Chemical Stability Of Curcumin Research Articles

Characteristics, physicochemical stability and in vitro release of curcumin-loaded glycated bovine serum albumin nanofibrils: Effects of molecular weight of saccharide

The goal of this study is to fabricate glycated bovine serum albumin nanofibrils as efficient curcumin nano-delivery systems to enhance its water solubility, storage stability against environmental stress, chemical stability and in vitro antioxidant activity, which can widely be applied in real food products. Glycosylation exhibited almost no impacts on the morphology of bovine serum albumin nanofibril as revealed by atomic force microscopy, regardless of saccharide types. Glycated bovine serum albumin nanofibrils possessed nanometric diameter (less than 15 nm) and micrometric length (1–1.5 μm). Glycation further enhanced the surface hydrophobicity of bovine serum albumin nanofibrils and its curcumin binding capacity. Water solubility of curcumin was sharply enhanced with bovine serum albumin nanofibril-based nanocarriers and curcumin-bovine serum albumin nanofibrils-glucose exhibited the highest aqueous solubility (50.2%). There was a strong positive proportion between curcumin solubility and surface hydrophobicity of bovine serum albumin nanofibril-based nanocarriers. Fluorescence data demonstrated that the formation of curcumin-glycated bovine serum albumin nanofibril nanocomposites was mainly through hydrophobic interactions. All three glycated bovine serum albumin nanofibrils were resistant to pH variation, high salt and heating. The chemical stability of curcumin was remarkably enhanced through glycation and there was a negative correlation between the chemical stability of curcumin and molecular weight of saccharides. Antioxidant capacities (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power) of curcumin were dramatically soared through complexation with three glycated bovine serum albumin nanofibrils and the antioxidant activity of glycated bovine serum albumin nanofibril was negatively correlated with the molecular weight of saccharides. The release of curcumin in bovine serum albumin nanofibril nanocomposites could be controlled through glycation. Generally, this research indicates that the glycated bovine serum albumin nanofibril would be employed to load, stabilize, and deliver hydrophobic nutraceuticals and expand the food application.

Effects of κ-carrageenan on the emulsifying ability and encapsulation properties of pea protein isolate-grape seed oil emulsions

This work investigated the characteristics of pea protein isolate and κ-carrageenan complexes in stabilizing curcumin-loaded emulsions. The complexes structured by electrostatic attraction exhibited biphasic wettability with increased three-phase contact angles close to 90°. Morphological differences in the complexes were the critical factor influencing their emulsifying ability at various pH. As a steric barrier via increasing net negative charge (up to −54.7 ± 2.4 mV) and adsorbed protein content (92.57 %–97.61 %), the interfacial layer could retard droplet coalescence and improve emulsions stability. Rheological tests verified the higher viscoelasticity of emulsions by raising the oil fraction. After 4 weeks of heating treatment, the chemical stability of curcumin was prominently enhanced from 18.6 ± 0.2 % to 64.3 ± 5.7 %. The confirmed synergistic antioxidant activity between grape seed oil and curcumin in emulsions might facilitate the development of specific functional delivery systems in foods.

Fabrication and characterization of low-fat Pickering emulsion gels stabilized by zein/phytic acid complex nanoparticles

Pickering emulsion gels (PKEGs) are being explored as solid fat substitutes and delivery systems due to their semi-solid textures and high stabilities. However, these PKEGs have relatively high-fat content, which is undesirable for nutritional and cost reasons. Therefore, in this study, low-fat PKEGs (10 % oil content) were successfully fabricated using zein/phytic acid (ZPA) complex nanoparticles with zein to phytic acid mass ratio of 1:0.006. These nanoparticles have a mean diameter of around 161 nm and wettability of around 89°. The formation of PKEGs were confirmed by the results of dynamic rheology (G′ > G″). Confocal laser scanning microscope showed that the complex nanoparticles formed a dense barrier on the surface of the oil droplets, which prevented the oil droplets against coalescence. The chemical stability of curcumin was greatly improved by encapsulation in the PKEGs. The low-fat PKEGs developed in this study may be effective delivery systems for hydrophobic bioactive substances.

