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Methylene chloride (MC) is a chemical with a high manufacturing volume that is primarily utilized as a paint remover and a commercial solvent. It is also utilized in the formation of photographic film and can be detected in various aerosol and pesticide goods. Research on the cancer-causing potential of MC in rats, mice and hamsters have only shown that it can cause malignant tumors in mice. This leads to the classification of MC as a cat. 2 carcinogen. A biotransformation process that becomes significant only at extremely high doses, the low affinity/high capacity GSTT1 pathway is thought to be the mechanism via which MC initiates potential for cancer in mice, according to dose-related toxicokinetics of the compound. The MCmetabolizing GST has very low activity in rats and hamsters and it has even lower activity in humans. Humans who inhale MC are susceptible to acute (short-term) impacts on their neurological systems, such as diminished motor, auditory, and visual abilities. However, these consequences are reversible as soon as exposure is stopped. Chronic (long-term) exposure to MC may have consequences that indicate the central nervous system (CNS) in both animals and humans may be a target. The evidence from humans about methylene chloride and cancer is inconclusive. It is important to take specific care when handling methylene chloride because it can also cause other related diseases and ailments. [ABSTRACT FROM AUTHOR]

Background: The emergence of the multidrug-resistant bacteria strain has become a global world crisis. This study was designed to evaluate the antibiofilm and synergistic effects of Lippia multiflora leaf extracts on the activity of cefotaxime against the methicillin-resistant Staphylococcus aureus (S. aureus). Methods: The synergistic effect of methanol and dichloromethane extracts on the bactericidal activity of cefotaxime was determined by using the antibiotic susceptibility test on agar medium. The antibiofilm activity of the extracts was measured by using the crystal violet method. The antioxidant potential of the extracts was assessed by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reduction Activity Potential (FRAP) methods. The main secondary metabolites groups were analyzed by using different standard analytical tests. The total phenolics and total flavonoids were quantified spectrophotometrically. Results: The methanol extract (final concentration of 100 µg/ml) inhibited the formation of bacterial biofilm more than salicylic acid (p<0.05). All extracts combined with cefotaxime (20 µg and 200 µg) showed good synergistic bactericidal effect on S. aureus with inhibitory diameters of up to 40 mm. The methanol extract showed higher total phenolics (462.20±10.90 mg EAG/g) and total flavonoids (26.20±0.20 mg EQ/g) contents than the dichloromethane extract (96.70±1.70 mg EAG/g and 8.00±1.20 mg EQ/g). Moreover, the methanol extract showed a higher FRAP reducing power (353.6± 4.17 mmol EQ/g) than the dichloromethane extract (385.3±7.01 mmol EQ/g). Qualitative phytochemical analysis showed the presence of tannins, flavonoids, terpenes and sterols in both extracts. Conclusion: These data showed that L. multiflora leaves contain effective antibacterial phytomolecules for combating bacterial resistance. [ABSTRACT FROM AUTHOR]

Meloidogyne spp. are important parasitic nematodes affecting a variety of plants worldwide. We investigated the nematicidal properties of specific compounds found in bio-fumigant plants, particularly linalool, nonanal, methylene chloride, and 2-Decanal. Laboratory findings revealed that methylene chloride and 2-Decenal effectively reduced populations of second-stage juveniles (J2s). Additionally, the research explored the effects of tomato (Solanum lycopersicum L.) on M. incognita J2s, observing that tomato leaves significantly increased J2 mortality for all time measurements and different temperatures, while the opposite results were observed for root-stems. In the study, leaf treatment resulted in a maximum mortality response (MRmax) and half-maximal effective concentration (EC50) of approximately 100% and 4.0 µg/mg, respectively, at a temperature of 35 °C by week 8. In contrast, the root-stems treatment showed an MRmax of 13.5% and an EC50 of 3.0 ± 1.7 µg/mg. GC-MS analysis identified key compounds in tomato leaves and root-stems, such as α-pinene, d-limonene, and linalool. The results suggest that tomato leaves have potential as effective bio-fumigants for controlling root-knot nematodes. [ABSTRACT FROM AUTHOR]

The recent rapid growth of the battery industry has led to a rapid increase in methylene chloride emissions. Methylene chloride causes health and social problems in humans. In this study, cellulose-based activated carbon fibers (CACFs) with improved yield were prepared for the removal of methylene chloride. The concentration of ammonium phosphate in the pretreatment controlled the crosslink density of cellulose fibers and improved the yield. From the results, the specific surface area and total pore volume of cellulose-based activated carbon fibers pretreated with ammonium phosphate (AP-CACFs) were determined to be 1920–2060 m2/g and 0.83–1.02 cm3/g, respectively, and the total yield improved by 6.78–11.59% compared to that of CACFs (4.97%). In particular, a correlation between the textural properties of CACFs and methylene chloride adsorption/desorption behavior was obtained. This correlation can be used to develop efficient adsorbents for methylene chloride removal. [ABSTRACT FROM AUTHOR]

