Dietary Sparassis crispa Reduces Body Fat Mass and Hepatic Lipid Levels by Enhancing Energy Expenditure and Suppressing Lipogenesis in Rats.

Accumulation of abdominal fat triggers metabolic syndrome, which is a cluster of metabolic abnormalities, such as dyslipidemia, glucose intolerance, insulin resistance or hyperinsulinemia, and hypertension, that leads to the development of diabetes and cardiovascular disease. Mushrooms have been used as a foodstuff and folk medicine worldwide. Among these mushrooms, Sparassis crispa (SC) is a relatively newly cultivated edible and medicinal mushroom, which has been reported to have anti-diabetic and anti-hypertensive properties. However, little is known about the anti-obesity and anti-hyperlipidemic properties of SC. In the present study, we investigated the effects of dietary SC on lipid metabolism and energy expenditure in Sprague-Dawley rats with diet-induced obesity and diabetes, and conducted respiratory gas analysis to determine how energy metabolism is altered by SC. After feeding periods of 3 and 7 weeks, dietary SC had significantly reduced hepatic triacylglycerol and cholesterol contents in a dose-dependent manner. These changes were attributable to suppression of fatty acid and cholesterol synthesis in the liver and increased insulin sensitivity in the body. In addition, after a feeding period of 6 weeks, dietary SC significantly increased energy expenditure through carbohydrate oxidation, reducing abdominal fat mass after 7 weeks. In conclusion, our results indicate that in addition to the previously reported anti-diabetic and anti-hypertensive activities, dietary SC exhibits anti-obesity and anti-hyperlipidemic activities that help protect against metabolic syndrome.

Theflavins and theasinensin A derived from fermented tea have antihyperglycemic and hypotriacylglycerolemic effects in KK-A(y) mice and Sprague-Dawley rats.

Although tea polyphenols are reported to improve serum glucose and lipid levels by inhibiting amylase activity and reducing lipid absorption, in vivo data are lacking. We evaluated in vivo the antihyperglycemic and hypotriacylglycerolemic effects of theaflavins (TFs) and theasinensin A (TSA) refined from fermented tea to purities of 12 and 59%, respectively. Feeding male KK-A(y) mice diets with 0.1% TFs or TSA for 6 weeks reduced serum glucose levels by >30% compared to a control diet. Rats fed diets containing 0.2% TFs or TSA for 4 weeks had higher fecal fat excretion and 33% lower hepatic triacylglycerol; hepatic fatty acid synthase activity was not affected. Oral administration of TFs or TSA reduced the increase in serum triacylglycerol after an oral bolus of a fat emulsion. These results indicate TFs and TSA induce antihyperglycemic responses in diabetic mice and are hypotriacylglycerolemic in rats by suppressing intestinal fat absorption.

Polyphenol composition of a functional fermented tea obtained by tea-rolling processing of green tea and loquat leaves.

Phenolic constituents of a new functional fermented tea produced by tea-rolling processing of a mixture (9:1) of tea leaves and loquat leaves were examined in detail. The similarity of the phenolic composition to that of black tea was indicated by high-performance liquid chromatography comparison with other tea products. Twenty-five compounds, including three new catechin oxidation products, were isolated, and the structures of the new compounds were determined to be (2R)-2-hydroxy-3-(2,4,6-trihydroxyphenyl)-1-(3,4,5-trihydroxyphenyl)-1-propanone 2-O-gallate, dehydrotheasinensin H, and acetonyl theacitrin A by spectroscopic methods. In addition, theacitrinin A and theasinensin H were obtained for the first time from commercial tea products. Isolation of these new and known compounds confirms that reactions previously demonstrated by in vitro model experiments actually occur when fresh tea leaves are mechanically distorted and bruised during the production process.

Hypotriacylglycerolemic and antiobesity properties of a new fermented tea product obtained by tea-rolling processing of third-crop green tea (Camellia sinensis) leaves and loquat (Eriobotrya japonica) leaves.

We manufactured a new fermented tea by tea-rolling processing of third-crop green tea (Camellia sinensis) leaves and loquat (Eriobotrya japonica) leaves. The mixed fermented tea extract inhibited pancreatic lipase activity in vitro, and effectively suppressed postprandial hypertriacylglycerolemia in rats. Rats fed a diet containing 1% freeze-dried fermented tea extract for 4 weeks had a significantly lower liver triacylglycerol concentration and white adipose tissue weight than those fed the control diet lacking fermented tea extract. The activity of fatty acid synthase in hepatic cytosol markedly decreased in the fermented tea extract group as compared to the control group. The serum and liver triacylglycerol- and body fat-lowering effects of the mixed fermented tea extract were strong relative to the level of dietary supplementation. These results suggest that the new fermented tea product exhibited hypotriacylglycerolemic and antiobesity properties through suppression of both liver fatty acid synthesis and postprandial hypertriacylglycerolemia by inhibition of pancreatic lipase.

