Colorants In Food Industry Research Articles

Stabilized chlorophyll-based food colorants from spinach: Kinetics of a tailored enzymatic extraction.

An organic solvent-free method based on limited dosing options (biocatalyst and zinc chloride) for the quick and mild recovery of chlorophyll (Chl) from spinach has been proposed. This tailored, custom-made protocol has been designed to produce stable green natural colorants. The kinetics of pigment extraction turned out to be a very useful tool to identify the proper conditions, in terms of biocatalyst dose (0.10-50U/g), extraction time (1-48h), and ZnCl2 amount (50-300ppm), both for enhancing the recovery yield and preserving the green color. Considering the extraction kinetics, the recovery yield, and the colorimetric data, the suitable conditions to produce stable green and food-grade colorants are 0.10U/g of enzyme, 3h, and 150ppm of ZnCl2 at 25°C. The extraction yield of Chl (4863µg/U) was about 51% greater than control, with a higher extraction rate constant (5.43×10-4g/(µgmin)). Considering the impact of ZnCl2 amount on Chl, its protective action resulted to be more noticeable toward Chl a: at 150ppm, an increased amount of about 2.5 and 1.5 times was found for Chl a and Chl b, respectively, in comparison to the reference (0ppm ZnCl2). PRACTICAL APPLICATION: This research demonstrates how a suitable kinetic approach helps to provide a tailored protocol, customized for the vegetable matrix, to produce stable green natural colorants from spinach. Lowering enzyme dosage and ZnCl2 amount during the extraction of chlorophyll at low temperature is crucial for its potential use as a colorant in food industry, providing high economic values through saving time and environmental protection.

Construction of the advanced flavin mononucleotide producers in the flavinogenic yeast Candida famata.

Flavin mononucleotide (FMN, riboflavin-5'-phosphate) is flavin coenzyme synthesized in all living organisms from riboflavin (vitamin B2 ) after phosphorylation in the reaction catalyzed by riboflavin kinase. FMN has several applications mostly as yellow colorant in food industry due to 200 times better water solubility as compared to riboflavin. Currently, FMN is produced by chemical phosphorylation of riboflavin, however, final product contains up to 25% of flavin impurities. Microbial overproducers of FMN are known, however, they accumulate this coenzyme in glucose medium. Current work shows that the recombinant strains of the flavinogenic yeast Candida famata with overexpressed FMN1 gene coding for riboflavin kinase in the recently isolated by us advanced riboflavin producers due to overexpression of the structural and regulatory genes of riboflavin synthesis and of the putative exporter of riboflavin from the cell, synthesized elevated amounts of FMN in the media not only with glucose but also in lactose and cheese whey. Activation of FMN accumulation on lactose and cheese whey was especially strong in the strains which expressed the gene of transcription activator SEF1 under control of the lactose-induced LAC4 promoter. The accumulation of this coenzyme by the washed cells of the best recombinant strain achieved 540 mg/L in the cheese whey supplemented only with ammonium sulfate during 48 h in shake flask experiments.

An efficient microbial-based method for production of high-purity Monascus azaphilones pigments

Monascus azaphilones (MAs) are widely used as food colorant in food industry. The MAs mixture, produced by Monascus strains., are traditionally classified into orange MAs (OMAs), yellow MAs (YMAs) and red MAs (RMAs). Each component exhibits great application potential due to their respective biological activities. However, there is a severe bottleneck in the production of high-purity MAs components. We identified an oxidoreductase MrPigF responsible for formation of OMAs, rubropunctatin and monascorubrin, by gene knockout and overexpression. The mrpigF-overexpressing strain selectively produced a pair of OMAs, rubropunctatin and monascorubrin, and mrpigF knockout strain predominantly yielded a pair of YMAs, monascin and ankaflavin. Furthermore, preparation of 19 pairs of RMAs by amination of OMAs in ionic liquid was achieved. This study describes a feasible microbial-based method for production of MAs components with high purity (>90%) on a preparative scale (>5 g/L), to our knowledge the highest values reported in literatures. Our results will not only contribute to our understanding of the biosynthetic steps of the classical YMAs and OMAs, but also have significance in guiding the industrial preparation of high-purity MAs components.