A comparative study of the chemical behavior of performic acid in chloroform and methylene chloride revealed that the HCOOH—H2O2—CH2Cl2 system ensured effective and chemoselective synthesis of 29-nor-20-O-formyl derivatives of betulin. [ABSTRACT FROM AUTHOR]

We investigated patterns of volatile organic compound (VOC) contamination in drinking water systems affected by the California 2018 Camp Fire. We performed spatial analysis of over 5000 water samples collected over a 17 month period by a local water utility, sampled tap water for VOCs in approximately 10% (N = 136) of standing homes, and conducted additional nontargeted chemical analysis of 10 samples. Benzene contamination was present in 29% of service connections to destroyed structures and 2% of service connections to standing homes. A spatial pattern was apparent. Tap water in standing homes 11 months after the fire contained low concentrations of benzene in 1% of samples, but methylene chloride was present in 19% of samples, including several above regulatory limits. Elevated methylene chloride was associated with greater distance from the water meter to the tap, longer stagnation time, and the presence of a destroyed structure on the service connection; it was inversely associated with certain trihalomethanes. Nontargeted analysis identified multiple combustion byproducts in the water at 2/10 homes. Our findings support the hypothesis that pyrolysis and smoke intrusion from depressurization contributed to the benzene contamination. Further research is needed to test the hypothesis that methylene chloride may be generated from the dehalogenation of disinfection byproducts stagnating in galvanized iron pipes.

ImportanceMethylene chloride is a halogenated organic solvent widely used in paint strippers, cleaners, adhesives, and sealants. Despite label warnings and occupational standards, methylene chloride-related fatalities continue to occur in the United States.ObjectiveTo identify and analyze methylene chloride-related fatalities in the US.Design, setting, and participantsFor this case series, we conducted systematic searches of sources, including PubMed and government databases, for unintentional fatalities in the US that were associated with exposure to methylene chloride or products containing methylene chloride between 1980 and 2018. We reviewed all available information, including inspection reports, autopsy reports, and medical records; data analyses were conducted from August 2018 to August 2020. Cases were categorized as those occurring in the home (consumer deaths) or at work (occupational deaths).ExposuresMethylene chloride or products containing methylene chloride.Main outcomes and measuresTo determine characteristics of the methylene chloride-related fatalities, we recorded demographic information; the setting; circumstances, including information on safety measures used, if available; and products used. Where medical records were available, we recorded toxicology results and autopsy findings. We also obtained data about nonfatal methylene chloride cases from the American Association of Poison Control Centers.ResultsFrom 1980 to 2018, 85 methylene chloride-related fatalities were identified in the US, including 74 (87%) in occupational settings; of those who died, 75 (94%) were men, and for the 70 cases with available information, the median (interquartile range) age of the decedents was 31 (24-46) years. Paint strippers were the most common products involved in methylene chloride-related fatalities (n = 60). The proportion of occupational fatalities related to paint stripping increased from 22 (55%) before 2000 to 30 (88%) after 2000. Similarly, occupational fatalities associated with bathtub or paint stripping in bathrooms increased from 2 (5%) before 2000 to 21 (62%) after 2000. From 1985 to 2017, the American Association of Poison Control Centers documented 37 201 nonfatal methylene chloride cases, with a decrease in the annual number of cases starting in the late 1990s.Conclusions and relevanceResults of this case series demonstrated that despite regulations to address the toxic effects of methylene chloride use for consumers and workers, there are continuing fatalities in the US, particularly in occupational settings. Prevention of fatalities associated with methylene chloride exposure should emphasize the use of safer substitutes, rather than hazard warnings or reliance on personal protective equipment.

Processes of dressing the surface of glass fiber and their effect on the properties of composite materials based on polyetherimide filled with glass fibers were evaluated. It was found that preliminary thermal treatment of glass fibers and their subsequent treatment with a dressing agent, copolyhydroxyether based on di(4-hydroxyphenyl)sulfone, 4,4′-dioxydiphenylpropane, and 3-chloro-1,2-epoxypropane, allow obtaining polyether—etherimide composite glass-filled materials exhibiting improved physical and mechanical properties. [ABSTRACT FROM AUTHOR]

Meloidogyne spp. are important parasitic nematodes affecting a variety of plants worldwide. We investigated the nematicidal properties of specific compounds found in bio-fumigant plants, particularly linalool, nonanal, methylene chloride, and 2-Decanal. Laboratory findings revealed that methylene chloride and 2-Decenal effectively reduced populations of second-stage juveniles (J2s). Additionally, the research explored the effects of tomato (Solanum lycopersicum L.) on M. incognita J2s, observing that tomato leaves significantly increased J2 mortality for all time measurements and different temperatures, while the opposite results were observed for root-stems. In the study, leaf treatment resulted in a maximum mortality response (MRmax) and half-maximal effective concentration (EC50) of approximately 100% and 4.0 µg/mg, respectively, at a temperature of 35 °C by week 8. In contrast, the root-stems treatment showed an MRmax of 13.5% and an EC50 of 3.0 ± 1.7 µg/mg. GC-MS analysis identified key compounds in tomato leaves and root-stems, such as α-pinene, d-limonene, and linalool. The results suggest that tomato leaves have potential as effective bio-fumigants for controlling root-knot nematodes.

