Brushing Up on Cartilage Lubrication: Polyelectrolyte-Enhanced Tribological Rehydration.

This study presents new insights into the potential role of polyelectrolyte interfaces in regulating low friction and interstitial fluid pressurization of cartilage. Polymer brushes composed of hydrophilic 3-sulfopropyl methacrylate potassium salt (SPMK) tethered to a PEEK substrate (SPMK-g-PEEK) are a compelling biomimetic solution for interfacing with cartilage, inspired by the natural lubricating biopolyelectrolyte constituents of synovial fluid. These SPMK-g-PEEK surfaces exhibit a hydrated compliant layer approximately 5 µm thick, demonstrating the ability to maintain low friction coefficients (µ ∼ 0.01) across a wide speed range (0.1-200 mm/s) under physiological loads (0.75-1.2 MPa). A novel polyelectrolyte-enhanced tribological rehydration mechanism is elucidated, capable of recovering up to ∼12% cartilage strain and subsequently facilitating cartilage interstitial fluid recovery, under loads ranging from 0.25 to 2.21 MPa. This is attributed to the combined effects of fluid confinement within the contact gap and the enhanced elastohydrodynamic behavior of polymer brushes. Contrary to conventional theories that emphasize interstitial fluid pressurization in regulating cartilage lubrication, this work demonstrates that SPMK-g-PEEK's frictional behavior with cartilage is independent of these factors and provides unabating aqueous lubrication. Polyelectrolyte-enhanced tribological rehydration can occur within a static contact area and operates independently of known mechanisms of cartilage interstitial fluid recovery established for converging or migrating cartilage contacts. These findings challenge existing paradigms, proposing a novel polyelectrolyte-cartilage tribological mechanism not exclusively reliant on interstitial fluid pressurization or cartilage contact geometry. The implications of this research extend to a broader understanding of synovial joint lubrication, offering insights into the development of joint replacement materials that more accurately replicate the natural functionality of cartilage.

Assessing the Fate of Benzophenone-Type UV Filters and Transformation Products during Soil Aquifer Treatment: The Biofilm Compartment as Bioaccumulator and Biodegrader in Porous Media.

The fate of selected UV filters (UVFs) was investigated in two soil aquifer treatment (SAT) systems, one supplemented with a reactive barrier containing clay and vegetable compost and the other as a traditional SAT reference system. We monitored benzophenone-3 (BP-3) and its transformation products (TPs), including benzophenone-1 (BP-1), 4,4'-dihydroxybenzophenone (4DHB), 4-hydroxybenzophenone (4HB), and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB), along with benzophenone-4 (BP-4) and avobenzone (AVO) in all involved compartments (water, aquifer sediments, and biofilm). The reactive barrier, which enhances biochemical activity and biofilm development, improved the removal of all detected UVFs in water samples. Among monitored UVFs, only 4HB, BP-4, and AVO were detected in sediment and biofilm samples. But the overall retained amounts were several orders of magnitude larger than those dissolved. These amounts were quantitatively reproduced with a specifically developed simple analytical model that consists of a mobile compartment and an immobile compartment. Retention and degradation are restricted to the immobile water compartment, where biofilm absorption was simulated with well-known compound-specific Kow values. The fact that the model reproduced observations, including metabolites detected in the biofilm but not in the (mobile) water samples, supports its validity. The results imply that accumulation ensures significant biodegradation even if the degradation rates are very low and suggest that our experimental findings for UVFs and TPs can be extended to other hydrophobic compounds. Biofilms act as accumulators and biodegraders of hydrophobic compounds.

iso-Guttiferone J and Structure Revision of Guttiferone J from Garcinia gummi-gutta: A Combined Experimental and Integrated QM/NMR Approach.