Extraction of natural pigments from red sorghum (Sorghum bicolor) husk by ultrasound and microwave assisted extraction: A comparative study through response surface analysis

AbstractSorghum (Sorghum bicolor) is an important source of bioactive compounds, such as the phenolic compounds. The phenolic compounds in sorghum grain are concentrated in its hull; however, its hull is usually being discarded as a waste. In this study, ultrasonication power intensity (916, 1018, and 1120 W/cm2), sonication time (20, 25, and 30 min), and particle size (100, 300 and 500 μm) for ultrasound assisted extraction and, microwave power (50, 60 and 70 W), microwave time (90, 105, and 120 s), and particle size (100, 300, and 500 μm) for microwave assisted extraction were investigated and optimized using Box–Behnken design. For ultrasound assisted extraction, optimized condition was found as 1078 W/cm2 power intensity, 23.6 min sonication time and 100 μm particle size, and corresponding values of responses were 8.55 mg LE/g dw total anthocyanin content, 779.0 mg GAE/g dw total phenolic content, 172.0 mg CE/g dw total flavonoid content, 70.0 and 73.4% antioxidant activity by DPPH and ABTS methods, respectively and 11.1 redness (a*). For microwave assisted extraction, optimized condition was found as 63 W power, 101 s time and 100 μm particle size, and the responses were 10.5 mg LE/g dw total anthocyanin content, 606.0 mg GAE/g dw total phenolic content, 195.0 mg CE/g dw total flavonoid content, 79.5 and 82.2% antioxidant activity by DPPH and ABTS methods, respectively and 13.6 redness (a*). For validation of model at optimum conditions, predicted values were insignificantly (p > .05) differ than actual values for all the responses for both ultrasound and microwave assisted extraction.Practical ApplicationsSorghum consists of a rare class of natural pigments (3‐deoxyanthocyanidins) in its husk. These natural pigments have antioxidant, anti‐proliferative activity, and thus, can be utilized as natural food colorant in food industry. Extraction and isolation of these natural pigments from sorghum husk are prerequisites for their application in food industry. In order to obtain an efficient extraction of sorghum anthocyanins, resulting in minimal degradation and high antioxidant capacity, the choice of the extraction method is important. This research provides information about standardization of novel extraction techniques (ultrasound and microwave assisted extraction) for effective utilization of sorghum husk for extraction of natural pigments, which can be utilized for application in various food products.

Exploration of Betalains and Determination of the Antioxidant and Cytotoxicity Profile of Orange and Purple Opuntia spp. Cultivars in Greece.

Replacing synthetic dyes with natural pigments has gained great attention over the past years in the food industry, due to the increased alertness of consumers for nontoxic and natural additives. Betalains are water-soluble nitrogenous natural pigments that are used as natural colorants in food industries, due to their applicability and their rich pharmacological profile including antioxidant, antimicrobial, and anticancer properties. Therefore, there is a need for a detailed exploration of betalains to fully exploit their properties. Opuntia spp. plants are one of the primary sources of betalains. The objective of this study was to identify betalain phytochemical content in prickly pear cactus of two different Opuntia species from Greece (an Opuntia ficus-indica (L.) Mill (OFI) orange prickly pear cultivar and an Opuntia spp. purple prickly pear cultivar) using modern analytical techniques as also to evaluate their antioxidant and cytotoxicity profile. To achieve this we used an array of analytical techniques, including ultra-violet-vis (UV-Vis) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and liquid chromatography-high resolution mass spectrometry (LC-HRMS) as also cell based in vitro assays. These enabled us to establish a rapid approach that can distinguish the different Opuntia spp. cultivars based on their phytochemical constituents through untargeted metabolomics analysis using ultra-high performance liquid chromatography-mass spectrometry - quadrupole time-of-flight (UPLC/MS Q-TOF). These findings could allow a further exploitation of Opuntia species and especially their enriched betalain phytochemical profile as viable source of natural food colorants.

