A multi-spectroscopic and molecular docking approach for DNA/protein binding study and cell viability assay of first-time reported pendent azide bearing Cu(II)-quercetin and dicyanamide bearing Zn(II)-quercetin complexes

In the current study, one new quercetin-based Zn(II) complex [Zn(Qr)(CNNCN)(H2O)2] (Complex 1) which is developed by condensation of quercetin with ZnCl2 in the presence of NaN(CN)2 and Cu(II) complex [Cu(Qr)N3(CH3OH)(H2O)] (complex 2) which is developed by the condensation reaction of quercetin and CuCl2 in presence of NaN3, are thoroughly examined in relation to their use in biomedicine. The results of several spectroscopic studied confirm the structure of both the complexes and the Density Functional Theory (DFT) study helps to optimize the structure of complex 1 and 2. After completion of the identification process, DNA and Human Serum Albumin (HSA) binding efficacy of both the investigated complexes are performed by implementing a long range of biophysical studies and a thorough analysis of the results unveils that complex 1 has better interaction efficacy with the macromolecules than complex 2. The binding efficacy of complex 1 is comparatively higher towards both macromolecules because of its pure groove binding mode during interaction with DNA and the presence of an extra H-bond during connection with HSA. The experimental host-guest binding results is fully validated by molecular docking study. Interestingly complex 1 shows better antioxidant properties than complex 2, as well as quercetin, and it has strong anticancer property with minimal damage to normal cells, which is proved by the MTT assay study. Better DNA and HSA binding efficacy of 1 may be the reason for the better anticancer property of complex 1.

DNA/Protein Binding and Apoptotic-Induced Anticancer Property of a First Time Reported Quercetin-Iron(III) Complex Having a Secondary Anionic Residue: A Combined Experimental and Theoretical Approach

A new quercetin-based iron(III) cationic complex [Fe(Qr)Cl(H₂O)(MeO)] (complex 1) is created in the current study by condensation of quercetin with ferric chloride in the presence of Et₃N. Comprehensive spectroscopic analysis and conductometric measurement are used to pinpoint complex 1. The generated complex's +3-oxidation state has been verified by electron paramagnetic resonance (EPR) research. Density functional theory analysis was used to structurally optimize the structure of complex 1. Before biomedical use, a variety of biophysical studies are implemented to evaluate the binding capacity of complex 1 with DNA and human serum albumin (HSA) protein. The findings of the electronic titration between complex 1 and DNA, as well as the stunning fall in the fluorescence intensities of the HSA and EtBr-DNA/DAPI-DNA domain after complex 1 is gradually added, give us confidence that complex 1 has a strong affinity for both macromolecules. It is interesting to note that the displacement experiment confirms partial intercalation as well as the groove binding mechanism of the title complex with DNA. The time-dependent fluorescence analysis indicates that after interaction with complex 1, HSA will exhibit static quenching. The thermodynamic parameter values in the HSA-complex 1 interaction provide evidence for the hydrophobicity-induced pathway leading to spontaneous protein-complex 1 interaction. The two macromolecules' configurations are verified to be preserved when they are associated with complex 1, and this is done via circular dichroism spectral titration. The molecular docking investigation, which is a theoretical experiment, provides complete support for the experimental findings. The potential of the investigated complex to be an anticancer drug has been examined by employing the MTT assay technique, which is carried out on HeLa cancer cell lines and HEK-293 normal cell lines. The MTT assay results validate the ability of complex 1 to display significant anticancer properties. Finally, by using the AO/PI staining approach, the apoptotic-induced cell-killing mechanism as well as the detection of cell morphological changes has been confirmed.

17β-estradiol and testosterone sorption in soil with and without poultry litter

17β-estradiol and testosterone are naturally occurring steroids that co-occur in poultry litter. The effects of litter on sorption of these hormones to soil are not known. Sorption isotherms were developed for C-labeled testosterone and H-labeled estradiol in a Cecil sandy clay loam with and without poultry litter addition. The effect of applying the hormones alone (single-sorbate) or together (multisorbate) was also investigated. C-testosterone sorption in soil increased from 2 to 48 h and remained relatively constant thereafter. H-estradiol sorption in soil was relatively constant from 2 to 24 h and then decreased to 72 h. These differences may reflect transformation of the parent hormones to products with different solid-phase affinity. The maximum sorption coefficient () in soil for C-testosterone (20.2 mL g) was similar to that for H-estradiol (19.6 mL g) in single-sorbate experiments. When hormones were applied together, sorption of both hormones in soil decreased, but the C-testosterone (12.5 mL g) was nearly twice as large as the H-estradiol (7.4 mL g). We propose this resulted from competition between the hormones and their transformation products for sorption sites, with C-testosterone and its expected transformation product (androstenedione) being better competitors than H-estradiol and its expected transformation product (estrone). When poultry litter was mixed with soil, sorption increased for H-estradiol but decreased for C-testosterone. This may have been because poultry litter slowed the transformation of parent hormones. Our results show that poultry litter could have important effects on the mobility of estradiol and testosterone.

Antinociceptive action of GABA-mimetic agent--N-phthaloyl GABA

N-phthaloyl GABA (P-GABA), a nonselective GABA-ergic drug, showed positive analgesic response in four different models in mice, viz-tail immersion, tail clip, hot plate and writhing-induced by acetic acid. Antinociceptive ED50 (ip in mice) of P-GABA was lowest in tail immersion method (ED50 = 24.27, mg/kg). Though pethidine (10 mg/kg, ip) significantly potentiated the antinociceptive action of P-GABA (20 mg/kg, ip), pretreatment of naloxone (5 mg/kg, im) did not influence the same. Pretreatment with atropine (10 mg/kg, im), picrotoxin (0.08 mg/kg) and 3-mercaptopropionic acid (2 mg/kg) reduced the antinociceptive action of P-GABA significantly. But pretreatment with bicuculline (0.4 mg/kg), a specific GABA antagonist, did not reduce the antinociceptive action of P-GABA.

Estimation of domain length of chicken erythrocyte chromatin

Chromatin of chicken erythrocyte nuclei was extracted by digestion with micrococcal nuclease. The length distribution of the soluble chromatin was determined by gel electrophoresis and electron microscopy. These results were fitted with a theoretical distribution which was an outcome of the domain model proposed by Igo-Kemenes and Zachau (Igo-Kemenes, T. and H.G. Zachau (1977) Cold Spring Harbour Symp. Quant. Biol. 42, 109-118). A domain length of 45 kbp was obtained.