Comprehensive properties of photodynamic antibacterial film based on κ-Carrageenan and curcumin-ß-cyclodextrin complex.

In this study, a biodegradable photodynamic antibacterial film (Car-Cur) was prepared using casting method with κ-Carrageenan (κ-Car) as film-forming substrate and curcumin-ß-cyclodextrin (Cur-ß-CD) complex as photosensitizer. The comprehensive performance of this Car-Cur film was investigated. The obtained results showed that the concentration of Cur-ß-CD was an important factor determining the properties of film including tensile strength (TS) elongation at break (EB), water vapor permeability (WVP), water content (WC) and thermal stability. When the concentration of Cur-ß-CD is 1%, the film demonstrated the maximum TS and EB, increased thermal stability, with desirable WVP and WC. Furthermore, this film also showed good photodynamic antibacterial potential against Staphylococcus aureus and Escherichia coli upon irradiation of blue LED light. Moreover, the film can be degraded in the soil in one week. In conclusion, our results suggested Car-Cur photodynamic film could be developed as biodegradable antimicrobial packaging material for food preservation.

Polysaccharides-Based Complex Particles' Protective Role on the Stability and Bioactivity of Immobilized Curcumin.

The curcumin degradation represents a significant limitation for its applications. The stability of free curcumin (FC) and immobilized curcumin in complex particles (ComPs) based on different polysaccharides was studied under the action of several factors. Ultraviolet-visible (UV-VIS) and Fourier-transform infrared (FTIR) spectroscopy proved the FC photodegradation and its role as a metal chelator: 82% of FC and between 26% and 39.79% of curcumin within the ComPs degraded after exposure for 28 days to natural light. The degradation half-life (t1/2) decreases for FC when the pH increases, from 6.8 h at pH = 3 to 2.1 h at pH = 9. For curcumin extracted from ComPs, t1/2 was constant (between 10 and 13 h) and depended on the sample's composition. The total phenol (TPC) and total flavonoids (TFC) content values increased by 16% and 13%, respectively, for FC exposed to ultraviolet light at λ = 365 nm (UVA), whereas no significant change was observed for immobilized curcumin. Antioxidant activity expressed by IC50 (µmoles/mL) for FC exposed to UVA decreased by 29%, but curcumin within ComPs was not affected by the UVA. The bovine serum albumin (BSA) adsorption efficiency on the ComPs surface depends on the pH value and the cross-linking degree. ComPs have a protective role for the immobilized curcumin.

Photo-physical, theoretical and photo-cytotoxic evaluation of a new class of lanthanide(iii)-curcumin/diketone complexes for PDT application.

Herein we report the synthesis, characterization, photophysical and photocytotoxicity studies of a new class of curcumin-based lanthanide(iii) complexes of general molecular formula [La(1,10-phen)2(L)(NO3)2] (1-4), where L = 1-phenylbutane-1,3-dione (L1, 1), 1-(anthracen-9-yl)butane-1,3-dione (L2, 2), 1-(3a1,5a1-dihydropyren-1-yl)butane-1,3-dione (L3, 3) and curcumin (L4, 4). Complex 1 was characterized by single-crystal X-ray crystallography and it exhibited the N4O6 coordination of La(iii). The presence of the low-lying and long-lived triplet excited state enabled the luminescent complexes (2-4) to generate singlet oxygen (1O2) in high yield when the complex was activated with visible light (400-700 nm, 10 J cm-2), which could be responsible for the photo-ablation of cancer cells. Complexes (2-4) exhibited remarkable photocytotoxicity in HeLa and MCF-7 cells with photocytotoxicity index 4-50 in the presence of visible light (400-700 nm, 10 J cm-2), while they were non-toxic in the dark with an IC50 value of >100 µM. The significantly lower toxicity (IC50 > 100 µM in the dark; IC50 in visible light ∼60 µM) of the complexes in MCF-10A (normal cells) in the dark and in visible light suggested their potential for targeting anticancer activity. Further studies showed that complex 4 induced caspase-dependent apoptosis through mitochondrial damage, mitochondrial respiration inhibition and reactive oxygen species (ROS) elevation. The cytosolic localization of complex 4 in HeLa cells, having a curcumin moiety as a fluorophore, was proved from the confocal microscopic studies. The photocytotoxicity of the complexes (1-4) was directly correlated to the efficacy of the complexes to generate singlet oxygen, which resulted in the photocytotoxicity order of 4 > 3>2 ≫ 1. Photo-physical studies revealed that the chelation of curcumin by La(iii) facilitated intersystem crossing in curcumin by reducing the energy gap of the singlet to triplet excited state. Therefore, the presence of low-lying and long-lived triplet excited state was responsible for increasing the generation of singlet oxygen and, thereby, photo-cytotoxicity in HeLa and MCF-7 cells. The present study has given an overall (Chemistry to Biology) perspective on the effect of La(iii) on the photo-cytotoxicity of selected photo-active curcumin-based ß-diketonate ligands.