Comparative estimations of betalains and sugars in fruits of five species of Selenicereus (Cactaceae)

Background and Aims: Betalains are water pigments reported for most species in the order Caryophyllales, to which the family Cactaceae belongs, with benefits as antioxidants in nutrition and human health. The objective of this paper is to determine the quantity of the betalains (betaxanthins and betacyanins) and sugars present in five taxa of Selenicereus, from the Hylocereus clade, commonly utilized for their edible fruit, including S. ocamponis which is an underutilized species, and scarcely cultivated in Mexico. Methods: Fruits from wild and cultivated plants were collected in Puebla, Veracruz and Yucatán (Mexico) and Valle del Cauca (Colombia) between April and June 2019, and their betalain and sugar content were estimated from frozen fruit. The method proposed by the Association of Official Analytical Chemists was followed to estimate the sugar content. A spectrophotometric method was utilized for estimation of betalains. Key results: The highest total betalain content was found in species with fruits of purple pulp and pericarp such as S. ocamponis (5.30 and 4.03 mg/100 g of fresh weight, respectively). Glucose and fructose content was considerable in some samples: S. undatus with 5.99 and 2.87 mg/100 g and S. ocamponis with 5.30 and 4.03 mg/100 g respectively. Conclusions: This study identified large variation in total betalain content in the pericarps of wild and cultivated fruits in S. undatus (2.47-37.11 mg/100 g of fresh weight), which might be related to their management and selection. Estimated total betalain content of wild plants of this species was higher than in some cultivated plants. These results suggest that wild S. undatus plants might represent a good source for breeding programs. The cultivation of species with purple pulp and pericarp should be promoted, so they can be utilized as colorants in food industry.

Genetic improvement of bougainvillea in Indian scenario - A review

Bougainvillea is a native of South America and it is a popular plant all over the world with tropical and warm climates. It is a thorny and woody plant having different coloured bracts viz., white, pink, purple, red, orange, yellow etc. Among the different species of Bougainvillea, Bougainvillea glabra and B. spectabilis are most popular across the world. Bougainvillea plants provide colour to the garden when the flowering of winter season annuals ceases and the blooming of summer annuals or other ornamental plants is yet to arrive. The ability of bougainvillea to grow under highly polluted conditions like traffic islands, roadsides and around industries has made it popular among the planners and architects. The plants can be grown as climbers by training them on walls of house or any building, parks, farms garden, open spaces and on arches or pergola or on a tree. The edible flowers of Bougainvillea are frequently used for the preparation of salads and flower teas in different parts of the world. The floral bracts are the rich source of betalain pigments particularly betacyanin which can be exploited as a natural colorant in food industries. Although, Bougainvillea has originated in South America, but approximately 50% of the present day cultivars were evolved and developed in India. The Division of Floriculture and Landscaping of IARI is a pioneering centre of Bougainvillea and have a good collection of germplasm of bougainvilleas. Besides, NBRI, Lucknow; IIHR, Bangalore; CAZRI, Jodhpur and BARC, Mumbai have contributed significantly in breeding of Bougainvillea. Division of Floriculture and Landscaping IARI, New Delhi has been recognized as the International Registration Authority for Bougainvilleas by Royal Horticultural Society, U.K, since, 1966 and again during the recent meeting of 2007 held at Wageningen, The Netherlands. The division is one of the major repository centre and more than 100 cultivars of Bougainvilleas are conserved here with different colour, thorny, thornless, variegated, bicoloured, multibracted etc. The varieties evolved at IARI include Dr. R.R. Pal, Stanza, Summer Time, Sonnet, Spring Festival and Vishakha.

