Solid-phase extraction of carotenoids

Carotenoids in Health as Studied by Omics-Related Endpoints

Carotenoids have been associated with risk reduction for several chronic diseases, including the association of their dietary intake/circulating levels with reduced incidence of obesity, type 2 diabetes, certain types of cancer, and even lower total mortality. In addition to some carotenoids constituting vitamin A precursors, they are implicated in potential antioxidant effects and pathways related to inflammation and oxidative stress, including transcription factors such as nuclear factor κB and nuclear factor erythroid 2-related factor 2. Carotenoids and metabolites may also interact with nuclear receptors, mainly retinoic acid receptor/retinoid X receptor and peroxisome proliferator-activated receptors, which play a role in the immune system and cellular differentiation. Therefore, a large number of downstream targets are likely influenced by carotenoids, including but not limited to genes and proteins implicated in oxidative stress and inflammation, antioxidation, and cellular differentiation processes. Furthermore, recent studies also propose an association between carotenoid intake and gut microbiota. While all these endpoints could be individually assessed, a more complete/integrative way to determine a multitude of health-related aspects of carotenoids includes (multi)omics-related techniques, especially transcriptomics, proteomics, lipidomics, and metabolomics, as well as metagenomics, measured in a variety of biospecimens including plasma, urine, stool, white blood cells, or other tissue cellular extracts. In this review, we highlight the use of omics technologies to assess health-related effects of carotenoids in mammalian organisms and models.

Nanoparticle-based polyacrylonitrile monolithic column for highly efficient micro solid-phase extraction of carotenoids and vitamins in human serum

In this work, a biocompatible monolithic column based micro-solid-phase extraction (µ-SPE) method was developed for biological fluid analysis. A novel nanoparticle-based polyacrylonitrile monolithic column (C30 NP-PMC) was fabricated by incorporating triacontyl (C30) modified silica nanoparticles (NPs) into the polyacrylonitrile monolithic matrix through thermally induced phase separation. With efficient mass transfer and sorption capacity, C30 NP-PMC exhibited outstanding performance for the extraction of carotenoids and fat-soluble vitamins (FSVs) from human serum samples, superior to commercial C18 cartridges as well as liquid-liquid extraction (LLE) method. Under optimal conditions, the proposed µ-SPE method coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD) achieved satisfactory limits of detection (LODs) (1.5-75.0 ng/mL) and good recoveries (85.0-106.5 %) with relative standard deviations (RSDs) of less than 12.1% by consuming lower sorbent (35.0 mg) and organic solvent (0.8 mL). Successful application of the developed method demonstrated the great potential of such monolithic sorbents for efficient isolation and preconcentration of trace analytes from blood samples.

A fast and simple method for determination of β-carotene in commercial fruit juice by cloud point extraction-cold column trapping combined with UV-Vis spectrophotometry

Cloud point extraction with cold column trapping (CPE-CCT) was used for the rapid preconcentration and UV-Vis spectroscopy of beta-carotene in fruit juice samples. A central composite design was employed to optimize parameters such as pH, incubation time, cloud point temperature and surfactant concentration. A detection limit of 0.01 mg/L of beta-carotene (3S_B/m), a coefficient of determination of 0.998 and a linear range of 0.04-10 mg/L were obtained. The CPE-CCT method was confirmed in comparison with the corresponding direct HPLC standard method. A simple, portable and cost-effective device was also utilized. Owing to eliminating centrifugation, the conditions of CPE-CCT were more moderate and its sample handling easier compared to conventional CPE.

In vitro dual (anticancer and antiviral) activity of the carotenoids produced by haloalkaliphilic archaeon Natrialba sp. M6

Halophilic archaea are a promising natural source of carotenoids. However, little information is available about the biological impacts of these archaeal metabolites. Here, carotenoids of Natrialba sp. M6, which was isolated from Wadi El-Natrun, were produced, purified and identified by Raman spectroscopy, GC-mass spectrometry, and Fourier transform infrared spectroscopy, LC-mass spectrometry and Nuclear magnetic resonance spectroscopy. The C₅₀ carotenoid bacterioruberin was found to be the predominant compound. Because cancer and viral hepatitis are serious diseases, the anticancer, anti-HCV and anti-HBV potentials of these extracted carotenoids (pigments) were examined for the first time. In vitro results indicated that the caspase-mediated apoptotic anticancer effect of this pigment and its inhibitory efficacy against matrix metalloprotease 9 were significantly higher than those of 5-fluorouracil. Furthermore, the extracted pigment exhibited significantly stronger activity for eliminating HCV and HBV in infected human blood mononuclear cells than currently used drugs. This antiviral activity may be attributed to its inhibitory potential against HCV RNA and HBV DNA polymerases, which thereby suppresses HCV and HBV replication, as indicated by a high viral clearance % in the treated cells. These novel findings suggest that the C₅₀ carotenoid of Natrialba sp. M6 can be used as an alternative source of natural metabolites that confer potent anticancer and antiviral activities.

Macular carotenoids in lipid food matrices: DOE-based high energy extraction of egg yolk xanthophylls and quantification through a validated APCI(+) LC-MS/MS method

Lutein and zeaxanthin exhibit significant biological activities therefore their dietary intake through carotenoid-rich foods and supplements is strongly recommended as preventive approach. Hence their extraction from natural substrates targets to their commercial exploitation as nutraceuticals and ocular pharmaceuticals. Since carotenoids' bioavailability is higher in fat-containing substrates, egg yolk is considered an ideal food matrix. DOE-based optimization of novel high energy extraction practices achieves efficient recovery of xanthophylls from lipid sources. In this research, 2³ full factorial and Box-Behnken designs (BBD) were applied for optimizing ultrasound- (UAE) and microwave-assisted extraction (MAE) variables (i.e. extraction solvent, temperature, time, US or MW power and solvent/material ratio). LC-MS/MS results pointed out the precedence of UAE in lutein and zeaxanthin extraction, where higher yields were obtained with 1:1 n-hexane-acetone as solvent mixture at 19 min, 600 W and 35 mL g^-1. UAE carotenoid content was higher than MAE due to the different mechanisms laying behind the two processes and due to more complete granule rupture caused by higher US power. Evaluating the current results, DOE-based UAE analytical methodology stands out as an auspicious and sustainable alternative for commercial-based extraction of lipidic bioactive compounds for food and drug industrial applications.

