Anaphylaxis reaction to Samsum ant (Pachycondyla sennaarensis): a case series study

Summary

Background. Anaphylaxis is a life-threatening hypersensitivity reaction. The present study aimed to investigate the cases of anaphylaxis to ant stings in Iran to determine the characteristics of patients, geographical distribution and the type of ants that cause anaphylaxis. Methods. Patients with a history of anaphylaxis to ant sting underwent skin allergy test with extracted substance from Solenopsis invicta. Samples of ants were collected from the sites where each patient was bitten and their species were identified by a medical entomologist. Results. Nineteen patients (mean age: 26.2 years; range: 4-48 years) were included in the study. Most patients (89.5 percent) were female. The lower limb was the most common site of the sting and most stings had occurred in the morning (31.6 %) and evening (31.6%). Skin manifestations were the most common clinical symptoms (94.7%). Most cases of stings were observed in the Hormozgan province (89.5%) located in southern Iran. Sixteen patients had positive skin prick test for ant venom. All collected ants that caused anaphylaxis belonged to the Pachycondyla sennaarensis species. Conclusions. Ant sting anaphylaxis is not uncommon in Iran, especially in its southern regions. All cases of anaphylaxis in this study were due to samsum ant sting (Pachycondyla sennaarensis), which is a species similar to the fire ant (Solenopsis invicta). Allergy skin testing with fire ant extract was positive and helpful in identifying samsum ant allergy in all cases.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Photocatalytic activity of new nanostructures of an Ag(i) metal–organic framework (Ag-MOF) for the efficient degradation of MCPA and 2,4-D herbicides under sunlight irradiation

A new Ag(i) metal–organic framework (Ag-MOF) [Ag(p-OH-C₆H₄COOH)₂(NO₃)]_n [Ag(PHBA)₂(NO₃)]_n, (1) (PHBA: C₈H₆O₄ {p-hydroxybenzoic acid}) was synthesized using two different methods; the laying method (single crystal) and sonochemical irradiation (nanostructures).

A 3D heterometallic Ni(ii)/K(i) MOF with a rare rna topology: synthesis, structural features, and photocatalytic dye degradation modeling

A new picolinate-driven Ni/K MOF was prepared by different methods, fully characterized, and explored in the photocatalytic degradation of bromocresol green.

Hot and cold executive functions in pure opioid users undergoing methadone maintenance treatment: Effects of methadone dose, treatment duration, and time between last methadone administration and testing

CONTEXT

Methadone maintenance is a standard treatment for opiate-dependent individuals. However, deficits in cognitive functioning have been associated with this treatment.

AIM

This study aimed to determine the dose and treatment duration-related effects of methadone on executive functions.

SETTING AND DESIGN

Pure male opioid users with no considerable history of other drug abuse, undergoing methadone maintenance treatment (MMT) were recruited from a major government-run de-addiction center.

METHODS

Hot executive functions including decision-making and emotion recognition were assessed using the Iowa gambling task and Ekman faces test, whereas cold executive functions including working memory (WM), cognitive flexibility, and response inhibition were assessed using n-back, Wisconsin card sorting test, and the GO/NOGO task, respectively. Statistical Analyses Used: Descriptive statistics, Pearson's correlation coefficients, and multiple regression analysis were used to test the hypotheses of the study.

RESULTS

Methadone dose and length of MMT were found to be associated with greater impairment in executive functions. Impairment in cognitive performance was also found to be inversely related to time since dosing. Regression analyses revealed that methadone dosage and time since dosing accounted for a significant proportion of the variance in cognitive flexibility, while the total amount of methadone administered was able to predict deficits in WM, methadone treatment duration predicted psychomotor speed, and time since dosing predicted decision-making ability.

CONCLUSIONS

To keep cognitive impairment at a minimum, methadone dose and treatment duration will have to be customized considering the history of opiate abuse so that impairment attributable to long-term opiate use may be differentiated from acute methadone dosing.

Oral complications at 6 months after radiation therapy for head and neck cancer

OBJECTIVE

To examine oral complications 6 months after modern radiation therapy (RT) for head and neck cancer (HNC).

