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Natural Products from the Amazon Region as Potential Antimicrobials
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Josiane E. A. Silva, Iasmin L. D. Paranatinga, Elaine C. P. Oliveira, Silvia K. S. Escher, Ananda S. Antonio, Leandro S. Nascimento, Patricia P. Orlandi, Valdir F. Veiga-Júnior
While oleoresins are specific and rare natural mixtures and EOs can only be obtained (industrially) by hydrodistillation, there are a large number of different ways to prepare organic extracts. In general, extracts are produced with organic solvents, but there are two main exceptions: extracts obtained in water and those obtained with fluids in their supercritical state. Thus, when it comes to the solvent, substances that have an affinity with the molecules of the plant to be extracted are usually applied. Water is often used with pH adjustments when the desired purpose is to extract acidic or basic substances. Hexane, ether, ethyl acetate, acetone, methanol and ethanol are the most common extracting solvents. Among the solvents that were frequent a few decades ago, but which are no longer used today because of their toxicity, are the aromatics (benzene and toluene) and those containing chlorine (carbon tetrachloride, chloroform, dichloromethane and dichloroethane). The solvents that have emerged in recent decades are supercritical fluids, ionic liquids and green solvents (limonene and glycerol, for example). As for the techniques for obtaining the extracts, the traditional infusion (in water) and maceration have been coupled with energy sources to assist the process of breaking down plant cell membranes, such as ultrasound and microwaves.
Xenobiotic Biotransformation
Published in Robert G. Meeks, Steadman D. Harrison, Richard J. Bull, Hepatotoxicology, 2020
Both P450 and glutathione transferase play a role in the bioactivation of dihaloalkanes. The major pathway for 1,2-dichloroethane involves glutathione transferase conjugation and subsequent formation of electrophilic episulfonium derivatives. In addition, P450-mediated carbon-halogen oxidation and halogen oxidation play a role in bioactivation. Carbon-halogen oxidation results in an unstable gem-chlorohydrin intermediate that nonenzymatically dehydrohalogenates to form the electrophile, 2-chloroacetaldehyde. Halogen oxidation by P450 yields l-chloroso-2-chloroethane, which is electrophilic. This product nonenzymatically forms additional electrophiles. Alternatively, it may be conjugated by glutathione transferases, with ultimate formation of the episulfonium electrophile. Additional, but minor, microsomal bioactivation pathways include initial carbon-halogen reduction and dehydrohalogenation to electrophilic species.
Comparison of Results from Carcinogenicity Tests of Two Halogenated Compounds By Oral, Dermal, and Inhalation Routes
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
1,2-Dichloroethane (EDC) is widely used in industry, largely as an intermediate in the production of vinyl chloride. It has other applications as a fuel additive, although that use may decrease also with the banning of leaded gasoline, as a solvent, and as part of a fumigant mixture. Production is estimated to range from 3.6 to 4.3 million tons annually with as many as 200,000 workers exposed.9 An indication of the importance of EDC is the issuance of a Banbury Report on the substance, covering various bioassays, metabolism, and other studies with EDC.10
Radiation induced mutagenesis, physio-biochemical profiling and field evaluation of mutants in sugarcane cv. CoM 0265
Published in International Journal of Radiation Biology, 2022
Madhavi V. Purankar, Ashok A. Nikam, Rachayya M. Devarumath, Suprasanna Penna
Glycine betaine content analysis was done as per Grieve and Grattan (1983); callus (500 mg) was crushed using liquid nitrogen, and 20 ml of deionized distilled water was added to it. Tubes were shaken mechanically for 16 hours at room temperature. Samples were filtered and 500 µl of 2 N H2SO4 was added to the 500 µl of the filtrate. The mixture was cooled in ice water for one hour and mixed with 200 µl of I2KI reagent (20% KI and 15.7% I2 in distilled water), and the tubes were stored at 4 °C for 16 hours. The tubes were centrifuged for 15 min at 10,000×g at 4 °C. The precipitated periodide crystals were dissolved in 9 ml of 1,2-dichloroethane and its absorbance was measured at 365 nm in UV–visible spectrophotometer after 2 h. The GB content from the sample was extrapolated using a standard curve prepared using GB as the standard. Total soluble sugars (TSS) were estimated by the Anthrone method as described by Sadasivam and Manickam (2008a). About 100 mg of the callus was crushed in 2 ml of 80% ethanol. The tubes were centrifuged at 10,000 rpm for 10 minutes at 4 °C and supernatant was used for the estimation. Determination of total phenolic content was done as described by Sadasivam and Manickam (2008b) by the Folin–Ciocalteu reagent using 100 mg sample.