Nanoceria-curcumin conjugate: Synthesis and selective cytotoxicity against cancer cells under oxidative stress conditions.

A water- and alcohol-soluble cerium oxide-curcumin conjugate was obtained by co-evaporation with poly(N-vinylpyrrolidone) (PVP). A nanocomposite consisting of hybrid organic-inorganic particles was stable in a wide range of pH values. Its properties were evaluated using nine cell lines: normal (MDBK, ST, Vero) and malignant (L929, T98G, HEp-2, A549, RIN-m5F, Hep G2). PVP-stabilised nanoceria was shown to inhibit autoxidation of curcumin, to enhance curcumin photostability, to promote bioaccumulation and to affect curcumin cytotoxicity and photocytotoxicity, depending on cell type, being more toxic to cancer cells in a selective manner. Under the conditions of UVA/UVC or H2O2-induced oxidative stress, the nanoceria-PVP-curcumin (NPC) conjugate was found to possess a selective cytotoxicity: it caused drastic inhibition of metabolic activity or a decrease in the total number of tumour cells, while in non-transformed cultures under the same conditions, the nanoceria-PVP-curcumin conjugate protected cells from these damaging factors. The NPC-conjugate, unlike curcumin itself, demonstrated a photosensitising effect in tumour cell cultures, while protecting non-transformed cultures from the damaging effects of UV radiation or oxidative stress. Based on the results obtained, we strongly believe that this novel hybrid material has enhanced characteristics compared to other curcumin formulations, and can be considered as a potent drug for biomedical applications, including cancer therapy.

Curcumin "Drug" Stabilized in Oxidovanadium(IV)-BODIPY Conjugates for Mitochondria-Targeted Photocytotoxicity.

Ternary oxidovanadium(IV) complexes of curcumin (Hcur), dipicolylamine (dpa) base, and its derivatives having pendant noniodinated and di-iodinated boron-dipyrromethene (BODIPY) moiety (L1 and L2, respectively), namely, [VO(dpa)(cur)]ClO4 (1), [VO(L1)(cur)]ClO4 (2), and [VO(L2)(cur)]ClO4 (3) and their chloride salts (1a-3a) were prepared, characterized, and studied for anticancer activity. The chloride salts were used for biological studies due to their aqueous solubility. Complex 1 was structurally characterized by single-crystal X-ray crystallography. The complex has a VO2+ moiety bound to dpa ligand showing N,N,N-coordination in a facial mode, and curcumin is bound in its mono-anionic enolic form. The V-O(cur) distances are 1.950(18) and 1.977(16) Å, while the V-N bond lengths are 2.090(2), 2.130(2), and 2.290(2) Å. The bond trans to V═O is long due to trans effect. The complexes are stable in a solution phase over a long period of time of 48 h without showing any apparent degradation of the curcumin ligand. The diiodo-BODIPY ligand (L2) or Hcur alone showed limited solution stability in dark. The emissive BODIPY (L1) containing complex 2a showed preferential mitochondrial localization in MCF-7 cells in cellular imaging experiments. The cytotoxicity of the complexes was studied by MTT assay. The BODIPY complex 3a showed excellent photodynamic therapy effect in visible light (400-700 nm) giving IC50 values of 2-6 µM in HeLa and MCF-7 cancer cells, while being less toxic in dark (∼100 µM). The cell death was apoptotic in nature involving reactive oxygen species (ROS). Mechanistic data from pUC19 DNA photocleavage studies revealed photogenerated ROS as primarily 1O2 from the BODIPY moiety and ·OH radicals from the curcumin ligand.

