Studies of curcumin and curcuminoids. XXVII. Cyclodextrin complexation: solubility, chemical and photochemical stability (original) (raw)
Related papers
Journal of Photochemistry and Photobiology B: Biology, 2016
In aqueous solution, curcumin is photodegradable (light sensitive), it is also self-degradable in the dark. In basic medium, the second process is enhanced. The dark process has been studied in water and also in a number of protic and aprotic solvents, and aqueous solutions of ionic liquids, pluronics, reverse micelles and salt. The kinetics of the process followed the first order rate law; a comparative as well as individual assessment of which has been made. The kinetics of curcumin self-degradation has been found to be fairly dependent on salt (NaCl) concentration. Curcumin molecules in solution may remain in the enol or keto-enol form. From the visible spectral analysis, an estimate of the proportions of these forms in aqueous ethanol medium has been made. The temperature effect on the visible and fluorescence spectra of curcumin has been also studied. The steady state fluorescence anisotropy of the photoactive curcumin has been evaluated in different solvent and solution media. The reversibility of the steady state fluorescence anisotropy of curcumin on heating and cooling conditions has been examined. The results herein presented are new and ought to be useful as the study of physicochemistry of curcumin has been gaining importance in the light of its biological importance.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2004
The stability of curcumin (H 3 Cur) in aqueous media is improved when the systems in which it is present are at high pH values (higher than 11.7), fitting a model describable by a pseudo-zero order with a rate constant k for the disappearance of the Cur 3− species of 1.39 (10 −9 ) M min −1 . There were three acidity constants measured for the curcumin as follows: pK A3 = 10.51 ± 0.01 corresponding to the equilibrium HCur 2− = Cur 3− + H + , a pK A2 = 9.88 ± 0.02 corresponding to the equilibrium H 2 Cur − = HCur −2 + H + . These pK A values were attributed to the hydrogen of the phenol part of the curcumin, while the pK A1 = 8.38 ± 0.04 corresponds to the equilibrium H 3 Cur = H 2 Cur − +H + and is attributed the acetylacetone type group. Formation of quinoid structures play an important role in the tautomeric forms of the curcumin in aqueous media, which makes the experimental values differ from the theoretically calculated ones, depending on the conditions adopted in the study.
A Mini-Review: Comparison between curcumin and tetrahydrocurcumin based on their activities
Croatian journal of food science and technology, 2021
Curcumin, a natural ingredient present in turmeric rhizome is known for its various therapeutic activities such as antioxidant, anti-inflammatory, anticancer, antidiabetic, NF-kB activation suppresser. The hydrogenated derivative of curcumin, i.e., tetrahydrocurcumin, is also found to reveal the same activities. Moreover, the pro-oxidant effect of curcumin is reported, whereas tetrahydrocurcumin does not show any pro-oxidant effects. This contrasting behaviour of the two is attributed to their structures, because conjugation is involved only in curcumin, not in the tetrahydrocurcumin. It can be evidently concluded that double bonds affect the keto-enol ratio of the molecules and are therefore responsible for the degradation of curcumin, whereas tetrahydrocurcumin remains stable. Nevertheless, these double bonds are liable to affect the kinetics of beneficial activities of curcumin and tetrahydrocurcumin.
Strategies for Improving Bioavailability, Bioactivity, and Physical-Chemical Behavior of Curcumin
Molecules
Curcumin (CCM) is one of the most frequently explored plant compounds with various biological actions such as antibacterial, antiviral, antifungal, antineoplastic, and antioxidant/anti-inflammatory properties. The laboratory data and clinical trials have demonstrated that the bioavailability and bioactivity of curcumin are influenced by the feature of the curcumin molecular complex types. Curcumin has a high capacity to form molecular complexes with proteins (such as whey proteins, bovine serum albumin, β-lactoglobulin), carbohydrates, lipids, and natural compounds (e.g., resveratrol, piperine, quercetin). These complexes increase the bioactivity and bioavailability of curcumin. The current review provides these derivatization strategies for curcumin in terms of biological and physico-chemical aspects with a strong focus on different type of proteins, characterization methods, and thermodynamic features of protein–curcumin complexes, and with the aim of evaluating the best performan...