The recent rapid growth of the battery industry has led to a rapid increase in methylene chloride emissions. Methylene chloride causes health and social problems in humans. In this study, cellulose-based activated carbon fibers (CACFs) with improved yield were prepared for the removal of methylene chloride. The concentration of ammonium phosphate in the pretreatment controlled the crosslink density of cellulose fibers and improved the yield. From the results, the specific surface area and total pore volume of cellulose-based activated carbon fibers pretreated with ammonium phosphate (AP-CACFs) were determined to be 1920–2060 m2/g and 0.83–1.02 cm3/g, respectively, and the total yield improved by 6.78–11.59% compared to that of CACFs (4.97%). In particular, a correlation between the textural properties of CACFs and methylene chloride adsorption/desorption behavior was obtained. This correlation can be used to develop efficient adsorbents for methylene chloride removal.

BackgroundThe incidence of childhood cancers has been increasing and environmental exposure to air toxics has been suggested as a possible risk factor. This study aims to explore ambient exposure to dichloromethane (methylene chloride).MethodsWe frequency matched by birth year approximately 20 cancer-free controls identified from birth records to all childhood cancers ages 0-5 in the California Cancer Registry diagnosed from 1988 to 2012; i.e. 13,636 cases and a total of 270,673 controls. Information on industrial releases of dichloromethane within 3km of birth addresses was retrieved from mandatory industry reports to the EPA's Toxics Release Inventory (TRI). We derived exposure to dichloromethane within close vicinity of birth residences using several modeling techniques including unconditional logistic regression models with multiple buffer distances, inverse distance weighting, and quadratic decay models.ResultsWe observed elevated risks for germ cell tumors [Odds Ratio (OR): 1.52, 95% Confidence Interval (CI) 1.11, 2.08], particularly teratomas (OR: 2.08, 95% CI 1.38-3.13), and possible increased risk for acute myeloid leukemias (AML) (OR: 1.64, 95% CI 1.15-2.32 in the quadratic decay model). Risk estimates were similar in magnitude whether releases occurred in pregnancy or the child's first year of life.ConclusionOur findings suggest that exposure to industrial dichloromethane releases may be a risk factor for childhood germ cell tumors, teratomas, and possibly AML.

The S U (2) -Lie algebraic approach based on the dynamical group U 1 (2) × U 2 (2) × ⋯ × U n (2) to describe a set of n local oscillators is analysed from the point of view of its connection with configuration space. First, the matrix elements of a general Hamiltonian involving Casimir operators of the two dynamical algebras S O i j (2) and S U i j (2) are revised and subsequently the equivalent Hamiltonian in configuration space is established. This relationship permits us to evaluate the order of the interactions traditionally taken into account in the S U (2) vibron model with the additional advantage of providing the connection with force constants. Starting from configuration space our analysis is applied to the description of vibrational excitations of the molecule of methylene chloride including both stretching and bending degrees of freedom. [ABSTRACT FROM AUTHOR]

Products derived from medicinal plants with antimicrobial activity are considered a promising alternative in the treatment of fungal infections. In this perspective, this study proposed to evaluate the antifungal activity of the dichloromethane fraction of Annona crassiflora Mart. against C. albicans strains. Tests were carried out to determine Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC), microbial growth kinetics, fungal cell wall and membrane mechanisms of action, antifungal biofilm activity, and cytotoxic effects on human erythrocytes. The extract presented MIC and MFC values that ranged from 256 µg/mL to 1,024 µg/mL, with fungicidal activity in the microbial growth kinetics assay. The mechanism of action did not occur through damage to the cell wall or via binding to ergosterol in the membrane, though the fraction presents activity against biofilm and is not cytotoxic in human erythrocytes. The dichloromethane fraction of Annona crassiflora Mart. presented antifungal activity and reduced biofilm growth, without toxicity against human erythrocytes; however, further studies are needed to define its mechanism of action.

