Curcumin In Foods Research Articles

Current State of Scientific Knowledge on Curcumin Encapsulation and Applications.

The yellow pigment curcumin has long been used in traditional medicine for its anti-inflammatory, antibacterial and antioxidant activities. Over the past half-century, scien-tific investigations have shown that curcumin is endowed with additional health benefits be-cause it can modify key molecular targets associated with a number of pathologies, such as diabetes, cancer, and arthritis, in addition to cardiovascular, multiple sclerosis, Alzheimer's, and Crohn's diseases. However, this molecule has several disadvantages, such as low bioavail-ability and solubility, severe oxidative destruction, light sensitivity, fast systemic clearance and breakdown at alkaline pH levels. To address these drawbacks, several methods of micro-encapsulation employing a variety of shell materials have been investigated. These techniques contributed toward the increase of curcumin's solubility and stability against heat, light, oxy-gen, and an alkaline pH. The various shell materials and methods used to microencapsulate this chemical are the main topics of this review. The use of microencapsulated curcumin in food, medicine, and cosmetics is also discussed in more detail. Recent relevant research from the last few years has been given in this area, along with future difficulties.

Metabolomics and Transcriptomics Analyses of Curcumin Alleviation of Ochratoxin A-Induced Hepatotoxicity.

Ochratoxin A (OTA) is one of the mycotoxins that poses a serious threat to human and animal health. Curcumin (CUR) is a major bioactive component of turmeric that provides multiple health benefits. CUR can reduce the toxicities induced by mycotoxins, but the underlying molecular mechanisms remain largely unknown. To explore the effects of CUR on OTA toxicity and identify the key regulators and metabolites involved in the biological processes, we performed metabolomic and transcriptomic analyses of livers from OTA-exposed mice. We found that CUR can alleviate the toxic effects of OTA on body growth and liver functions. In addition, CUR supplementation significantly affects the expressions of 1584 genes and 97 metabolites. Integrated analyses of transcriptomic and metabolomic data showed that the pathways including Arachidonic acid metabolism, Purine metabolism, and Cholesterol metabolism were significantly enriched. Pantothenic acid (PA) was identified as a key metabolite, the exogenous supplementation of which was observed to significantly alleviate the OTA-induced accumulation of reactive oxygen species and cell apoptosis. Further mechanistical analyses revealed that PA can downregulate the expression level of proapoptotic protein BAX, enhance the expression level of apoptosis inhibitory protein BCL2, and decrease the level of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2). This study demonstrated that CUR can alleviate the adverse effects of OTA by influencing the transcriptomic and metabolomic profiles of livers, which may contribute to the application of CUR in food and feed products for the prevention of OTA toxicity.

Determination of Curcumin in Food with Homogenous Liquid-Phase Microextraction Preconcentration and Spectrophotometric Determination

Antioxidants play a role in the transformation of free radicals into more stable chemical structures. Work on phenolic antioxidants has accelerated in recent years. Curcumin is a natural phenolic with antioxidant properties. In this study, a salt-supported homogenous liquid-phase microextraction method was used for preconcentration and spectrophotometric determination of curcumin for the first time. The curcumin was transferred into the organic phase using cyclohexylamine as the extraction solvent at pH values between 2.0 and 7.0 and determined by spectrophotometry. The results showed that the performance of the method for curcumin was unaffected by pH. The pH of the sample solution, the mass of salt, and the volume of the solvent were optimized, and the influence of the matrix types was investigated. The limits of detection and quantification were 1.44 and 4.80 µg L−1 for curcumin. The developed method was employed for the analysis of food samples.