Water-Soluble Pd8L4 Self-assembled Molecular Barrel as an Aqueous Carrier for Hydrophobic Curcumin.

A tetrafacial water-soluble molecular barrel (1) was synthesized by coordination driven self-assembly of a symmetrical tetrapyridyl donor (L) with a cis-blocked 90° acceptor [cis-(en)Pd(NO3)2] (en = ethane-1,2-diamine). The open barrel structure of (1) was confirmed by single crystal X-ray diffraction. The presence of a hydrophobic cavity with large windows makes it an ideal candidate for encapsulation and carrying hydrophobic drug like curcumin in an aqueous medium. The barrel (1) encapsulates curcumin inside its molecular cavity and protects highly photosensitive curcumin from photodegradation. The photostability of encapsulated curcumin is due to the absorption of a high proportion of the incident photons by the aromatic walls of 1 with a high absorption cross-sectional area, which helps the walls to shield the guest even against sunlight/UV radiations. As compared to free curcumin in water, we noticed a significant increase in solubility as well as cellular uptake of curcumin upon encapsulation inside the water-soluble molecular barrel (1) in aqueous medium. Fluorescence imaging confirmed that curcumin was delivered into HeLa cancer cells by the aqueous barrel (1) with the retention of its potential anticancer activity. While free curcumin is inactive toward cancer cells in aqueous medium at room temperature due to negligible solubility, the determined IC50 value of ∼14 µM for curcumin in aqueous medium in the presence of the barrel (1) reflects the efficiency of the barrel as a potential curcumin carrier in aqueous medium without any other additives. Thus, two major challenges of increasing the bioavailability and stability of curcumin in aqueous medium even in the presence of UV light have been addressed by using a new supramolecular water-soluble barrel (1) as a drug carrier.

Modes of antibacterial action of curcumin under dark and light conditions: A toxicoproteomics approach.

Curcumin is a potent natural food-grade antimicrobial compound. Exposure to light further enhances its antimicrobial capacity. Proteomic methods were used in this study for investigating the mechanistic aspects of the antibacterial curcumin effects in the dark and upon illumination. Escherichia coli cells exposed to water-dispersible curcumin-methyl-ß-cyclodextrin inclusion complex under dark and light conditions were compared with the non-treated cells kept under the same illumination regimes. Curcumin treatment in the dark evoked adaptive responses aimed at mitigation of oxidative stress, DNA protection, proteostasis, modulation of redox state via changing NADH level, and gasotransmitter (H2S and NH3) biosynthesis. Although part of these phenomena were also present in E. coli treated under light, the light-induced curcumin toxicity was prevailed by maladaptive responses. The ROS burst induced upon curcumin treatment under light overrode the cellular adaptive mechanisms disrupting the iron metabolism, deregulating the iron-sulfur cluster biosynthesis and eventually leading to cell death. The toxicoproteomic findings were validated by transcriptomic analysis and by assessment of intracellular ROS, NADH, NADPH and iron levels. SIGNIFICANCE: The results of this study elucidate putative mechanistic basis of antibacterial effects of curcumin, suggesting ways towards more efficient contamination control. In particular, the antimicrobial efficacy of curcumin can be potentiated by targeting bacterial systems that remediate its dark toxicity by free radical detoxification and modulation of cell redox status. To the best of the authors' knowledge, this is the first proteomic study differentiating between the dark and light-induced antimicrobial activity of curcumin.

Photoactive platinum(ii) ß-diketonates as dual action anticancer agents.

