The red yeast
Xanthophyllomyces dendrorhous
is one of the microbiological production systems for natural carotenoids. High-performance liquid chromatography (HPLC) and electron paramagnetic resonance ...spectroscopy (EPR) experiments were performed on
X. dendrorhous
membranes in order to study the effect of incorporation rates of different type of carotenoids. In the case of fluid-phase membranes, it was found that polar carotenoids, such as astaxanthin and
cis
-astaxanthin, increased the EPR order parameter and decreased the motional freedom and phase-transition temperature. In contrast the non-polar carotenoids β-cryptoxanthin and β-carotene decreased the EPR order parameter and increased motional freedom and phase-transition temperature. A noteworthy coherence was observed between the polarities of the strains and the phase-transition temperatures.
This paper summarizes the important progress in the field of oil and gas production engineering during the “Thirteenth Five-Year Plan” period of China, analyzes the challenges faced by the current ...oil and gas production engineering in terms of technological adaptability, digital construction, energy-saving and emission reduction, and points out the future development direction. During the “Thirteenth Five-Year Plan” period, series of important progresses have been made in five major technologies, including separated-layer injection, artificial lift, reservoir stimulation, gas well de-watering, and workover, which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields. Under the current complex international political and economic situation, oil and gas production engineering is facing severe challenges in three aspects: technical difficulty increases in oil and gas production, insignificant improvements in digital transformation, and lack of core technical support for energy-saving and emission reduction. This paper establishes three major strategic directions and implementation paths, including oil stabilization and gas enhancement, digital transformation, and green and low-carbon development. Five key research areas are listed including fine separated-layer injection technology, high efficiency artificial lift technology, fine reservoir stimulation technology, long term gas well de-watering technology and intelligent workover technology, so as to provide engineering technical support for the transformation, upgrading and high-quality development of China’s oil and gas industry.
The development of multidrug resistance (MDR) causes difficulties in the chemotherapy of of human cancer. Investigation of the possibility of reversal of MDR has been greatly aided by the use of cell ...lines with acquired resitance to anticancer agents in vitro or transfected with the mdrl gene. The aim of this study was to examine new perspectives of chemotherapy focused on natural, carotenoid compounds, in connection with the modification of MDR. The function of the MDR protein was examined via the R123 drug accumulation of both cell lines in the presence of carotenoids. The fluorescence of the cell population was measured by flow cytometry. The most effective resistance modifiers Monoepoxy-beta-carotene, (SS, 8S)-capsochrome, (8'S) Luteoxanthin, (9Z)-Violaxanthin, (9Z)-Zeaxanthin, (13Z)-Zeaxanthin were assayed for their antiproliferative effects in combination with the anti-cancer drug epirubicin. (13Z)-Zeaxanthin was able to enhance the antiproliferative effect on human mdrl gene transfected mouse lymphoma and anthracycline resistant human breast cancer cell line MCF7. (8'S)-luteoxanthin, (5S, 8S)-capsochrome and (9Z)-zeaxanthin treatment revealed synergism with epirubicin on resistant mouse lymphoma. The enhanced antiproliferative activity of epirubicin combinated with (9Z)-Violaxanthin was more significant on MCF7 cells resistant to anthracycline.