A dynamic kinetic resolution (DKR) of allylic sulfoxides has been demonstrated by combining the Mislow [2,3]-sigmatropic rearrangement with catalytic asymmetric hydrogenation. The efficiency of our DKR was optimized by using low pressures of hydrogen gas to decrease the rate of hydrogenation relative to the rate of sigmatropic rearrangement. Kinetic studies reveal that the rhodium complex acts as a dual-role catalyst and accelerates the substrate racemization while catalyzing olefin hydrogenation. Scrambling experiments and theoretical modeling support a novel mode of sulfoxide racemization which occurs via a rhodium π-allyl intermediate in polar solvents. In nonpolar solvents, however, the substrate racemization is primarily uncatalyzed. Computational studies suggest that the sulfoxide binds to rhodium via O-coordination throughout the catalytic cycle for hydrogenation.

Introduction: Methylene chloride, also known as dichloromethane, is a volatile hydrocarbon used in paint strippers and removers. Toxicity from methylene chloride may include narcosis and elevated carbon monoxide (CO) levels. Significant injury to the skin can occur after prolonged exposure to methylene chloride and other hydrocarbon-based solvents causing a chemical dermal injury. Case Report: This case series describes three male patients with prolonged exposure to a methylene chloride–containing paint remover to the bilateral hands with two of the three patients requiring transfer to a tertiary burn center and operative intervention. The clinical significance and impressive resolution of dermal injury from prolonged methylene chloride exposure are highlighted with detailed images and a literature review. Discussion: Chemical dermal injury secondary to methylene chloride exposure likely results from destruction of lipids within the epidermis and dermis and direct chemical injury. Prolonged exposure to skin can result in clinically important injury that requires management by a burn specialist and may necessitate operative intervention. The severity of the dermal injury can range from severe to mild and should be considered by a clinician after skin exposure to hydrocarbons. [ABSTRACT FROM AUTHOR]

This paper is the first to demonstrate the application of U(2) Lie algebraic Hamiltonian in reproducing and predicting the vibrational energy levels of an asymmetric penta-atomic molecule – methylene chloride (CH2Cl2) – having odorant properties similar to ether in the gas phase. The results indicated that the U(2) Lie algebraic Hamiltonian is successful in realising seven of the nine fundamental (stretching and bending) vibrational modes of CH2Cl2 observed experimentally. The lowest, highest, and RMS deviations of the derived vibrational fundamental frequencies stand, respectively, within 0.006%, 0.23%, and 0.7075 cm−1 of the experimental values suggested that the proposed model is successful in predicting the experimental results at the realised fundamental mode vibrations. This study also suggests that further research is needed to make the U(2) Lie algebraic Hamiltonian more robust so as to accommodate for the unrealised out-of-the-plane complex bending vibrational modes of CH2Cl2 molecule. [ABSTRACT FROM AUTHOR]

Introduction: Epidemiologic and toxicology studies suggest that exposure to various solvents, especially chlorinated hydrocarbon solvents, might increase Parkinson disease (PD) risk. Methods: In a population-based case-control study in Finland, we examined whether occupations with potential for solvent exposures were associated with PD. We identified newly diagnosed cases age 45–84 from a nationwide medication reimbursement register in 1995–2014. From the population register, we randomly selected non-PD controls matched on sex, along with birth and diagnosis years (age). We included 11,757 cases and 23,236 controls with an occupation in the 1990 census, corresponding to age 40–60. We focused on 28 occupations with ≥ 5% probability of solvent exposure according to the Finnish Job Exposure Matrix. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by logistic regression modeling, adjusting for age, sex, socioeconomic status, and smoking probability. Results: Similar proportions of cases (5.5%) and controls (5.6%) had an occupation with potential exposure to any solvents. However, all occupations with a point estimate above one, and all significantly or marginally significantly associated with PD (electronic/telecommunications worker [OR = 1.63, 95% CI 1.05–2.50], laboratory assistant [OR = 1.40, 95% CI 0.98–1.99], and machine/engine mechanic [OR = 1.23, 95% CI 0.99–1.52]) entailed potential for exposure to chlorinated hydrocarbon solvents, specifically. Secondary analyses indicated exposure to polycyclic aromatic hydrocarbons and some metals might contribute to the association for mechanics. Conclusion: PD risk might be slightly increased in occupations with potential exposure to chlorinated hydrocarbon solvents. Confirmation is required in additional studies that adjust for other occupational exposures and smoking.

