Dimethyl Sulphoxide Water Research Articles

In Vitro Antimicrobial Activity of Crude Leaf Extracts from Aloe secundiflora, Bulbine frutescens, Vernonia lasiopus and Tagetes minuta against Salmonella typhi

Four medicinal plants leaves were investigated to evaluate their antibacterial potential of the methanol extracts against Salmonella typhi by disc diffusion method. The methanol extract from Aloe secundiflora showed strong antibacterial activity against a clinical isolate of Salmonella typhi at low concentrations (5.5 mg/ml) as compared to Bulbine frutescens extract (8.8 mg/ml). The minimum inhibitory concentration ranged from 5 mg/ml - 9 mg/ml whereas the maximum bactericidal concentration range from 7 mg/ml - 11 mg/ml. The standard antibiotic used was ciprofloxacin (15 μg/ml) was used as a positive control while dimethyl sulphoxide and distilled water were used as the negative control. The extracts were preliminary screened for the presence of secondary metabolites to determine the presence of flavonoids, alkaloids, tannins and saponins. The results supported the use of the medicinal plants in the treatment of infections caused by Salmonella typhi.

Antimicrobial Potency of Methanolic Leaf Extracts from Selected Medicinal Plants against Staphylococcus aureus

The main aim of the study was to test for the antimicrobial potency of Aloe secundiflora, Bulbine frutescens, Tagetes minuta and Vernonia lasiopus against Staphylococcus aureus. All the plants showed a pronounced antimicrobial activity against Staphylococcus aureus with Tagetes minuta being the most active at low concentrations (MIC 8.9 mg/ml; MBC 10.0 mg/ml) whereas Vernonia lasiopus showing less activity (MIC 12.2 mg/ml; MBC 14.2 mg/ml). The efficacy test was carried out using the disc diffusion method. The standard antibiotics used were ciprofloxacin (5 μg/ml) and vancomycin (3 μg/ml) showed significant antimicrobial activity by producing zones of inhibition of 22 mm and 25 mm respectively. Dimethyl sulphoxide and distilled water were used as negative control. The extracts from the plants were also screened for the presence of phytochemicals with the results showing the presence of flavonoids, alkaloids, tannins and saponins in all the extracts. The study suggested that the selected medicinal plants can be used effectively in the treatment of bacterial infection caused by Staphylococcus aureus.

In vitro Antifungal activity of leaf extracts from Aloe secundiflora, Bulbine frutescens, Vernonia lasiopus and Tagetes minuta against Candida albicans

Crude leaf extracts from medicinal plants were screened for in vitro antifungal properties against clinical isolate of Candida albicans. The antifungal test was carried out using the Kirby Bauer method. All the extracts from the plants tested showed antifungal activity against clinical isolate of Candida albicans with the extract from Vernonia lasiopus being more active as compared to the others. The minimum inhibitory concentration ranged from 4.0 to 8.9 mg/ml. The standard antifungal used as positive control was fluconazole (15 μg/ml) whereas dimethyl sulphoxide and distilled water were used as negative control. Preliminary screening for the presence of phytochemicals was also done to determine if there was presence of any, flavonoids, saponins, tannins and alkaloids.

Relation between the Surface Tension and Roughness of the Intrinsic Liquid Surface

Previously published computer simulation data concerning the surface tension and surface roughness of various different liquid systems (i. e., binary water-methanol and water-dimethyl sulphoxide (DMSO) mixtures, water-poly-(ethylene-oxide) systems containing adsorbed sodium dodecyl sulphate, and room temperature ionic liquids) are re-analysed in order to find a relation between these quantities. It is found that the amplitude of the molecularly wavy liquid surface is inversely proportional to the logarithm of the surface tension while no clear correlation between the periodicity of the wavy surface and the surface tension is observed. It is also seen that the determination of the roughness parameters in a way analogous with the Langmuir formalism results in considerably more robust values than when an extra parameter is introduced in the procedure using a formula in analogy with the Langmuir-Freundlich isotherm.

Water as a solute in aprotic dipolar solvents: 3. D 2O–H 2O solute isotope effects on the enthalpy of water dissolution in dimethylsulphoxide, N, N-dimethylformamide and N, N-dimethylacetamide at 298.15 K

The enthalpies of solution of ordinary (H 2O) and heavy (D 2O) water in dimethylsulphoxide (DMSO), N, N-dimethylformamide (DMF) and N, N-dimethylacetamide (DMA) have been measured using an isoperibol sealed calorimeter at 298.15 K. Standard (at infinite dilution) enthalpies of solution and solvation, together with D 2O–H 2O solute isotope effects on the quantities in question, were calculated. The enthalpies of solution of water H/D isotopologues have been found to be negative by sign and increasing in magnitude on going from DMF to DMSO and DMA. The corresponding positive solute isotope effects are very insignificant and slightly increase in a consequence: DMF < DMSO ≤ DMA. It has been concluded that the enthalpy-isotopic effects of water solvation are qualitatively connected with the donor-accepting and structure-packing properties of the aprotic dipolar solvents compared.

