First-Pass Metabolism of Chlorophylls in Mice.

SCOPE: The dietary intake of chlorophylls is estimated to be ≈50 mg d-1 . However, their first pass metabolism and systemic assimilation is not well characterized. METHODS AND RESULTS: A group of 30 mice are fed a diet rich in chlorophylls, while 10 mice received a standard diet without chlorophylls (control group). Liver extracts are analyzed every 15 days by HPLC-ESI(+)/APCI(+)-hrTOF- MS/MS to measure the accretion of specific chlorophyll metabolites. The chlorophyll profile found in the livers of mice fed a chlorophyll-rich diet shows that the formation and/or absorption of pheophorbides, pyro-derivatives, and phytyl-chlorin e6 require the occurrence of a precise first-pass metabolism. In addition, the apical absorption of pheorphorbide a-rich micelles is significantly inhibited in Caucasian colon adenocarcinoma-2 cells pre-incubated with BLT1. CONCLUSION: Pheophorbide a absorption is, at least partly, protein-mediated through SR-BI. This active absorption process could explain the specific accumulation of pheophorbide a in the livers of animals fed a chlorophyll-rich diet. A complementary mechanism could be the de-esterification of pheophytin a in the liver, yielding pheophorbide a and phytol, which can explain the origin of phytol in the liver. Hence, the results suggest two molecular mechanisms responsible for the accumulation of the health-promoting compounds pheophorbide and phytol.

Xanthophyll esters are found in human colostrum.

SCOPE: Carotenoids in human milk are associated with other lipid counterparts in several metabolic processes. One interesting association that has not been demonstrated to date is the presence of xanthophyll esters. Colostrum and mature milk samples were analyzed to determine the occurrence of xanthophyll esters and identify the compounds. Thus, the association of the amounts of these compounds with lactation and whether they are significant contributors to the carotenoid profile of human milk was assessed. METHODS AND RESULTS: Pre-term and term delivering mothers were included in the study to donate colostrum at 3-5 days postpartum and mature milk at 15 days postpartum. Carotenoids extracts were subjected to a clean-up procedure to remove the triacylglycerol fraction and then analyzed by HPLC-MSn . Identification of xanthophyll esters was achieved by considering their chromatographic behaviour, UV-visible characteristics and MSn features. CONCLUSION: Xanthophyll esters are significant contributors to the carotenoid profile in the colostrum, while mature milk does not contain these compounds. Therefore, fatty acid acylation to xanthophylls is activated during the accumulation of carotenoids in the human mammary gland. The sharp decline in the amount of xanthophyll esters in mature milk indicates that the lipophilic components are those recently incorporated in the mammary epithelium.

In vitro intestinal absorption of carotenoids delivered as molecular inclusion complexes with beta-cyclodextrin is not inhibited by high-density lipoproteins.

This study analyzed the assimilation efficiency of carotenoids when they are delivered as inclusion complexes with beta-cyclodextrin (CyDIC) in water. The in vitro assimilation model used was the brush border membrane vesicles (BBMV) system in which the BBMVs were incubated with CyDIC. Carotenoid suspensions in Tween were used as a reference. Regardless of the form in which the carotenoids were delivered to the BBMV preparation, a higher assimilation efficiency was observed for carotenes than for the xanthophyll lutein. At the highest donor solution concentration, supplying carotenoids in CyDIC produced a significant increase in carotenoid assimilation compared to the corresponding carotenoid suspensions in Tween. The assimilation process using CyDIC takes place by means of a dissociation process in which the carotenoids are released from the beta-cyclodextrin to later be assimilated. At the highest concentration of CyDIC in the donor solution, the dissociation equilibrium will be shifted toward the free forms of the complex, thus increasing the amount of carotenoids available for assimilation. In another set of experiments, the effect of high-density lipoproteins as activity inhibitors for the receptors involved in carotenoid assimilation was analyzed. In carotenoid suspensions in Tween, with an inhibitor, a significant decrease in the assimilated quantity compared was observed with values reached without the inhibitor. Lutein presented the most significant decrease (70%). The fact that complete inhibition was not reached suggests that both simple and facilitated diffusion contributes to the assimilation process. When the donor solution composed of CyDIC and inhibitor was added, significant increases were observed in beta-carotene and lycopene assimilation for all concentrations and in lutein for the highest concentration. This effect is due to the exchange between lipoprotein lipid components and CyDIC, which promotes the dissociation and liberation processes of the carotenoid, which then becomes available for assimilation.