The analysis of chlorinated paraffins (CPs) is today an analytical challenge. Indeed, it is still impractical to describe their real composition in terms of polychlorinated alkanes (PCAs) homologue groups, which dominate technical mixtures. The co-elution of PCA congeners generates interferences due to the competition phenomena which occur during the ionisation process as well as to the dependence of the ionisation sources on the PCA chemistry. Therefore, the aim of this study was to investigate the influence of chromatographic separation, by LC-ESI-HRMS coupling, on the PCA homologue group pattern and, eventually, on their determination in food samples from interlaboratory studies. For this, three different mobile phases and six LC chromatographic columns were studied in order to optimise the analysis of CP mixtures. The first results showed that the use of a MeOH/H 2 O mobile phase reveals more appropriately the higher chlorinated PCAs. However, using ACN/H 2 O led to less ion species, with almost exclusively [M + Cl] - adducts, formed using post-column dichloromethane addition. Regarding the choice of the stationary phases, Hypercarb column provided a completely different homologue group pattern from the other chromatographic columns, in relation with the stronger retention of PCAs. Among the other columns, the C30 column better highlighted the short-chain PCAs compared to the C18 column conventionally used. Because the regulations now concern short-chain CPs, the quantification of food samples was then carried out on the C30 column. The optimised LC-ESI-HRMS conditions using C30 column and MeOH/H 2 O solvent mixture led to a quantification of PCAs in samples from interlaboratory studies with satisfactory accuracy (|Z-score| ≤ 2) and precision (<15%)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To evaluate the effect of different chemical surface treatments on the adhesion of self-adhesive resin cements to commercially pure titanium (cp Ti) by means of strain energy release rate (G-value, J/m2). Materials and Methods: Machined cp Ti plates grade II were prepared and divided into ten groups in each test according to the surface treatment used; Gr 1: control, machined; Gr 2: sandblasted; Gr 3: methylene chloride (CH2Cl2) for 5 min; Gr 4: CH2Cl2 for 10 min; Gr 5: 10% hydrogen peroxide (H2O2) for 5 min; Gr 6: 10% H2O2 for 10 min; Gr 7: 30% H2O2 for 5 min; Gr 8: 30% H2O2 for 10 min; Gr 9: 9% hydrofluoric acid (HF) for 5 min; Gr 10: 9% HF for 10 min. For bond strength testing, each group was further divided into two subgroups according to the type of resin cement used (G-CEM and Rely × Unicem). Surface roughness examination and SEM analysis of treated cp Ti surfaces were carried out. Data were analyzed using ANOVA and Tukey's test. Statistical significance was set at the 0.05 probability level. Results: The cp Ti/G-CEM and cp Ti/Rely × Unicem (9% HF for 5 or 10 min) groups showed the highest G-values (13.7 ± 2.2, 13.8 ± 2.1, 11.6 ± 1.6 and 11.8 ± 1.2, respectively) among their groups. The sandblasted group showed the highest surface roughness value (3.4 ± 0.2 μm) when compared with other treated groups. Conclusion: Adhesion between resin cements and cp Ti can be improved by the use of certain chemical baths as surface treatments of titanium prior to cementation as alternative techniques to sandblasting treatment. [ABSTRACT FROM AUTHOR]

Paint and varnish removers constitute a major potential source of organic solvent exposure to contractors and home improvement enthusiasts. Unfortunately, the leading paint remover formulations have traditionally contained, as major ingredients, chemicals classified as probable human carcinogens (eg, methylene chloride) or reproductive toxicants (eg, N‐methylpyrrolidone). In addition, because of its unique toxicology (ie, hepatic conversion to carbon monoxide compounding generic solvent narcosis and arrythmogenesis), high volatility, and rigorous requirements for personal protective equipment, methylene chloride exposures from paint removers have been linked to numerous deaths involving both occupational and consumer usage. The aim of this review is to summarize the known toxicology of solvent‐based paint remover constituents (including those found in substitute formulations) in order to provide health risk information to regulators, chemical formulators, and end‐users of this class of products, and to highlight any data gaps that may exist. Solvent‐based paint and varnish removers are an important source of potential consumer and worker exposures. Two historically prominent ingredients, methylene chloride and N‐methylpyrrolidone, have come under increasing scrutiny (and in one case, regulatory action) for their toxicities. This review considers, not only historically prominent paint remover constituents, but also alternative/emerging formulations, and documents important information gaps in their toxicologic testing portfolios. [ABSTRACT FROM AUTHOR]

We earlier discovered a new reaction in the chemistry of organoaluminum compounds (OACs), specifically, the formation of O-isobutyl acetals on low-temperature (–70°C) treatment of seven-membered lactones with a double (or more) molar amount of diisobutylaluminum hydride (DIBAH) in methylene chloride. To assess the boundaries for the formation of isobutyl acetals depending on the ring size, we involved in the low-temperature hydride reduction six-, eight-, and thirteen-membered lactones. To determine how the scope of the new reaction depends on the nature of the organoaluminum reagent, we tested triisobutylaluminum (TIBA). To determine how the formation of isobutyl acetals on low-temperature (–70°C) reduction with excess DIBAH in CH2Cl2 depends on whether the starting ester is cyclic or acyclic and, if the former is the case, on the ring size in the ester, we used the acyclic methyl octadecanoate as the starting compound. It was found that the new reaction in the chemistry of AOC with DIBAH as the reducer is characteristic only of seven-membered lactones and atypical of acyclic methyl octadecanoate and ricinoleate (i.e. acids with the carbon chain length more than 6). [ABSTRACT FROM AUTHOR]

