Synthesis of 17α-substituted ethynylestradiols: Potential ligands for drug vectors

17α-substituted ethynylestradiols, derived from estrone, were converted to their corresponding 17α-(bromo- or iodo-propargyl)estrone intermediates. Nucleophilic substitution onto these moieties with malonate diester followed by hydrolysis and complexation with cis-Pt(Me₂en)I₂ (Me₂en = N,N-dimethylethylenediamine) gave cis-Pt(Me₂en)(2-(3-(17β-estradiol-17α-yl)-prop-2-ynyl)malonato) 7, thus demonstrating that these estrogen-derived compounds can be used to synthesize stable Pt(II) complexes. The 3-(17β-estradiol-17α-yl)-prop-2-ynyl-1-sulfanylethylthiol 23 was also prepared.     

Influence of pH on the culture of Scenedesmus obliquus in olive-mill wastewater

Olive-mill wastewater (OMW), an agro-industrial by-product from olive-oil milling (with the three-phase extraction method), was used experimentally as 5% (v/v) of the medium to culture Scenedesmus obliquus CCAP 276/3A. The characterization of the wastewater indicated a nitrogen deficiency. The highest specific growth rate of S. obliquus μ_m = 0.022 h⁻¹ was found when the medium was maintained at a constant pH value of 7.0. The biomass productivity, P_b was determined by the influence of pH on the speciation of the dissolved CO₂. The greatest elimination of BOD₅ occurred at extreme pH values. The protein and chlorophyll contents presented a maximum value close to pH = 7.0. The highest crude-protein content in the biomass was 25.6%. The polyunsaturated and essential fatty acids presented a clear trend to increase with the pH, at pH 9.0, representing 26.2 and 19.4%, respectively, of the total fatty-acid content of the biomass.     

Adsorption of trypsin on commercial silica gel

The immobilization of trypsin onto various commercial silica gels was studied. Silica gels were used directly and characterized by mercuric porosimetry. Agitation rates (100–740 rpm) and particles size (35–75 to 250–500 μm) of silica gels did not affect the trypsin immobilization capacity. The pore size (3 to 15 nm) is a limiting factor of the trypsin adsorption onto the mesopores structure of silica gels. The adsorption of trypsin was determined as a function of their initial concentration and multilayer formed at high trypsin concentration.     

Influence of temperature on growth of Scenedesmus obliquus in diluted olive mill wastewater as culture medium

Scenedesmus obliquus can help to reduce the environmental impact of industrial olive mill wastewater from olive oil extraction in the three‐phase system. This work examines the effect of temperature changes (288–308 K) on algal growth, culture medium, and biochemical composition of S. obliquus. The maximum specific growth rate of 0.024 h^?1 occurred at an optimal temperature of 302.7 K. The apparent activation energies of cell growth and cell death were determined as 61.8 and 142.8 kJ/mol, respectively. At the end of culture the percentages of pigments, proteins, and carbohydrates were greater at the two ends of the temperature range studied, as it was also observed for the maximum elimination of biochemical oxygen demand (BOD₅). The mono‐ and polyunsaturated fatty acid content of the biomass was greater at the lowest temperature used (288 K).     

Use of industrial wastewater from olive-oil extraction for biomass production of Scenedesmus obliquus

The use of rinse water (RW) from two-phase centrifugation in the olive-oil extraction industry has been studied in relation to the production of the microalga Scenedesmus obliquus (CCAP 276/3A). The characterization of the wastewater indicates that it is N deficient. The highest value of maximum specific growth rate, 0.044 h(-1) was registered in the culture with 5% RW. However, biomass productivity proved greater in the culture with 100% RW. The specific growth rates were adjusted to a model of inhibition by substrate. The content in normalized chlorophyll diminished with the duration of the cultures, reaching a minimum CHL'(min) value, which showed an inhibition type similar to that of the specific growth rate. The yield in protein indicates that the cultures were limited by N to approximately 50% RW. The greater specific rate of protein synthesis during the exponential phase was 3.7 mg/gh to 50% RW. It was found that the composition of the lipid fraction of the biomass depended on the percentage of wastewater used as the nutrient medium, reaching the highest percentages of monounsaturated, polyunsaturated, and essential fatty acids in the culture with 100% RW.     