Encapsulation of curcumin within oil-in-water emulsions prepared by premix membrane emulsification: Impact of droplet size and carrier oil on the chemical stability of curcumin

Oil-in-water emulsions containing curcumin with different droplet sizes were produced by premix membrane emulsification with different carrier oils: tributyrin (short chain triglycerides, SCT), medium chain triglycerides (MCT) and corn oil (long chain triglycerides, LCT). The influence of carrier oil type and droplet size on the physical stability, chemical stability of curcumin and lipid oxidation stability of emulsions were investigated. Turbiscan results indicated that the physical stability of emulsions was related to both carrier oils and emulsion droplet sizes. The oil type and droplet size of emulsions stored at 25 °C showed limited effect on the stability of curcumin, but significantly affected the stability of curcumin at 55 °C. Chemical stability of curcumin decreased with the decrease of emulsion droplet sizes. For each droplet size emulsions, the stability of curcumin decreased in the order SCT > MCT > LCT. Moreover, the lipid oxidation in LCT-based emulsions resulted in lower zeta potential of droplets, which was independent of emulsion droplet sizes. The presence of curcumin improved the oxidative stability of emulsions.

Study on curcumin encapsulated in whole nutritional food model milk: Effect of fat content, and partitioning situation

Curcumin was encapsulated within dairy milk products (skim, low-fat and whole) using a pH-driven method. The curcumin was incorporated into all milk products at a high encapsulation efficiency (>85%) and was shown to be in an amorphous state. Ultracentrifugation analysis showed that the curcumin was mainly associated with the milk fat globules in the whole and low-fat milk but with the casein micelles or whey proteins in the skimmed milk. The chemical stability of curcumin during storage and heat treatment was higher for the whole milk. Encapsulation of curcumin within milk using the pH-driven method led to a higher in vitro bioaccessibility (after simulated gastrointestinal digestion) and in vivo antioxidant activity (after oral administration to rats) than simply mixing powdered curcumin with milk. This study may lead to the production of nutraceutical-enriched dairy products that could be used as functional foods to improve human health and wellbeing.

Effects of Emulsifier Type and Post-Treatment on Stability, Curcumin Protection, and Sterilization Ability of Nanoemulsions.

Curcumin has a high inhibitory effect on many potential diseases caused by bacteria and fungi. However, its degradability and low water solubility limit its application. Loading curcumin with an emulsion delivery system can overcome these problems. Five different types of emulsifiers were used to prepare the curcumin-loaded nanoemulsions, namely, Tween 80 (T80), Span 80 (S80), sodium dodecyl sulfate (SDS), soybean protein isolate (SPI), and lecithin (LEC). The effects of emulsifier types and post-treatment methods on emulsion stability and curcumin-load efficiency were studied. In addition, photodynamic inactivation was used to test the antibacterial effect of nanoemulsions on Escherichia coli under blue light excitation. The five types of emulsifiers could form uniform emulsions with good storage stability and with antibacterial capacity on Escherichia coli. Among them, the T80 and LEC emulsions had good stability, coating effect, and sterilization performance under heating or room temperature. Both curcumin-loaded bactericidal emulsions had the potential for large-scale applications. A nanoemulsions delivery system could effectively improve the dispersion and chemical stability of curcumin in water. An emulsion loaded with antibacterial photosensitizer represents a new idea for the storage and preservation of food commodities.

Curcumin-loaded nanoMOFs@CMFP: A biological preserving paste with antibacterial properties and long-acting, controllable release

Food spoilage is one of the biggest concerns for food safety worldwide. Here, we describe the construction of a carrier for biological agents by chemical combination of porous nanoMOFs and carboxymethylated filter paper (CMFP). When curcumin was encapsulated in nanoMOFs@CMFP, they showed the ability to act as super-long-acting food preserving agents with controllable release of curcumin. Although only 22.3% of curcumin was released into water in 600 h, 65.8% was released into PBS in the same time, and the release into PBS could be tuned by adding citric acid at the time of greatest requirement. Furthermore, the chemical stability of curcumin in nanoMOFs@CMFP was >4.9 times greater than for free curcumin. The outstanding antioxidant and antimicrobial activity of curcumin-loaded nanoMOFs@CMFP paste was demonstrated by prolonging the shelf life of pitayas, which illustrates its potential for development as long-acting and stable preserving paste for use in food preservation.

