Methanolic Extract and Brominated Compound from the Brazilian Marine Sponge Aplysina fulva Are Neuroprotective and Modulate Inflammatory Profile of Microglia.

Neurodegenerative diseases involve neuroinflammation and a loss of neurons, leading to disability and death. Hence, the research into new therapies has been focused on the modulation of the inflammatory response mainly by microglia/macrophages. The extracts and metabolites of marine sponges have been presented as anti-inflammatory. This study evaluated the toxicity of an extract and purified compound from the Brazilian marine sponge Aplysina fulva as well as its neuroprotection against inflammatory damage associated with the modulation of microglia response. PC12 neuronal cells and neonatal rat microglia were treated with the methanolic extract of A. fulva (AF-MeOH, 0.1-200 µg/mL) or with its purified dimethyl ketal of 3,5-dibromoverongiaquinol (AF-H1, 0.1-100 µM). Cytotoxicity was determined by MTT tetrazolium, Trypan blue, and propidium iodide; microglia were also treated with the conditioned medium (CM) from PC12 cells in different conditions. The microglia phenotype was determined by the expression of Iba-1 and CD68. AF-MeOH and AF-H1 were not toxic to PC12 or the microglia. Inflammatory damage with Escherichia coli lipopolysaccharide (LPS, 5 µg/mL) was not observed in the PC12 cells treated with AF-MeOH (1-10 µg/mL) or AF-H1 (1-10 µM). Microglia subjected to the CM from PC12 cells treated with LPS and AF-MeOH or AF-H1 showed the control phenotype-like (multipolar, low-CD68), highlighting the anti-neuroinflammatory and neuroprotective effect of components of this marine sponge.

Integrated analysis of exoskeletal surface profile and chitin-related gene expression on Macrophthalmus japonicus mud crabs exposed to hexabromocyclododecane.

Hexabromocyclododecanes (HBCDs), widely used brominated flame retardants, easily accumulate in aquatic organisms such as Macrophthalmus japonicus crabs, which inhabit tidal flat sediments. To analyze the effects of HBCD exposure in chitin-formed exoskeleton, we investigated molecular responses of chitin-related genes as well as physical changes of the exoskeletal surface form as a new biological end-point on M. japonicus. The expression patterns of chitin biosynthesis-, modification-, and degradation-related genes in the gills and hepatopancreases of M. japonicus were also analyzed. Additionally, the survivability and exoskeleton surface profiles of M. japonicus crabs were evaluated. M. japonicus chitin synthase expression was significantly downregulated, whereas that of the chitinase transcript was significantly upregulated upon exposure to all HBCD concentrations on day 7. Contrastingly, the gene expression of chitin deacetylase 1 significantly increased upon exposure to all HBCD concentrations on day 1, and this increase was significantly elevated on day 4. The expression of chitin deacetylase 1 was dose-dependent. Additionally, decreased survival and exoskeleton surface profile changes were observed in M. japonicus crabs exposed to all HBCD concentrations. These results suggest that exposure to HBCD induces changes in the synthesis, modification, and degradation of chitin, a pivotal component of the cuticular exoskeleton, and may disrupt the exoskeletal surface structure in M. japonicus crabs.

Transcriptomic Analysis of the Differential Nephrotoxicity of Diverse Brominated Flame Retardants in Rat and Human Renal Cells.

Brominated flame retardants (BFRs) are environmentally persistent, are detected in humans, and some have been banned due to their potential toxicity. BFRs are developmental neurotoxicants and endocrine disruptors; however, few studies have explored their potential nephrotoxicity. We addressed this gap in the literature by determining the toxicity of three different BFRs (tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), and tetrabromodiphenyl ether (BDE-47)) in rat (NRK 52E) and human (HK-2 and RPTEC) tubular epithelial cells. All compounds induced time- and concentration-dependent toxicity based on decreases in MTT staining and changes in cell and nuclear morphology. The toxicity of BFRs was chemical- and cell-dependent, and human cells were more susceptible to all three BFRs based on IC50s after 48 h exposure. BFRs also had chemical- and cell-dependent effects on apoptosis as measured by increases in annexin V and PI staining. The molecular mechanisms mediating this toxicity were investigated using RNA sequencing. Principal components analysis supported the hypothesis that BFRs induce different transcriptional changes in rat and human cells. Furthermore, BFRs only shared nine differentially expressed genes in rat cells and five in human cells. Gene set enrichment analysis demonstrated chemical- and cell-dependent effects; however, some commonalities were also observed. Namely, gene sets associated with extracellular matrix turnover, the coagulation cascade, and the SNS-related adrenal cortex response were enriched across all cell lines and BFR treatments. Taken together, these data support the hypothesis that BFRs induce differential toxicity in rat and human renal cell lines that is mediated by differential changes in gene expression.

