C.E. Rüfer

Bioavailability and Nutritional Effects of Carotenoids from Organically and Conventionally Produced Carrots in Healthy Men

It has been hypothesised that organically grown vegetables are healthier than conventionally produced ones due to a higher content of phytochemicals. However, few data from controlled human studies exist. The aim of the present study was to compare the carotenoid content and antioxidant capacity of organically and conventionally produced carrots under defined conditions. Furthermore, a human intervention study was conducted to compare bioavailability, plasma antioxidant capacity, endogenous DNA strand breaks and immune parameters in healthy men ingesting carrots from different agricultural systems. Thirty-six volunteers consumed either organically or conventionally produced blanched carrots (200 g/d; 2 weeks) or no carrots in a double-blind, randomised intervention study. No statistically significant differences were observed in the total carotenoid contents (121 (sd 7) microg/g organic v. 116 (sd 13) microg/g conventional) and the antioxidant capacities (0.43 (sd 0.08) mumol Trolox equivalents/g organic v. 0.32 (sd 0.07) mumol Trolox equivalents/g conventional) of the carrots administered to the volunteers. Intake of organically or conventionally produced carrots significantly increased (P < 0.001) plasma alpha- and beta-carotene concentrations in both intervention groups without differences in plasma carotenoid concentrations. Consumption of carrots did not lead to significant changes in the plasma antioxidant status, endogenous DNA strand breaks and parameters of the immune system in all groups. Therefore, these results indicate that the agricultural system has neither an effect on the carotenoid content, the antioxidant capacity of carrots, nor on the bioavailability of carotenoids and on antioxidant, antigenotoxic and immunological effects as assessed in a human intervention study.

STRUCTURAL ELUCIDATION OF HYDROXYLATED METABOLITES OF THE ISOFLAVAN EQUOL BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

Equol has, as have other isoflavonoids, recently gained considerable interest due to its possible health effects. However, detailed studies on the metabolism of equol are scarce. Therefore, we investigated the phase I metabolism of equol using liver microsomes from Aroclor-treated male Wistar rats as well as from a male human. The identification of the metabolites formed was elucidated using high performance liquid chromatography (HPLC) with diode array detection, HPLC/atmospheric pressure ionization electrospray mass spectrometry, and gas chromatography-mass spectrometry, as well as reference compounds. (±)-Equol was converted to 11 metabolites by the liver microsomes from Aroclor-pretreated rats comprising three aromatic monohydroxylated and four aliphatic monohydroxylated as well as four dihydroxylated products. The main metabolite was identified as 3′-hydroxy-equol. Using human liver microsomes, equol was converted to six metabolites with 3′-hydroxy- and 6-hydroxy-equol as main products. Furthermore, the aliphatic hydroxylated metabolite 4-hydroxyequol, which was recently detected in human urine after soy consumption, was formed. On the basis of these findings, it is suggested that phase I metabolism of equol is part of a complex biotransformation of the soy isoflavone daidzein in humans in vivo.

Influence of the Production Method on Phytochemical Concentrations in Whole Wheat (Triticum aestivum L.): A Comparative Study

The present study was performed to evaluate the concentrations of phytochemicals (carotenoids and phenolic acids) in wheat varieties grown under comparable organic and conventional conditions over three years as part of a long-term field trial. Phenolic acids of the hydroxybenzoic acid and hydroxycinnamic acid group were quantified by HPLC-DAD after extraction as free, soluble conjugated, and bound forms. Furthermore, the carotenoids lutein and zeaxanthin were determined by HPLC-DAD. There were no statistically significant differences between the two farming systems (sum of carotenoids (microg/g) for 2003, 0.91 +/- 0.55 organic vs 0.96 +/- 0.34 conventional; for 2005, 1.61 +/- 0.22 organic vs 1.33 +/- 0.19 conventional; for 2006, 0.87 +/- 0.33 organic vs 0.83 +/- 0.11 conventional; sum of phenolic acids (microg/g) for 2003, 448.4 +/- 151.1 organic vs 327.3 +/- 232.8 conventional; for 2005, 502.8 +/- 168.3 organic vs 484.4 +/- 111.2 conventional; for 2006, 659.1 +/- 112.5 organic vs 945.9 +/- 353.6 conventional). However, statistically significant year-to-year differences up to 55% were observed. Taken together, these results indicate that climate factors have a greater impact on the phytochemical concentrations in whole wheat than the production method (organic/conventional).