METHODS

Prospective multicenter cohort study of patients with HNC receiving intensity-modulated radiation therapy or more advanced RT. Stimulated whole salivary flow, maximal mouth opening, oral mucositis, oral pain, oral health-related quality of life (OH-QOL), and oral hygiene practices were measured in 372 subjects pre-RT and 216 subjects at 6 months from the start of RT.

RESULTS

Mean stimulated whole salivary flow declined from 1.09 to 0.47 ml/min at 6 months (p < .0001). Mean maximal mouth opening reduced from 45.58 to 42.53 mm at 6 months (p < .0001). 8.1% of subjects had some oral mucositis at 6 months, including 3.8% with oral ulceration. Mean overall pain score was unchanged. OH-QOL was reduced at 6 months, with changes related to dry mouth, sticky saliva, swallowing solid foods, and sense of taste (p ≤ .0001). At 6 months, there was greater frequency of using dental floss and greater proportion using supplemental fluoride (p < .0001).

CONCLUSIONS

Despite advances in RT techniques, patients with HNC experience oral complications 6 months after RT, with resulting negative impacts on oral function and quality of life.

EFFECT OF TIME EXPOSURE ON THERMOLUMINESCENCE GLOW CURVE FOR UV-INDUCED ZRO2:MG PHOSPHOR

In this research, the effect of magnesium (Mg) impurity on thermoluminescence (TL) response of ZrO2 phosphors is studied experimentally. In the experimental procedure, ZrO2:Mg phosphors in the powder form were synthesised by the sol-gel method. The obtained hydrogel was dried in air and then calcinated in air at 1200°C for 5 h and next was annealed at 250°C for 2 h. Sample characterisations were done by X-ray diffraction and scanning electron microscopy. Obtained materials had monoclinic phase and porous microstructure. Then, known amounts of ZrO2:Mg powder were exposed to ultraviolet lamp from 0.5 to 120 min. The TL peaks were obtained at the same temperature as 75, 137 and 260°C, respectively. Adding Mg to pure zirconia caused to increase TL intensity and shift peaks related to pure zirconia. The TL peaks of the pure zirconia were seen at the 83, 132 and 235°C. Finally, ZrO2:Mg TL experimental results show the linear dose response, high stability and less fading.

Responses of Soil Microbial Biomass and Enzyme Activities to Tillage and Fertilization Systems in Soybean (Glycine max L.) Production

Tillage operation and fertilizer type play important roles in soil properties as far as soil microbial condition is concerned. Information regarding the simultaneous evaluation of the effect of long-term tillage and fertilization on the soil microbial traits of soybean farms is not available. Accordingly, it was hypothesized that, the microbial biomass and enzyme activity, more often than not, respond quickly to changes in soil tillage and fertilization. Therefore, the experiments were aimed at analyzing the responses of soil microbial traits to tillage and fertilization in a soybean field in Kurdistan University, Iran. The field soil is categorized into coarse Loamy, mixed, superactive, calcareous, and mesic Typic Xerorthents. The experiments were arranged in split plot, based on randomized complete block design with three replications. Main plots consisted of long-term (since 2002) tillage systems including conventional tillage (CT), minimum tillage (MT), and no-tillage (NT). Eight fertilization methods were employed in the sub-plots, including (F1): farmyard manure (FYM); (F2): compost; (F3): chemical fertilizers; (F4): FYM + compost; (F5): FYM + chemical fertilizers; (F6): compost + chemical fertilizers; (F7): FYM + compost + chemical fertilizers and (F8): Control (without fertilizer). The highest microbial biomass carbon (385.1 μg) was observed in NT-F4 treatment. The NT treatment comparatively recorded higher values of acid phosphatase (189.1 μg PNP g^-1 h^-1), alkaline phosphatase (2879.6 μg PNP g^-1 h^-1) and dehydrogenase activity (68.1 μg PNP g^-1 h^-1). The soil treated with a mixture of compost and FYM inputs had the maximum urease activity of all tillage treatments. Organically manured treatment (F4) showed more activity in dehydrogenase (85.7 μg PNP g^-1 h^-1), acid phosphatase (199.1 μg PNP g^-1 h^-1), and alkaline phosphatase (3183.6 μg PNP g^-1 h^-1) compared to those treated with chemical fertilizers. In NT-F4 treatment, using on-farm inputs is most suitable for sustainable management and improvement in soil biological activities in soybean cultivation. We concluded that applying organic manures and employing reduced tillage systems increased soil microbial biomass and enzyme activities.