Identification of alpha-glucosidase inhibitors from a new fermented tea obtained by tea-rolling processing of loquat (Eriobotrya japonica) and green tea leaves.

BACKGROUND: A new fermented tea produced by tea-rolling processing of loquat (Eriobotrya japonica) leaf with green tea leaf (denoted as LG tea) showed a potent antihyperglycaemic effect in maltose-loaded rats. The aim of this study, therefore, was to identify alpha-glucosidase inhibitors in the antihyperglycaemic tea product. RESULTS: LG tea had a threefold higher maltase-inhibitory activity (IC(50) 0.065 mg dried extract mL(-1)) than either the constituent loquat leaf or green tea alone. In addition, LG tea favourably inhibited maltase action rather than sucrase action. As a result of bio-guided high-performance liquid chromatography separations of LG tea, theasinensin A, theasinensin B, strictinin and 1,6-digalloylglucose were newly identified as maltase inhibitors with IC(50) values of 142, 225, 398 and 337 micromol L(-1) respectively, along with previously identified catechins and theaflavins. CONCLUSION: Judging from the magnitude of the alpha-glucosidase-inhibitory contribution of each isolated compound to the overall inhibition of LG tea, catechins were the main candidates responsible for alpha-glucosidase or maltase inhibition in LG tea, followed by theaflavins, theasinensins, strictinin and 1,6-digalloylglucose.

Suppression of blood glucose level by a new fermented tea obtained by tea-rolling processing of loquat (Eriobotrya japonica) and green tea leaves in disaccharide-loaded Sprague-Dawley rats.

BACKGROUND: In the field of food science, much interest has been focused on the development of alternative medicinal foods with the ability to regulate excess blood glucose level (BGL) rise. The authors have successfully developed a new fermented tea product (LG tea) by co-fermentation of loquat (Eriobotrya japonica) leaf and summer-harvested green tea leaf. The objective of this study was to examine the acute suppression effect of LG tea on BGL rise in disaccharide-loaded Sprague-Dawley (SD) rats and to evaluate its possible usage as an antidiabetic functional food material. RESULTS: As a result of single oral administration of hot water extract of LG tea (50 mg kg(-1)) to maltose-loaded SD rats, BGL at 30 min was significantly decreased by 23.8% (P < 0.01) compared with the control. A corresponding reduction in serum insulin secretion was also observed. The ED(50) value of LG tea (50.7 mg kg(-1)) was estimated to be about 16-fold higher than that of the therapeutic drug acarbose (3.1 mg kg(-1)). CONCLUSION: No significant change in BGL was observed when sucrose or glucose was administered, suggesting that the suppression effect of LG tea was achieved by maltase inhibition, not by sucrase inhibition or glucose transport inhibition at the intestinal membrane.

Increase of theaflavin gallates and thearubigins by acceleration of catechin oxidation in a new fermented tea product obtained by the tea-rolling processing of loquat ( Eriobotrya japonica ) and green tea leaves.

In a project to produce a new fermented tea product from non-used tea leaves harvested in the summer, we found that kneading tea leaves ( Camellia sinensis ) with fresh loquat leaves ( Eriobotrya japonica ) accelerated the enzymatic oxidation of tea catechins. The fermented tea obtained by tea-rolling processing of tea and loquat leaves had a strong, distinctive flavor and a plain aftertaste, which differed from usual black, green, and oolong teas. The phenolic constituents were similar to those of black tea. However, the concentrations of theaflavin 3-O-gallate, theaflavin 3,3'-di-O-gallate, and thearubigins were higher in the tea leaves kneaded with loquat leaves than in tea leaves kneaded without loquat leaves. The results from in vitro experiments suggested that acceleration of catechin oxidation was caused by the strong oxidation activity of loquat leaf enzymes and a coupled oxidation mechanism with caffeoyl quinic acids, which are the major phenolic constituents of loquat leaves.

alpha-Glucosidase inhibitory profile of catechins and theaflavins.