Curcumin prevents proteins expression changes of oxidative phosphorylation, cellular stress response, and lipid metabolism proteins in liver of mice fed a high-fructose diet

Increased fructose consumption has been associated with the development of metabolic diseases due to the modification in protein expression, altering metabolic and signaling pathways. Curcumin is a natural compound with a regulatory effect on genes and metabolic pathways. To identify the fructose-induced protein expression changes and the effect of curcumin on the change of protein expression in the liver of mice fed a standard diet and a high fructose diet, to elucidate the global role of curcumin. Four groups (n = 4/group) of male mice (C57BL6J) of six-weeks-old were formed. One group received a standard diet (C); another received curcumin at 0.75% w/w in the feed (C + C); one more received 30% w/v fructose in drinking water (F); and one group received 30% w/v fructose in drinking water and 0.75% w/w curcumin in food (F + C); for 15 weeks. Proteomic analysis was performed by LC-MS/MS, using the label-free technique with the MaxQuant programs for identification and Perseus for expression change analysis. Differentially expressed proteins (fold change ≥1.5 and p < 0.5) were analyzed by gene ontology and KEGG. A total of 1047 proteins were identified, of which 113 changed their expression in mice fed fructose, compared to the control group, and curcumin modified the expression of 64 proteins in mice fed fructose and curcumin compared to mice that only received fructose. Curcumin prevented the change of expression of 13 proteins involved in oxidative phosphorylation (NDUFB8, NDUFB3, and ATP5L) in the cellular response to stress (PSMA5, HIST1H1D) and lipid metabolism (THRSP, DGAT1, ECI1, and ACOT13). Curcumin in mice fed the standard diet increased the expression of proteins related to oxidative phosphorylation, ribosomes, and PPAR pathways. In addition to fructose, increased expression of proteins involved in oxidative phosphorylation, ribosomes, lipid metabolism, and carbon metabolism. However, curcumin prevented expression change in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response, and lipid metabolism. SignificanceCurcumin is a natural compound with a regulatory effect on proteins and metabolic pathways. So, curcumin prevents the change of expression in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response and lipid metabolism, as a supplement with protector activity on fructose-induced toxic effects.

Self-assembled micelles of dual-modified starch via hydroxypropylation and subsequent debranching with improved solubility and stability of curcumin

The purpose of this study was to fabricate curcumin-encapsulated self-assembled micelles by dual-modified starch (hydroxypropylation and subsequent debranching) to improve the water solubility and stability of curcumin. Double modified starches with different amylose content (13%, 30% and 47%) were prepared by controlling the debranching time. Fluorescent probe method showed that the dual-modification of hydroxypropylation and debranching is necessary for the formation of self-assembled micelles, and dual-modified starch with 13% amylose content has the strongest self-assembly ability (the lowest critical micelle concentration, 0.43 mg/mL). The self-assembled micelles exhibited a particulate morphology with a size of about 80–200 nm. Cytotoxicity and hemolysis evaluation confirmed the good cytological compatibility (cell viability > 90%) as well as hematological compatibility (hemolysis rates < 5%) of the self-assembled micelles as nano-oral systems. Curcumin was encapsulated into self-assembled micelles by the self-assembly (encapsulation efficiency, 70.33%; loading capacity, 5.33%). The water solubility and stability of curcumin were successfully improved (200-fold and 3-6-fold compared to free curcumin, respectively), which was attributed to the encapsulation of hydrophilic core in the self-assembled micelles, and the hydrophobicity and hydrogen bonding provided by hydroxypropyl. In vitro gastrointestinal sequential release simulations confirmed the sustainable release of curcumin, and First-order and Korsmeyer-Peppas modeling for curcumin were confirmed to be the best release models in the gastric and intestinal phases, respectively. Based on the above, the self-assembled micelles of dual-modified starch would potentially serve as a curcumin-encapsulated nanocarrier to improve the oral bioavailability and shelf life of curcumin in food, medical and cosmetic applications.