Synthesis, Characterization, Spectral Studies, Antibacterial Evaluation, Thermodynamics and DFT Calculations of Dimethyltin(IV) Dichloride Schiff Base

A number of new 1:1 complexes of SnMe(2)Cl(2) with unsymmetrical tetradentate Schiff base ligand with NNOS coordination sphere have been synthesized and fully characterized by a variety of physico-chemical techniques viz. elemental analysis, molar conductivity, (1)H and (119)Sn NMR, IR and mass spectroscopy. IR spectral data show that the fifth coordination position of tin atom is occupied by an oxygen atom of Schiff base ligands. In the light of titled techniques, trigonal bipyramidal geometry around the tin atom is proposed for the synthesized complexes. The in vitro antibacterial activities of the complexes against Staphylococcus aureus and Escherichia Coli have been studied. It was found that they possess significant antibacterial activity. Also, DFT/B3LYP method was used to analyze the electronic structures and study of the geometries. The thermodynamic formation constants of the complexes were determined spectrophotometrically at 25ºC in DMF solvent.

A novel nano-sized binuclear nickel(ii) Schiff base complex as a precursor for NiO nanoparticles: synthesis, characterization, DFT study and antibacterial activity

We prepared a new nano-hexadentate Schiff base and its nickel(ii) complex using an ultrasonic method, which produced NiO with an average size of 53 nm.

Investigating the effect of gallium curcumin and gallium diacetylcurcumin complexes on the structure, function and oxidative stability of the peroxidase enzyme and their anticancer and antibacterial activities

Curcumin has a wide spectrum of biological and pharmacological activities including anti-inflammatory, antioxidant, antiproliferative, antimicrobial and anticancer activities. Complexation of curcumin with metals has gained attention in recent years for improvement of its stability. In this study, the effect of gallium curcumin and gallium diacetylcurcumin on the structure, function and oxidative stability of horseradish peroxidase (HRP) enzyme were evaluated by spectroscopic techniques. In addition to the enzymatic investigation, the cytotoxic effect of the complexes was assessed on bladder, MCF-7 breast cancer and LNCaP prostate carcinoma cell lines by MTT assay. Furthermore, antibacterial activity of the complexes against S. aureus and E. coli was explored by dilution test method. The results showed that the complexes improve activity of HRP and also increase its tolerance against the oxidative condition. After addition of the complexes, affinity of HRP for hydrogen peroxide substrate decreases, while the affinity increases for phenol substrate. Circular dichroism, intrinsic and synchronous fluorescence spectra showed that the enzyme structure around the catalytic heme group becomes less compact and also the distance between the heme group and tryptophan residues increases due to binding of the complexes to HRP. On the whole, it can be concluded that the change in the enzyme structure upon binding to the gallium curcumin and gallium diacetylcurcumin complexes results in an increase in the antioxidant efficiency and activity of the peroxidise enzyme. The result of anticancer and antibacterial activities suggested that the complexes exhibit the potential for cancer treatment, but they have no significant antibacterial activity.

New tetradentate Schiff bases of 2-amino-3,5-dibromobenzaldehyde with aliphatic diamines and their metal complexes: synthesis, characterization and thermal stability

The tetradentate Schiff base ligands (L(1)-L(4)), were synthesized by reaction between 2-amino-3,5-dibromobenzaldehyde and aliphatic diamines. Then, nickel and oxovanadium(IV) complexes of these ligands were synthesized and characterized by (1)H NMR, Mass, IR, UV-Vis spectroscopy and thermogravimetry. The kinetic parameters of oxovanadium(IV) complexes were calculated from thermal studies. According to the results of thermogravimetric data, the thermal stability of oxovanadium(IV) complexes is as follow: [Formula: see text].