Platinum(ii) complexes, viz. [Pt(L)(cur)] (1), [Pt(L)(py-acac)] (2) and [Pt(L)(an-acac)] (3), where HL is 4,4'-bis-dimethoxyazobenzene, Hcur is curcumin, Hpy-acac and Han-acac are pyrenyl and anthracenyl appended acetylacetone, were prepared, characterized and their anticancer activities were studied. Complex [Pt(L)(acac)] (4) was used as a control. Complex 1 showed an absorption band at 430 nm (ε = 8.8 × 10(4) M(-1) cm(-1)). The anthracenyl and pyrenyl complexes displayed bands near 390 nm (ε = 3.7 × 10(4) for 3 and 4.4 × 10(4) M(-1) cm(-1) for 2). Complex 1 showed an emission band at 525 nm (Φ = 0.017) in 10% DMSO-DPBS (pH, 7.2), while 2 and 3 were blue emissive (λem = 440 and 435, Φ = 0.058 and 0.045). There was an enhancement in emission intensity on glutathione (GSH) addition indicating diketonate release. The platinum(ii) species thus formed acted as a transcription inhibitor. The released ß-diketonate base showed photo-chemotherapeutic activity. The complexes photocleaved plasmid DNA under blue light of 457 nm forming ∼75% nicked circular (NC) DNA with hydroxyl radicals and singlet oxygen as the ROS. Complexes 1-3 were photocytotoxic in skin keratinocyte HaCaT cells giving IC50 of 8-14 µM under visible light (400-700 nm, 10 J cm(-2)), while being non-toxic in the dark (IC50: ∼60 µM). Complex 4 was inactive. Complexes 1-3 generating cellular ROS caused apoptotic cell death under visible light as evidenced from DCFDA and annexin-V/FITC-PI assays. This work presents a novel way to deliver an active platinum(ii) species and a phototoxic ß-diketone species to the cancer cells.

Curcumin liposomes prepared with milk fat globule membrane phospholipids and soybean lecithin.

Using thin film ultrasonic dispersion method, the curcumin liposomes were prepared with milk fat globule membrane (MFGM) phospholipids and soybean lecithins, respectively, to compare the characteristics and stability of the 2 curcumin liposomes. The processing parameters of curcumin liposomes were investigated to evaluate their effects on the encapsulation efficiency. Curcumin liposomes were characterized in terms of size distribution, ζ-potential, and in vitro release behavior, and then their storage stability under various conditions was evaluated. The curcumin liposomes prepared with MFGM phospholipids had an encapsulation efficiency of about 74%, an average particle size of 212.3 nm, and a ζ-potential of -48.60 mV. The MFGM liposomes showed higher encapsulation efficiency, smaller particle size, higher absolute value of ζ-potential, and slower in vitro release than soybean liposomes. The retention rate of liposomal curcumin was significantly higher than that of free curcumin. The stability of the 2 liposomes under different pH was almost the same, but MFGM liposomes displayed a slightly higher stability than soybean liposomes under the conditions of Fe(3+), light, temperature, oxygen, and relative humidity. In conclusion, MFGM phospholipids have potential advantages in the manufacture of curcumin liposomes used in food systems.

Curcumin-Eudragit® E PO solid dispersion: A simple and potent method to solve the problems of curcumin.

Using a simple solution mixing method, curcumin was dispersed in the matrix of Eudragit® E PO polymer. Water solubility of curcumin in curcumin-Eudragit® E PO solid dispersion (Cur@EPO) was greatly increased. Based on the results of several tests, curcumin was demonstrated to exist in the polymer matrix in amorphous state. The interaction between curcumin and the polymer was investigated through Fourier transform infrared spectroscopy and (1)H NMR which implied that OH group of curcumin and carbonyl group of the polymer involved in the H bonding formation. Cur@EPO also provided protection function for curcumin as verified by the pH challenge and UV irradiation test. The pH value influenced curcumin release profile in which sustained release pattern was revealed. Additionally, in vitro transdermal test was conducted to assess the potential of Cur@EPO as a vehicle to deliver curcumin through this alternative administration route.

Remarkable enhancement in photocytotoxicity and hydrolytic stability of curcumin on binding to an oxovanadium(IV) moiety.

