Kiyotaka Nakagawa 교수

To investigate the absorption and metabolism of an anticarcinogenic tea catechin, (-)-epigallocatechin-3-gallate (EGCg), in rats, a newly developed chemiluminescence-detection high-performance liquid chromatography (CL-HPLC) method was employed and the EGCg concentrations in blood plasma, liver, brain, small intestinal mucosa and colon mucosa were determined before and after EGCg administration. The recovery of EGCg, extracted consecutively with ethyl acetate and methanol, was 86.1% from plasma

The effect of green tea catechin supplementation on antioxidant capacity of human plasma was investigated. Eighteen healthy male volunteers who orally ingested green tea extract (254 mg of total catechins/subject) showed 267 pmol of epigallocatechin-3-gallate (EGCg) per milliliter of plasma at 60 min after administration. The plasma phosphatidylcholine hydroperoxide (PCOOH) levels attenuated from 73.7 pmol/mL in the control to 44.6 pmol/mL in catechin-treated subjects, being correlated inversely

Phospholipid hydroperoxides (PLOOH) accumulate abnormally in the erythrocytes of dementia patients, and dietary xanthophylls (polar carotenoids such as astaxanthin) are hypothesised to prevent the accumulation. In the present study, we conducted a randomised, double-blind, placebo-controlled human trial to assess the efficacy of 12-week astaxanthin supplementation (6 or 12 mg/d) on both astaxanthin and PLOOH levels in the erythrocytes of thirty middle-aged and senior subjects. After 12 weeks of

Luteolin is a flavonoid present in plants in the form of aglycone or glucosides. In this study, luteolin glucosides (i.e., luteolin-7- O-β-d-glucoside, luteolin-7- O-[2-(β-d-apiosyl)-β-d-glucoside], and luteolin-7- O-[2-(β-d-apiosyl)-6-malonyl-β-d-glucoside]) prepared from green pepper leaves as well as luteolin aglycone were orally administered to rats. Regardless of the administered luteolin form, luteolin glucuronides were mainly detected from plasma and organs. Subsequently, luteolin aglycon

Broccoli sulforaphane has received attention as a possible anticarcinogen. Sulforaphane analysis is difficult due to the lack of a chromophore for spectrometric detection. Hence, we developed a method for determining sulforaphane by using high-performance liquid chromatography (HPLC) coupled with an evaporative light-scattering detector (ELSD). Sulforaphane was extracted from acid-hydrolyzed broccoli samples, followed by solid-phase extraction and reversed-phase HPLC. Sulforaphane was detected b

1-deoxynojirimycin (DNJ), a potent glucosidase inhibitor, is a characteristic constituent of the mulberry leaf. Dietary mulberry DNJ may be beneficial for the suppression of abnormally high blood glucose levels, thereby preventing diabetes mellitus. Although there is considerable interest in the effects of mulberry DNJ, the intestinal absorption and pharmacokinetic profile of orally administered mulberry DNJ have never been characterized. In this study, we developed a method for determining the

Peroxidized phospholipid-mediated cytotoxicity is involved in the pathophysiology of diseases [i.e., an abnormal increase of phosphatidylcholine hydroperoxide (PCOOH) in plasma of type 2 diabetic patients]. The PCOOH accumulation may relate to Amadori-glycated phosphatidylethanolamine (Amadori-PE; deoxy-D-fructosyl phosphatidylethanolamine), because Amadori-PE causes oxidative stress. However, the occurrence of lipid glycation products, including Amadori-PE, in vivo is still unclear. Consequentl