Rotational Diffusion of Coumarins in Aqueous DMSO

The rotational dynamics of four structurally similar polar molecules viz., coumarin 440, coumarin 450, coumarin 466 and coumarin 151 has been studied in binary mixtures comprising of dimethyl sulphoxide and water at room temperature using the steady state fluorescence depolarization method and time correlated single photon counting technique. The binary mixtures are characterized by the fact that at a particular composition the viscosity (eta) of the solution reaches a maximum value that is higher than the viscosities of either of the two co-solvents. The dielectric properties of the solution change across the composition range and the qualitative features of the solvent relaxation dynamics in complex systems are known to differ from those in simple solutions. A hook type profile of rotational reorientation time (tau(r)) vs viscosity (eta) is obtained for all the solutes in dipolar aprotic mixture of dimethyl sulphoxide-water, with the rotational reorientation times being longer in organic solvent-rich zone, compared to the corresponding isoviscous point in water-rich zone due to strong hydrogen bonding. Fluorescence lifetimes as well as rotational reorientation times are sensitive to the composition of the binary solvent system under study than to the viscosity suggesting the importance of local structure. The results are discussed in the light of hydrodynamic and dielectric friction models.

Tyrosinase-Inhibitory Activity in Some Species of the Lichen Family Graphidaceae

Twenty-five species of the lichen family Graphidaceae have been investigated for tyrosinase-inhibitory activity. Tyrosinase-inhibiting material was extracted with solvents methanol, acetone, ethanol, dimethyl sulphoxide in water, and with water only. Methanol has been found to be suitable for extracting adequate amounts of tyrosinase-inhibiting component from the natural thallus. The lichen species such as Graphina glaucorufa, Graphina multistriata, Graphina salacinilabiata, Graphis assamensis, Graphis nakanishiana, and Phaeographopsis indica, have shown inhibition of tyrosinase over a range of 30-78%. Half-inhibiting concentration (IC(50), microg/ml) has been found to be much lower than the standard tyrosinase inhibitors and thus can compete with other commercially available tyrosinase inhibitors. The extracts of these species have been found to be stable at 4 degrees C.

Studies of the Accelerating Effect of Thiourea on the Reduction of ZnII in Mixed Water–Organic Solvents at the Mercury Electrode

The accelerating influence of thiourea on the Zn II /Zn(Hg) reduction process was investigated in the following mixed solutions: water-methanol (MeOH); water-ethanol (EtOH); water-dimethyl sulphoxide (DMSO); water-dimethylformamide (DMF). It was suggested that the dominant role in acceleration of the electrode process is played by the composition of the activated complex, which is presumably composed of solvent molecules and thiourea molecules adsorbed on to the electrode. A mechanism was proposed for the process occurring.

Atomic force microscopy studies on the surface morphology of {1 1 1} tabular AgBr crystals

Both ex situ and in situ atomic force microscopy have been applied to study the {1 1 1} and {1 0 0} surfaces of tabular silver bromide crystals grown from dimethyl sulphoxide–water solutions. This resulted in observations of monosteps, macrosteps, etch pits, pinning of steps and nucleated crystals showing twin planes. These examinations indicate that the growth and dissolution of both the {1 0 0} and the polar {1 1 1} faces occur via steps in many configurations. The registered 40-nm distance between the parallel twin planes of the nucleated crystals agrees with transmission electron microscopy measurements done on tabular crystals grown by the industrial double-jet precipitation method.

Molecular dynamics simulations of sodium chloride solutions in water–dimethyl sulphoxide mixtures: Potentials of mean force and solvation structures

Five solutions of sodium chloride in mixtures of water and dimethyl sulphoxide (DMSO) have been simulated using the conventional molecular dynamics technique. The potentials of mean force (PMFs) of the sodium chloride ion pair in the presence of the five water–DMSO mixtures with DMSO mole fractions (xDMSO) of 0.10, 0.21, 0.35, 0.48 and 0.91 have been computed. The derived PMFs have been confirmed by the long time dynamical ion-pair trajectories. The solvation structures of the ions in the presence of these mixtures have been analyzed using the ion-solvent radial distribution functions and the corresponding integration numbers. It has been found that the Na+ ion is always preferentially solvated by the water molecules in all the water–DMSO solvent mixtures. The Cl− ion is slightly preferred by the DMSO molecules in these mixed solvents.