Oxovanadium(IV) complexes of polypyridyl and curcumin-based ligands, viz. [VO(cur)(L)Cl] (1, 2) and [VO(scur)(L)Cl] (3, 4), where L is 1,10-phenanthroline (phen in 1 and 3), dipyrido[3,2-a:2',3'-c]phenazine (dppz in 2 and 4), Hcur is curcumin and Hscur is diglucosylcurcumin, were synthesized and characterized and their cellular uptake, photocytotoxicity, intracellular localization, DNA binding, and DNA photo-cleavage activity studied. Complex [VO(cur)(phen)Cl] (1) has V(IV)N2O3Cl distorted octahedral geometry as evidenced from its crystal structure. The sugar appended complexes show significantly higher uptake into the cancer cells compared to their normal analogues. The complexes are remarkably photocytotoxic in visible light (400-700 nm) giving an IC50 value of <5 µM in HeLa, HaCaT and MCF-7 cells with no significant dark toxicity. The green emission of the complexes was used for cellular imaging. Predominant cytosolic localization of the complexes 1-4 to a lesser extent into the nucleus was evidenced from confocal imaging. The complexes as strong binders of calf thymus DNA displayed photocleavage of supercoiled pUC19 DNA in red light by generating ˙OH radicals as the ROS. The cell death is via an apoptotic pathway involving the ROS. Binding to the VO(2+) moiety has resulted in stability against any hydrolytic degradation of curcumin along with an enhancement of its photocytotoxicity.

Flow cytometric assessment of Streptococcus mutans viability after exposure to blue light-activated curcumin.

BACKGROUND: Streptococcus mutans biofilms are considered as primary causative agents of dental caries. Photodynamic antimicrobial chemotherapy (PACT) has been recently proposed as a strategy for inactivating dental biofilms. This study aimed to investigate the effect of blue light-activated curcumin on S. mutans viability and to explore its potential as a new anti-caries therapeutic agent. The effect of different concentrations and incubation times of photo-activated curcumin on the survival of S. mutans in planktonic and biofilm models of growth was assessed by flow cytometry. METHODS: Streptococcus mutans in planktonic suspensions or biofilms formed on hydroxyapatite disks were incubated for 5 or 10min with curcumin prior to blue light activation. Bacteria were labeled with SYTO 9 and propidium iodide before viability was assessed by flow cytometry. Results were statistically analyzed using one-way ANOVA and Tukey multiple comparison intervals (α=0.05). RESULTS: For planktonic cultures, 0.2µM of light-activated curcumin significantly reduced S. mutans viability (p<0.05). For biofilm cultures, light-activated curcumin at concentration of 40-60µM only suppressed viability by 50% (p<0.05). Independently of the mode of growth, incubation time has no significant effect on PACT efficiency. CONCLUSION: This study indicates that blue light-activated curcumin can efficiently inactivate planktonic cultures of S. mutans whereas biofilms were more resistant to treatment. Flow cytometry allowed the detection of bacteria with damaged membranes that were unable to replicate and grow after cell sorting. Further studies seem warranted to optimize the efficacy of light-activated curcumin against S. mutans biofilms.

Curcumin as a potential non-steroidal contraceptive with spermicidal and microbicidal properties.

OBJECTIVE: Curcumin, a component of the curry powder turmeric, has immense biological properties, including anticancer effects. The objective of this study was to determine if curcumin can provide a novel non-steroidal contraceptive having both spermicidal and microbicidal properties. STUDY DESIGN: The effect of curcumin, with and without photosensitization, was examined on human sperm forward motility and growth of several aerobic (n=8) and anaerobic bacteria (n=4) and yeast (n=7) strains implicated in vaginosis, vaginitis, and vaginal infections in women. The effect of various concentrations of curcumin on human sperm and microbes (aerobic and anaerobic bacteria and yeast) was tested. The effect on sperm was examined by counting the sperm forward motility, and on microbes by agar and broth dilutions and colony counting. Each experiment was repeated using different semen specimens, and bacteria and yeast stocks. RESULTS: Curcumin caused a concentration-dependent inhibition of sperm forward motility with a total block at ≥250µM concentration. After photosensitization, the effective concentration to completely block sperm forward motility decreased 25-fold, now requiring only 10µM concentration for total inhibition. Curcumin concentrations between 100 and 500µM completely blocked the growth of all the bacteria and yeast strains tested. After photosensitization, the effective concentration to completely inhibit microbial growth decreased 10-fold for aerobic bacteria and yeast, and 5-fold for anaerobic bacteria. CONCLUSIONS: These findings suggest that curcumin can block sperm function and bacteria/yeast growth. It can potentially provide an ideal non-steroidal contraceptive having both spermicidal and microbicidal properties against vaginal infections.

