol had no cytotoxicity against tumor cells. To clarify the antitumor activity of ergosterol, we examined the effects of ergosterol on tumor-induced angiogenesis using two in vivo models. Intraperitoneal administration of ergosterol at doses of 5, 10 and 20 mg/kg for 5 consecutive d inhibited the neovascularization induced by Lewis lung carcinoma cell-packed chambers, suggesting that either ergosterol or its metabolites may be involved in the inhibition of tumor-induced neovascularization. Therefore, we further examined the inhibitory effects of ergosterol on Matrigel-induced neovascularization. Female C57BL/6 mice were subcutaneously inoculated with Matrigel containing acidic fibroblast growth factor and heparin with or without ergosterol. Ergosterol inhibited the Matrigel-induced neovascularization, suggesting that ergosterol directly inhibits Matrigel-induced neovascularization. From these results, it seems likely that the antitumor activity of ergosterol might be due to direct inhibition of angiogenesis induced by solid tumors. This is the first report of ergosterol as an antiangiogenic substance.

In vitro, the inhibition by epsilon-polylysine depends on how the substrate is presented to the lipase. We therefore examined whether epsilon-polylysine can interact with the lipid emulsion and prevent lipase activity in digestive organs. To confirm lipase inhibition by epsilon-polylysine, a (14)C-trioleoylglycerol emulsion with or without epsilon-polylysine was orally administered to rats, and the radioactive lipid distribution determined at regular intervals. The radioactive plasma lipid was decreased, and radioactive fecal lipid was increased by the administration of epsilon-polylysine. The peak of radioactive lipids in the intestine was delayed by the administration of epsilon-polylysine. We used 20-week-old rats as a model for the middle-aged and elderly to test the effect of epsilon-polylysine on the body weight increase. epsilon-Polylysine significantly prevented any elevation in body weight and weight of the liver and epididymal adipose tissues. These data show that epsilon-polylysine inhibited the lipase activity in the digestive organ and had an anti-obesity function in the middle-aged rats.

Inhibitors of carbohydrate-hydrolyzing enzyme play an important role to control postprandial blood glucose levels. In this paper, we investigated the effect of an ethanol extract from chestnut astringent skin (CAS) on alpha-amylase. Chestnut astringent skin extract strongly inhibited human and porcine pancreatic alpha-amylase. We also investigated the effect of CAS extract on carbohydrate absorption in rats and humans. Oral administration of CAS extract to normal rats fed corn starch (2 g/kg body weight), significantly suppressed the increase of blood glucose levels after starch loading in a dose-dependent manner. The effective dose of CAS extract required to achieve 20 and 40% suppression of the rise in blood glucose level was estimated to be 40 and 155 mg/kg body weight, respectively. Chestnut astringent skin extract also suppressed the rise in plasma insulin level and the fall in plasma non-esterified fatty acid level. In the type 2 diabetic rat model, CAS extract significantly suppressed the rise in blood glucose level after starch loading in a dose-dependent manner. Chestnut astringent skin extract also suppressed the rise in plasma glucose level after boiled rice loading in a dose-dependent manner in humans. The amount of CAS extract required to achieve 11 and 23% suppression in the rise in plasma glucose level was 300 and 600 mg/person, respectively. These results suggest that CAS extract retards absorption of carbohydrate and reduces post-prandial hyperglycemia.

In vitro, -polylysine (EPL) strongly inhibited the hydrolysis of trioleoylglycerol emulsified with phosphatidylcholine (PC) and taurocholate by either pancreatic lipase or carboxylester lipase. The EPL concentration required for 50% inhibition of pancreatic lipase, 0.12 microM, was eight times lower than the concentration of orlistat required for the same effect. The 50% inhibition concentration by EPL was affected by emulsifier species: it was increased approximately 150 times, 70 times, and 230 times on gum arabic, phosphatidylserine, and phosphatidic acid emulsion, respectively, compared with PC emulsion. The 50% inhibition concentration by orlistat was little changed by emulsifier species. Gel-filtration experiments suggested that EPL did not bind strongly to pancreatic lipase, whereas orlistat did. To test the effect of EPL on obesity, mice were fed a high-fat diet containing 0.1, 0.2, or 0.4% EPL. EPL prevented the high-fat diet-induced increase in body weight and weight of the liver and visceral adipose tissues (epididymal and retroperitoneal). EPL also decreased plasma triacylglycerol and plasma cholesterol concentrations and liver triacylglycerol content after they had been increased by the high-fat diet. The fecal weights of mice were increased by the high-fat diet containing EPL compared with the high-fat diet alone. Fecal lipid was also increased by the diet containing EPL. These data clearly show that EPL has an antiobesity function in mice fed a high-fat diet that acts by inhibiting intestinal absorption of dietary fat.

Erythropoietin (Epo) is a hematopoietic factor, which stimulates proliferation and differentiation of erythroid precursor cells. Epo also functions as a neuroprotective factor and protects neurons from ischemic damage. Recently a 17-mer peptide sequence (Epopeptide AB) in Epo (AEHCSLNENITVPDTKV) with a neuroprotective function was reported. In this study, we showed in vivo evidence that Epopeptide AB protected neurons from ischemic damage at similar dose compared to Epo. Epopeptide AB could not stimulate the proliferation of Epo-dependent growing murine myeloid Ep-FDC-P2 cells and also did not compete the proliferative function of Epo on these cells. Together with these results, Epopeptide AB did not transduce signals through direct binding to the known Epo receptor on hematopoietic cells but has neuroprotective activity against ischemia.