Pinto bean protein-based acid-induced cold-set gels as carriers for curcumin delivery: Fabrication and characterization

In this study, a new acid-induced cold-set gel based on pinto bean protein isolate (PBI) was developed, and then its textural, morphological, rheological, and physical properties were evaluated. Textural and rheological properties of the gels improved when protein and glucono-delta-lactone (GDL) concentrations were increased. Acid-induced gels showed a disordered structure of aggregates. The water holding capacity (WHC) of the gels increased significantly (p<0.05) from 85 to 86% to 92–96% when the protein concentration increased from 5% to 7%. The gel fabricated with 7% protein and 15% GDL indicated better mechanical and rheological properties; hence it was selected for curcumin entrapment and further evaluations. According to circular dichroism (CD) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results, the pre-heating process at pH ∼ 7.3 ± 0.08 allowed to fabricate thermally aggregated PBI (TA-PBI). The pre-heating process caused a significant increase in particles diameter (p<0.05), but surface hydrophobicity decreased (p<0.05). PBI cold-set gel presented an excellent embedding potential (98.54%) at a curcumin concentration of 0.7 mg/mL. Fluorescence spectroscopy indicated that curcumin was attached to PBI. The results of confocal laser scanning microscopy (CLSM) revealed a homogeneous distribution of curcumin in TA-PBI gels. The thermal analysis confirmed the presence of curcumin in an amorphous form within the cold-set gel. PBI gels could effectively inhibit curcumin's immediate release in a simulated gastric medium (22.6% after 2 h) and led to its sustained release in a simulated intestinal condition (61.68% after 4 h). Release test results were aligned with the protein digestibility pattern. Peppas model could predict the release of curcumin from hydrogel in the gastrointestinal tract. In conclusion, TA-PBI gels can be introduced as promising delivery vehicles for the sustained release of curcumin in food and pharmaceutical systems.

An ultra-sensitive analytical platform based on bluish green emitting carbon quantum dots for the detection of curcumin in dietary foods

This work reports the development of a new analytical method for the rapid detection of curcumin in food samples by using bluish green emissive fluorescence carbon quantum dots (BG-CQDs) as nanoprobe. The sensing mechanism behind the detection work is the quenching effect of curcumin on the fluorescence intensity of BG-CQDs, where curcumin and BG-CQDs interact via a combined effect of inner filter effect (IFE) and dynamic interaction process. After optimisation of the experimental parameters, the developed analytical method is capable of detecting curcumin with good selectivity and high sensitivity, achieving good linearity in the concentration range of 0.01–25.0 μM. A limit of detection (LOD) of 28.7 nM was obtained, which is lower than that of any of the previously reported CQDs-based fluorescence methods. The developed analytical method was applied to the analyses of food samples with a high degree of accuracy and precision. This work highlights a robust BG-CQDs-based analytical platform of rapid response, low cost, great simplicity, high selectivity and favourable sensitivity, which exhibits immense potential for the accurate monitoring of the curcumin content in dietary food samples.

Electrochemical Detection of Curcumin in Food with a Carbon Nanotube-Carboxymethylcellulose Electrode.

Herein, an electrochemical method is presented for the detection of curcumin in food using a carbon nanotube (CNT)-carboxymethylcellulose (CMC) electrode. The CNT-CMC electrode exhibited ideal characteristics for curcumin detection, namely, a high response current and adequate peak separation toward curcumin oxidation. Cyclic voltammetry revealed two oxidation peaks. In the first scan, only the irreversible peak (Peak I) was observed at a higher potential. In the second scan, the reversible redox peak pairs (Peaks II and II') appeared at lower potentials, and the potential of Peak I was decreased. Peak I corresponded to oxidation of the hydroxyl groups of the benzene ring to the catechol group via a phenoxy radical, while Peaks II and II' indicated the redox loop system of the generated catechol group. The current at Peak II was used to quantify the concentration of curcumin in the linear range of 1 - 48 μM and detection limit of 0.084 μM. The concentrations of curcumin determined by the CNT-CMC electrode in real food samples were consistent with those determined by high-performance liquid chromatography.