Synthesis, multinuclear magnetic resonance and crystal structures of Pt(II) complexes containing amines and bidentate carboxylate ligands

A novel synthetic method for the synthesis of the complexes cis-Pt(amine)₂R(COO)₂ is compared to two other methods involving the use of either barium dicarboxylate or sodium carboxylate. Pt(II) compounds with monodentate and bidentate amines were studied. The reaction involves the use of a silver dicarboxylato complex, which is the intermediate in the new synthetic procedure. The crystal structure of the silver intermediate with the ligand 1,1-cyclobutanedicarboxylate (1,1-CBDCA) was determined by X-ray diffraction. The crystal Ag₂(1,1-CBDCA) has a very interesting 3-D extended structure. The complexes cis-Pt(amine)₂R(COO)₂ were studied in solution by multinuclear (¹H, ¹³C and ¹⁹⁵Pt) magnetic resonance spectroscopy, but the solubilities are very low. D₂O was found to be the best solvent. In ¹⁹⁵Pt NMR, the complexes containing bidentate amines forming five-membered chelates were observed at higher fields than those containing monodentate amines. The resonances of the NH₃ compounds were also found at lower fields than the primary amine complexes. All the dicarboxylato ligands form six-membered chelates except 1,2-CBDCA, whose Pt(II) compounds were observed at lower fields than the others. The crystal structures of Pt(en)(1,1-CBDCA), Pt(Meen)(1,1-CBDCA) and Pt(en)(benzylmalonato) were confirmed by X-ray diffraction methods. Several compounds are disordered. The crystals are stabilized by intermolecular hydrogen bonds between the -NH₂ groups and the carboxylato O atoms.     

Synthesis and study of Pt(II)-aromatic amines complexes of the types cis- and trans-Pt(amine)2(NO3)2 and cis-Pt(amine)2(R(COO)2)

Complexes of the types cis- and trans-Pt(amine)₂(NO₃)₂ with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear magnetic resonance spectroscopies. The cis complexes could be synthesized pure only with the amines of the type Ph-R-NH₂ (R = alkyl), while pure trans compounds were synthesized with all the studied amines. In ¹⁹⁵Pt NMR spectroscopy, the dinitrato complexes of the amines Ph-R-NH₂ were observed around −1700 ppm for the cis isomers and at about −1580 for the trans complexes. For the other amines, where a phenyl ring is directly attached to the amino group, the signals were observed at lower fields, −1528 ppm for cis-Pt(PhNH₂)(NO₃)₂ and around −1450 ppm for all the trans isomers. There is a linear relationship between the δ(Pt) of the Pt(amine)₂(NO₃)₂ complexes and the pK_a of the protonated amines. The coupling constants ²J(¹⁹⁵Pt-¹HN) are larger in the cis compounds (ave. 76 Hz) than in the trans isomers (ave. 63 Hz). The complexes cis-Pt(amine)₂(R(COO)₂) with bidentate dicarboxylato ligands were also synthesized and characterized mainly by IR spectroscopy. The compounds apparently decompose in DMF and are too insoluble in other solvents for solution studies.     

Mixotrophic culture of Chlorella pyrenoidosa with olive-mill wastewater as the nutrient medium

With olive-mill wastewater (`alpechín') as the nutrient medium, theinfluence of specific rate of aeration and initial alpechín concentrationhave been analysed in cultures of Chlorella pyrenoidosa, exposed bothto continuous and intermittent illumination (12/12 h light/dark cycles). The stirring rate in the bioreactor, as well as pH and temperature werefixed previously at 180 rpm, 6.5 and 30 ^°C, respectively. Themaximum specific growth rate (_m) and biomass productivity(b) were determined as kinetic parameters. The chlorophyll, protein andcarbohydrate contents were evaluated, as well as the fatty-acid compositionof the lipid fraction. The experimental conditions most conducive to abalanced biomass composition with regard to proteins and lipids were: initial alpechín concentration of 10% (v/v), continuous illumination,and aeration rate of 1 L (litre cell suspension)^-1 min^-1. Under these conditions, the highest values of _m and b wereclose to 0.04 h^-1 and 1.4 10^-3 g L^-1 h^-1, respectively.     

A novel approach towards studying non-genotoxic enediynes as potential anticancer therapeutics

A novel uracil-containing enediyne was synthesized by the fusion at N(1) and N(3) of uracil with an 11-membered cyclic enediyne. Compound was found to be stable against cycloaromatization at 80 degreesC. Thus, it did not cause DNA-damage. Unlike other alkylated uracil derivatives 2--6, highly strained uracil-containing enediyne was reacted with methyl thioglycolate at 25 degreesC to produce uracil () and linear enediyne. This reactivity toward a sulfhydryl group may play a significant role in the mechanism by which compound directed its cytotoxicity toward tumor cell lines. Tumor cells were found to be more susceptible to enediyne than normal human embryonic lung cells. A combination of with adriamycin or 1-(beta-D-arabinofuranosyl)cytosine resulted in synergistic anticancer activity against murine L1210 and P388 leukemias, Sarcoma 180, and human CCRF--CEM lymphoblastic leukemia. After treatment of Molt-4 cells with uracil-containing enediyne, light microscope examination demonstrated the presence of cell shrinkage and nuclear segmentation. Treatment of cultured Molt-4 human leukemia cells with enediyne resulted in a time-dependent depletion of glutathione (GSH) whereas the exposure of the cells to the GSH precursor N-acetylcysteine (NAC) resulted in a substantial suppression of this effect. As such, involvement of GSH depletion in the process of apoptosis may explain the mechanism of action of non-genotoxic enediyne against malignant tumor cell lines.