Effect of HPMCAS/curcumin amorphous solid dispersion in enhancing dissolution and chemical stability of curcumin

To enhance in vitro dissolution of Cur by preparing Cur solid dispersions. The ability of HPMCAS-HF,HPMCAS-MF,HPMCAS-LF and PVPK30 to maintain supersaturated solution was investigated by supersaturation test. Amorphous solid dispersions were prepared by the solvent-evaporation method. The prepared samples were characterized using infrared spectroscopy( IR) and differential scanning calorimetry( DSC),and in vitro dissolution was investigated. DSC and IR results showed that in 1 ∶3 and 1 ∶9 solid dispersions,Cur was amorphously dispersed in the carrier,and the interaction existed between drug and carrier. The supersaturation test showed that the order of the ability of polymer to inhibit crystallization of Cur was MF>HF>LF>K30. The dissolution results showed that Cur-K30 amorphous solid dispersion had the highest drug release rate; Cur-K30 and Cur-LF amorphous solid dispersions had a quicker but not stable dissolution rate,and the drug concentration decrease after 4 h; Cur-MF and Cur-HF solid dispersions had a low dissolution,which however increased steadily,attributing to the strong ability of the polymers to inhibit the crystallization of Cur. HPMCAS could inhibit the degradation of Cur better than K30,especially MF and HF. The amorphous solid dispersions of cur significantly enhanced the dissolution of Cur and improved the chemical stability of Cur. This study can provide a basis for the rational selection of the polymer used for Cur solid dispersion.

New insights on the Chemical Stability of Curcumin in Aqueous Media at Different pH: Influence of the Experimental Conditions

New insights on the Chemical Stability of Curcumin in Aqueous Media at Different pH: Influence of the Experimental Conditions

Encapsulation of anticancer drug curcumin and co-loading with photosensitizer hypericin into lipoproteins investigated by fluorescence resonance energy transfer

Low-density lipoproteins (LDL) and high-density lipoproteins (HDL) are natural occurring vehicles attractive for drug delivery and targeting tumor cells. Here we have investigated the encapsulation and interaction of a well-known anticancer agent curcumin with LDL and HDL. LDL particles have been found to accumulate more curcumin molecules inside their structure than HDL. The chemical stability of curcumin is enhanced and its photo-physical properties are altered due to encapsulation inside both lipoproteins. Combining photodynamic therapy with chemotherapy can improve anticancer treatment by overcoming drug resistance in cancer therapy. Therefore, we have also investigated a co-loading of curcumin with a natural potent photosensitizer hypericin into molecules of LDL using fluorescence resonance energy transfer. The loading patterns of curcumin and hypericin into LDL particles were found to be different as revealed by the fluorescence resonance energy transfer experiments. Present study illustrates the potential of LDL nanoparticles in combination therapy because of simultaneous loading of more than one type of drugs into these nanoparticles with high level of efficiency.

Unravelling the Excellent Chemical Stability and Bioavailability of Solvent Responsive Curcumin-Loaded 2-Ethyl-2-oxazoline-grad-2-(4-dodecyloxyphenyl)-2-oxazoline Copolymer Nanoparticles for Drug Delivery.

A new gradient copolymer has been synthesized by the living cationic ring-opening polymerization of hydrophilic 2-ethyl-2-oxazoline with lipophilic 2-(4-dodecyloxyphenyl)-2-oxazoline (EtOx-grad-DPOx). The prepared copolymer is capable of assembling in water to yield polymeric nanoparticles that are successfully loaded with an anticancer agent, curcumin. Self-assembly of the copolymer was found to be tuned by the polarity as well as the hydrogen bonding ability of solvents. Solvent took distinctive role in the preparation of unloaded and curcumin-loaded nanoparticles. The stability of the nanoparticles was increased by curcumin loading promoted by curcumin-polymer interactions. Further, the chemical stability of curcumin in water is largely enhanced inside the polymeric nanoparticles. Curcumin-loaded (EtOx-grad-DPOx) copolymer nanoparticles showed excellent stability in the biological medium, low cytotoxicity, and concentration dependent uptake by U87 MG and HeLa cells, which indicate the possibility of their efficient application in drug delivery.