Many polyprenylated acylphloroglucinols with fascinating chemical structures and intriguing biological activities have been identified as key to phytochemicals isolated from Garcinia, Hypericum, and related genera. In the present work, two chiral, tautomeric, highly-oxygenated polyprenylated acylphloroglucinols tethered with acyl and prenyl moieties on a bicyclo[3.3.1]nonanetrione core were isolated from the 95% ethanolic extract of Garcinia gummi-gutta fruit. The structures of both compounds were elucidated based on the NMR and MS data with ambiguity in the exact position of the enol and keto functions at C-1 and C-3 of the core structure. The structures of both polyprenylated acylphloroglucinols were established as a structurally revised guttiferone J and the new iso-guttiferone J with the aid of gauge-independent atomic orbital NMR calculations, CP3 probability analyses, specific rotation calculations, and electronic circular dichroism calculations in combination with the experimental data. The structures of both compounds resemble hyperforin, a potent activator of the human pregnane X receptor. As expected, both compounds showed strong pregnane X receptor activation at 10 µM [7.1-fold (guttiferone J) and 5.0-fold (iso-guttiferone J)], explained by a molecular docking study, necessitating further in-depth investigation to substantiate the herb-drug interaction potential of G. gummi-gutta upon co-administration with pharmaceutical drugs.

Hydrophobic eutectic solvents for surface water treatment with a focus on benzophenone type UV filters.

Effective removal of organic UV filters from aquatic environmental compartments and swimming waters is very important because these substances are hazardous to humans and wildlife at low concentrations and act as endocrine disruptors. Therefore, the aim of the present article is to determine the extraction efficiencies of hydrophobic deep eutectic solvents (HDES) for the selected UV filters based on benzophenone structure (benzophenone, 2,4-dihydroxybenzophenone, 2,2´,4,4´-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2´-dihydroxy-4-methoxybenzophenone, 4-methacryloxy-2-hydroxybenzophenone) from aqueous matrices. For this purpose, six HDESs based on dl-menthol in combination with caprylic, decanoic and lauric acid are prepared and compared with referent terpene solvents such as terpineol and linalool. The effect of various parameters such as HDES composition, volume ratio, frequency and shaking time are studied. The highest extraction efficiency is shown by HDES of menthol:caprylic acid (1:1) composition at the aqueous:organic phase volume ratio of 1:1, shaking frequency of 1500 rpm and shaking time of 15 min. The achieved extraction efficiencies are higher than 99.6 % for all benzophenones studied in the purification of stagnant pond water, swimming pool water and river water samples. After a simple and fast sample treatment, the residual levels of benzophenones in the waters are controlled by a newly developed sensitive HPLC-MS/MS method with LOQs in the range of 0.7 - 5.0 ng/mL.

A multiplex approach of MS, 1D-, and 2D-NMR metabolomics in plant ontogeny: A case study on Clusia minor L. organs (leaf, flower, fruit, and seed).

INTRODUCTION: The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives. OBJECTIVES: The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages. MATERIAL AND METHODS: In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC-MS and 1H- and heteronuclear multiple-bond correlation (HMBC)-NMR-based metabolomics. RESULTS: This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5-hydroxy-8-methyltocotrienol (8.5 µg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 µg/mg f.w.). Nemorosone and 5-hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5-hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 µg/mg f.w. Seeds as typical storage organ were rich in sugars and omega-6 fatty acids. CONCLUSION: To the best of our knowledge, this is the first report on a comparative 1D-/2D-NMR approach to assess compositional differences in ontogeny studies compared with LC-MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed.

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators.

Photoinitiators (PIs) are a family of anthropogenic chemicals used in polymerization systems that generate active substances to initiate polymerization reactions under certain radiations. Although polymerization is considered a green method, its wide application in various commercial products, such as UV-curable inks, paints, and varnishes, has led to ubiquitous environmental issues caused by PIs. In this study, we present an overview of the current knowledge on the environmental occurrence, human exposure, and toxicity of PIs and provide suggestions for future research based on numerous available studies. The residual concentrations of PIs in commercial products, such as food packaging materials, are at microgram per gram levels. The migration of PIs from food packaging materials to foodstuffs has been confirmed by more than 100 reports of food contamination caused by PIs. Furthermore, more than 20 PIs have been detected in water, sediment, sewage sludge, and indoor dust collected from Asia, the United States, and Europe. Human internal exposure was also confirmed by the detection of PIs in serum. In addition, PIs were present in human breast milk, indicating that breastfeeding is an exposure pathway for infants. Among the most available studies, benzophenone is the dominant congener detected in the environment and humans. Toxicity studies of PIs reveal multiple toxic end points, such as carcinogenicity and endocrine-disrupting effects. Future investigations should focus on synergistic/antagonistic toxicity effects caused by PIs coexposure and metabolism/transformation pathways of newly identified PIs. Furthermore, future research should aim to develop "greener" PIs with high efficiency, low migration, and low toxicity.