Stability of Phycobiliproteins Using Natural Preservative ε- Polylysine (ε-PL)

C-Phycocyanin (PC) and C-Phycoerythrin (PE) are important phycobiliproteins (PBs) with their possible application as colorants in food industries. In the present study, effect of natural preservative, e-polylysine and chemical preservative, citric acid on the stability of C-PC and C-PE at 4 ± 2°C was studied. Percentage loss of C-PE and C-PC content and effect of pH and fluorescence on C-PC and C-PE was studied. 0.02% e-polylysine (w/v) was found to be optimum for storage of C-PC and C-PE at 4 ± 2°C and lesser loss of C-PC and C-PE content as compared to citric acid for its storage up to 8 days without any change in colour and pH. The amount of C-PC and CPE left in the solution containing e-polylysine was 90.5 and 95.24% respectively. 0.02% e-polylysine (w/v) was found to be optimum for storage of C-PC and C-PE at 4 ± 2°C and lesser loss of CPC and C-PE content as compared to citric acid for its storage up to 8 days without any change in colour and pH. The amount of C-PC and C-PE left in the solution containing e-polylysine was 90.5 and 95.24% respectively. Further, there is a need to replace chemical or synthetic preservatives with natural preservative ɛ-polylysine as prolonged consumption of these chemical or synthetic preservatives possess health hazard. The present work provides an effective option for replacing these chemical or synthetic preservatives with e-polylysine as natural preservative.

Development of beetroot (Beta vulgaris) powder using foam mat drying

Beetroot (Beta vulgaris) is normally used as natural food colorants in food industry. The objectives of this research are (1) to determine the effect of types (egg albumen and fish gelatine) and different concentrations of foaming agents on foam properties of foam mat drying beetroot, (2) to evaluate the physicochemical properties (color, pH, Brix, bulk density, water activity, hygroscopicity and moisture content) of foam dried beetroot powder, and (3) to determine the effect of temperature on rehydration ratio and color changes of rehydrated foam mat dried beetroot powder. Beetroot foam was spread at 3 mm thickness and hot air dried at 50 °C for 6 h in cabinet dryer. Beetroot pulp can be successfully foamed using egg albumen and fish gelatine as foaming agents, further hot air dried and grinded into powder. In this experiment, beetroot powder after foam mat drying was considered as hygroscopic food and resulted in lighter and reddish in colour. After rehydrating foam mat dried beetroot powder, L* value decreased but a* and b* values increased. Generally, sample beetroot with fish gelatine (BFG) had good foam expansion, foam density, hygroscopicity, water activity, and red color's powder.

Structural insights into the binding mode and conformational changes of BSA induced by bixin and crocin

Bixin and crocin are natural apocarotenoids utilized as food colorants and additives in food industries worldwide. For safety assessment, it is necessary to understand the biological interaction of food colorants. In our present study, we report the interaction of two apocarotenoids with bovine serum albumin (BSA) at physiological pH using spectroscopic techniques and in silico tools. The binding constant and the mode of binding sites have been studied. The enthalpic and entropic contribution to the intermolecular binding event was analyzed and it was found that the contribution of hydrogen bonding and hydrophobic interactions was dominant. The adverse temperature dependence in the unusual static quenching is found to be a reasonable consequence of the large activation energy requirement in the binding process, which is required to overcome the fundamental block and is a direct result of the unique microstructure of the binding sites. To confirm the experimental analysis, we investigated the binding patterns using different in silico tools. A combination of molecular docking, molecular dynamics, and toxicity analysis was performed, and the obtained results revealed that both the apocarotenoids had high binding affinity with a binding energy of −5.44 and −5.93 kcal/mol for bixin and crocin, respectively, with no toxic effects and are in accordance with our experimental analysis. The results directly revealed the flexibility of the protein toward bixin and crocin which has a great impact on the interaction. Thus bixin and crocin can guardedly be used as food colorants in food industries.