Impact of delivery system type on curcumin stability: Comparison of curcumin degradation in aqueous solutions, emulsions, and hydrogel beads

The impact of molecular environment on the chemical stability of curcumin was determined. Equal amounts of curcumin were incorporated into different kinds of delivery system: aqueous dimethyl sulfoxide (DMSO) solutions; oil-in-water emulsions; or filled hydrogel beads. Two types of filled hydrogel beads were fabricated by injecting solutions containing curcumin-loaded lipid droplets and gelling polysaccharides (alginate or chitosan) into ionic gelling solutions (calcium or tripolyphosphate) using an extrusion device. The delivery systems were then incubated under acidic (pH 3) and neutral (pH 7) conditions at 55 °C for 14 days. The initial rate of curcumin degradation, determined by measuring the color change (b* value) over time, depended on storage pH and delivery system type. At pH 7, the curcumin degradation rate increased in the following order: chitosan beads < emulsion < aqueous solution < alginate beads, but at pH 3 it increased in a different order: emulsion < aqueous solutions < chitosan beads < alginate beads. Overall, our results showed that curcumin was more stable under acidic than neutral conditions. Interestingly, encapsulation of curcumin in alginate beads promoted its degradation at both acidic and neutral pH, but encapsulation in chitosan beads enhanced its stability at pH 7 by reduced it at pH 3. These effects may be related to the different charge status of the polysaccharides used to fabricate the hydrogel beads: alginate is anionic, whereas chitosan is cationic. Overall, our results provide valuable information for the design and development of emulsion-based delivery systems to encapsulate and protect curcumin for functional food applications.

Zein/tannic acid complex nanoparticles‐stabilised emulsion as a novel delivery system for controlled release of curcumin

SummaryThe present work was aimed to evaluate the potential of the gel‐like Pickering emulsions (50%, v/v, oil) stabilised by zein/tannic acid (TA) complex colloidal particles (ZTPE) as a new encapsulation system of lipophilic ingredients. Compared with sodium caseinate‐stabilised emulsions (SCE) and bulk oil, the better protective effects of ZTPE on the chemical stability of curcumin were observed when they suffered from UV light, and the lipid oxidation rate remarkably reduced in ZTPE. Also, the zein particle layers loaded with TA around the oil droplets can provide protection against harsh gastric environment, facilitating to slow down the release of free fatty acids (FFA) and curcumin during in vitro simulated digestion. These findings show that ZTPE have a good potential to act as an efficient encapsulating agent to protect functional ingredients from degradation and control their release during digestion, which can further improve the bioavailability of bioactive ingredients.

Physical and Chemical Stability of Curcumin in Aqueous Solutions and Emulsions: Impact of pH, Temperature, and Molecular Environment.

The utilization of curcumin as a nutraceutical in food and supplement products is often limited because of its low water solubility, poor chemical stability, and low oral bioavailability. This study examined the impact of pH, storage temperature, and molecular environment on the physical and chemical stability of pure curcumin in aqueous solutions and in oil-in-water emulsions. Unlike naturally occurring curcuminoid mixtures (that contain curcumin, demethoxy-curcumin, and bisdemethoxy-curcumin), pure curcumin was highly unstable to chemical degradation in alkaline aqueous solutions (pH ≥7.0) and tended to crystallize out of aqueous acidic solutions (pH <7). These effects were attributed to changes in the molecular structure of curcumin under different pH conditions. The curcumin crystals formed were relatively large (10-50 μm), which made them prone to rapid sedimentation. The incorporation of curcumin into oil-in-water emulsions (30% MCT, 1 mg curcumin/g MCT, d32 ≈ 298 nm) improved its water dispersibility and chemical stability. After incubation at 37 °C for 1 month, >85% of curcumin was retained by emulsions stored under acidic conditions (pH <7), whereas 62, 60, and 53% was retained by emulsions stored at pH 7.0, 7.4, and 8.0, respectively. There was little change in the color of curcumin-loaded emulsions when stored under acidic conditions, but their yellow color faded when stored under alkaline conditions. There was no evidence of droplet aggregation or creaming in emulsions stored for 31 days at ambient temperature. These results suggest that emulsion-based delivery systems may be suitable for improving the water dispersibility and chemical stability of curcumin, which would facilitate its application in foods and supplements.