Mechanisms and energetics of benzophenone photosensitized thymine damage and repair from Paternò-Büchi cycloaddition.

Here, we report the detailed mechanisms of benzophenone (BZP) photosensitized thymine damage and repair by Paternò-Büchi (PB) cycloaddition. It was found that the head-to-head and head-to-tail PB cycloadditions lead to the formation of the C-O bonds in the 3(nπ*) state and the 3(ππ*) state, respectively. The conical intersection occurs before the head-to-tail C-O bonding. Then, the C-C bonds are formed via intersystem crossing (ISC). The C-O bonding is the rate-determining step of PB cycloaddition. For the cycloreversion reactions, the ring-opening processes completely occur in the singlet excited states of oxetanes. The head-to-head oxetane goes through a conical intersection before cycloreversion with a little energy barrier of 1.8 kcal mol-1. The head-to-tail oxetane splits without a barrier. Then, the ISC processes take place to restore thymine. Throughout the ring-closing and ring-opening processes, ISC plays an important role. These findings are in good agreement with the available experimental findings. We hope that this comprehensive work can provide a deeper understanding of photosensitive DNA damage and repair.

Garcinol and its analogues: Synthesis, cytotoxic activity and mechanistic investigation.

Garcinol is a polyisoprenylated benzophenone isolated from Garcinia. It has been reported to have a variety of intriguing biological effects, including anticancer, anti-inflammatory, and antioxidant capabilities. The purpose of this research is to thoroughly evaluate garcinol and a series of its analogues in terms of synthesis, structural diversity, biosynthesis, and potential for preventing carcinoma cell proliferation. Garcinopicrobenzophenone and eugeniaphenone, which contain a unique cyclobutyl unit at C-5, were initially synthesized using the procedures utilized in the synthesis of garcinol. All the natural analogs of garcinol were produced at completion of the synthesis, and their structures and absolute configurations were clarified. Based on the synthesis, a possible biogenetic synthesis pathway towards cambogin, 13,14-didehydroxyisogarcinol via O-cyclization, and garcinopicrobenzophenone or eugeniaphenone via C-cyclization was proposed. The cytotoxicity of polyisoprenylated benzophenones produced in our group was tested, and the structure-activity relationship was summarized. The mechanism by which garcinol, cambogin, and 21' induce apoptosis was studied. Cambogin and 21' were shown to have a greater capacity to cause apoptosis in pancreatic cancer BXPC3 cells, and the suppression of BXPC3 cells by 21' might be attributed to the target of STAT3 signaling. Garcinol could cause pyroptosis and apoptosis in pancreatic cancer cells at the same time, which was the first time that garcinol was identified as a possible chemotherapeutic agent that could significantly promote pyroptosis in cancer cells.

Benzophenones in the Environment: Occurrence, Fate and Sample Preparation in the Analysis.