Introduction: Car painters are routinely exposed to organic solvents classified as carcinogenic and mutagenic substances. Objective: To characterize the population susceptibility and evaluate the genotoxic effects of exposure to organic solvents. Methods: A cross-sectional study comparing a group of car painters exposed to organic solvents with a non-exposed group. CYP2E1 polymorphisms and the presence of micronuclei in lymphocytes were determined. Results: One hundred twenty-two workers participated in the study: 62 who worked in car paint shops and were exposed to solvents, and 60 who were not exposed. There were statistically significant differences between the two groups regarding micronucleated cells and nucleoplasmic bridges frequencies (p= 0.042 and p= 0.046, respectively; exact likelihood ratio). Significant differences were found at the interaction between the CYP2E1 genotype c1c1 and occupational exposure to solvents, with higher frequencies of micronuclei (p= 0.013) and micronucleated cells (p= 0.015). However, when the frequencies of micronuclei, micronucleated cells and nucleoplasmic bridges in the exposure group were compared between the c1c1 and c2c2/c1c2 allele groups of the CYP2E1 polymorphism, statistically significant differences were found. Conclusions: This study confirms that when workers with CYP2E1 polymorphisms, specifically the c1c1 genotype, are exposed to organic solvents, they are more likely to have somatic cell mutations, a condition associated with increased susceptibility to diseases such as cancer. [ABSTRACT FROM AUTHOR]

The objective of the study is to establish exposure-excretion relationship between dichlorometane (DCM) in air (DCM-A) and in urine (DCM-U) in workplace to confirm a previous report. Male workers in a screen-printing plant participated in the study. Time-weighted average DCMA was measured by diffusive sampling followed by gas-chromatography (GC), and DCM in end-ofshift urine samples was by head-space GC. The data were subjected to regression and other statistical analyses. In practice, 30 sets of DCM-A and DCM-U values were available. The geometric mean DCM-A was 8.4 ppm and that of DCM-U (as observed) was 41.1 µg/l. The correlation coefficients (0.70-0.85) were statistically significant across the correction for urine density. Thus, the analysis for un-metabolized DCM in end-of-shift urine samples is applicable for biological monitoring of occupational exposure to DCM, in support of and in agreement with the previous report. In conclusion, biological monitoring of occupational DCM exposure is possible by use of analysis for unmetabolized DCM in end-of-shift urine. [ABSTRACT FROM AUTHOR]

Methylene chloride is a volatile, chlorinated hydrocarbon and colorless solvent found in multiple industrial products including paint strippers, metal cleaners, automotive products, pesticides and aerosol containers. Occupational exposure to methylene chloride is reported in automotive technicians, painters, and other industrial workers with adverse health effects including gastrointestinal, neurological, as well as hepato-renal injuries. International Agency for Research on Cancer (IARC) classifies methylene chloride as a 2 A carcinogen. Through a series of reactions catalyzed by cytochrome P450 2E1 (CYP2E1), metabolism of methylene chloride leads to the formation of formyl chloride, and ultimately carbon monoxide (CO). Most reports of methylene chloride toxicity are due to dermal and inhalational exposure in occupational settings. Ingestion of methylene chloride is uncommon, yet can lead to significant toxicity and prolonged CO toxicity. Methylene chloride is frequently formulated with methanol; individuals who intentionally ingest methylene chloride can experience concomitant methanol toxicity. We present a case of acute ingestion of paint stripper containing methanol and methylene chloride. We discuss the clinical presentation, key management decisions, relevant pathophysiology and biochemistry, as well as the clinical course and management. [ABSTRACT FROM AUTHOR]

A calix[4]arene scaffolding has been used to construct bisporphyrin ("jaws" porphyrin) hosts for supramolecular binding of fullerene guests. Fullerene affinities were optimized by varying the nature of the covalent linkage of the porphyrins to the calixarenes. Binding constants for C60 and C70 in toluene were explored as a function of substituents at the periphery of the porphyrin, and 3,5-di-tert-butylphenyl groups gave rise to the highest fullerene affinities (26,000 M(-1) for C60). The origin of this high fullerene affinity has been traced to differential solvation effects rather than to electronic effects. Studies of binding constants as a function of solvent (toluene < benzonitrile < dichloromethane < cyclohexane) correlate inversely with fullerene solubility, indicating that desolvation of the fullerene is a major factor determining the magnitude of binding constants. The energetics of fullerene binding have been determined in terms of DelatH and DeltaS and are consistent with an enthalpy-driven, solvation-dependent process. A direct relationship between supramolecular binding of a fullerene guest to a bisporphyrin host and the appearance of a broad NIR absorption band have been established. The energy of this band moves in a predictable manner as a function of the electronic structure of the porphyrin, thereby establishing its origin in porphyrin-to-fullerene charge transfer.

