Synthesis,Characterization, Biological Evaluation and DNA Interaction Studies of 4-Aminophenol Derivatives: Theoretical and Experimental Approach

In the present study, five 4-aminophenol derivatives (4-chloro-2-(((4-hydroxyphenyl)imino)methyl)phenol(S-1), 4-((4-(dimethylamino)benzylidene)amino)phenol(S-2), 4-((3-nitrobenzylidene)amino)phenol(S-3), 4-((thiophen-2-ylmethylene)amino)phenol(S-4) and 4-(((E)-3-phenylallylidene)amino)phenol(S-5)) were synthesized and characterized by FT-IR, ¹H-NMR, ¹³C-NMR and elemental analyses. The synthesized compounds were tested for their antimicrobial (Gram-positive and Gram-negative bacteria and Saccharomyces cervesea fungus) and antidiabetic (α-amylase and α-glucosidase inhibitory) activities. All the compounds showed broad-spectrum activities against the Staphylococcus aureus (ATCC 6538), Micrococcus luteus (ATCC 4698), Staphylococcus epidermidis (ATCC 12228), Bacillus subtilis sub. sp spizizenii (ATCC 6633), Bordetella bronchiseptica (ATCC 4617) and Saccharomyces cerevisiae (ATCC 9763) strains. The newly synthesized compounds showed a significant inhibition of amylase (93.2%) and glucosidase (73.7%) in a concentration-dependent manner. Interaction studies of Human DNA with the synthesized Schiff bases were also performed. The spectral bands of S-1, S-2, S-3 and S-5 all showed hyperchromism, whereas the spectral band of S-4 showed a hypochromic effect. Moreover, the spectral bands of the S-2, S-3 and S-4 compounds were also found to exhibit a bathochromic shift (red shift). The present studies delineate broad-spectrum antimicrobial and antidiabetic activities of the synthesized compounds. Additionally, DNA interaction studies highlight the potential of synthetic compounds as anticancer agents. The DNA interaction studies, as well as the antidiabetic activities articulated by the molecular docking methods, showed the promising aspects of synthetic compounds.     

Dynamics of shearing in flocculating fine sediment suspensions

The variability of rheological properties in cohesive sediment suspensions are studied and related to the flocculation process. It was found that the steady state shear stress increases exponentially with increasing sediment concentration and increases logarithmically by increasing the salinity of the suspension. The salinity dependence of the shear stress was correlated with changes in the floc-size. These results reflect the dominant influence of fluid-sediment interactions on the flocculation behavior of the suspension. An analytic model predicting shear stress as a function of the physical and electrochemical properties of the fine sediment suspension is developed.     

Characterization of banana peel by scanning electron microscopy and FT-IR spectroscopy and its use for cadmium removal

This study describes the use of banana peel, a commonly produced fruit waste, for the removal of Cd(II) from environmental and industrial wastewater. The banana peel was characterized by FT-IR and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis. The parameters pH, contact time, initial metal ion concentration and temperature were investigated and found to be rapid ( approximately 97% within 10min). The Langmuir adsorption isotherm was used to describe partitioning behavior for the system at room temperature. The value of Q(L) was found to be (35.52mgg(-1)) higher than the previously reported materials. The binding of metal ions was found to be pH-dependent with the optimal sorption occurring at pH 8. The retained species were eluted with 5mL of 5x10(-3)M HNO(3) with the detection limit of 1.7x10(-3)mgL(-1). Kinetics of sorption followed the pseudo-first-order rate equation with the rate constant k, equal to 0.13+/-0.01min(-1). Thermodynamic parameters such as Gibbs free energy at 303K (-7.41+/-0.13kJmol(-1)) and enthalpy (40.56+/-2.34kJmol(-1)) indicated the spontaneous and endothermic nature of the sorption process. The developed method was utilized for the removal of Cd(II) ions from environmental and industrial wastewater samples using flame atomic absorption spectrophotometer (FAAS).     

Marine natural products of fungal origin

In the search for novel and bioactive molecules for drug discovery, marine-derived natural resources are becoming an important research area. Over 15 marine-derived secondary metabolites are currently in human clinical trials. Terrestrial fungi have produced many therapeutically significant molecules. However, the potential of marine fungi has only been investigated to a limited extent. This review article contains 103 marine-derived fungal metabolites and 77 references.     

Homogenization of food samples for gamma spectrometry using tetramethylammonium hydroxide and enzymatic digestion

Journal of Radioanalytical and Nuclear Chemistry - We have developed a method of food sample preparation for gamma spectrometry involving the use of tetramethylammonium hydroxide (TMAH) and/or...     

Ferrite Nanocomposite Based Electrochemical Sensor: Characterization,Voltammetric and Amperometric Studies for Electrocatalytic Detection of Formaldehyde in Aqueous Media

Development of nanocomposite based electrochemical sensors for detection of toxic chemicals describes an environmentally benign strategy for monitoring the health of ecosystem. Herein, we reported in situ preparation of graphitic carbon nitride (g-C₃N₄) decorated Ag₂S/NiFe₂O₄ nanocomposite sensor by facile precipitation method. The electrochemical studies demonstrated efficient electrocatalytic activity of ternary nanocomposite pasted glassy carbon electrode (g-C₃N₄@Ag₂S/NiFe₂O₄/GCE) for selective detection of formaldehyde. Moreover, fabricated sensor exhibit rapid amperometric response with excellent selectivity, remarkable sensitivity (1681 μA mmol L⁻¹ cm⁻²) and lower detection limit (LOD: 1.63 μmol L⁻¹). It is noteworthy to mention that sensor exhibits good operational and long-term storage stability.     