Mechanisms of the potent anti-inflammatory actions of carotenoids are unknown. Since carotenoids are incorporated into membranes, they might modulate transient receptor potential ankyrin 1 and ...vanilloid 1 (TRPA1 and TRPV1) activation predominantly on peptidergic sensory nerves. We therefore investigated the effects of three carotenoids (β-carotene, lutein and lycopene) on cutaneous neurogenic inflammation. Acute neurogenic edema and inflammatory cell recruitment were induced by smearing the TRPA1 agonist mustard oil (5 %) or the TRPV1 activator capsaicin (2.5 %) on the mouse ear. Ear thickness was then determined by micrometry, microcirculation by laser Doppler imaging and neutrophil accumulation by histopathology and spectrophotometric determination of myeloperoxidase activity. The effects of lutein on the stimulatory action of the TRPA1 agonist mustard oil were also tested on the guinea-pig small intestine, in isolated organ experiments. Mustard oil evoked 50–55 % ear edema and granulocyte influx, as shown by histology and myeloperoxidase activity. Swelling was significantly reduced between 2 and 4 h after administration of lutein or β-carotene (100 mg/kg subcutane three times during 24 h). Lutein also decreased neutrophil accumulation induced by TRPA1 activation, but did not affect mustard oil-evoked intestinal contraction. Lycopene had no effect on any of these parameters. None of the three carotenoids altered capsaicin-evoked inflammation. It is proposed that the dihydroxycarotenoid lutein selectively inhibits TRPA1 activation and consequent neurogenic inflammation, possibly by modulating lipid rafts.
The carotenoid compositions of the peel and the pulp of various citrus fruits were compared with HPLC methods using C18 and C30 columns. The extracts usually contain β-cryptoxanthin and lutein in ...considerable amounts and in all species except lime, the red apocarotenoid β-citraurin as well. In case of lime and mandarin the carotenoid compositions of peel and pulp show a good coincidence while in orange, clementine, grapefruit, lemon and kumquat there are a lot more differences. Lime extracts contain practically only two carotenoids: β-carotene and lutein. The carotenoid components of the saponified extracts of kumquat were separated on calcium carbonate columns and were investigated in detail. The components were identified with HPLC–DAD and HPLC–MS.
Citrus fruits are important starting materials for juice production. Their carotenoid fingerprint shows differences not only in different species but the proportion of certain pigments can be different in the same fruit according to where the plants were grown and how they were processed. Comparison of the carotenoid content of different fruit products (e.g. juices) can give us useful hints about the quality of the product and about the amount of these important natural antioxidants.
Algal mass productions are widespread events throughout the world. Most research deals with the environmental impact, ecology and toxicity of these phenomena, but the algae are also promising sources ...of bioactive natural products, and also are potential food additives. In the current study, we aimed to characterize the carotenoid composition of three non-toxic algal isolates with distinct taxonomical position, namely Dunaliella salina, Euglena sanguinea and a Nostoc strain.
The strains were screened for carotenoid composition with HPLC–UV–APCI-MS with comparison with authentic standards. Carotenoids were purified with open column chromatography, and characterized by LC–UV–MS and NMR.
All three species contained a high amount of carotenoids. The composition of the carotenoid pattern was somewhat different compared to literature data. The Dunaliella carotenoid fraction contained lutein (52.1% of total carotenoid), β-carotene (13.1%), violaxanthin (11.5%) and neoxanthin (6.2%) as chief compounds. The chief carotenoids in the Nostoc strain was echinenone (34.9%), while the main components of the Euglena isolate were diatoxanthin (39.0%), lutein (23.7%), an unidentified carotenoid (9.6%) and β-carotene (5.4%). Diatoxanthin is identified by NMR spectroscopy.
The carotenoid patterns of the examined strains are somewhat different from the patterns described in the literature. This can be the results of genetic or environmental differences, or combinations thereof. Despite these differences, our study shows the potency of these algae in production of carotenoids, and possibly, usage as food additives.
•Characterization of the carotenoids of a lutein-rich Dunaliella salina strain•Characterization of the carotenoids of an echinenone-rich Nostoc strain•Characterization of the carotenoids of a diatoxanthin-rich Euglena sanguinea strain•Three non-toxic algae were shown to be excellent natural sources of carotenoids.
From the ripe fruits of
Asparagus falcatus capsoneoxanthin, a minor carotenoid was isolated and, based on its spectral data, identified as (all-
E,3
S,5
R,6
R,3′
S,5′
...R)-6,7-didehydro-5,6-dihydro-3,5,3′-trihydroxy-β,κ-caroten-6′-one.