A calix[4]arene scaffolding has been used to construct bisporphyrin ("jaws" porphyrin) hosts for supramolecular binding of fullerene guests. Fullerene affinities were optimized by varying the nature of the covalent linkage of the porphyrins to the calixarenes. Binding constants for C60 and C70 in toluene were explored as a function of substituents at the periphery of the porphyrin, and 3,5-di-tert-butylphenyl groups gave rise to the highest fullerene affinities (26,000 M(-1) for C60). The origin of this high fullerene affinity has been traced to differential solvation effects rather than to electronic effects. Studies of binding constants as a function of solvent (toluene < benzonitrile < dichloromethane < cyclohexane) correlate inversely with fullerene solubility, indicating that desolvation of the fullerene is a major factor determining the magnitude of binding constants. The energetics of fullerene binding have been determined in terms of DelatH and DeltaS and are consistent with an enthalpy-driven, solvation-dependent process. A direct relationship between supramolecular binding of a fullerene guest to a bisporphyrin host and the appearance of a broad NIR absorption band have been established. The energy of this band moves in a predictable manner as a function of the electronic structure of the porphyrin, thereby establishing its origin in porphyrin-to-fullerene charge transfer.

Jatropha variegata and Jatropha spinosa (family: Euphorbiaceae) are utilized in Yemeni traditional medicine to treat respiratory tract infection and in different skin conditions such as wound healing, as antibacterial and hemostatic. In this study, we evaluated the cytotoxicity and the antiviral activities of the methanolic J. variegata (leaves: Ext-1, stems: Ext-2, and roots: Ext-3), and J. spinosa extracts (aerial parts: Ext-4 and roots: Ext-5), in addition to their methylene chloride fractions of roots extracts (F-6 and F-7, respectively). All samples were tested against three human cancer cell lines in vitro (MCF-7, HepG2, and A549) and two viruses (HSV-2 and H1N1). Both plants showed significant cytotoxicity, among them, the methylene chloride fractions of roots of J. variegata (F-6) and J. spinosa roots (F-7) showed the highest activity on MCF-7 (IC 50  = 1.4 and 1 μg/mL), HepG2 (IC 50  = 0.64 and 0.24 μg/mL), and A549 (IC 50  = 0.7 and 0.5 μg/mL), respectively, whereas the IC 50 values of the standard doxorubicin were (3.83, 4.73, and 4.57 μg/mL) against MCF-7, HepG2, and A549, respectively. These results revealed that the roots of both plants are potential targets for cytotoxic activities. The in vitro results revealed potential antiviral activity for each of Ext-3, Ext-5, F-6, and F-7 against HVS-2 with IC 50 of 101.23, 68.83, 4.88, 3.24 μg/mL and against H1N1 with IC 50 of 51.29, 27.92, 4.24, and 3.06 μg/mL respectively, whereas the IC 50 value of the standard acyclovir against HVS-2 was 83.19 μg/mL and IC 50 value of the standard ribavirin against H1N1 was 52.40 μg/mL .The methanol extracts of the roots (Ext-3 and Ext-5) of both plants were characterized using UPLC/MS. A total of 73 metabolites were annotated, including fourteen diterpenoids, eleven flavonoids, ten phenolic acid conjugates, twelve fatty acids and their conjugates, five triterpenes and steroids, two sesquiterpenes, and six coumarins. The cytotoxicity and antiviral activities determined in the present work are explained by the existence of flavonoids, coumarins and diterpenes with commonly known cytotoxicity and antiviral activities., (© 2024. The Author(s).)