Design, synthesis and destructive dynamic effects of BODIPY-containing and curcuminoid boron tracedrugs for neutron dynamic therapy.

BACKGROUND: We previously designed the boron tracedrugs UTX-42, UTX-43, and UTX-44, which possess antioxidant potency. In order to explore their destructive dynamic effects when bombarded by weak thermal neutrons, we performed thermal neutron irradiation of bovine serum albumin (BSA) treated with the boron tracedrugs. MATERIALS AND METHODS: Boron tracedrugs, including the boron dipyrromethene (BODIPY)-containing compounds UTX-42, UTX-44, and UTX-47 and the curcuminoid compounds UTX-50 and UTX-51, were designed for neutron dynamic therapy based on their molecular orbital calculation. Newly designed UTX-47, UTX-50, and UTX-51 were synthesized. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect decomposition by thermal neutron irradiation of BSA treated with these boron tracedrugs. RESULTS: The combination of 1.0 µM BSA with 100 µM of each of the boron tracedrugs showed a decrease in band intensity after irradiation. CONCLUSION: All boron tracedrugs tested caused destructive dynamic damage of BSA during thermal neutron irradiation, suggesting that boron tracedrugs could be used as dynamic drugs for neutron dynamic therapy.

Photoinduced trans-to-cis isomerization of cyclocurcumin.

The photophysical properties of cyclocurcumin in various solvents are studied for the first time to shed light on the nonradiative processes of the parent compound, curcumin, which has a range of medicinal properties. Steady-state fluorescence and fluorescence-excitation spectra of cyclocurcumin in polar aprotic solvents are strongly dependent on excitation (λ(ex)) and emission (λ(em)) wavelength, respectively. The fluorescence quantum yield also depends on λ(ex) and increases with the viscosity of the medium. Time-resolved studies show nonexponential fluorescence decay in all solvents studied. The two fluorescence decay components of cyclocurcumin in alcohols exhibit a strong dependence on viscosity and temperature. NMR spectroscopy indicates that cyclocurcumin is entirely in the trans form with respect to the C6-C7 double bond in methanol, chloroform, and acetone. It is suggested that at least two conformational isomers about another single bond (C5-C6 or C7-C1″ or both) and that trans-to-cis isomerization about the C6-C7 double bond of these isomers provide the most likely means of rationalizing the steady-state spectra and the nonradiative decay mechanisms in both protic and aprotic polar solvents.

Enhancement of pancreatic lipase inhibitory activity of curcumin by radiolytic transformation.

The naturally occurring yellow dietary diarylheptanoid curcumin (1) was converted by γ-ray to two new γ-lactones, curculactones A (2) and B (3), as well as four known transformates, erythro-1-(3-methoxy-4-hydroxy-phenyl)-propan-1,2-diol (4), threo-1-(3-methoxy-4-hydroxy-phenyl)-propan-1,2-diol (5), vanillic acid (6), and vanillin (7). The structures of the two new γ-lactone derivatives were elucidated on the basis of spectroscopic methods. The steroisomeric phenylpropanoids 4 and 5 exhibited significantly enhanced inhibitory activity against pancreatic lipase when compared to parent curcumin.

Formulation and characterization of curcuminoids loaded solid lipid nanoparticles.