The ubiquitous presence of emerging contaminants in the environment is an issue of great concern. Notably, for some of them, no established regulation exists. Benzophenones are listed as emerging contaminants, which have been identified in the environment as well as in human fluids, such as urine, placenta, and breast milk. Their accumulation and stability in the environment, combined with the revealed adverse effects on ecosystems including endocrine, reproductive, and other disorders, have triggered significant interest for research. Benzophenones should be extracted from environmental samples and determined for environmental-monitoring purposes to assess their presence and possible dangers. Numerous sample preparation methods for benzophenones in environmental matrices and industrial effluents have been proposed and their detection in more complex matrices, such as fish and sludges, has also been reported. These methods range from classical to more state-of-the-art methods, such as solid-phase extraction, dispersive SPE, LLE, SBSE, etc., and the analysis is mostly completed with liquid chromatography, using several detection modes. This review critically outlines sample preparation methods that have been proposed to date, for the extraction of benzophenones from simple and complex environmental matrices and for cleaning up sample extracts to eliminate potential interfering components that coexist therein. Moreover, it provides a brief overview of their occurrence, fate, and toxicity.

Costa Rican Propolis Chemical Compositions: Nemorosone Found to Be Present in an Exclusive Geographical Zone.

BACKGROUND: The chemistry of Costa Rican propolis from Apis mellifera remains underexplored despite its potential applications. This study identified its chemical composition, linking chemotypes to antioxidant potential. METHODS: Proton nuclear magnetic resonance (1H NMR) spectra were obtained for 119 propolis extracts and analyzed using multivariate analyses. In parallel, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was used to assess antioxidant activity. A generalized linear regression model (GLM) correlated this with its chemical profiles and geographical origin. Chromatographic methods were used to isolate active and inactive compounds, which were identified using nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). RESULTS: Principal component analysis (PCA) revealed three chemical profile groups for the 119 propolis extracts, explaining 73% of the total variance with two components. Radical scavenging activity was found to correlate with chemical composition. Isolation yielded n-coniferyl benzoate in type I (EC50 = 190 µg/mL, ORAC = 0.60 µmol TE/µmol) and nemorosone in type II (EC50 = 300 µg/mL, ORAC = 0.7 µmol TE/µmol). Type III was represented in terpene-like components, which exhibited lower antioxidant activity. CONCLUSIONS: This study categorizes Costa Rican propolis into three chemical types and identifies two key components linked to antioxidant activity. Notably, nemorosone, a valuable natural product, was found to be highly concentrated in a particular region of Costa Rica.

The Chemical Space of Marine Antibacterials: Diphenyl Ethers, Benzophenones, Xanthones, and Anthraquinones.

The emergence of multiresistant bacteria and the shortage of antibacterials in the drug pipeline creates the need to search for novel agents. Evolution drives the optimization of the structure of marine natural products to act as antibacterial agents. Polyketides are a vast and structurally diverse family of compounds that have been isolated from different marine microorganisms. Within the different polyketides, benzophenones, diphenyl ethers, anthraquinones, and xanthones have shown promising antibacterial activity. In this work, a dataset of 246 marine polyketides has been identified. In order to characterize the chemical space occupied by these marine polyketides, molecular descriptors and fingerprints were calculated. Molecular descriptors were analyzed according to the scaffold, and principal component analysis was performed to identify the relationships among the different descriptors. Generally, the identified marine polyketides are unsaturated, water-insoluble compounds. Among the different polyketides, diphenyl ethers tend to be more lipophilic and non-polar than the remaining classes. Molecular fingerprints were used to group the polyketides according to their molecular similarity into clusters. A total of 76 clusters were obtained, with a loose threshold for the Butina clustering algorithm, highlighting the large structural diversity of the marine polyketides. The large structural diversity was also evidenced by the visualization trees map assembled using the tree map (TMAP) unsupervised machine-learning method. The available antibacterial activity data were examined in terms of bacterial strains, and the activity data were used to rank the compounds according to their antibacterial potential. This potential ranking was used to identify the most promising compounds (four compounds) which can inspire the development of new structural analogs with better potency and absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties.

Enhanced Antibacterial Ability and Bioactivity of Polyetherketoneketone Modified with LL-37.