One-pot green synthesis of flower-liked Au NP@GQDs nanocomposites for surface-enhanced Raman scattering

The Au nanoparticles (Au NPs) with bumpy shapes take the advantages of the stronger localized surface plasmon resonance (LSPR) and more hot spots, which cause them to be the talented surface-enhanced Raman scattering (SERS) substrate. In this work, we reported a one-pot, rapid and green method to fabricate mutli-branched Au nanoparticle@graphene quantum dots (Au NP@GQDs) core-shell nanocomposites via using GQDs as the reducer without adding any other reagents for the first time. The hybrids with a mean diameter of ca. 47 nm have ultrathin 1-nm-thick GQDs shells which coat the flower-liked Au cores. The core-shell structure could provide a win-win pattern to substantially enhance the SERS signals of the dye molecules owing to the GQD coating for its high affinity to absorb the analytes and the bumpy Au NP-core for strong improvement of the LSPR. The Au NP@GQDs exhibited remarkably high SERS activity on different charged dyes, which revealed its universality on SERS detection. Further application of the nanocomposites for simple, sensitive and lable-free SERS detection of malachite green (MG), one of the illegal additives in aquaculture, was conducted, which revealed a superior SERS signals with the enhancement factor of 1.4 × 104 and the minimum detected concentration was as low as 0.5 nM. Moreover, the fantastic SERS repeatability and good structural stability also demonstrated the potential for SERS application. These properties make the flower-liked Au NP@GQDs a promising SERS substrate to detect the banned dye pollutants in the aquaculture and additive colorants in food industry.

Change of Monascus pigment metabolism and secretion in different extractive fermentation process

Monascus pigments that were generally produced intracellularly from Monascus spp. are important natural colorants in food industry. In this study, change of pigment metabolism and secretion was investigated through fed-batch extractive fermentation and continuous extractive fermentation. The biomass, secreting rate of pigment and total pigment yield closely correlated with the activated time of extractive fermentation as well as the composition of feeding nutrients. Metal ions played a key role in both the cell growth and pigment metabolism. Nitrogen source was necessary for a high productivity of biomass but not for high pigment yield. Furthermore, fermentation period for the fed-batch extractive fermentation could be reduced by 18.75% with a nitrogen source free feeding medium. Through a 30-day continuous extractive fermentation, the average daily productivity for total pigments reached 74.9AUday-1 with an increase by 32.6 and 296.3% compared to that in a 6-day conventional batch fermentation and a 16-day fed-batch extractive fermentation, respectively. At the meantime, proportions of extracellular pigments increased gradually from 2.7 to 71.3%, and yellow pigments gradually became dominated in both intracellular and extracellular pigments in the end of continuous extractive fermentation. This findings showed that either fed-batch or continuous extractive fermentation acted as a promising method in the efficient production of Monascus pigments.

Red pigment production by Monascus purpureus using sweet potato-based medium in submerged fermentation

Monascus pigments have potential application as natural colorants in food industries. Sweet potato-based medium was optimised by statistical methods for maximised production of water-soluble red pigment from Monascus purpureus. Significant medium components (sweet potato, K2HPO4 and MgSO4·7H2O) were identified by employing a Plackett-Burman screening experiment for pigment and biomass production. A five-level central composite design of the response surface method was applied to evaluate the optimal concentration and the interaction effects between the selected components. Maximum pigment absorbance of 4.488 (ODU/ml) was predicted at the optimum level of sweet potato, 3.341%, K2HPO4, 0.082% and MgSO4·7H2O, 0.033%. Model verification was performed at the predicted optimal level and the model was well fitted with the experimental results. The results of this study showed that sweet potato can be utilised as a low-cost substrate for red pigment production.

Thermokinetic stability of phycocyanin and phycoerythrin in food-grade preservatives

Phycocyanin (PC) and phycoerythrin (PE) are the main phycobiliproteins (PBPs) with application as colorants in food industries. In the present study, the thermokinetic stability of PBPs extracted and purified from a hot spring cyanobacterium, Nostoc sp. strain HKAR-2, was investigated. The individual components of PC and PE were isolated with a high purity ratio of 3.18 (A615/A280) and 7.2 (A563/A280), respectively. The thermokinetic stability of purified PC and PE was studied in the presence of edible preservatives such as benzoic acid, citric acid, sucrose, ascorbic acid, and calcium chloride over 30 days of incubation at 4, 25, and 40 °C. The rate of degradation (k value) of PC/PE was increased in the control (without preservative), while it declined in the presence of preservatives. The k value (day−1) was found to be the lowest for benzoic acid-treated PC/PE in comparison to the control at 4 °C. The rate of degradation also declined in benzoic acid-treated PC (0.008 day−1) and PE (0.012 day−1) at 40 °C in comparison with the control. Citric acid and sucrose were also found to maintain the stability of both PC and PE at the same temperature. Calcium chloride and ascorbic acid were shown to be the preservatives that support the least stability of PC and PE in comparison to the other preservatives studied. Overall, benzoic acid was found to be the best preservative for both PC and PE at 4 °C.