Simultaneous spectrophotometric determination of Cu2+, Hg2+, and Cd2+ ions using 2-(3-hydroxy-1-methylbut-2-enylideneamino)pyridine-3-ol

New complexes of Cu2+, Hg2+, and Cd2+ with a recently synthesized Schiff base derived from 2-(3-hydroxy-1-methylbut-2-enylideneamino)pyridine-3-ol were applied for their simultaneous determination with artificial neural networks. A new analytical method using principal component-feed forward neural networks (PC-FFNNs) and principal component-radial basis function networks (PC-RBFNs) was used. Spectral data was reduced using principal component analysis and subjected to ANNs. The data obtained from synthetic mixtures of metal ions were processed by PC-FFNNs and PC-RBFNs. Performances of the proposed methods were tested with regard to relative standard error of prediction. Limit of detections and limit of quantifications were determined. The results obtained by PC-FFNNs and PC-RBFNs were compared to each other. Under the working conditions, the proposed methods were successfully applied to simultaneous determination of Hg2+, Cu2+, and Cd2+ in different water and soil samples. Concentrations of metal ions in the samples were also determined by flame atomic absorption spectrometry (FAAS) and standard addition method. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by FAAS and standard addition method.

Coordination chemistry, thermodynamics and DFT calculations of copper(II) NNOS Schiff base complexes

Synthesis, magnetic and spectroscopy techniques are described for five copper(II) containing tetradentate Schiff bases are synthesized from methyl-2-(N-2'-aminoethane), (1-methyl-2'-aminoethane), (3-aminopropylamino)cyclopentenedithiocarboxylate. Molar conductance and infrared spectral evidences indicate that the complexes are four-coordinate in which the Schiff bases are coordinated as NNOS ligands. Room temperature μeff values for the complexes are 1.71-1.80B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1M (NaClO4), at 25˚C in DMF solvent. Also, the DFT calculations were carried out to determine the structural and the geometrical properties of the complexes. The DFT results are further supported by the experimental formation constants of these complexes.

New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: synthesis, characterization and thermodynamics

Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L(1)), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L(2)) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L(4)). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L(3)) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, (1)H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.

Synthesis, characterization, and thermodynamics of some new unsymmetrical Schiff bases of salicylaldehyde with 3,4-diaminopyridine and their cobalt(III) complexes

Some new Schiff bases derived from 3,4-diaminopyridine (3,4-DAP) and their new unsymmetrical Co(III) five coordinate complexes described as [Co(Chel)(L)]ClO4⋅H2O where (Chel) is the deprotonated form of a series of unsymmetric ligands containing 3,4-diaminopyridine (3,4-DAP) and substituted salicylaldehyde moieties and a new Co(III) six coordinate Co(III) complex, were synthesized and characterized by (1)H NMR, IR, UV-Vis, and elemental analysis. For the new synthesized five coordinate complexes, the formation constants of the interaction of the Co(III) Schiff bases with various donors were measured spectrophotometrically. The trend of the formation constants of the five coordinate Co(III) Schiff base complexes toward a given phosphine is as follow: 5-H>5-Br and the formation constants trend of these donors are as follow: PBu3>PPh2Me. Furthermore the adduct formation of the five coordinate [Co(3,4-Salpyr)(PBu3)] ClO4⋅H2O, with aromatic amines shows the following binding trend: Im>2-MeIm>2-EtIm>BzIm. The trend of the formation constants of Co(III) Schiff base complexes toward a given donor according to the phosphine axial ligand is as follow: PBu3>PPh2Me.