Polyetherketoneketone (PEKK) is considered to be a potential substitute material for metal bone implants because of its advantageous biocompatibility, chemical stability, and mechanical properties, but clinical application has been severely restricted due to PEKK's lack of antibacterial ability and biological activity. In this study, LL-37, a natural human antimicrobial peptide, was successfully modified on the PEKK surface with polydopamine as the intermediate layer and released continuously for more than 6 days. The results of the MTT assay, colony counts, and Live/Dead staining demonstrated that compared to unmodified PEKK, the LL-37-modified PEKK significantly inhibited the adhesion, vitality, and bacterial biofilm growth of Staphylococcus aureus and Escherichia coli in a concentration-dependent way. Furthermore, the LL-37-modified PEKK enhanced biocompatibility (cell adhesion and viability) and promoted osteogenic differentiation of human umbilical cord Wharton's jelly-derived mesenchymal stem cells. Our data suggested that LL-37-modified PEKK might be a promising material for use in orthopedic implants.

Benzophenone Glucosides and B-Type Proanthocyanidin Dimers from Zambian Cassia abbreviata and Their Trypanocidal Activities.

Two benzophenone glucosides (1 and 2), five flavan-3-ol dimers (5-9), and 17 known compounds (3, 4, and 10-24) were identified from the bark extract of Cassia abbreviata. The chemical structures display two points of interest. First, as an unusual characteristic feature of the 1H NMR spectra of 1 and 2, the signals for the protons on glucosidic carbons C-2 are shielded as compared to those generally observed for glucosyl moieties. The geometrically optimized 3D structures derived from conformational analysis and density functional theory (DFT) calculations revealed that this shielding effect originates from intramolecular hydrogen bonds in 1 and 2. Additionally, 3-15 were identified as dimeric B-type proanthocyanidins, which have 2R,3S-absolute-configured C-rings and C-4-C-8″ linkages, as evidenced by X-ray crystallography and by NMR and ECD spectroscopy. These results suggest the structure-determining procedures for some reported dimers need to be reconsidered. The trypanocidal activities of the isolated compounds against Trypanosoma brucei brucei, T. b. gambiense, T. b. rhodesiense, T. congolense, and T. evansi were evaluated, and the active compounds were identified.

Benzophenone Rhamnosides and Chromones from Hypericum seniawinii Maxim.

Two new benzophenone glycosides, hypersens A and B, along with four known compounds, (S)-(+)-5,7-dihydroxy-2-(1-methylpropyl) chromone (3), 5,7-dihydroxy-2-isopropylchromone (4), urachromone B (5), and 3-8'' bisapigenin (6), were isolated from Hypericum seniawinii. The structures of new compounds (1 and 2) were elucidated according to comprehensive spectroscopic data analyses. The absolute configurations of 1 and 2 were determined by electronic circular dichroism (ECD) calculations. All isolated compounds were evaluated for their neuroprotective effect using corticosterone-induced PC12 cell injury. In addition, compounds 1-6 were evaluated for their anti-inflammatory activity in lipopolysaccharide-induced RAW 264.7 cells. Compound 6 was a biflavonoid and significantly inhibited the production of nitric oxide with an IC50 value of 11.48 ± 1.23 µM.

Photoreactive Molecular Glue for Enhancing the Efficacy of DNA Aptamers by Temporary-to-Permanent Conjugation with Target Proteins.

We developed a photoreactive molecular glue, BPGlue-N3, which can provide a universal strategy to enhance the efficacy of DNA aptamers by temporary-to-permanent stepwise stabilization of their conjugates with target proteins. As a proof-of-concept study, we applied BPGlue-N3 to the SL1 (DNA aptamer)/c-Met (target protein) conjugate system. BPGlue-N3 can adhere to and temporarily stabilize this aptamer/protein conjugate multivalently using its guanidinium ion (Gu+) pendants that form a salt bridge with oxyanionic moieties (e.g., carboxylate and phosphate) and benzophenone (BP) group that is highly affinitive to DNA duplexes. BPGlue-N3 is designed to carry a dual-mode photoreactivity; upon exposure to UV light, the temporarily stabilized aptamer/protein conjugate reacts with the photoexcited BP unit of adhering BPGlue-N3 and also a nitrene species, possibly generated by the BP-to-N3 energy transfer in BPGlue-N3. We confirmed that SL1, covalently conjugated with c-Met, hampered the binding of hepatocyte growth factor (HGF) onto c-Met, even when the SL1/c-Met conjugate was rinsed prior to the treatment with HGF, and suppressed cell migration caused by HGF-induced c-Met phosphorylation.