Spray drying of violet pigment from Chromobacterium violaceum UTM 5 and its application in food model systems

Spray drying is one of the well-established one-step processes of encapsulation technique to form micro particles. The concentrated violet pigment produced from Chromobacterium violaceum UTM 5 was encapsulated using Gum Arabic and spray dried under optimum conditions: atomizing air (1.15 kg/cm3), temperature feed rate (30 °C), air flow rate (60 m3/h), inlet (180 °C) and outlet (85 °C) temperatures to produce violet powder. On further investigation, the encapsulated pigment exhibited greatest stability during the entire storage period of 30 days at pH 7, temperature 25–60 °C and under dark condition. The violet powders produced were utilized in coloring food products, yogurt and jelly. Results confirmed promising use of this healthy natural colorant in food industry. This is the first report on spray drying of violet pigment from Chromobacterium violaceum and its potential for application in food items.

Microfiltration of Red Beet Juice Using Mixed Cellulose Ester Membrane

Red beet juice was clarified with microfiltration and the effects of operating parameters on clarification efficiency were evaluated. The red beet juice was clarified at transmembrane pressures of 0.1, 0.5 and 1 bar at two different flow rates (4.4 and 6 mL/s). Different mechanisms of membrane fouling were evaluated during the clarification process. The results showed that the best efficiency of membrane processing was at high transmembrane pressure and feed flow rate. The most dominant fouling mechanism at the process under high transmembrane pressure was the standard blocking; however, at high flow rate, the cake resistance was the main mechanism. Evaluation of physicochemical properties of red beet juice showed that the microfiltration process decreased turbidity, as well as total phenolic contents, total soluble solid and juice color. Also, evaluation of nutritional value of red beet juice showed that the antioxidant value of the juice and betacyanin and betaxanthin contents reduced. Practical Applications Concentrate of red beet extract can be used as a natural colorant in food industry. Large particles can be adhered on the walls of evaporators during concentration process and cause off flavor. Current study showed that microfiltration can remove large particles; hence, the above-mentioned problems reduced. Efficiency of membrane processing was limited by fouling mechanism. Experiments showed that the cake formation is the main fouling mechanism, so membrane washing at high velocity can be useful to repair membrane efficiency.

Binding properties of food colorant allura red with human serum albumin in vitro

Allura red (AR) is a widely used colorant in food industry, but may have a potential security risk. In this study, the properties of interaction between AR and human serum albumin (HSA) in vitro were determined by fluorescence, UV-Vis absorption and circular dichroism (CD) spectroscopy combining with multivariate curve resolution-alternating least squares (MCR-ALS) chemometrics and molecular modeling approaches. An expanded UV-Vis data matrix was resolved by MCR-ALS method, and the concentration profiles and pure spectra for the three reaction components (AR, HSA, and AR-HSA complex) of the system were then successfully obtained to evaluate the progress interaction of AR with HSA. The calculated thermodynamic parameters indicated that hydrogen binding and hydrophobic interactions played major roles in the binding process, and the interaction induced a decrease in the protein surface hydrophobicity. The competitive experiments revealed that AR mainly located in Sudlow's site I of HSA, and this result was further supported by molecular modeling studies. Analysis of CD spectra found that the addition of AR induced the conformational changes of HSA. This study have provided new insight into the mechanism of interaction between AR and HSA.