Thermal degradation products formed from carotenoids during a heat-induced degradation process of paprika oleoresins (Capsicum annuum L.).

The high-temperature treatment of paprika oleoresins (Capsicum annuum L.) modified the carotenoid profile, yielding several degradation products, which were analyzed by HPLC-APCI-MS. From the initial MS data, compounds were grouped in two sets. Set 1 grouped compounds with m/z 495, and set 2 included compounds with m/z 479, in both cases for the protonated molecular mass. Two compounds of the first set were tentatively identified as 9,10,11,12,13,14,19,20-octanor-capsorubin (compound II) and 9,10,11,12,13,14,19,20-octanor-5,6-epoxide-capsanthin (compound IV), after isolation by semipreparative HPLC and analysis by EI-MS. Compounds VII, VIII, and IX from set 2 were assigned as 9,10,11,12,13,14,19,20-octanor-capsanthin and isomers, respectively. As these compounds were the major products formed in the thermal process, it was possible to apply derivatization techniques (hydrogenation and silylation) to analyze them by EI-MS, before and after chemical derivatization. Taking into account structures of the degradation products, the cyclization of polyolefins could be considered as the general reaction pathway in thermally induced reactions, yielding in the present study xylene as byproduct and the corresponding nor-carotenoids.

Modification of volatile compound profile of virgin olive oil due to hot-water treatment of olive fruit.

The effect of hot-water treatments of olive fruits before processing on the biosynthesis of virgin olive oil aroma was investigated by quantifying the variation within the major classes of volatile compounds. Data showed that hot-water treatments gave rise to changes in the volatile aroma profile of virgin olive oil from the three olive cultivars under study, Manzanilla, Picual, and Verdial. Different effects by thermal treatments were observed according to cultivar. In general, these changes are mainly due to a decrease in the contents of C(6) aldehydes and C(5) compounds. Contents of C(6) alcohols and esters remained constant or decreased slightly when the temperature of the treatment was increased. Thus, heat treatments seemed to promote a partial deactivation of the lipoxygenase/hydroperoxide lyase enzyme system, whereas other enzymatic activities, within the lipoxygenase pathway, such as alcohol dehydrogenase and alcohol acyltransferase, remained apparently unaffected as a consequence of heat treatments.

Characterization of anthocyanins from the fruits of baguaçu (Eugenia umbelliflora Berg).

Anthocyanin pigments in the berries of baguaçu (Eugenia umbelliflora Berg), a tropical fruit from Brazil, were extracted with 0.1% HCl in ethanol, and the crude anthocyanin extract was purified by Amberlite XAD-7 open-column chromatography. Six major anthocyanins were isolated by preparative HPLC, and their chemical structures were identified by spectroscopic methods (TLC, UV-vis, MS, and (1)H NMR). Delphinidin 3-O-beta-glucopyranoside, cyanidin 3-O-beta-glucopyranoside, petunidin 3-O-beta-glucopyranoside, pelargonidin 3-O-beta-glucopyranoside, peonidin 3-O-beta-glucopyranoside, and malvidin 3-O-beta-glucopyranoside were identified. On the basis of chromatographic data the total anthocyanin content was 342 mg/100 g of fresh baguaçu berries. Therefore, the concomitant presence of six anthocyanins in a single plant species makes this product promising as a new pigment source.