Synthesis of Quinoxalinophenazine Derivatives and Reaction of 3,12-Dimethylbenzo[a]quinoxalino-[2,3-c]phenazine with Mercury(Ⅱ) Bromide: Spectral and Structural Characterization

A new series of quinoxalinophenazine derivatives were synthesized in good yields by the reaction of 2,3-dibromonaphthalene-1,4-dione with different aryl-1,2-diamines in DMF as solvent at 120~130℃ or under reflux conditions. 3,12-dimethylbenzo[a]quinoxalino[2,3-c] phenazine with bidentate character reacts with mercury(II) bromide to give suitable crystals. All products were confirmed by IR, 1H and 13 C NMR, and the metal complex by single-crystal X-ray method. The crystal(C24H16Br2HgN4, Mr = 720.82) belongs to the triclinic system, space group P1 with a = 10.186(6), b = 10.421(6), c = 11.470(7) , α = 98.670(7), β = 95.069(7), γ = 109.831(7)o, V = 1119.4(12) 3, Z = 2, Dc = 2.139 Mg/m3, μ = 10.46 mm-1, F(000) = 676, R = 0.043 and wR = 0.115 for 3982 observed reflections with I 2σ(I).     

LC-MS/MS-Based Metabolomic Profiling of Constituents from Glochidion velutinum and Its Activity against Cancer Cell Lines

This study aimed to establish the phytochemical profile of Glochidion velutinum and its cytotoxic activity against prostate cancer (PC-3) and breast cancer (MCF-7) cell lines. The phytochemical composition of G. velutinum leaf extract and its fractions was established with the help of total phenolic and flavonoid contents and LC-MS/MS-based metabolomics analysis. The crude methanolic extract and its fractions were studied for pharmacological activity against PC-3 and MCF-7 cell lines using the MTT assay. The total phenolic content of the crude extract and its fractions ranged from 44 to 859 µg GAE/mg of sample whereas total flavonoid contents ranged from 20 to 315 µg QE/mg of sample. A total of forty-eight compounds were tentatively dereplicated in the extract and its fractions. These phytochemicals included benzoic acid derivatives, flavans, flavones, O-methylated flavonoids, flavonoid O- and C-glycosides, pyranocoumarins, hydrolysable tannins, carbohydrate conjugates, fatty acids, coumarin glycosides, monoterpenoids, diterpenoids, and terpene glycosides. The crude extract (IC₅₀ = 89 µg/mL), the chloroform fraction (IC₅₀ = 27 µg/mL), and the water fraction (IC₅₀ = 36 µg/mL) were found to be active against the PC-3 cell line. However, the crude extract (IC₅₀ = 431 µg/mL), the chloroform fraction (IC₅₀ = 222 µg/mL), and the ethyl acetate fraction (IC₅₀ = 226 µg/mL) have shown prominent activity against breast cancer cells. Moreover, G. velutinum extract and its fractions presented negligible toxicity to normal macrophages at the maximum tested dose (600 µg/mL). Among the compounds identified through LC-MS/MS-based metabolomics analysis, epigallocatechin gallate, ellagic acid, isovitexin, and rutin were reported to have anticancer activity against both prostate and breast cancer cell lines and might be responsible for the cytotoxic activities of G. velutinum extract and its bioactive fractions.     

Thermal performance of micro-polymers containing nano-solid structures during transport phenomenon

Journal of Thermal Analysis and Calorimetry - The inclusion of solid nano-structures in the liquid changes its rheology and hence its thermal performance. This article considers the impact of...     

Recent advances in microchip electrophoresis for analysis of pathogenic bacteria and viruses

Life-threatening diseases, such as hepatitis B, pneumonia, tuberculosis, and COVID-19, are widespread due to pathogenic bacteria and viruses. Therefore, the development of highly sensitive, rapid, portable, cost-effective, and selective methods for the analysis of such microorganisms is a great challenge. Microchip electrophoresis (ME) has been widely used in recent years for the analysis of bacterial and viral pathogens in biological and environmental samples owing to its portability, simplicity, cost-effectiveness, and rapid analysis. However, microbial enrichment and purification are critical steps for accurate and sensitive analysis of pathogenic bacteria and viruses in complex matrices. Therefore, we first discussed the advances in the sample preparation technologies associated with the accurate analysis of such microorganisms, especially the on-chip microfluidic-based sample preparations such as dielectrophoresis and microfluidic membrane filtration. Thereafter, we focused on the recent advances in the lab-on-a-chip electrophoretic analysis of pathogenic bacteria and viruses in different complex matrices. As the microbial analysis is mainly based on the analysis of nucleic acid of the microorganism, the integration of nucleic acid-based amplification techniques such as polymerase chain reaction (PCR), quantitative PCR, and multiplex PCR with ME will result in an accurate and sensitive analysis of microbial pathogens. Such analyses are very important for the point-of-care diagnosis of various infectious diseases.