Sakura Kawakami

Dietary L-Cysteine Improves the Antioxidative Potential and Lipid Metabolism in Rats Fed a Normal Diet

L-Cysteine works as a precursor of the antioxidant, glutathione. We investigated the effects of L-cysteine (1% and 2%) on lipid metabolism and the antioxidative system in rats fed a normal diet. Administering L-cysteine dependently decreased the food intake, fat mass weight and body weight dose. Dietary L-cysteine also decreased the triglyceride levels in the serum and liver. However, there were no significant differences in the hepatic TBARS and glutathione (GSH) levels among the groups. The activities of catalase and glutathione reductase in the rats receiving 2% L-cysteine were significantly higher (p<0.05) than in the control rats. These results suggest that dietary L-cysteine dose-dependently affected the antioxidative enzyme activities, and the lipid levels in the serum and liver which might be related to the reduced food intake.

Amelioration of D-Galactosamine-Induced Acute Liver Injury in Rats by Dietary Supplementation with Betaine Derived from Sugar Beet Molasses

The effects of betaine supplementation on D-galactosamine-induced liver injury were examined in terms of hepatic and serum enzyme activities and of the levels of glutathione and betaine-derived intermediates. The rats induced with liver injury showed marked increases in serum enzyme activity, but those receiving dietary supplementation of 1% betaine showed enzyme activity levels similar to a control group without liver injury. Administration of betaine also increased both hepatic and serum glutathione levels, even following D-galactosamine injection. The activity of glutathione-related enzymes was markedly decreased following injection of D-galactosamine, but remained comparable to that of the control group in rats receiving 1% betaine. The concentrations of hepatic S-adenosyl methionine and cysteine showed similar trends to that observed for hepatic glutathione levels. These results indicate that 1% betaine has a hepatoprotective effect by increasing hepatic and serum glutathione levels along with glutathione-related enzyme activities in rats.

Effect of Fermented Bean Paste on Serum Lipids in Rats Fed a Cholesterol-Free Diet

We examined the effects of fermented bean pastes derived from bean vinegar by-products on serum cholesterol in rats. The rats were fed boiled paste from adzuki (A), kintoki (K), or tebou (T), or fermented paste from adzuki (AP), kintoki (KP), or tebou (TP) for 4 weeks. The serum non-high-density lipoprotein (HDL) cholesterol levels in all the experimental groups, except for A group, were significantly lower than in the control (CN) group. Likewise, the serum triglyceride levels in K and all the fermented bean groups were significantly lower than in the CN group. The levels of hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase mRNA in all the experimental groups except for A were significantly lower than in the CN group. These findings indicate that fermented bean pastes also suppress cholesterol synthesis, resulting in a reduced serum cholesterol concentration. These effects might be related not only to the resistant starch but also to the protein or peptide in the fermented bean paste.

Comparison of the effect of two types of whole mushroom (Agaricus bisporus) powders on intestinal fermentation in rats

The effects of two types of mushroom (Agaricus bisporus; white, WM; brown, BM) powders on intestinal fermentation in rats were investigated in terms of the physical characteristics of animals and by bacterial and HPLC analyses of cecal contents. Short-chain fatty acid levels were found to be significantly higher in the WM group than in the BM and the control (CN) groups; coliform bacteria levels in the BM group were significantly lower than those in the CN group, with the WM group inducing an apparent but insignificant decrease in coliforms. Anaerobe levels in the WM group were significantly higher than those in the CN group and, compared with the CN group, the BM and WM groups exhibited significantly increased feces weight and cecum weight, respectively. These results indicate that the mushroom powders, and in particular the WM powder, have beneficial effects on the intestinal environment in rats. Graphical abstract SCFA concentrations of cecal contents in rats fed a diet supplemented with mushroom powders (a) Acetic acid; (b) Butyric acid; (c) Propionic acid; (d) Total SCFA.

Dietary l-cysteine inhibits d-galactosamine-induced acute liver injury in rats

The effects of l-cysteine (1 and 2%) on the antioxidative system were examined in rats with d-galactosamine (d-GalN)-induced injury. These rats showed increases in serum antioxidative enzyme and hepatic thiobarbituric acid reactive substances (TBARS) activities, with decreased hepatic/serum glutathione (GSH) levels and GSH-related enzyme activities. However, l-cysteine supplementation resulted in a decrease of hepatic TBARS levels, and increased catalase and serum GSH levels. The activities of serum enzymes in rats receiving 2% l-cysteine were significantly (p<0.05) lower than in d-GalN-injected group rats, and similar to levels in control group rats without acute liver injury. In addition, 2% l-cysteine increased the glutathione reductase activity and decreased the serum TBARS level in liver injury group rats. Dietary l-cysteine, especially at a 2% level, exerts a hepatoprotective effect by alteration of the GSH level and antioxidative enzyme activities.

Potato powders prepared by successive cooking-process depending on resistant starch content affect the intestinal fermentation in rats

The effects of resistant starch (RS) in dry potato powders prepared by various processes on intestinal fermentation in rats were assessed. Rats were fed raw potato powder (RP), blanched potato powder (BP), steamed potato powder (SP), or drum-dried potato powder (DP) for 4 weeks. The cecal RS content was significantly higher in the RP group than in the control diet (CN) group and other dry potato powder groups. Cecum pH was significantly lower in the RP group compared to the CN group, and was also significantly lower than that in the SP, BP, and DP groups. Lactic acid bacteria levels in the RP group were significantly higher than those in the CN group, and levels in the SP group also increased relative to the control group. Lactobacillus levels in the RP group were higher than in the CN and other dry potato powder groups. Cecal short-chain fatty acid (SCFA) concentrations in the RP group followed by the SP group exhibited significantly higher levels relative to the control levels. Dry potato powders containing RS produced during the cooking process may represent a useful food material that increases intestinal concentrations of SCFA and enhances the growth of certain lactic acid bacteria. Graphical abstract Cecal SCFAs contents, especially n-butyric acid in rats fed a diet supplemented with potato powders produced during the cooking process were varied depending on resistant starch content.