Ethnopharmacological Relevance: Clerodendrum infortunatum L. is commonly distributed in tropical and subtropical countries and is widely used in the indigenous systems of medicine including Ayurveda, Unani, and Homeopathy. The plant has important uses in the treatment of various inflammatory disorders which includes asthma, cough, chest complaints, pain, rheumatism, osteoarthritis, gastric ulcer, cancer, diabetes, skin diseases etc. AIM OF THE STUDY: Regarding the extensive healing properties of C. infortunatum in folk medicine, we aimed to explore the anti-inflammatory activity of the plant and analyze its bioactive components., Materials and Methods: Sequential extracts were prepared from C. infortunatum leaves using n-hexane, dichloromethane, ethyl acetate, methanol, ethanol and water. In vitro anti-inflammatory activity of these extracts were evaluated using membrane stabilization and protein anti-denaturation assays. Toxicity of the extracts was tested using brine shrimp lethality assay. GC-MS analysis has been carried out to analyze and characterize various bioactive constituents present in the plant., Results: Each of the tested extracts showed significant (p < 0.05) in vitro anti-inflammatory activity. Sequential ethyl acetate extract demonstrated the strongest membrane stabilization and protein anti-denaturation activities with IC 50 values of 331.3, 308.3 and 279.2 μg/mL for heat and hypotonicity induced membrane stabilization and protein anti-denaturation assays, respectively. Sequential methanol extract also exhibited strong activity in heat and hypotonicity induced membrane stabilization and protein anti-denaturation assays with IC 50 values of 371.5, 331.6 and 284.6 μg/mL, respectively. The extracts demonstrated a range of toxicity in the brine shrimp lethality assay with LC 50 values of 51.4, 59.7, 47.3, 37.1, 68.1 and 77.3 μg/mL for n-hexane, dichloromethane, ethyl acetate, methanol, ethanol and water extracts respectively. The GC-MS analysis of direct n-hexane, ethyl acetate and methanol extracts detected 32 different compounds. The major compounds (> 5%) were phenol, 3,5-bis(1,1-dimethylethyl)-, hexadecanoic acid methyl ester, estragole, methyl stearate, lanosterol, 9-methoxybicyclo[6.1.0]nona-2,4,6-triene, benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl) 4 hydroxy methyl ester, 22,23-dibromostigmasterol acetate, 3-methyl-4-(phenylthio)-2-prop-2-enyl-2,5-dihydrothiophene 1,1-dioxide, benzenemethanol, α-methyl-α-propyl- and 9-octadecenoic acid (Z)- methyl ester., Conclusions: The findings of our study revealed that C. infortunatum is rich with diverse bioactive phytoconstituents and the scientific evidences support the anti-inflammatory potential of the plant., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Asteraceae (Compositae), commonly known as the sunflower family, is one of the largest plant families in the world and includes several species with pharmacological properties. In the search for new antiviral candidates, an in vitro screening against dengue virus (DENV) was performed on a series of dichloromethane and methanolic extracts prepared from six Asteraceae species, including Acmella bellidioides , Campuloclinium macrocephalum , Grindelia pulchella , Grindelia chiloensis , Helenium radiatum , and Viguiera tuberosa , along with pure phytochemicals isolated from Asteraceae: mikanolide ( 1 ), eupatoriopicrin ( 2 ), eupahakonenin B ( 3 ), minimolide ( 4 ), estafietin ( 5 ), 2-oxo-8-deoxyligustrin ( 6 ), santhemoidin C ( 7 ), euparin ( 8 ), jaceidin ( 9 ), nepetin ( 10 ), jaceosidin ( 11 ), eryodictiol ( 12 ), eupatorin ( 13 ), and 5-demethylsinensetin ( 14 ). Results showed that the dichloromethane extracts of C. macrocephalum and H. radiatum and the methanolic extracts prepared from C. macrocephalum and G. pulchella were highly active and selective against DENV-2, affording EC 50 values of 0.11, 0.15, 1.80, and 3.85 µg/mL, respectively, and SIs of 171.0, 18.8, >17.36, and 64.9, respectively. From the pool of phytochemicals tested, compounds 6 , 7 , and 8 stand out as the most active (EC 50 = 3.7, 3.1, and 6.8 µM, respectively; SI = 5.9, 6.7, and >73.4, respectively). These results demonstrate that Asteraceae species and their chemical constituents represent valuable sources of new antiviral molecules.

The concentration of carbazoles in highly mature crude oil is quite low, making it challenging to separate carbazole compounds for the gas chromatography-mass spectrometry (GC-MS) detection. This study presents a small-scale column chromatography method for separating carbazoles from highly mature crude oil using silica gel as a solid phase adsorbent and a Pasteur pipette as a separation device. The carbazole-rich crude oil from the Pearl River Mouth Basin was selected to explore the impact of reagent polarity and injection mode on the separation of carbazoles. The oil sample was eluted with solvents mixed with different volume proportions of n-hexane and dichloromethane and each eluted fraction was collected for GC-MS testing. The results indicated that increasing the reagent polarity caused the aromatic hydrocarbons and carbazole compounds in crude oil to be eluted sequentially. Most aromatic compounds in the crude oil could be selectively eluted using a reagent polarity ratio of 9:1 (V n -hexane : V dichloromethane ), with no carbazole compounds. A significant amount of carbazole compounds were eluted in the polar segments of 8:2-6:4, with the eluted carbazoles concentration accounting for more than 98 % of the total concentration. Moreover, the concentration and recovery of carbazoles eluted by direct injection mode were about 10 % higher than those after adsorption by silica gel. The standard deviation of the parameter ratio for the separated carbazole compounds in the three groups of repeatable parallel experiments was less than 0.2 %. Our method is superior to traditional two-step method and C 18 column method in separation efficiency and damage to human body. This method can be applied to both highly mature crude oil and other kinds of oils including biodegradable oil. It could be a versatile method for the carbazoles separation and provide technical support in unveiling the geochemical implications of these compounds in complex areas., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)