Curcuminoids loaded solid lipid nanoparticles (SLNs) have been successfully developed using a microemulsion technique at approximately 75 degrees C. It was found that variation in the amount of ingredients had profound effects on the curcuminoid loading capacity, the mean particle size, and size distribution. At optimized process conditions, lyophilized curcuminoids loaded SLNs showed spherical particles with a mean particle size of approximately 450nm and a polydispersity index of 0.4. Up to 70% (w/w) curcuminoids incorporation efficacy was achieved. In vitro release studies showed a prolonged release of the curcuminoids from the solid lipid nanoparticles up to 12h following the Higuchi's square root model. After 6-month storage at room temperature in the absence of sunlight, the physical and chemical stabilities of the lyophilized curcuminoids loaded SLNs could be maintained, i.e. the mean particle size and the amount of curcuminoids showed no significant changes (P>0.05) compared to the freshly prepared SLNs. In addition, the chemical stability of curcuminoids incorporated into SLNs was further investigated by dispersing them into a model cream base. The results revealed that after storage in the absence of sunlight for 6 months, the percentages of the remaining curcumin, bisdemethoxycurcumin and demethoxycurcumin were 91, 96 and 88, respectively.

Effect of photo-irradiated curcumin treatment against oxidative stress in streptozotocin-induced diabetic rats.

Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of diabetes mellitus. Although phenolic compounds attenuate oxidative stress-related damage, there are concerns over toxicity of synthetic phenolic antioxidants, and this has considerably stimulated interest in investigating the role of natural phenolics in medicinal application. In the present study, we examined the effect of photo-irradiated curcumin in experimental diabetes to evaluate the anti-hyperglycemic properties of this compound on streptozotocin (40 mg/kg of body weight)-induced diabetes. Photo-irradiated curcumin was given at a dose of 10 or 30 mg/kg of body weight. The level of blood glucose was elevated in diabetic animals. Circulatory lipid peroxidation, vitamin C, vitamin E, and enzymic antioxidants such as superoxide dismutase and catalase were analyzed. The antioxidant status decreased in diabetic animals. Oral administration of photo-irradiated curcumin for 45 days resulted in a significant decrease in the levels of blood glucose along with near-normalization of the enzymic activities and the levels of lipid peroxidative markers. The most effective results were obtained on treatment with 30 mg/kg of body weight of photo-irradiated curcumin.

Study of the interaction of proteins with curcumin and SDS and its analytical application.

It is found that protein and sodium dodecyl sulphonate (SDS) can enhance resonance light scattering (RLS) of curcumin (CU). Based on this phenomenon, a new quantitative method for protein in aqueous solution has been developed. In the BR (pH 3.5) buffer, the RLS intensity of CU-SDS system is greatly enhanced by protein. The enhanced RLS is proportional to the concentration of protein in the range of 0.00020-20.0 microgml(-1) for bovine serum albumin (BSA) and 0.00040-1.0 microgml(-1) for human serum albumin (HSA) and their detection limits are 0.16 and 0.041 ngml(-1), respectively. An actual sample is satisfactorily determined. In addition, the interaction mechanism between protein and CU-SDS is also studied by using multi-techniques such as RLS, absorption spectroscopy and fluorescence, zeta potential assay measurement.

Photo-irradiated curcumin supplementation in streptozotocin-induced diabetic rats: effect on lipid peroxidation.

BACKGROUND: Diabetes mellitus is one of the most common endocrine disorders. A large number of studies are in progress to identify natural substances that are effective in reducing the severity of diabetes. Although a number of drugs are currently marketed, their long-term use can cause a number of adverse effects. MATERIALS AND METHODS: In the present study, we examined the effect of photo-irradiated curcumin on experimental diabetes in order to evaluate the antihyperglycaemic effects of this compound on streptozotocin (40 mg/kg bodyweight)-induced diabetes. Photo-irradiated curcumin was given at a dose of 10, 30 and 80 mg/kg bodyweight. The level of blood glucose was elevated in the diabetic animals. The liver, kidney and brain were assayed for the degree of lipid peroxidation, reduced glutathione content and the activity of enzymic and levels of non-enzymic antioxidants. RESULTS: Antioxidant status decreased in the diabetic animals. Oral administration of photo-irradiated curcumin for 45 days resulted in a significant decrease in the levels of blood glucose, together with near normalisation of enzymic activity and the markers of lipid peroxidation. The best results were obtained in rats treated with 30 mg/kg bodyweight of photo-irradiated curcumin.