Visible-Light-Driven and Self-Hydrogen-Donated Nanofibers Enable Rapid-Deployable Antimicrobial Bioprotection.

The novel coronavirus SARS-CoV-2 has prompted a worldwide pandemic and poses a great threat to public safety and global economies. Most present personal protective equipment (PPE) used to intercept pathogenic microorganisms is deficient in biocidal properties. Herein, we present green nanofibers with effective antibacterial and antiviral activities that can provide sustainable bioprotection by continuously producing reactive oxygen species (ROS). The superiority of the design is that the nanofibers can absorb and store visible light energy and maintain the activity under light or dark environment. Moreover, the nanofibers can uninterruptedly release ROS in the absence of an external hydrogen donor, acting as a biocide under all weather conditions. A facile spraying method is proposed to rapidly deploy the functional nanofibers to existing PPE, such as protective suits and masks. The modified PPE exhibit stable ROS production, excellent capacity for storing activity potential, long-term durability, and high bactericidal (>99.9%) and viricidal (>99.999%) efficacies.

Benzophenone Accumulates over Time from the Degradation of Octocrylene in Commercial Sunscreen Products.

Benzophenone is a mutagen, carcinogen, and endocrine disruptor. Its presence in food products or food packaging is banned in the United States. Under California Proposition 65, there is no safe harbor for benzophenone in any personal care products, including sunscreens, anti-aging creams, and moisturizers. The purpose of this study was to determine (1) if benzophenone was present in a wide variety of commercial sun protection factor (SPF)/sunscreen products, (2) whether benzophenone concentration in the product increased over time, and (3) if the degradation of octocrylene was the likely source for benzophenone contamination. Benzophenone concentration was assayed in nine commercial sunscreen products from the European Union and eight from the United States (in triplicate), including two single ingredient sources of octocrylene. These same SPF items were subjected to the United States Food and Drug Administration (U.S. FDA)-accelerated stability aging protocol for 6 weeks. Benzophenone was measured in the accelerated-aged products. Sixteen octocrylene-containing product lines that were recently purchased had an average concentration of 39 mg/kg benzophenone, ranging from 6 mg/kg to 186 mg/kg. Benzophenone was not detectable in the product that did not contain octocrylene. After subjecting the 17 products to the U.S. FDA-accelerated stability method, the 16 octocrylene-containing products had an average concentration of 75 mg/kg, ranging from 9.8 mg/kg to 435 mg/kg. Benzophenone was not detectable in the product that did not contain octocrylene. Benzophenone was detected in the pure octocrylene manufactured ingredient. Octocrylene generates benzophenone through a retro-aldol condensation. In vivo, up to 70% of the benzophenone in these sunscreen products may be absorbed through the skin. U.S. FDA has established a zero tolerance for benzophenone as a food additive. In the United States, there were 2999 SPF products containing octocrylene in 2019. The safety of octocrylene as a benzophenone generator in SPF or any consumer products should be expeditiously reviewed by regulatory agencies.

Enhanced Disrupting Effect of Benzophenone-1 Chlorination Byproducts to the Androgen Receptor: Cell-Based Assays and Gaussian Accelerated Molecular Dynamics Simulations.