Improving the Solubility and Pharmacological Efficacy of Curcumin by Heat Treatment
ASSAY and Drug Development Technologies, 2007
Lipid peroxidation has been implicated in a variety of diseases. 4-Hydroxy-2-nonenal (HNE), a major oxidation by-product, is cytotoxic, mutagenic, and genotoxic, being involved in disease pathogenesis. Naturally occurring pharmacologically active small molecules are very attractive as natural nonsteroidal anti-inflammatory agents. Interest has greatly increased recently in the pharmacotherapeutic potential of curcumin, the yellow pigment found in the rhizomes of the perennial herb Curcuma longa (turmeric). Curcumin is efficacious against colon cancer, cystic fibrosis, and a variety of other disorders. Curcumin's full pharmacological potential is limited owing to its extremely limited water solubility. We report here that the water solubility of curcumin could be increased from 0.6 g/ml to 7.4 g/ml (12-fold increase) by the use of heat. Spectrophotometric (400-700 nm) and mass spectrometric profiling of the heat-extracted curcumin displays no significant heat-mediated disintegration of curcumin. Using an enzyme-linked immunosorbent assay that employed HNE modification of solid-phase antigen, we found that the heat-solubilized curcumin inhibited HNE-protein modification by 80%. Thus, inhibition of HNE modification may be a mechanism by which curcumin exerts its effect. We also report a simple assay to detect curcumin spectrophotometrically. Curcumin was solubilized in methanol and serially diluted in methanol to obtain a set of standards that were then read for optical density at 405 nm. Curcumin in the heatsolubilized samples was determined from this standard. Heat-solubilized curcumin should be considered in clinical trials involving curcumin, especially in the face of frustrating results obtained regarding curcumin-mediated correction of cystic fibrosis defects. 567 tion of cellular targets would be critical as pharmacotherapeutic agents.
2014
Purpose: To evaluate the effect of the preparation method on the inclusion complex of curcumin and hydroxypropyl-β-cyclodextrin (HP- β-CD). Methods: HP-β-CD was selected to prepare an inclusion complex with curcumin at a molar ratio of 1:1. The inclusion complexes were prepared using three different methods: common solvent evaporation (CSE), freeze drying (FD), and pH shift. The inclusion complexes were characterized by differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy. The content, solubility, dissolution, and stability of the complexes were evaluated and compared with curcumin and their physical mixture. Results: Formation of inclusion complexes was confirmed by DSC and FTIR results. CSE and FD methods gave a high content of curcumin in the inclusion complexes (> 88.39 %), while pH shift gave a lower content (64.04 %). All three methods significantly (p < 0.05) increased curcumin solubility (> 276.43-fold). However, higher stabilit...
Food Research International, 2005
The objective of this work was to separate and determine the physico-chemical and color characteristics of isolated curcuminoid pigments. Thin-layer chromatographic separation of curcuminoid pigments was possible on silica gel 60G plates using dichloromethane:methanol, 99:1. The preparative separation of curcuminoid pigments was accomplished by crystallization of curcumin in methanol:water and further separation by column chromatography using silica gel 60G impregnated with sodium hydrogen phosphate and dichloromethane as the eluent. The purity of each curcuminoid pigment was confirmed by high performance liquid chromatography and determination of the melting point. The isolated pigments were characterized with respect to ultraviolet, visible, infrared, nuclear magnetic resonance and color characteristics. The molar absorptivity of each pigment was determined. This data can be used for the identification and quantification of individual curcuminoid pigments.
Curcumin: Analysis and Stability
Journal of Advanced Pharmacy Research
Curcumin is a polyphenol extracted from Curcuma longa, used as a spice, in food coloring, and as a traditional herbal medicine. It has wide therapeutic platform as anti-oxidant, anticancer, anti-inflammatory and anti-infection properties. This review discusses the analytical methods used in determination of curcumin in various matrices with degradation profile, expected degradation products and stability tests.