To clarify the postprandial glucose suppression effect of flavonoids, the inhibitory effects of catechins and theaflavins against alpha-glucosidase (AGH) were examined in this study. It was initially demonstrated that theaflavins and catechins preferentially inhibited maltase rather than sucrase in an immobilized AGH inhibitory assay system. For the maltase inhibitory effects of theaflavins, the effects were observed in descending order of potency of theaflavin (TF)-3-O-gallate (Gal) > TF-3,3'-di-O-Gal > TF-3'-O-Gal > TF. This suggests that the AGH inhibition induced by theaflavins is closely associated with the presence of a free hydroxyl group at the 3'-position of TF as well as the esterification of TF with a mono-Gal group. In addition, the R-configuration at the 3'-position of TF-3-O-Gal showed a higher inhibitory activity than the S-configuration. As a result of a single oral administration of maltose (2 g/kg) in rats, a significant reduction in blood glucose level was observed at a dose of 10 mg/kg of TF-3-O-Gal, demonstrating for the first time that TF-3-O-Gal can suppress glucose production from maltose through inhibition of AGH in the gut.

Depressor effect induced by dipeptide, Val-Tyr, in hypertensive transgenic mice is due, in part, to the suppression of human circulating renin-angiotensin system.

1. In the present study, the depressor action of the dipeptide Val-Tyr, with an in vivo antihypertensive effect, was investigated in transgenic mice carrying the human renin gene cross-mated with mice bearing the human angiotensinogen gene (Tsukuba Hypertensive Mouse; THM). 2. Single oral administration of Val-Tyr (0.1 mg/g) to 11-week-old THM resulted in a prolonged reduction of blood pressure for up to 9 h. The effect clearly demonstrated that the Val-Tyr absorbed acted on the enhanced human renin-angiotensin system (RAS). 3. After Val-Tyr administration, an approximate eightfold higher increment of plasma Val-Tyr was observed at 1 h (3406 +/- 211 fmol/mL plasma) compared with the level observed at 0 h; plasma concentrations of Val-Tyr returned to baseline levels at 6 h. 4. Transient changes in plasma concentrations of angiotensin (Ang) I and AngII only at 1 h were consistent with plasma Val-Tyr concentrations, suggesting that that the long-lasting reduction in blood pressure was achieved by the latent hypotensive mechanism of Val-Tyr and not by transient suppression of the circulatory RAS. 5. Ageing of the THM greatly affected the depressor action of Val-Tyr, with no significant reduction in blood pressure observed in 18- and 24-week-old THM.

Absorption of Val-Tyr with in vitro angiotensin I-converting enzyme inhibitory activity into the circulating blood system of mild hypertensive subjects.

The change in plasma level of dipeptide, Val-Tyr (VY), with in vitro angiotensin I-converting enzyme inhibitory activity was investigated after a single oral administration of a VY-drink at doses of 0, 6 or 12 mg given to mild hypertensive subjects. During this protocol for up to 24 h after the intake, patient/subject blood pressure (BP) was measured for a 15 min period at designated times (0, 1, 2, 4, 8, 24 h) with the individual supine. Based on the VY determination, the maximal increment of plasma VY level was observed over the second hour postprandially (12 mg-dose; 2041+/-148 fmol/ml-plasma). In addition, the plasma VY level increased with the VY dosage. However, no marked BP change was observed with the increase of plasma VY level, suggesting that VY did not exert an acute hypotensive effect. The area under the curve at 12 mg-dose was estimated to be 8644+/-420 fmol x h/ml-plasma, comparable to that in normotensive subjects. This finding suggests that absorption of VY would not be influenced by a complaint of hypertension.

Val-Tyr as a natural antihypertensive dipeptide can be absorbed into the human circulatory blood system.

1. Intact absorption of the bioactive dipeptide Val-Tyr (VY), with in vivo antihypertensive ability in normotensive human subjects, was investigated. 2. As a result of a single oral administration of VY, the VY absorption curve occurred maximally over the second hour postprandially; a greater than 10-fold higher increment of VY following a dose of 12 mg was observed in the plasma at 2 h compared with the baseline concentration of VY at 0 h (1934 +/- 145 vs 159 +/- 11 fmol/mL plasma, respectively). 3. Plasma VY levels increased with dose administered (3, 6 and 12 mg), suggesting that exogenous VY could be absorbed intact into the human blood depending on the dose. The elimination half time (t1/2) of VY was estimated to be 3.1 h. The area under the curve for the 12 mg VY dose was 9185 +/- 688 fmol small middle doth/mL plasma.