Synthesis, spectral, thermal and thermodynamic studies of oxovanadium(IV) complexes of Schiff bases derived from 3,4-diaminobenzoic acid with salicylaldehyde derivatives

Synthesis and evaluation of three new oxovanadium(IV) complexes, formed by the interaction of vanadyl acetylacetonate and the Schiff bases: 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (L(1)), 3,4-bis-((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (L(2)) and 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (L(3)) in methanol. The complexes have been characterized and studied by IR spectra, UV-Vis spectroscopy and thermogravimetry in order to evaluate their thermal stability and thermal decomposition. According to the results discussed from TG curves, the order of thermal stability for the complexes is VOL(3)>VOL(1)>VOL(2). Their formation constants (Kf) were obtained by UV-Vis spectroscopic titration at 15, 25, 35 and 45 °C in methanol by SQUAD software. The trend of formation constants of the complexes as follows: VOL(3)>VOL(2)>VOL(1).

New tetradentate Schiff bases of 2,2-dimethyl-1,3-diaminopropane and acetylacetone derivatives and their vanadyl complexes

A series of new VO(IV) complexes with two new tetradentate Schiff base of 4,4'-(2,2-dimethylpropane-1,3-diyl)-bis(azan-1-yl-1-yldene)dipent-2-en-2-ol) [H(2)L(1)] and 3,3'-(2,2-dimethylpropane-1,3-diyl)azan-1-yl-1-ylidene)-bis(1-phenylbut-1-en-1-ol) [H(2)L(2)] (which have been derived from 2,2-dimethyl-1,3-diaminopropan, and diketones of acetylacetone and benzoylacetone) were synthesized and characterized by (1)H NMR, (13)C NMR, FT-IR, mass and UV-Vis spectrophotometry. The electrochemical properties of the vanadyl complexes were investigated by means of cyclic voltammetry. The oxidation potentials are increased by increasing the electron-withdrawing properties of functional groups of the Schiff base ligands according to the trend of Me<Ph. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the VO(IV) complexes were carried out in the range of 20-700°C. The complexes were decomposed in two stages. Also, decomposition of the synthesized complexes is related to the Schiff base characteristics. The thermal decomposition of the studied reactions was first order. The kinetic parameters for the decomposition steps in vanadyl complexes thermograms have been calculated.

Contrasting soil microbial responses to fertilization and tillage systems in canola rhizosphere

Information regarding the simultaneous evaluation of tillage and fertilization on the soil biological traits in canola production is not available. Therefore, field experiments were conducted in 2007-2010 in a split plot based on randomized complete block design with three replications. Main plots consisted of conventional tillage (CT); minimum tillage (MT) and no tillage (NT). Six strategies of fertilization including (N1): farmyard manure (cattle manure); (N2): compost; (N3): chemical fertilizers; (N4): farmyard manure + compost; (N5): farmyard manure + compost + chemical fertilizers and (N6): control, were arranged in sub plots. Results showed that the addition of organic manure increased the soil microbial biomass. No tillage system increased microbial biomass compared to other tillage systems. The activities of all enzymes were generally higher in the N4 treatment. The activity of phosphatase and urease tended to be higher in the no tillage treatment compared to the CT and MT treatments.

Application of metalloporphyrins as new catalysts for the efficient, mild and regioselective synthesis of quinoxaline derivatives

A simple, highly efficient and green procedure for the condensation of aryl and alkyl 1,2-diamines with α-diketones in the presence of catalytic amounts of metalloporphyrins at room temperature is described. Using this method, quinoxaline derivatives as biologically interesting compounds are produced in high to excellent yields and short reaction times. In this report, the effects of central metal in porphyrin core and substituents on tetraphenylporphyrin skeleton have been studied.

Evaluation of antiviral activities of curcumin derivatives against HSV-1 in Vero cell line

Antiviral drug resistance is one of the most common problems in medicine, and, therefore, finding new antiviral agents, especially from natural resources, seems to be necessary. This study was designed to assay the antiviral activity of curcumin and its new derivatives like gallium-curcumin and Cu-curcumin on replication of HSV-1 in cell culture. The research was performed as an in vitro study in which the antiviral activity of different concentrations of three substances including curcumin, Gallium-curcumin and Cu-curcumin were tested on HSV-1. The cytotoxicity of the tested compounds was also evaluated on the Vero cell line. The CC50 values for curcumin, gallium-curcumin and Cu-curcumin were 484.2 microg/mL, 255.8 microg/mL and 326.6 microg/mL, respectively, and the respective IC50 values 33.0 microg/mL, 13.9 microg/mL and 23.1 microg/mL. The calculated SI values were 14.6, 18.4 and 14.1, respectively. The results showed that curcumin and its new derivatives have remarkable antiviral effects on HSV-1 in cell culture.

