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The study aimed to characterize the antioxidant properties regarding the Sida cordifolia with special reference to its detailed biochemical analysis. The study revealed that chlorophyll A (0.9 ± 0.3 mg/g), total chlorophyll content (3.0 ± 0.7 mg/g), total carotenoid content (0.3 ± 0.1 mg/g), total soluble proteins (7.5 ± 0.1 mg/g), and total phenolic contents (5.6 ± 1.3 mg/g) were found highest in flower tissue of S. cordifolia. However, peroxidase (POD) contents (118 ± 31 units/g), superoxide dismutase (SOD) activity (64 ± 1.5 units/g) were maximum in the leaf tissues, while catalase (CAT) contents (133 ± 25 units/g), ascorbate peroxidase (APX) contents (145 ± 44 units/g) were also found more in the flowers of S. cordifolia rather than other parts. Our results conclude that leaves, stem, flower of S. cordifolia could be exploited in pharmacology due to presence of different antioxidants reflected in flower and leaf extract make them potent and profound therapeutic agents. [ABSTRACT FROM AUTHOR]

The ground state neutral geometries of some natural tropolones, i.e. stipitatonic acid (AF1), stipitalide (AF2), stipitaldehydic acid (AF3) and methyl stipitate (AF4) have been optimized by using Density Functional Theory (DFT) at B3LYP/6-31G*, B3LYP/6-31G**, B3LYP/6-31+G* and B3LYP/6-31+G** levels of theory. The excited state geometries of AF1-AF4 were optimized by adopting the Time Dependent Density Functional Theory (TDDFT) at the same levels of theory. The frequencies and cation species of AF1-AF4 were also computed at all the above mentioned levels of theory. We shed light on the electro-optical and molecular properties, e.g. energy gaps, highest occupied molecular orbitals, lowest unoccupied molecular orbitals, absorption wavelengths, electronegativity (χ), hardness (η), electrophilicity (ω), softness (S), electrophilicity index (ωi) and the radical scavenging activity (RSA). Hydrogen atom transfer (HAT) and one-electron transfer mechanisms have been discussed to shed light on the RSA. The smallest ionization potential and bond dissociation energy of AF4 are revealing that this compound would have more RSA than those of other counterparts. [ABSTRACT FROM AUTHOR]

The quinazolinone compounds (1 and 2) in this work were examined for their in vitro antibacterial activities against gram-positive (Staphylococcus aureus) and gram-negative bacteria (Klebsiella pneumonia, Proteus bacilli and Shigella flexneri). Compared to the reference antibiotic chloramphenicol, these compounds showed high antibacterial activities against studied strains with inhibition zones observation. The ground state geometries have been optimized by using density functional theory (DFT) at B3LYP/6-31G* level of theory. The absorption spectra have been calculated by using time dependent density functional theory (TDDFT) with and without solvent. The effect of different functionals (B3LYP, MPW1PW91, and PBE1PBE) on the absorption wavelengths has been studied. The ionization potential (IP), electron affinity (EA), energy gap (Egap), electronegativity (χ), hardness (η), electrophilicity (ε), softness (S) and electrophilicity index (εi) were computed and discussed. The nonlinear optical (NLO) properties vary by changing the theory (DFT to HF) or functional (B3LYP to CAM-B3LYP). The physicochemical parameters have been studied by quantitative structure-activity relationship (QSAR). The computed properties of investigated compounds have been compared with the Chloramphenicol as well as available experimental data. [ABSTRACT FROM AUTHOR]

The 2-{4-[2-benzylidenehydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 1), 2-{4-[2-(1- naphthylmethylene)hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 2) and 2-{4-[2-(9-anthrylmethylene)- hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 3) were synthesized by direct tricyanovinylation of hydrazones. The bathochromic shift in absorption spectra has been observed by increasing the solvent polarity. The FTIR spectra of these new dyes exhibited three important absorption bands. The first band centered near 3260 cm-1 in System 1 while 3208 cm-1 and 3211 cm-1 in System 2 and System 3 for the • NH absorption, respectively. The second band is a sharp absorption band in the region of 2212-2209 cm-1, which was attributed to the cyano group absorption. The third is an absorption band in the region of 1611-1603 cm-1 ascribed for the C=N. Density functional theory (DFT) calculation of relative energies, relative enthalpies and free energies shows that E isomers are the most stable except System 3 in which the most stable is Z isomers. The conformational energy profile shows two maxima near (-90 and 90°) while three local minima observed at (-180, 0 and 180) for N1-N2-C1-C2 torsional angle. The highest occupied molecular orbitals (HOMOs) are localized on the whole molecules while lowest unoccupied molecular orbitals (LUMOs) are distributed on the tricarbonitrile. [ABSTRACT FROM AUTHOR]

We synthesized a number of aniline derivatives containing acyl groups to compare their barriers of rotation around the N-CO groups. Geometry optimization for all the rotamers have been performed using density functional theory (DFT) at the B3LYP/6-31G** level of theory. For each stationary point we carried out vibrational frequency calculations at the same level to characterize their nature as minima or transition states. The methoxy group substituent on the benzene ring causes some changes in the C-C bond distances. We carried out potential energy surface scanning to find out all possible low-energy conformations, which would be used as the initial structure for further molecular calculations. There were only three kinds of conformations with local minimum potential energy and two transition states. The optimized bond lengths and bond angles are in better agreement with the experimental values. [ABSTRACT FROM AUTHOR]