Solvation effects of dimethyl sulphoxide on the structure of phospholipid bilayers

The effect of dimethylsulphoxide (DMSO), a widely used solvent in life sciences to stabilise biological membrane structures at low temperatures, on the structure of model membranes has been examined using X-ray diffraction methods. It was found that increasing concentrations of DMSO in water caused a progressive decrease in lamellar repeat spacings of multilamellar dispersions of both saturated and mono-unsaturated phosphatidylcholines. The lamellar repeat spacings were temperature-dependent but with dispersions in excess 40 wt.% DMSO, repeat spacings were less than that of the phospholipids in the dry state. One dimensional electron density profiles of the lipid bilayers were calculated and the thickness of the phosphatidylcholine bilayers were determined. It was inferred from the data that the thickness of liquid-crystal bilayers decreases in the presence of DMSO and that the DMSO molecules penetrate between the polar head groups of the phosphatidylcholines, resulting in an increase in area occupied by phospholipid at the bilayer surface.

Bifunctional etherification of a bead cellulose for ligand attachment with allyl bromide and allyl glycidyl ether

Efficient carboxymethylation of a bead cellulose was achieved with dimethyl sulphoxide–water mixtures but low activation levels were found with epoxidation reagents. The highest activation levels were obtained with allyl bromide and allyl glycidyl ether. This was attributed to the relative inertness of the allyl group towards water and cellulose, limiting hydrolysis and crosslinking. Advantages over epoxidation chemistry for bead cellulose were efficient reagent use, reproducible activation up to high levels and specificity of matrix modification. Predictable activation was obtained and facile titration methods were developed. Efficient activations of agarose and methacrylate matrices were also obtained with the allyl reagents.

Transient electric birefringence study of agarose aggregates in water‐dimethyl sulphoxide mixtures

AbstractThe dynamical behavior of agarose aggregates in a mixture of water and dimethyl sulphoxide (DMSO) has been investigated using a Transient Electric Birefringence (TEB) set up. Different agarose concentrations for different water/DMSO proportions were considered. The relaxation of the birefringence curves can be fitted with a stretched exponential of the form Δn(t) = Δn0 exp(‐(Dt)0.5). The exponent 0.5 suggests a high polydispersity of the aggregates. The rotational diffusion coefficient, D, depends strongly on the water/DMSO proportion. For small values of the applied electric field it presents a maximum for a water volume fraction equal to 0.5. A strong dependence of D on the applied electric field is also observed. However, the same kind of behavior as for weak fields is recovered when a subtle representation of the data is used. Differential Scanning Calorimetry (DSC) results also show a maximum in the temperature of fusion of the aggregates for a water volume fraction of 0.5. This set of results suggest strongly that « complexes » of water/DMSO/agarose are formed in the mixture and that the process of aggregate formation is more « efficient » for a water/DMSO mixture of same proportions.

Local DMSO treatment of macular and papular amyloidosis

Macular amyloidosis (MA) and lichen amyloidosus (LA) are the two major variants of the primary cutaneous amyloidoses which present with severe and therapy resistant itching. Various therapeutic modalities such as antihistamines, intralesional injection or topical application of corticosteroids, etretinate, UVB irradiation and dermoabrasion have been employed with variable success. Recently, in a few case reports authors have observed encouraging beneficial clinical effects by using topical dimethyl sulphoxide (DMSO). In our study 10 patients with either MA or LA or biphasic amyloidosis were treated with a 50% solution of DMSO in water. 9 of them showed marked clinical improvement at the end of 6-20 weeks of treatment. Degranulation and depletion of the mast cells by DMSO is the most probable explanation for the rapid improvement of itching beginning within the first week of therapy. Remarkable flattening of the lichenoid papules which was obtained within 11 weeks of treatment is interpreted as a result of the improvement of itching and the related scratch effect. Histological examination after treatment revealed no disappearance of amyloid deposits in the papillary dermis. In the follow-up period relapses of itching and papules were observed. Therefore further studies are needed to find out the optimal procedure of therapy.

Heat effects and water sorption by human serum albumin on its suspension in water-dimethyl sulphoxide mixtures

The heat effects on suspending solid human serum albumin (HSA) in various water-dimethyl sulphoxide (DMSO) mixtures were measured calorimetrically at 298 K. The isotherm of the water sorption for HSA suspended in the water-DMSO mixtures was also measured. The recording of the calorimetric heat effects exhibits endothermic and exothermic peaks. The endothermic heat effects were estimated graphically from the calorimetric curves. These values are shown to obey the Langmuir isotherm of the water sorption. The quasi-thermodynamic constant of water adsorption (1.2 ± 0.3 M −1) and the monolayer formation energy (−20.1 ± 1.0 J g −1) were estimated from the calorimetric data with the Langmuir model. The adsorption constant (0.16 ± 0.08 M −1) was evaluated from fitting the water sorption isotherm by the Langmuir model also. There is a divergence between the latter constant and the adsorption constant obtained from the calorimetric data. It appears that the processes accompanying the exothermic heat evolution influence the HSA's ability to bind water. The surface area of the water monolayer was also calculated from the fitting of the water sorption isotherm. It essentially exceeds the recognised values for proteins estimated from the data for water vapour sorption. The aqueous solubility of the protein after the exposure of the HSA preparation in the water-DMSO mixtures is also essentially decreased. Hence, changes in the protein-protein interactions of a diverse nature might accompany the exothermic heat evolution on suspending HSA in water-DMSO mixtures.