A Fluorescent "Turn-Off" Probe for the Determination of Curcumin Using Upconvert Luminescent Carbon Quantum Dots

Curcumin is used as a natural pigment and flavoring agent and food additive in food processing industries. Also, curcumin has a wide range of applications in the medical industry and clinical treatment because of its anti-cancer, anti-oxidation, anti-coagulant, anti-HIV choleretic and hypolipidemic effects. Therefore, it is crucial to properly control the concentration of curcumin in food and medicine. In our work, a new and simple method for quantitative detection of curcumin was established by developing a “turn-off” fluorescence probe based on upconvert luminescent carbon quantum dots (p-CDs). The carbon quantum dots were synthesized with p-aminobenzoic acid (PABA) and ethanol by solvothermal method and have specific up-conversion luminescence properties which could be applied in other sensing field. In this sensor, the sensing mechanism of this fluorescent probe was based on the internal filter effect (IFE) between curcumin and p-CDs, the increasing in the concentration of curcumin causes the selective fluorescence quenching of p-CDs. Under optimum conditions, the fluorescence quenching intensity of p-CDs has a good liner relationship with curcumin in the range of 0.4-45 μΜ and with a detection limit of 0.133 μM. What's more, the fluorescent “turn-off” probe constructed with p-CDs exhibited high accuracy and recovery in the analysis of actual sample curry powder, demonstrating the fluorescence “turn-off” probe has potential application for the detection of curcumin in the complex matrixes.

Enhancement of Curcumin Bioavailability by Encapsulation in Sophorolipid-Coated Nanoparticles: An in Vitro and in Vivo Study.

There is great interest in developing colloidal delivery systems to enhance the water solubility and oral bioavailability of curcumin, which is a hydrophobic nutraceutical claimed to have several health benefits. In this study, a natural emulsifier was used to form sophorolipid-coated curcumin nanoparticles. The curcumin was loaded into sophorolipid micelles using a pH-driven mechanism based on the decrease in curcumin solubility at lower pH values. The sophorolipid-coated curcumin nanoparticles formed using this mechanism were relatively small (61 nm) and negatively charged (-41 mV). The nanoparticles also had a relatively high encapsulation efficiency (82%) and loading capacity (14%) for curcumin, which was present in an amorphous state. Both in vitro and in vivo studies showed that the curcumin nanoparticles had an appreciably higher bioavailability than that of free curcumin crystals (2.7-3.6-fold), which was mainly attributed to their higher bioaccessibility. These results may facilitate the development of natural colloidal systems that enhance the oral bioavailability and bioactivity of curcumin in food, dietary supplements, and pharmaceutical products.

Vortex assisted deep eutectic solvent (DES)-emulsification liquid-liquid microextraction of trace curcumin in food and herbal tea samples

We developed a new microextraction method for separation and preconcentration of curcumin using deep eutectic solvent known as green solvent. Deep eutectic solvent (DES) formed by mixing of choline chloride and phenol was used as an extraction solvent in microextraction study to extract the curcumin at pH 4.0. The curcumin concentration in enriched DES phase was analyzed by UV–Visible spectrophotometer. The effect of parameters such as pH, mol ratio of DES composition, volume of DES, volume of tetrahydrofuran (THF) and sample volume were examined. Interference effects of matrix components were investigated. The preconcentration factor was 12.5. The detection limit of method (n = 10) was 2.86 µg L−1 and the relative standard deviation (RSD, n = 8) was 1.8%. The method was successfully applied to determination of curcumin in food and herbal tea samples. The mean recoveries were between 96% and 102% and standard deviations were found in the range of 1–6%.

A simple and sensitive sensor based on a molecularly imprinted polymer-modified carbon paste electrode for the determination of curcumin in foods

A highly sensitive and selective molecularly imprinted polymer-modified carbon paste electrode (MIP-CPE) was designed.