Circular dichroism and fluorescence spectroscopic study on the interaction of bisdemethoxycurcumin and diacetylbisdemethoxycurcumin with human serum albumin

The interactions of bisdemethoxycurcumin (BDMC) as a bioactive constituent of turmeric and diacetylbisdemethoxycurcumin (DABC) as a novel synthetic derivative of curcumin with human serum albumin (HSA) have been investigated by fluorescence and circular dichroism (CD) spectroscopy. The binding parameters, including the number of substantive binding sites and the binding constants, have been estimated from the analysis of fluorescence measurements. The estimated binding parameters indicated that BDMC has higher affinity than DABC to bind HSA, suggesting the essential role of the phenolic OH groups of BDMC, which are acetylated in DABC. It was found that the binding site for BDMC and DABC is located in the vicinity of Trp-214 in subdomain IIA, which is the same as binding site for curcumin (CUR). The minor changes on the far-UV circular dichroism spectra resulted in partial changes in the calculated secondary structure contents of HSA. The negligible alteration in the secondary structure of HSA indicated that ligand-induced conformational changes are localized in the binding site and do not involve considerable changes in the protein folding. The visible CD spectra indicated that the optical activity observed during the ligand binding is due to induced-protein chirality.

Interaction of curcumin and diacetylcurcumin with the lipocalin member beta-lactoglobulin

The binding of curcumin (CUR) and diacetylcurcumin (DAC) to bovine beta-lactoglobulin (BLG) genetic variant B was investigated by fluorescence and circular dichroism techniques. The binding parameters including number of substantive binding sites and the binding constants have been evaluated by fluorescence quenching method. The distance (r) between donor (BLG) and acceptor (CUR and DAC) was obtained according to the Förster's theory of non-radiative energy transfer. The far-UV circular dichroism spectra were used to investigate the possible changes in the secondary structure of BLG in the presence of CUR and DAC and showed that these two ligands change the alpha-helix and random coil contents of this protein to some extent. The visible circular dichroism spectra indicated that the optical activity during the ligand binding was observed due to the induced-protein chirality. All of the achieved results suggested the important role of the phenolic OH group of CUR in the binding process resulted in more affinity of CUR than DAC for binding to BLG.

Synthesis and characterization of dual function vanadyl, gallium and indium curcumin complexes for medicinal applications

Novel bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin) complexes with the formula, ML(3), where M is Ga(III) or In(III), or of the formula, ML(2) where M is [VO](2+), have been synthesized and characterized by mass spectrometry, infrared and absorption spectroscopies, and elemental analysis. A new ligand, bis[4-acetyl-3-hydroxyphenyl]-1,6-heptadiene-3,5-dione (diacetylbisdemethoxycurcumin, DABC) was similarly characterized; an X-ray structure analysis was performed. Vanadyl complexes tested in an acute i.p. testing protocol in STZ-diabetic rats showed a lack of insulin enhancing potential. Vanadyl complexes were, however, more cytotoxic than were the ligands alone in standard MTT (3-[4,5-dimethylthiazole-2-yl]ate, -2,5-diphenyl-tetrazolium bromide) cytotoxicity testing, using mouse lymphoma cells. With the exception of DABC, that was not different from VO(DABC)(2), the complexes were not significantly different from one another, with IC(50) values in the 5-10 microM range. Gallium and indium curcumin complexes had IC(50) values in the same 5-10 microM range; whereas Ga(DAC)(3) and In(DAC)(3) (where DAC=diacetylcurcumin) were much less cytotoxic (IC(50)=20-30 microM). Antioxidant capacity was decreased in VO(DAC)(2), Ga(DAC)(3), and In(DAC)(3), compared to vanadyl, gallium and indium curcumin, corroborating the importance of curcumin's free phenolic OH groups for scavenging oxidants, and correlated with reduced cytotoxic potential.