LC-MS/MS quantification of sulforaphane and indole-3-carbinol metabolites in human plasma and urine after dietary intake of selenium-fortified broccoli

This study aimed at developing a sensitive LC-MS/MS method for the quantification of sulforaphane (SFN) and indole-3-carbinol metabolites in plasma and urine after dietary intake of regular and selenium-fertilized broccoli using stable isotope dilution analysis. In a three-armed, placebo-controlled, randomized human intervention study with 76 healthy volunteers, 200 g of regular (485 μg of total glucosinolates and <0.01 μg of selenium per gram fresh weight) or selenium-fertilized broccoli (589 μg of total glucosinolates and 0.25 μg of selenium per gram fresh weight) was administered daily for 4 weeks. Glucoraphanin and glucobrassicin metabolites quantified in plasma and urine were SFN-glutathione, SFN-cysteine, SFN-cysteinylglycine, SFN-acetylcysteine, and indole-3-carboxaldehyde, indole-3-carboxylic acid, and ascorbigen, respectively. Dietary intake of selenium-fertilized broccoli increased serum selenium concentration analyzed by means of atomic absorption spectroscopy by up to 25% (p < 0.001), but affected neither glucosinolate concentrations in broccoli nor their metabolite concentrations in plasma and urine compared to regular broccoli.

Role of plasma lipoproteins in the transport of the soyabean isoflavones daidzein and daidzein-7- O -β- d -glucoside

Isoflavone intake is associated with various properties beneficial to human health which are related to their antioxidant activity, for example, to their ability to increase LDL oxidation resistance. However, the distribution of isoflavones among plasma lipoproteins has not yet been elucidated in vivo. Therefore, the objective of the present study was to investigate the association between daidzein (DAI) and lipoproteins in human plasma upon administration of the aglycone and glucoside form. Five men aged 22-30 years participated in a randomised, double-blind study in cross-over design. After ingestion of DAI and daidzein-7-O-beta-D-glucoside (DG) (1 mg DAI aglycone equivalents/kg body weight) blood samples were drawn before isoflavone administration as well as 1, 2, 3, 4.5, 6, 8, 10, 12, 24 and 48 h post-dose. Concentrations of DAI in the different lipoprotein fractions (chylomicrons, VLDL, LDL, HDL) and in the non-lipoprotein fraction were analysed using isotope dilution capillary GC/MS. The lipoprotein fraction profiles were similar for all subjects and resembled those obtained for plasma in our previously published study. The lipoprotein distribution based on the area under the concentration-time profiles from 0 h to infinity in the different fractions were irrespective of the administered form: non-lipoprotein fraction (53%) > LDL (20%) > HDL (14%) > VLDL (9.5%) > chylomicrons (2.5%). Of DAI present in plasma, 47 % was associated to lipoproteins. Concentrations in the different lipoprotein fractions as well as in the non-lipoprotein fraction were always higher after the ingestion of DG than of DAI. Taken together, these results demonstrate an association between isoflavones and plasma lipoproteins in vivo.

Abstract A148: Concomitant activation of pro‐ and antiproliferative mechanisms abrogate tumor growth inhibition by kale sprout intervention in a human prostate cancer xenograft model

Cruciferous vegetables are rich in glucosinolates, which are converted to isothiocyanates (ITCs) and indole‐based compounds by the enzymatic activity of myrosinase. Tumor‐growth inhibitory efficacy of purified constituents derived from cruciferous vegetables has been demonstrated in animal models at various organ sites including the prostate. However, except induction of detoxifying enzymes, relatively little is known on mechanisms affected by dietary intervention with cruciferous vegetables, which represent a mixture of various constituents potentially enhancing or blocking their activities (Pappa et al., 2007). In the present study, we tested the tumor growth inhibitory potential of kale sprouts in a human prostate cancer xenograft model. LNCaP human prostate cancer cells were injected to male nude Balb/c mice (10 per group). Mice were fed with either regular rodent chow or chow supplemented with 20% kale sprouts (containing about 60 µmol glucosinolates per 5 g chow consumed daily, together with active myrosinase) from a week before cell injection until sacrifice after 7.5 weeks of intervention. Compared with normal diet, kale sprout intervention did not significantly inhibit average tumor weights. Secreted prostate specific antigen (PSA), which is used as a biomarker for prostate cancer, was highly correlated with tumor size in both intervention groups. Interestingly however, plasma PSA levels in the kale sprout group were 2.5‐fold higher (p Overall, our in vivo study indicates that components in kale sprouts or their metabolites concomitantly affect both anti‐proliferative (histone H4 acetylation, cell cycle arrest, anti‐angiogenesis) and pro‐proliferative mechanisms (hormone signaling), which in combination may abrogate inhibitory effects on tumor growth. These data may contribute to a better understanding of the effects of cruciferous vegetable consumption in cancer prevention. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A148.