Genipin Inhibits IL-1ß-Induced CCL20 and IL-6 Production from Human Periodontal Ligament Cells

Background/Aims: Genipin, the aglycon of geniposide found in gardenia fruit has long been considered for treatment of various diseases in traditional oriental medicine. Genipin has been used as a blue colorant in food industry. Genipin has recently been reported to have some pharmacological functions, such as antimicrobial, antitumor, and anti-inflammatory effects. The aim of this study was to examine whether genipin could modify CCL20 and IL-6, which are related to bone resorption in periodontal disease, expression in human periodontal ligament cells (HPDLCs). Methods: CCL20 and IL-6 productions from HPDLCs were determined by ELISA. Western blot analysis was used for the detection of signal transduction molecules expressions in HPDLCs. Results: Genipin prevented IL-1ß-mediated CCL20 and IL-6 production in HPDLCs. Moreover, genipin could suppress nuclear factor kappa B (NF-κB) p65, extracellular signalregulated kinase (ERK) and MAPK/ERK kinase (MEK) phosphorylations in IL-1ß-stimulated HPDLCs. NF-κB inhibitor and ERK inhibitor significantly inhibited IL-6 and CCL20 productions from IL-1ß-stimulated HPDLCs. Conclusions: These data provide a novel mechanism through which genipin could be used to provide direct benefits in periodontal disease to inhibit IL-6 and CCL20 productions in periodontal lesions.

Genipin inhibits lipopolysaccharide-induced acute systemic inflammation in mice as evidenced by nuclear factor-κB bioluminescent imaging-guided transcriptomic analysis

Genipin is a natural blue colorant in food industry. Inflammation is correlated with human disorders, and nuclear factor-κB (NF-κB) is the critical molecule involved in inflammation. In this study, the anti-inflammatory effect of genipin on the lipopolysaccharide (LPS)-induced acute systemic inflammation in mice was evaluated by NF-κB bioluminescence-guided transcriptomic analysis. Transgenic mice carrying the NF-κB-driven luciferase genes were administered intraperitoneally with LPS and various amounts of genipin. Bioluminescent imaging showed that genipin significantly suppressed LPS-induced NF-κB-dependent luminescence in vivo. The suppression of LPS-induced acute inflammation by genipin was further evidenced by the reductions of cytokine levels in sera and organs. Microarray analysis of these organs showed that the transcripts of 79 genes were differentially expressed in both LPS and LPS/genipin groups, and one third of these genes belonged to chemokine ligand, chemokine receptor, and interferon (IFN)-induced protein genes. Moreover, network analysis showed that NF-κB played a critical role in the regulation of genipin-affected gene expression. In conclusion, we newly identified that genipin exhibited anti-inflammatory effects in a model of LPS-induced acute systemic inflammation via downregulation of chemokine ligand, chemokine receptor, and IFN-induced protein productions.

Oxidative decolorization of carmosine with acidic chloramine-T: Spectrophotometric, kinetic and mechanistic chemistry

Carmosine is mainly used as a colorant in food industries. The oxidative decolorization of this dye is of greater significance and understanding of its kinetic and mechanistic aspects in redox reactions is important. Chloramine-T bears diverse chemical properties and has been exploited as oxidant for a variety of substrates. It is commercially available, inexpensive, non toxic, water tolerant and easy to handle. A systematic kinetic study of the oxidation of carmosine with acidic chloramine-T (CAT: TsNClNa here Ts = CH 3 C 6 H 4 SO 2 - ) has been carried out in order to explore the mechanistic aspects of this redox system. UV-Visible spectrophotometry is used to monitor the reaction. Optimum conditions for the oxidative decolorization of carmosine with CAT were established. The kinetic results revealed that the reaction rate exhibits a first-order dependence each on [CAT] o and [carmosine] o and less than unit order dependence on [H + ]. The reaction rate was examined for the effects of (a) p -toluenesulfonamide, (b) halide ions, (c) ionic strength, (d) dielectric permittivity and (e) solvent isotope. The reaction was studied at different temperatures and the activation parameters have been deduced. Oxidation products were characterized. Test for free radicals was found to be negative. The derived rate law based on the proposed mechanism is in complete agreement with the observed kinetic data.