Voltammetric quantification of surfactant stabilized curcumin at MWCNT/GCE sensor

Abstract A simple voltammetric method has been developed for selective quantification of curcumin, primary bioactive component of turmeric in phosphate buffer system at pH 2.5 in solubilized system at Multiwalled-carbon nanotube/Glassy carbon electrode (MWCNT/GCE) sensor using squarewave voltammetry as an analytical technique. Effect of different types of surfactants on the solubilization and stability of curcumin were compared to identify the most suitable surfactant for conducting voltammetric studies. Cetyltrimethylammonium bromide (CTAB), sodium lauryl sulphate (SLS), Tween 20 and Triton X surfactants were used in the study. The experimental results suggested that solubility and chemical stability of curcumin were substantially increased in Cetyltrimethylammonium bromide as compared to other solvent systems. Under the optimized conditions the oxidation peak current for curcumin was found to be proportional to its concentration in the range of 4 × 10 − 7 g/mL to 20 × 10 − 7 g/mL with 3.28 × 10 − 7 g/mL and 10.94 × 10 − 7 g/mL as limit of detection and limit of quantification respectively. As it is a well-known fact that curcumin exhibits wide therapeutic potential but its low aqueous solubility at neutral and acidic pH limits its use, therefore the present research focuses on development of method for preparation of water soluble curcumin by incorporation of surfactant micellar system in order to increase solubility and stability of curcumin in aqueous form. Also present investigation deals with finding out alternatives to the use of organic solvents with the aim of diverting research towards greener chemistry by using less hazardous solubilizing media.

Curcumin Delivery by Poly(Lactide)-Based Co-Polymeric Micelles: An In Vitro Anticancer Study.

This work describes the synthesis of block co-polymeric micelles, methoxy-poly(ethylene glycol)-poly(D,L-lactide) (mPEG-PLA) to encapsulate Curcumin (CUR), thereby improving the dispersibility and chemical stability of curcumin, prolonging its cellular uptake and enhancing its bioavailability. CUR-mPEG-PLA micelles, was prepared using the thin-film hydration method and evaluated in vitro. The preparation process was optimized with a central composite design (CCD). Micelles were characterized by size, transmission electron microscopy, loading capacity, and critical micelle concentration (CMC). The cytotoxicity of CUR-mPEG-PLA micelles was investigated against murine melanoma cells, B16F10 and human breast cancer cells, MDA-MB-231. The average size of the CUR-mPEG-PLA micelles was 110 ± 5nm with polydispersity index in the range of 0.15-0.31, and the encapsulating efficiency for CUR was 91.89 ± 1.2, and 11.06 ± 0.8% for drug-loading. Sustained release of CUR from micelles was observed with 9.73% CUR release from micelles compared to 64.24% release of free curcumin in first 6h under sink condition. The CUR-mPEG-PLA was efficiently taken up by the cancer cells, B16F10 and MDA-MB-231. Following 24h incubation, CUR-mPEG-PLA induced higher cytotoxicity compared to free CUR in MDA-MB-231 cell lines indicating exposure of higher dose of free CUR to cells lead to up-regulation of drug efflux mechanisms leading to decreased cell death in case of free CUR administration. Our results indicate that the proposed micellar system has the potential to serve as an efficient carrier for CUR by effectively solubilizing, stabilizing and delivering the drug in a controlled manner to the cancer cells.

