Isolation and structural elucidation of different geometrical isomers of lycopene.

Five geometrical isomers of lycopene were isolated from a photoisomerized mixture on a semi-preparative C30 column and characterized by UV-vis spectroscopy, mass spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. 1H NMR and 2D NMR measurements were used to unambiguously assign the double bond configuration of five isomers: (5Z,9'Z)-, (9Z)-, (5Z,9Z)-, (all-E)-, and (5Z)-lycopene. This will allow other laboratories to use the results for their C30 HPLC.

Comparison of the absorption efficiency of alpha- and beta-cryptoxanthin in female Wistar rats.

Xanthophylls, such as lutein and zeaxanthin, have received increasing interest in recent years because of positive correlations between their consumption and the prevention of eye diseases. Numerous human intervention studies have been conducted with lutein to estimate the bioavailability from different formulations. The present study was designed to obtain basic data on the absorbance efficiency of the monohydroxylated counterparts of lutein and zeaxanthin: alpha- and beta-cryptoxanthin.

Solubility, uptake and biocompatibility of lutein and zeaxanthin delivered to cultured human retinal pigment epithelial cells in tween40 micelles.

Carotenoids lutein and zeaxanthin are proposed to protect ocular tissues from free-radical damage that can cause cataract and age-related macular degeneration (AMD). They accumulate selectively in the lens and macular region of the retina. Changes in the retinal pigment epithelium are characteristic in AMD.

Quantification of 3R,3'R-zeaxanthin in plant derived food by a diastereomeric dilution assay applying chiral high-performance liquid chromatography.

For quantification of 3R,3'R-zeaxanthin in plant derived food, a new diastereomeric dilution assay (DIDA) was developed using chiral high-performance liquid chromatography coupled to diode-array detection (HPLC/DAD). As diastereomeric internal standard (I.S.

Plasma responses in human subjects after ingestions of multiple doses of natural alpha-cryptoxanthin: a pilot study.

Xanthophylls have attracted a lot of interest since their health benefits were documented. Unfortunately, studying their intestinal absorption is often affected by high baseline levels present in the fasting plasma. As alpha-cryptoxanthin is rarely found in the traditional European diet, its concentration in human plasma is extremely low.

Xanthophylls in commercial egg yolks: quantification and identification by HPLC and LC-(APCI)MS using a C30 phase.

The xanthophylls lutein and zeaxanthin have attracted a lot of interest since it was presumed that an increased nutritional uptake may prevent adult macula degeneration (AMD). Although egg yolks serve as an important dietary source of lutein and zeaxanthin, data on xanthophyll concentrations in commercial egg yolks are not available. Thus, an high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed allowing for simultaneous separation of eight xanthophylls used to fortify poultry feed.

Cryptoxanthin structural isomers in oranges, orange juice, and other fruits.

Citrus fruits contain a wide range of bioactive compounds. Their carotenoid fraction is inter alia dominated by structural cryptoxanthin isomers as beta-cryptoxanthin and zeinoxanthin. Both xanthophylls were identified in saponified citrus fruit extracts by comparison to reference compounds extracted from corn and by their typical fragmentation pattern in LC-(APCI)MS analyses.

An extracellular carboxylesterase from the basidiomycete Pleurotus sapidus hydrolyses xanthophyll esters.

An extracellular enzyme capable of efficient hydrolysis of xanthophyll esters was purified from culture supernatants of the basidiomycete Pleurotus sapidus. Under native conditions, the enzyme exhibited a molecular mass of 430 kDa, and SDS-PAGE data suggested a composition of eight identical subunits. Biochemical characterisation of the purified protein showed an isoelectric point of 4.

Identification and quantification of astaxanthin esters in shrimp (Pandalus borealis) and in a microalga (Haematococcus pluvialis) by liquid chromatography-mass spectrometry using negative ion atmospheric pressure chemical ionization.

Negative ion liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [negative ion LC-(APCI)MS] was used for the identification of astaxanthin esters in extracts of commercial shrimp (Pandalus borealis) and dried microalga (Haematococcus pluvialis) samples. A cleanup step using a normal phase solid phase extraction (SPE) cartridge was applied prior to analysis. Recovery experiments with astaxanthin oleate as model compound proved the applicability of this step (98.

Comparison of plasma responses in human subjects after the ingestion of 3R,3R'-zeaxanthin dipalmitate from wolfberry (Lycium barbarum) and non-esterified 3R,3R'-zeaxanthin using chiral high-performance liquid chromatography.

Age-related macular degeneration (AMD) is one of the most common eye diseases of elderly individuals. It has been suggested that lutein and zeaxanthin may reduce the risk for AMD. Information concerning the absorption of non-esterified or esterified zeaxanthin is rather scarce.

Identification and quantification of zeaxanthin esters in plants using liquid chromatography-mass spectrometry.