Lithium isotope effects in water-dimethyl sulphoxide mixed-solvent ion-exchange chromatography

Cation-exchange chromatography of lithium was successfully carried out to investigate the lithium isotope effects in water-dimethyl sulphoxide (DMSO) mixed-solvent ion-exchange systems at 25°C. The value of the separation factor minus 1 (ε) was 1.4 · 10 −3 to 2.2 · 10 −3; ε had a maximum value of 2.2 · 10 −3 when the molar fraction of water in the solution phase, x water, was about 0.57, and decreased as x water deviated from this value. A consideration based on a theory of isotope distribution between two phases indicated that DMSO was slightly preferentially fractionated into the ion-exchange phase rather than into the solution phase.

Studies on the equilibria of o-phthalic and phosphoric acids in mixed dimethyl sulphoxide—water mixture

The secondary dissociation constants of o-phthalic and phosphoric acids have been determined in 50% w/w dimethyl sulphoxide—water from reversible emf measurements of the cell of the type: Pt, H 2 (1 atm), M 2A (m), MHA (m), MCl, AgCl; Ag at different temperatures (288.15–308.15 K) and at different ionic strengths. To minimize the unsteadiness in potential measurements palladium-coated platinum electrodes have been used. The large set of such emf values has been analysed in terms of a multi-linear regression method recommended in recent IUPAC documents. The thermodynamic values Δ G°, Δ H°, Δ S°, for the respective equilibria were estimated. The possibility of using these acids as a basis for some buffer solutions in 50% dimethyl sulphoxide (Me 2SO)-water mixture is discussed.

A neutron diffraction study of dimethyl sulphoxide–water mixtures

Neutron diffraction with hydrogen/deuterium isotope substitution is used to investigate the structure of water in concentrated dimethyl sulphoxide (DMSO) aqueous solutions. Partial structure factors and pair correlation functions involving the hydrogen atom on the water molecule are determined. Water structure is not found to be strongly affected by the presence of DMSO. However, the percentage of water molecules which hydrogen bond to themselves is substantially reduced compared to pure water, with a large proportion of the hydrogens available for bonding associated with the lone pairs on the DMSO. These experimental findings are in good agreement with the assumptions made in the simple mean-field type model for hydrogen-bonded mixtures, developed by Luzar [J. Chem. Phys. 91, 3603 (1989)]. A general scheme for analyzing experimental data on the HH and OH pair correlation functions in terms of coordination numbers is presented. The hydrogen–hydrogen correlation in the solvent (water) is also used to discuss the interparticle correlations between solute (DMSO) particles.

Solvolysis of 1,1‐diphenylethyl derivatives in highly aqueous media. Reaction via ion pairs

AbstractSolvolysis of 1,1‐diphenyl‐1‐X‐ethane (1‐X) [X = 4‐nitrobenzoate (PNB), 3,5‐dinitrobenzoate (DNB), AcO, MeOH+, EtOH+ or H2O+] was studied in 20 vol% dimethyl sulphoxide in water, in which specific salt effects are very small, and in 25 vol% acetonitrile in water. Substrates with negatively charged leaving groups yield more elimination product 1,1‐diphenylethene (3) than those with uncharged groups, indicating the intermedicacy of ion pairs. Thus, three times more alkene is formed in the reactions of the substrates 1‐OAc and 1‐PNB than in the acid‐catalysed hydrolysis of 1‐OMe and 1‐OAc. The substitution products may be formed via the solvent‐equilibrated carbocation since the measured nucleophilic selectivities are very similar with different leaving groups.

Ionization constants of 5‐furylmethylenehydantoins and 5‐thienylmethylenehydantoins in 80% (w/w) dimethyl sulphoxide–water at 25°C

AbstractThe ionization constants of sixteen 5‐furylmethylenehydantoins and 5‐thienylmethylenehydantoins were measured in 80% (w/w) dimethyl sulphoxide–water solvent at 25°C. The effects of the 2‐/3‐furyl and 2‐/‐3‐thienyl rings and the effects of configuration and conformation on acidity are discussed. The very low acidity of (Z)‐5‐(2‐furyl)methylene‐3‐methylhydantoin suggests the possibility of some weak intramolecular interaction between the proton at N‐1 and the 2‐furyl oxygen in the s‐cis conformation.