Kafirin Nanoparticle-Stabilized Pickering Emulsions as Oral Delivery Vehicles: Physicochemical Stability and in Vitro Digestion Profile.

Kafirin nanoparticle-stabilized Pickering emulsions (KPEs) were used to encapsulate curcumin. The stability of KPEs under processing conditions and their protective effects against photo-oxidation of curcumin and lipid oxidation of oil in emulsions, as well as the digestion profiles in gastrointestinal tract, were investigated. KPEs were found to be more stable under acidic than basic environment, and elevated temperature induced their structural instability. The protective effect of KPEs on the chemical stability of curcumin was manifested when subjected to UV radiation as compared to other comparable formulations, such as bulk oil or Tween 80 stabilized emulsions (TEs). Meanwhile, the lipid oxidation rate was retarded in KPEs as compared to those of TEs. Due to hydrolysis of pepsin, KPEs could not survive through the gastric digestion process. After the intestinal digestion process, the extent of lipolysis of KPEs and the curcumin bioaccessibility fell between those of TEs and bulk oil. These results will fill the gap between the physicochemical properties of protein particle-based Pickering emulsions and their realistic applications in the oral delivery of functional food ingredients.

Both solubility and chemical stability of curcumin are enhanced by solid dispersion in cellulose derivative matrices

Amorphous solid dispersions (ASD) of curcumin (Cur) in cellulose derivative matrices, hydroxypropylmethylcellulose acetate succinate (HPMCAS), carboxymethylcellulose acetate butyrate (CMCAB), and cellulose acetate adipate propionate (CAAdP) were prepared in order to investigate the structure–property relationship and identify polymer properties necessary to effectively increase Cur aqueous solution concentration. XRD results indicated that all investigated solid dispersions were amorphous, even at a 9:1 Cur:polymer ratio. Both stability against crystallization and Cur solution concentration from these ASDs were significantly higher than those from physical mixtures and crystalline Cur. Remarkably, curcumin was also stabilized against chemical degradation in solution. Chemical stabilization was polymer-dependent, with stabilization in CAAdP>CMCAB>HPMCAS>PVP, while matrices enhanced solution concentration as PVP>HPMCAS≫CMCAB≈CAAdP. HPMCAS/Cur dispersions have useful combinations of pH-triggered release profile, chemical stabilization, and strong enhancement of Cur solution concentration.

Curcumin-loaded solid lipid nanoparticles have prolonged in vitro antitumour activity, cellular uptake and improved in vivo bioavailability

PurposeThe aim of the present study was to blend liquid lipids with solid lipids to encapsulate curcumin in solid lipid nanoparticles (SLNs), thereby improving the dispersibility and chemical stability of curcumin, prolonging its antitumour activity and cellular uptake and enhancing its bioavailability. MethodsCurcumin-loaded SLNs (C-SLNs) were prepared by high-pressure homogenisation with liquid lipid Sefsol-218®. The morphology, stability and release of curcumin in the optimised formulation were investigated. The anti-cancer activity of the formulation was evaluated in MCF-7 cells. Fluorescence spectrophotometry was used to quantify cellular uptake of the drug. The pharmacokinetic profiles of curcumin in SLNs after intravenous administration were studied in rats. ResultsBlending Sefsol-218® into a lipid matrix reduced the particle size without improving drug loading. An optimised formulation consisting of Dynasan 114®, Sefsol-218®, and Pluronic F68® (630:70:300, w/w) loaded with 0.8% drug was prepared. This formulation could be dispersed in water with a mean particle size of 152.8±4.7nm and a 90% entrapment efficiency. Curcumin displayed a two-phase sustained release profile from C-SLNs with improved chemical stability. Compared to the solubilised solution, C-SLNs exhibited prolonged inhibitory activity in cancer cells, as well as time-dependent increases in intracellular uptake. After intravenous administration to rats, the bioavailability of curcumin was increased by 1.25-fold. ConclusionsC-SLNs with improved dispersibility and chemical stability in an aqueous system have been successfully developed. C-SLNs may represent a potentially useful cancer therapeutic curcumin delivery system.