Total Synthesis and Anti-Inflammatory Bioactivity of (-)-Majusculoic Acid and Its Derivatives.

The first total synthesis of marine natural product, (-)-majusculoic acid (1) and its seven analogs (9-15), was accomplished in three to ten steps with a yield of 3% to 28%. The strategy featured the application of the conformational controlled establishment of the trans-cyclopropane and stereochemical controlled bromo-olefination or olefination by Horner-Wadsworth-Emmons (HWE) reaction. The potential anti-inflammatory activity of the eight compounds (1 and 9-15) was evaluated by determining the nitric oxide (NO) production in the lipopolysaccharide (LPS)-induced mouse macrophages RAW264.7. (-)-Majusculoic acid (1), methyl majusculoate (9), and (1R,2R)-2-((3E,5Z)-6-bromonona-3,5-dien-1-yl)cyclopropane-1-carboxylic acid (12) showed significant effect with inhibition rates of 33.68%, 35.75%, and 43.01%, respectively. Moreover, they did not show cytotoxicity against RAW264.7 cells, indicating that they might be potential anti-inflammatory agents.

Asialoglycoprotein Receptor-Targeted Superparamagnetic Perfluorooctylbromide Nanoparticles.

Background: The decrease in asialoglycoprotein receptor (ASGPR) levels is observed in patients with chronic liver disease and liver tumor. The aim of our study was to develop ASGPR-targeted superparamagnetic perfluorooctylbromide nanoparticles (M-PFONP) and wonder whether this composite agent could target buffalo rat liver (BRL) cells in vitro and could improve R2 ∗ value of the rat liver parenchyma after its injection in vivo. Methods: GalPLL, a ligand of ASGPR, was synthesized by reductive amination. ASGPR-targeted M-PFOBNP was prepared by a film hydration method coupled with sonication. Several analytical methods were used to investigate the characterization and safety of the contrast agent in vitro. The in vivo MR T2 ∗ mapping was performed to evaluate the enhancement effect in rat liver. Results: The optimum concentration of Fe3O4 nanoparticles inclusion in GalPLL/M-PFOBNP was about 52.79 µg/mL, and the mean size was 285.6 ± 4.6 nm. The specificity of GalPLL/M-PFOBNP for ASGPR was confirmed by incubation experiment with fluorescence microscopy. The methyl thiazolyl tetrazolium (MTT) test showed that there was no significant difference in the optical density (OD) of cells incubated with all GalPLL/M-PFOBNP concentrations. Compared with M-PFOBNP, the increase in R2 ∗ value of the rat liver parenchyma after GalPLL/M-PFOBNP injection was higher. Conclusions: GalPLL/M-PFOBNP may potentially serve as a liver-targeted contrast agent for MR receptor imaging.

Potentiation of (α4)2(ß2)3, but not (α4)3(ß2)2, nicotinic acetylcholine receptors reduces nicotine self-administration and withdrawal symptoms.

The low sensitivity (α4)3(ß2)2 (LS) and high sensitivity (α4)2(ß2)3 (HS) nAChR isoforms may contribute to a variety of brain functions, pathophysiological processes, and pharmacological effects associated with nicotine use. In this study, we examined the contributions of the LS and HS α4ß2 nAChR isoforms in nicotine self-administration, withdrawal symptoms, antinociceptive and hypothermic effects. We utilized two nAChR positive allosteric modulators (PAMs): desformylflustrabromine (dFBr), a PAM of both the LS and HS α4ß2 nAChRs, and CMPI, a PAM selective for the LS nAChR. We found that dFBr, but not CMPI, decreased intravenous nicotine self-administration in male mice in a dose-dependent manner. Unlike dFBr, which fully reverses somatic and affective symptoms of nicotine withdrawal, CMPI at doses up to 15 mg/kg in male mice only partially reduced nicotine withdrawal-induced somatic signs, anxiety-like behavior and sucrose preference, but had no effects on nicotine withdrawal-induced hyperalgesia. These results indicate that potentiation of HS α4ß2 nAChRs is necessary to modulate nicotine's reinforcing properties that underlie nicotine intake and to reverse nicotine withdrawal symptoms that influence nicotine abstinence. In contrast, both dFBr and CMPI enhanced nicotine's hypothermic effect and reduced nicotine's antinociceptive effects in male mice. Therefore, these results indicate a more prevalent role of HS α4ß2 nAChR isoforms in mediating various behavioral effects associated with nicotine, whereas the LS α4ß2 nAChR isoform has a limited role in mediating body temperature and nociceptive responses. These findings will facilitate the development of more selective, efficacious, and safe nAChR-based therapeutics for nicotine addiction treatment.