Oral administration of epsilon-polylysine to rats reduced the peak plasma triacylglycerol concentration. In vitro, epsilon-polylysine and polylysine strongly inhibited the hydrolysis, by either pancreatic lipase or carboxylester lipase, of trioleoylglycerol (TO) emulsified with phosphatidylcholine (PC) and taurocholate. The epsilon-polylysine concentration required for complete inhibition of pancreatic lipase, 10 microg/ml, is 1,000 times lower than that of BSA required for the same effect. Inhibition requires the presence of bile salt and, unlike inhibition of lipase by other proteins, is not reversed by supramicellar concentrations of bile salt. Inhibition increases with the degree of polylysine polymerization, is independent of lipase concentration, is independent of pH between 5.0 and 9.5, and is accompanied by an inhibition of lipase binding to TO-PC emulsion particles. However, epsilon-polylysine did not inhibit the hydrolysis by pancreatic lipase of TO emulsions prepared using anionic surfactants, TO hydrolysis catalyzed by lingual lipase, or the hydrolysis of a water-soluble substrate. In the presence of taurocholate, epsilon-polylysine becomes surface active and adsorbs to TO-PC monomolecular films. These results are consistent with epsilon-polylysine and taurocholate forming a surface-active complex that binds to emulsion particles, thereby retarding lipase adsorption and triacylglycerol hydrolysis both in vivo and in vitro.

In this study, we examined the effects of fish oils on 5-fluorouracil (5-FU)-induced antitumor activity in mice. First, we examined the antitumor activity of the oral administration of two fish oils (carp oil and tuna oil) in sarcoma 180-bearing mice. Carp oil (0.2 and 0.4 mL/mouse) and tuna oil (0.2 and 0.4 mL/mouse) had no effects on tumor growth. Next, we examined the combined effects of 5-FU plus two fish oils (carp oil and tuna oil) on the antitumor activity and side effects compared to the effects of 5-FU alone (12.5 mg/kg/d). We found that carp oil (0.4 mL/mouse) or tuna oil (0.2 or 0.4 mL/mouse) enhanced the ability of 5-FU (12.5 mg/kg/d) to prevent tumor growth, without increasing side effects such as myelotoxicity and immunocompetent organ toxicity. Tuna oil (0.2 mL/mouse) slightly reduced body weight as compared to the effects of 5-FU alone and water alone (control). The area under the curve (AUC) (0–120 min) of blood 5-FU levels was reduced by the oral co-administration of 5-FU with carp oil or tuna oil. Apparent T max was shortened by the oral co-administration of 5-FU with carp oil or tuna oil. On the other hand, AUC (0–4 h) of 5-FU incorporation into tumor RNA fraction was not affected by the oral co-administration of 5-FU with carp oil or tuna oil.

Microglial activation has recently been recognized as a cause of damage in various neurodegenerative diseases. A possible mechanism underlying this damage is the activation of microglia by serum factors leaked through a disruption of the blood-brain barrier, which in turn trigger microglial cell proliferation and the release of various substances toxic to neurons, such as superoxide (O(2)(-)). We recently reported that serum albumin enhanced O(2)(-) production in cultured rat microglia stimulated by phorbol ester. In the present report, we identify the active site of this enhancement within the albumin molecule. We purified an active subfragment from trypsin-treated bovine serum albumin that was composed of 12-mer and 33-mer peptides connected by a disulfide bond. The chemically synthesized 12-mer peptide showed activity within a concentration range ( approximately 10(-7) M:) equivalent to that of albumin. The activities of a series of synthesized peptides conclusively indicated that the minimum active sequence was Leu-His-Thr-Leu. The present study may shed light on the mechanism of neuronal cell damage in various neurodegenerative diseases.

Korean red ginseng powder was found to contain adenosine and an acidic substance which inhibited epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis from glucose (3, 4). In the present experiment, the chemical structure of this acidic substance is determined to be pyro-glutamic acid. Pyroglutamic acid exhibits selective modulations toward the opposite metabolic pathways in rat adipocytes; it inhibits the lipolysis but rather stimulates the lipogenesis. Based on these results, we suggest to call these substances (adenosine and pyro-glutamic acid) "selective modulators".

The leaves of the persimmon Diospyros kaki, have been traditionally used for treatment of hypertensive diseases in Japan. We have studied the inhibitory effects of four flavonoids isolated from the leaves of the persimmon on angiotensin-converting enzyme activity. The four flavonoids astragalin [1], kaempferol-3-O-(2"-O-galloyl)-glucoside [2], isoquercitrin [3], and quercetin-3-O-(2"-O-galloyl)-glucoside [4] inhibited the angiotensin-converting enzyme activity in a dose-dependent fashion. Compounds 1-4 produced 67%, 53%, 33%, and 48% inhibition at a concentration of 300 micrograms/ml, respectively. The 50% inhibitory concentrations (IC50) of 1 and 2 for the angiotensin-converting enzyme were 180 micrograms/ml and 280 micrograms/ml, respectively. On the other hand, 2 and 4 were shown to have tannin activities, but 1 and 3 had no tannin activities. These results suggest that there is no relationship between the inhibition for angiotensin converting enzyme activity and the tannin activity for the four flavonoids.