It has been suggested that lutein and zeaxanthin may decrease the risk for age-related macular degeneration. Surprisingly, oleoresins rich in zeaxanthin are not yet available on the market. Several authors have reported enhanced stability of esterified xanthophylls, so plants containing zeaxanthin esters were investigated to establish valuable sources for the production of durable oleoresins.

Detection of unusual carotenoid esters in fresh mango (Mangifera indica L. cv. 'Kent').

The carotenoid pattern of mango cv. 'Kent' was investigated by LC-(APcI)MS analyses. In solvent extracts from the mesocarp an unusual carotenoid ester was identified as violaxanthin dibutyrate.

Plasma response to a single dose of dietary beta-cryptoxanthin esters from papaya (Carica papaya L.) or non-esterified beta-cryptoxanthin in adult human subjects: a comparative study.

Many orange-coloured fruits contain beta-cryptoxanthin in its non-esterified as well as its esterified form. Information concerning the absorption of beta-cryptoxanthin, especially with regard to the metabolism of its fatty acid esters, is rather scarce. The present study assessed the plasma concentration reached after consumption of a single dose of native beta-cryptoxanthin esters from papaya (Carica papaya L.

Quantification of carotenoids in chicken plasma after feeding free or esterified lutein and capsanthin using high-performance liquid chromatography and liquid chromatography-mass spectrometry analysis.

The present study reports about the plasma carotenoid levels of chickens achieved after feeding diets containing free and esterified lutein (from marigold) and capsanthin (from red pepper) by applying HPLC analyses using a RP-C30 column. Forty chickens were divided at random into four groups and were fed 2 wk with different diets after receiving a basal diet with a low carotenoid content for carotenoid depletion (3 wk). One group was fed a diet containing free lutein (G1), another group received a diet with esterified lutein (G2), two other diets contained free (R1) and esterified capsanthin (R2), respectively.

Carotenoids and carotenoid esters in potatoes (Solanum tuberosum L.): new insights into an ancient vegetable.

The carotenoid pattern of four yellow- and four white-fleshed potato cultivars (Solanum tuberosum L.), common on the German market, was investigated using HPLC and LC(APCI)-MS for identification and quantification of carotenoids. In each case, the carotenoid pattern was dominated by violaxanthin, antheraxanthin, lutein, and zeaxanthin, which were present in different ratios, whereas neoxanthin, beta-cryptoxanthin, and beta,beta-carotene generally are only minor constituents.

Carotenol fatty acid esters: easy substrates for digestive enzymes?

To study the specificity of gastric lipases on carotenoid mono- and diesters, an enzymatic assay was applied. Digestions were carried out in phosphate buffer at pH 7.4 and 37 degrees C.

Differentiation between lutein monoester regioisomers and detection of lutein diesters from marigold flowers (Tagetes erecta L.) and several fruits by liquid chromatography-mass spectrometry.

Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCIMS) was employed for the identification of eight lutein monoesters, formed by incomplete enzymatic saponification of lutein diesters of marigold (Tagetes erecta L.) by Candida rugosa lipase. Additionally, the main lutein diesters naturally occurring in marigold oleoresin were chromatographically separated and identified.

Carotenoid esters in vegetables and fruits: a screening with emphasis on beta-cryptoxanthin esters.

Carotenoids are found in food plants in free form or as fatty acid esters. Most studies have been carried out after saponification procedures, so the resulting data do not represent the native carotenoid composition of plant tissues. Therefore, nonsaponified extracts of 64 fruits and vegetables have been screened to determine the amount of carotenoid esters in food plants.

Identification and characterization of a mammalian enzyme catalyzing the asymmetric oxidative cleavage of provitamin A.

In vertebrates, symmetric versus asymmetric cleavage of beta-carotene in the biosynthesis of vitamin A and its derivatives has been controversially discussed. Recently we have been able to identify a cDNA encoding a metazoan beta,beta-carotene-15,15'-dioxygenase from the fruit fly Drosophila melanogaster. This enzyme catalyzes the key step in vitamin A biosynthesis, symmetrically cleaving beta-carotene to give two molecules of retinal.

Enzymatic hydrolysis of carotenoid fatty acid esters of red pepper (Capsicum annuum L.) by a lipase from Candida rugosa.

Analyses of red pepper extracts which had been pretreated with lipase type VII (EC 3.1.1.

Photoinduced addition of the fungicide anilazine to cyclohexene and methyl oleate as model compounds of plant cuticle constituents.

Photoreactions, initiated by sunlight irradiation, between organochlorine pesticides and olefinic compounds of plant cuticles have been postulated. Concerning the formation of bound residues, which so far have not been detectable by common analytical techniques, photoaddition reactions are of main interest. In order to study the photochemical behavior of chlorinated fungicides, anilazine was irradiated in cyclohexene and methyl oleate as model compounds for olefinic plant cuticle constituents.

Survival in traumatic spinal cord injury.

The present study was conducted on 1510 persons between 1 December 1973 and 31 December 1980. Of these, 1478 (97.9 per cent) were traced by questionnaire.