Nanodelivery systems based on mucoadhesive polymer coated solid lipid nanoparticles to improve the oral intake of food curcumin

Although curcumin shows promising therapeutic efficacy, its food related and clinical application suffers from poor water solubility, stability and oral bioavailability. Chitosan coated solid lipid nanoparticles (NC)-based nanodelivery systems were developed in order to enhance the stability and oral bioavailability of curcumin and help incorporate it in functional foods and nutraceuticals. These NC nanoformulations were characterized by analyses of their mean particle size, zeta potential, encapsulation efficiency, drug loading capacity, crystallinity, stability, and in vivo studies. The NC showed prolonged physical stability at room and refrigerated temperature conditions. NC has been shown to increase the bioavailability of curcumin above that of curcumin suspensions after oral administration. Such nanoformulations will contribute to broadening the application of the bioactive curcumin in foods and nutraceuticals.

Magnetic molecularly imprinted polymers for spectrophotometric quantification of curcumin in food

Herein, we present a simple and rapid method for monitoring curcumin in food samples using a magnetic molecularly imprinted technique combined with ultraviolet–visible (UV–Vis) spectrophotometry. Magnetic molecularly imprinted polymers (mag-MIPs) were first synthesized by fabricating MIPs on to the surface of Fe3O4 nanobeads using curcumin as a template and methacrylic acid as a functional monomer. The obtained mag-MIPs were evaluated in detail with different techniques (such as binding isotherm, Scatchard analysis, and selectivity) and various adsorption experiments. Finally, mag-MIPs were constructed and UV–Vis spectrophotometry was used to quantify curcumin under optimized conditions. Good recoveries between 79.37% and 88.89% were obtained with the limits of detection and quantification of 1.31 and 4.38μg/mL, respectively.

Stabilization of curcumin against photodegradation by encapsulation in gamma-cyclodextrin: A study based on chromatographic and spectroscopic (Raman and UV–visible) data

Application of curcumin in foods is limited because of its low bioavailability and its high sensitivity to light. The effect of light irradiation, temperature and time stabilization of both free and encapsulated curcumin in γ-cyclodextrin was studied by chromatography, UV–vis absorption, and vibrational spectroscopy (Raman). Curcumin is degraded drastically in the presence of light, but it is highly stable with the temperature. From this work it was deduced that the exposure of curcumin to light induces two possible effects (i) demethoxylation and (ii) isomerization of keto-enol to diketo form in curcumin and the formation of small sub-products such as methanol or acetate. UV–vis and Raman spectroscopy were important to determine the nature of the structural modifications. The complexation of curcumin with γ-cyclodextrin was demonstrated to protect this molecule from the photodegradation.

Effect of Curcumin on Selenite-Induced Cataractogenesis in Wistar Rat Pups

Purpose: The present study was aimed at investigating the possible antioxidant potential of curcumin at a dose of 75 mg/kg body weight on selenite-induced cataract in experimental rat pups.Methods: Group I: Control rat pups receiving physiological saline; Group II: Selenite-induced group (15 µM/kg body wt); Group III: Selenite-induced group co-treated with curcumin (single dose of curcumin orally 75 mg/kg body wt); Group IV: Selenite-induced animals post-treated (after 24 hrs) with curcumin at a dose mentioned for group III; Group V: Rat pups were pretreated with curcumin (dose as mentioned in Group III), 24 hrs before the administration of selenite. Encapsulated lenses liver, kidney, and serum were analyzed for antioxidant enzymes and malondialdehyde, a marker of lipid peroxidation.Results: Intraperitoneal injection of sodium selenite (15 µM/kg body wt) to 8–10-day-old rat pups led to severe oxidative stress in eye lens as evidenced by enhanced LPO levels that led to cataract formation. Sodium selenite also led to decrease in activities of SOD, GST, GPx, CAT with simultaneous decrease in the levels of GSH, vitamin C, and vitamin E. Treatment with curcumin (75 mg/kg body wt) led to a significant decrease in the levels of LPO, enzymic antioxidants, and nonenzymic antioxidants, which were similar to that of control.Conclusions: Curcumin suppressed selenite-induced oxidative stress and cataract formation in rat pups. The presence of oxidative stress in selenite cataract development and its prevention by curcumin support the possibility that the natural consumption of curcumin in food can help prevent the onset of senile cataract.