Benzophenone-1 (BP-1), one of the commonly used ultraviolet filters, has caused increasing public concern due to frequently detected residues in environmental and recreational waters. Its susceptibility to residual chlorine and the potential to subsequently trigger endocrine disruption remain unknown. We herein investigated the chlorination of BP-1 in swimming pool water and evaluated the endocrine disruption toward the human androgen receptor (AR). The structures of monochlorinated (P1) and dichlorinated (P2) products were separated and characterized by mass spectrometry and 1H-1H NMR correlation spectroscopy. P1 and P2 exhibited significantly higher antiandrogenic activity in yeast two-hybrid assays (EC50, 6.13 µM and 9.30 µM) than did BP-1 (12.89 µM). Our 350 ns Gaussian accelerated molecular dynamics simulations showed the protein dynamics in a long-time scale equilibrium, and further energy calculations revealed that although increased hydrophobic interactions are primarily responsible for enhanced binding affinities between chlorinated products and the AR ligand binding domain, the second chloride in P2 still hinders the complex motion because of the solvation penalty. The mixture of BP-1-P1-P2 elicited additive antiandrogenic activity, well fitted by the concentration addition model. P1 and P2 at 1 µM consequently downregulated the mRNA expression of AR-regulated genes, NKX3.1 and KLK3, by 1.7-9.1-fold in androgen-activated LNCaP cells. Because chlorination of BP-1 occurs naturally by residual chlorine in aquatic environments, our results regarding enhanced antiandrogenic activity and disturbed AR signaling provided evidence linking the use of personal care products with potential health risks.

Synergistic bactericidal effects of pairs of photosensitizer molecules activated by ultraviolet A light against bacteria in plasma.

BACKGROUND: The current approach to reducing bacterial contamination in blood transfusion products is through detection or pathogen reduction methods, some of which utilize ultraviolet (UV) light photosensitizers. A small number of photosensitizers are being used as single agents in combination with UV light, but their efficacy can be limited against some pathogens. Benzophenone (BP) and vitamins B1, B6, and K3 have been identified as effective UVA photosensitizers for inactivation of bacteria. We evaluated whether combining pairs of photosensitizers in this group would have synergistic bactericidal effects on Gram-negative and Gram-positive bacteria. STUDY DESIGN AND METHODS: Bacteria species of Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Klebsiella pneumoniae were mixed with 0 to 100 mM concentrations of photosensitizers and exposed to UVA irradiation at 18 J/cm2 to assess their bactericidal effects. RESULTS: Single photosensitizers irradiated with UVA produced a range of bactericidal activity. When combined in pairs, all demonstrated some synergistic bactericidal effects with up to 4-log reduction above the sum of activities of individual molecules in the pair against bacteria in plasma. Photosensitizer pairs with BP had the highest synergism across all bacteria. With vitamin K3 in the pair, synergism was evident for Gram-positive but not for Gram-negative bacteria. Vitamin B1 and vitamin B6 had the least synergism. These results indicate that a combination approach with multiple photosensitizers may extend effectiveness of pathogen reduction in plasma. CONCLUSIONS: Combining photosensitizers in pathogen reduction methods could improve bactericidal efficacy and lead to use of lower concentrations of photosensitizers to reduce toxicities and unwanted side effects.

Stability of Diazepam Solution for Injection Following Long-Term Storage in an Ambient Temperature of the Mediterranean Climate.

PURPOSE: Diazepam is utilized as a convulsion antidote following nerve gas attacks. As an emergency medicine, it requires storage at ambient temperatures which often doesn't meet manufacturers' requirements, leading to an early invalidation of the product. Current work investigated this issue. METHODS: Long-term stability of diazepam ampoules for injection stored in an ambient temperature of the Mediterranean climate for ~10 years vs storage at room temperature was studied. RESULTS: Diazepam assay and pH remained within pharmacopeial specifications irrespective of storage conditions. A major degradation product 2-methylamino-5-chlorobenzophenone (MACB) showed a clear trend of accumulation as a function of storage time, exceeding the permitted limit at ~2 years, irrespective of storage conditions. A strong correlation between the discoloration of the solutions and the concentration of MACB was obtained. Intravenous administration of MACB to rats at doses ~2200-fold higher than permissible specification levels caused neither mortality nor any toxicological nor post-mortem findings. CONCLUSIONS: Regarding the parameters tested: diazepam assay, MACB assay, and pH, storing ampoules of diazepam solution for injection in field conditions of high temperatures of the Mediterranean climate did not cause accelerated degradation as compared to room temperature. These findings open an option for the usage of expired ampoules in special scenarios.