Graphene oxide influence in soil bacteria is dose dependent and changes at osmotic stress: growth variation, oxidative damage, antioxidant response, and plant growth promotion traits of a Rhizobium strain
Published in Nanotoxicology, 2022
Tiago Lopes, Paulo Cardoso, Diana Matos, Ricardo Rocha, Adília Pires, Paula Marques, Etelvina Figueira
Glycine betaine content was determined using the method described by Grieve and Grattan (1983). E20-8 was grown in the presence and absence of GO and PEG as previously described (2.2.4). Bacterial cells were collected (2.3.3) and samples suspended in deionized water and lysed in an ultrasonic probe for 45 s at 0.5 Hz of amplitude, always keeping the samples in an ice bath to prevent overheating. Samples were centrifuged at 12,000 ×g for 10 min at 4 °C. The supernatant was collected and 250 μL 1 M sulfuric acid and 200 μL KI-I2 (1.205 M potassium iodide (KI), 0.619 M iodine (I2)) were added and incubated overnight in ice. Samples were centrifuged at 12,000 ×g for 30 min at 0 °C, the supernatant discarded, and the pellet dissolved in 400 μL dichloroethane (reagent grade) and incubated for 2 h. The absorbance was measured at 356 nm. Glycine betaine standards (50–200 μg/mL) were used, and results were expressed in nanograms of glycine betaine per million cells (ng betaine/M cells).
Discovery of new 3-methylquinoxalines as potential anti-cancer agents and apoptosis inducers targeting VEGFR-2: design, synthesis, and in silico studies
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Mohammed M. Alanazi, Alaa Elwan, Nawaf A. Alsaif, Ahmad J. Obaidullah, Hamad M. Alkahtani, Abdulrahman A. Al-Mehizia, Sultan M. Alsubaie, Mohammed S. Taghour, Ibrahim H. Eissa
The key intermediates were synthesised as described in Scheme 2. The commercially available p-amino benzoic acid 7 was treated with chloroacetyl chloride in dry DMF in the presence of NaHCO3 to afford 4–(2-chloroacetamido)benzoic acid 8. Chlorination of 8 was achieved by its reflux with SOCl2 in dichloroethane in the presence of catalytic amount of dry DMF to give the key compound 4–(2-chloroacetamido)benzoyl chloride 9. At the end, in acetonitrile and TEA mixture, compound 9 was stirred at room temperature with appropriate amines namely, methylamine, sec-butylamine, cyclopentylamine, 2-methoxyaniline, 3-methoxyaniline, 4-methoxyaniline, 4-aminoacetophenone, 4-fluoroaniline, 2-aminopyridine, m-toluidine, p-toluidine, and 2-aminothiazole to give the corresponding key intermediates 10a-l, respectively. The IR spectra of the key intermediates 10a-l exhibited the appearance of absorption bands at the ranges of 3254 − 3326 cm−1 and 1702 − 1625 cm−1 due to the NH and 2C=O groups, respectively. In addition, 1H NMR analyses exhibited the appearance of characteristic singlet signals for amidic NHs around δ 10.00 ppm. Also, it showed singlet signals for CH2 protons of acetamide moiety around δ 4.30 ppm. Besides, such CH2 group was detected around δ 44.02 ppm in 13 C NMR spectra.