The later steps of carotenoid biosynthesis involve the formation of cyclic carotenoids. The reaction is catalyzed by lycopene β-cyclase (LCY-B), which converts lycopene into β-carotene, and by ...capsanthin-capsorubin synthase (CCS), which is mainly dedicated to the synthesis of κ-cyclic carotenoids (capsanthin and capsorubin) but also has LCY-B activity. Although the peptide sequences of plant LCY-Bs and CCS contain a putative dinucleotide-binding motif, it is believed that these two carotenoid cyclases proceed via protic activation and stabilization of resulting carbocation intermediates. Using pepper (Capsicum annuum) CCS as a prototypic carotenoid cyclase, we show that the monomeric protein contains one noncovalently bound flavin adenine dinucleotide (FAD) that is essential for enzyme activity only in the presence of NADPH, which functions as the FAD reductant. The reaction proceeds without transfer of hydrogen from the dinucleotide cofactors to β-carotene or capsanthin. Using site-directed mutagenesis, amino acids potentially involved in the protic activation were identified. Substitutions of alanine, lysine, and arginine for glutamate-295 in the conserved 293-FLEET-297 motif of pepper CCS or LCY-B abolish the formation of β-carotene and κ-cyclic carotenoids. We also found that mutations of the equivalent glutamate-196 located in the 194-LIEDT-198 domain of structurally divergent bacterial LCY-B abolish the formation of β-carotene. The data herein reveal plant carotenoid cyclases to be novel enzymes that combine characteristics of non-metal-assisted terpene cyclases with those attributes typically found in flavoenzymes that catalyze reactions, with no net redox, such as type 2 isopentenyl diphosphate isomerase. Thus, FAD in its reduced form could be implicated in the stabilization of the carbocation intermediate.
The multidrug resistance (MDR) proteins are member of the ATP-binding cassette superfamily and are present in a majority of human tumors. Their activity is a crucial factor leading to therapeutic ...failure. It is likely that compounds which inhibit the function of the MDR-efflux proteins such as MDR1 will improve the cytotoxic action of anticancer chemotherapy. Therefore, a search for MDR reversing compounds was conducted among three classes of plant derived compounds such as diterpenes, triterpenes and carotenoids in a hope to find inhibitors without adverse effects in these natural compounds. The inhibition of efflux activity was determined by measuring the accumulation of substrate analogues such as rhodamine in tumor cells in the presence of potential inhibitors. Thus we determined the effect of structurally unrelated diterpenes, triterpenes and carotenoids on reversal of multidrug resistance in MDR-1 gene-transfected L1210 mouse lymphoma cells and MDR mediated multidrug resistance of human breast cancer cells MDA-MB-231 (HTB-26) and MCF-7. The majority of diterpenes, cycloartane triterpenes and carotenoids isolated from vegetables and medicinal plants were able to enhance rhodamine 123 accumulations of MDR-cells. Synergistic interaction was found between epirubicine and resistance modifier terpenoids in vitro. It is supposed that these MDR modulators bind into transmembrane domains and the action of ABC transporters is inhibited by induced conformational changes.
The changes in the carotenoid pigments of the Capsicum annuum var. lycopersiciforme rubrum during maturation have been investigated quantitatively by means of a HPLC technique. In all of the ...chromatograms, 40 peaks were detected; 34 carotenoids were identified. The total carotenoid content of the ripe fruits was about 1.3 g/100 g of dry weight, of which capsanthin constituted 37%, zeaxanthin was 8%, cucurbitaxanthin A was 7%, capsorubin constituted 3.2%, and beta-carotene accounted for 9%. The remainder was composed of capsanthin 5,6-epoxide, capsanthin 3,6-epoxide, 5,6-diepikarpoxanthin, violaxanthin, antheraxanthin, beta-cryptoxanthin, and several cis isomers and furanoid oxides. The possible biosynthetic routes for the formation of minor carotenoids containing 3,5,6-trihydroxy-beta-, 3,6-epoxy-beta-, and 6-hydroxy-gamma-end groups are described.
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