Search

Protection against cholestasis and its consequences are considered an essential issue to improve the quality of a patient's life and reduce the number of death every year from liver diseases. Lycopene, a natural carotenoid, has antioxidant scavenger capacity and inhibits inflammation in many experimental models. The present study aimed to elucidate the potential protective effects of lycopene, in comparison to silymarin, in a rat model of cholestatic liver. Animals were daily injected with 17α-ethinylestradiol (EE; 5 mg/kg) for 18 successive days. Silymarin (100 mg/kg) and lycopene (10 mg/kg) were orally administered once per day through the experimental period. Lycopene significantly decreased the EE-induced rise in the serum levels of total bile acid and total bilirubin as well as the activities of alanine aminotransaminase, aspartate aminotransaminase, alkaline phosphatase, and gamma-glutamyl transaminase. Moreover, lycopene reduced the hepatic levels of thiobarbituric acid reactive substances and tumor necrosis factor-α as well as the hepatic activity of myeloperoxidase that were markedly elevated by EE. Lycopene increased the hepatic levels of total protein and albumin and reduced glutathione. In addition, lycopene improved the hepatic histopathological changes induced by EE. These protective effects of lycopene were comparable to that of silymarin. In conclusion, lycopene was effective in protecting against estrogen-induced cholestatic liver injury through its antioxidant and anti-inflammatory activities. Therefore, lycopene might be a potentially effective drug for protection against cholestasis in susceptible women during pregnancy, administration of oral contraceptives, or postmenopausal replacement therapy.

The mechanism of the suppressive effect of rice albumin (RA) on postprandial hyperglycemia after glucose loading was investigated. In order to examine if small peptides derived from RA are responsible for prevention of postprandial hyperglycemia, RA was hydrolysed to indigestible high-molecular-weight peptides (HMP) and low-molecular-weight peptides (LMP) by trypsin, HMP and LMP being fractionated by gel-filtration chromatography. In oral glucose tolerance test (OGTT), both HMP and LMP suppressed the increase in blood glucose levels. In vitro diffusion test results showed that HMP adsorbed glucose and retarded its diffusion rate like dietary fibers. On the other hand, LMP suppressed the expression of sodium-dependent glucose transporter-1 (SGLT1) in STC-1 cells. Therefore, the suppressive effect of RA on postprandial hyperglycemia would be due to the dual actions of HMP and LMP. Our results demonstrated the potential use of RA as a functional food material to prevent diabetes.

Inhibiting starch hydrolysis into sugar could reduce postprandial blood glucose elevation and contribute to diabetes prevention. Here, both buckwheat and wheat albumin that inhibited mammalian &alpha, amylase in vitro suppressed blood glucose level elevation after starch loading in vivo, but it had no effect after glucose loading. In contrast to the non-competitive inhibition of wheat &alpha, amylase inhibitor, buckwheat albumin acted in a competitive manner. Although buckwheat &alpha, amylase inhibitor was readily hydrolysed by digestive enzymes, the hydrolysate retained inhibitory activity. Together with its thermal stability, this suggests its potential use in functional foods that prevent diabetes.