Simple and sensitive dilute-and-shoot analysis of carotenoids in human plasma

Carotenoids in human plasma are used as biomarkers of vegetable and fruit intake. Large sample volumes and intensive sample processing make measurement of these species cumbersome. We developed a dilute-and-shoot method for the quantitation of α-carotene, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin using 10 μL of plasma. Plasma was injected into methanol containing internal standard and deproteinized by centrifugation. The carotenoids in the supernatant were separated using a YMC C-30 column and quantified by tandem mass spectrometry. The linearity for carotenoids ranged from sub-fmol to approximately 300 fmol on-column. Spike recovery experiments were used to correct for matrix effects. The method was validated using the human plasma standard NIST SRM 968e. Over 400 sample analyses were performed using the same guard and analytical columns. This method represents an improvement over current techniques because of the small sample size needed, ease of sample preparation, and improvement in the determination of carotenoid content.

Determination of Carotenoids in Egg Yolk by High Performance Liquid Chromatography with Vortex-Assisted Hollow Fiber Liquid-Phase Microextraction using Mixed Extraction Solvent

A vortex-assisted hollow fiber liquid-phase microextraction method using a mixed solvent as the extraction solvent followed by high performance liquid chromatography diode-array detection was developed for the extraction and determination of two carotenoids including lutein and β-carotene from egg yolk. The method is based on the microextraction of carotenoids from sample solution into extracting agent (20 μL), which is located in the lumen of hollow fiber followed by vortex-mixing. The mixed solvent (1-octanol+1-undecanol, 6:4, v:v) was employed as extracting agent for it has suitable viscosity and compatible with carotenoids via hollow fiber. Vortex-mixing was utilized to provide effective and mild mixing of sample solution and increase the contact between analytes and boundary layers of the hollow fiber. Parameters influencing recoveries were investigated and optimized. Under the optimum conditions, the linear range of lutein and β-carotene were from 50 to 1,000 ng mL^-1 The correlation coefficients of the calibration curves were >0.9982, relative standard deviations (n = 5) were between 2.23% and 3.51% and the limits of detection were 0.038 and 0.045 μg mL^-1 for lutein and β-carotene, respectively. The proposed method was successfully applied to the extraction and determination of caroteonids in egg yolk with the satisfactory relative recoveries (90.2-101.8%).

Red pepper (Capsicum annuum) carotenoids as a source of natural food colors: analysis and stability-a review

Carotenoids are increasingly drawing the attention of researchers as a major natural food color due to their inherent nutritional characteristics and the implicated possible role in prevention and protection against degenerative diseases. In this report, we review the role of red pepper as a source for natural carotenoids. The composition of the carotenoids in red pepper and the application of different methodologies for their analysis were discussed in this report. The stability of red pepper carotenoids during post-harvest processing and storage is also reviewed. This review highlights the potential of red pepper carotenoids as a source of natural food colors and also discusses the need for a standardized approach for the analysis and reporting of composition of carotenoids in plant products and designing model systems for stability studies.

Screening of edible oils for polycyclic aromatic hydrocarbons using microwave-assisted liquid-liquid and solid phase extraction coupled to one- to three-way fluorescence spectroscopy analysis

The potential of microwave-assisted liquid-liquid and solid phase extraction coupled with fluorescence spectroscopy and employing one- to three-way spectral data was assessed in terms of their capacity for the rapid detection of heavy polycyclic aromatic hydrocarbons (PAHs) in olive and sunflower oils. Tocopherols and pigments groups (chlorophyll and pheophytin) present in oil matrices were the main interference compounds in the detection of PAHs using fluorescence spectroscopy. Partial spectral overlap and inner-filter effects were observed in the emission range of the analytes. The effectiveness of removing these interferences using solid phase extraction (silica, C18 and graphitized carbon black) was examined. Solid phase extraction with silica was the most effective method for the removal of pigments and tocopherol and allowed for the detection of PAHs in edible oils using fluorescence spectroscopy. The limit of detection was observed to depend on the use of one-, two- or three-way fluorescence spectral data in the range of 0.8 to 7.0 μg kg(-1). The individual recoveries of PAHs following the microwave-assisted L-L extraction and SPE with silica were assessed using HPLC-FD with satisfactory results.

Microalgae as sources of carotenoids

Marine microalgae constitute a natural source of a variety of drugs for pharmaceutical, food and cosmetic applications-which encompass carotenoids, among others. A growing body of experimental evidence has confirmed that these compounds can play important roles in prevention (and even treatment) of human diseases and health conditions, e.g., cancer, cardiovascular problems, atherosclerosis, rheumatoid arthritis, muscular dystrophy, cataracts and some neurological disorders. The underlying features that may account for such favorable biological activities are their intrinsic antioxidant, anti-inflammatory and antitumoral features. In this invited review, the most important issues regarding synthesis of carotenoids by microalgae are described and discussed-from both physiological and processing points of view. Current gaps of knowledge, as well as technological opportunities in the near future relating to this growing field of interest, are also put forward in a critical manner.