Minoru Sugiura

Antioxidant xanthones from Garcinia subelliptica

Abstract From the woods of Garcinia subelliptica four new xanthones, garciniaxanthone C, 1,2,5-trihydroxyxanthone, 2,6-dihydroxy-1,5-dimethoxyxanthone and 1,2-dihydroxy-5,6-dimethoxyxanthone have been isolated along with a new benzophenone derivative, 4′,6-dihydroxy-2,3′4-trimethoxybenzophenone. Their structures have been determined on the basis of mainly spectroscopic data and some chemical reactions. Antioxidative properties of all the isolated xanthones have been evaluated in vitro using three assay systems to measure antilipidperoxidation, free radical and superoxide anion scavenging activity.

High Serum Carotenoids Associated with Lower Risk for Bone Loss and Osteoporosis in Post-Menopausal Japanese Female Subjects: Prospective Cohort Study

Introduction Recent epidemiological studies show that high intakes of carotenoids might be useful to maintain bone health, but little is known about the association of serum carotenoids with change of bone mineral density (BMD). The objective of this study was to investigate longitudinally whether serum carotenoids are associated with bone loss. Methods We conducted a follow-up on 146 male and 99 pre- and 212 post-menopausal female subjects from the Mikkabi study. Those who participated in previous BMD surveys and completed four years of follow-up were examined longitudinally. Results During a 4-year follow-up, 15 of the post-menopausal female subjects developed new-onset osteoporosis. In contrast, none of the male and pre-menopausal female subjects did. In male and pre-menopausal female subjects, the six serum carotenoids at the baseline were not associated with bone loss. On the other hand, in post-menopausal female subjects, the 4-year bone loss of radius was inversely associated with the serum carotenoid concentrations, especially in β-carotene. After adjustments for confounders, the odds ratios (OR) for osteoporosis in the highest tertiles of serum β-carotene and β-cryptoxanthin against the lowest tertiles were 0.24 (95% confidence interval 0.05–1.21) and 0.07 (CI: 0.01–0.88), respectively. Serum β-cryptoxanthin was also inversely associated with the risk for osteopenia and/or osteoporosis (P for trend, 0.037). In addition, our retrospective analysis revealed that subjects who developed osteoporosis and/or osteopenia during the survey period had significantly lower serum concentrations of β-cryptoxanthin and β-carotene at the baseline than those in the normal group. Conclusions Antioxidant carotenoids, especially β-cryptoxanthin and β-carotene, are inversely associated with the change of radial BMD in post-menopausal female subjects.

Associations of serum carotenoid concentrations with the metabolic syndrome: interaction with smoking

Recent epidemiological studies show the associations of serum antioxidant status with the metabolic syndrome. Oxidative stress may play an important role in the pathogenesis of diabetes and CVD. Actually, smoking is a potent oxidative stressor in man, but little is known about the interaction of serum carotenoids and the metabolic syndrome with smoking status. In this study, the associations of the serum carotenoids with the metabolic syndrome stratified by smoking habit were evaluated cross-sectionally. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Among total subjects, the OR for the metabolic syndrome in the highest tertile of serum beta-carotene was 0.41 (95 % CI 0.18, 0.92) after adjusting confounders. In current smokers, significantly lower OR were observed in the middle (OR 0.10; 95 % CI 0.01, 0.72) and highest (OR 0.06; 95 % CI 0.01, 0.73) tertiles of serum beta-carotene. Furthermore, lower OR were observed in accordance with tertiles of serum alpha-carotene and beta-cryptoxanthin in current smokers (P for trend 0.042 and 0.036, respectively). In contrast, in non-smokers, a significantly lower OR was observed in the highest tertile of serum beta-carotene (OR 0.30; 95 % CI 0.10, 0.89) after multiple adjustment. Inverse associations of serum carotenoids with the metabolic syndrome were more evident among current smokers than non-smokers. These results support that antioxidant carotenoids may have a protective effect against development of the metabolic syndrome, especially in current smokers who are exposed to a potent oxidative stress.

Synergistic interaction of cigarette smoking and alcohol drinking with serum carotenoid concentrations: findings from a middle-aged Japanese population

Previous studies have indicated low serum carotenoid concentrations among cigarette smokers and/or alcohol drinkers, but little is known about the interaction of smoking and drinking with serum carotenoids. We tested the hypothesis that smoking and drinking reduce serum carotenoid concentrations synergistically. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. The subjects were divided into six groups according to alcohol intake (non-drinkers, < 1 g/d; light drinkers, > or = 1, < 25 g/d; moderate-to-heavy drinkers, > or = 25 g/d) and smoking status (non-smokers and current smokers). The dietary intakes and serum concentrations of six carotenoids (lycopene, alpha-carotene, beta-carotene, lutein, beta-cryptoxanthin and zeaxanthin) within each group were evaluated cross-sectionally. The dietary intakes of all carotenoids did not differ in the six groups after adjusting for age and sex. The multivariate-adjusted means of the serum carotenoid concentrations in non-drinkers did not differ between non-smokers and current smokers. In contrast, the adjusted means of serum alpha-carotene, beta-carotene and beta-cryptoxanthin were significantly lower than those with increased alcohol intake, and these lower serum carotenoids among alcohol drinkers were more evident in current smokers than in non-smokers. Serum lycopene of moderate-to-heavy drinkers was significantly lower than that of non-drinkers, but it was not influenced by smoking. Neither smoking nor drinking was associated with the serum concentrations of lutein and zeaxanthin. These results suggest that smoking and drinking may reduce the serum alpha-carotene, beta-carotene and beta-cryptoxanthin concentrations in a synergistic manner.

Comparison of bioavailability between β-cryptoxanthin and β-carotene and tissue distribution in its intact form in rats

The bioavailability of two intact carotenoids in several tissues of β-cryptoxanthin- and β-carotene-fed rats (20 mg/kg of diet) was investigated. Although metabolites of provitamin A are not included in our study, β-cryptoxanthin was found at higher concentrations in majority of the tissues. The results show that the bioavailability of intact β-cryptoxanthin seemed to be higher than that of β-carotene.

Cohort Study and Case-control Study

疫学は，実験動物や培養細胞ではなく，実際の人口集団を対象として，疾病とその規定要因との関連を明らかにする科学であり，明確に規定された人間集団の中で出現する健康関連のいろいろな事象の頻度と分布およびそれらに影響を与える要因を明らかにして，健康関連の諸問題に対する有効な対策樹立に役立てることを目的とする．疫学研究のデザインには大きく分けると，地域相関研究·断面研究·症例対照研究·コホート研究·無作為割付臨床試験（介入研究）などがあり，因果関係を明らかに出来るという点においては一般にコホート研究や介入研究ほど信頼性の高い情報が得られると考えられる．また研究の規模や調査の精度により，得られた情報の評価は異なる．