Synthesis and antibacterial activities of marine natural product ianthelliformisamines and subereamine synthetic analogues.

Marine sponges of the genusSuberea produce variety of brominated tyrosine alkaloids which display diverse range of biological activities including antiproliferative, antimicrobial and antimalarial activities. In continuation of our search for biologically active marine natural products for antibacterial compounds, we report here the synthesis and evaluation of biological activity of panel of ianthelliformisamines and subereamine analogues using the literature known acid-amine coupling reaction. Several derivatives of Ianthelliformisamine were achieved by the coupling of Boc-protected polyamine chain with brominated aromatic acrylic acid derivatives by varying the bromine substituents on aromatic acid derivatives, amine spacer as well as geometry of the double bond, and then Boc-deprotection using TFA. Similarly, subereamine analogues were also synthesized employing coupling reaction between various brominated phenyl acrylic acids with commercially available chiral amino ester derivatives followed by ester hydrolysis. We screened these synthetic analogues for antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains. One of the compound 7c showed bactericidal activity against Staphylococcus aureus with an IC50 value of 3.8 µM (MIC = 25 µM).

Progress of Bromophenols in Marine Algae from 2011 to 2020: Structure, Bioactivities, and Applications.

Marine algae contain various bromophenols that have been shown to possess a variety of biological activities, including antiradical, antimicrobial, anticancer, antidiabetic, anti-inflammatory effects, and so on. Here, we briefly review the recent progress of these marine algae biomaterials and their derivatives from 2011 to 2020, with respect to structure, bioactivities, and their potential application as pharmaceuticals.

Novel effective antibacterial small-molecules against Staphylococcus and Enterococcus strains.

Background: Resistance developments against established antibiotics are an emerging problem for antibacterial therapies. Novel antibiotics are urgently needed. Materials & methods: We developed novel small-molecule antibacterials which are easily accessible in a simple one-pot synthesis. The central cyclopentaindole core is substituted with two indole residues. Various indole and cyclopentane substituents have been introduced. Additionally, first indole substituted propene compounds as ring-open variants of the cyclopentaindoles have been yielded and evaluated as antibacterials against Staphylococcus aureus and Enterococcus strains. Results: Most effective compounds have been those with a bromo cyclopentane and a chloro indole substitution. First lead compounds were identified with promising activities similar to that observed in vitro for last resort antibiotics, so that the novel compounds enriche the pool of perspective small-molecule antibacterial drug candidates.

Antimycobacterial Activity of Laurinterol and Aplysin from Laurencia johnstonii.

Marine environments represent a great opportunity for the discovery of compounds with a wide spectrum of bioactive properties. Due to their large variety and functions derived from natural selection, marine natural products may allow the identification of novel drugs based not only on newly discovered bioactive metabolites but also on already known compounds not yet thoroughly investigated. Since drug resistance has caused an increase in infections by Mycobacterium tuberculosis and nontuberculous mycobacteria, the re-evaluation of known bioactive metabolites has been suggested as a good approach to addressing this problem. In this sense, this study presents an evaluation of the in vitro effect of laurinterol and aplysin, two brominated sesquiterpenes isolated from Laurencia johnstonii, against nine M. tuberculosis strains and six nontuberculous mycobacteria (NTM). Laurinterol exhibited good antimycobacterial activity, especially against nontuberculous mycobacteria, being remarkable its effect against Mycobacterium abscessus, with minimum inhibitory concentration (MIC) values lower than those of the reference drug imipenem. This study provides further evidence for the antimycobacterial activity of some sesquiterpenes from L. johnstonii, which can be considered interesting lead compounds for the discovery of novel molecules to treat NTM infections.

Desformylflustrabromine, a positive allosteric modulator of α4ß2-containing nicotinic acetylcholine receptors, enhances cognition in rats.

RATIONALE: The α4ß2 nicotinic acetylcholine receptors (α4ß2-nAChRs) may represent useful targets for cognitive improvement. It has been recently proposed that a strategy based on positive allosteric modulation of α4ß2-nAChRs reveals several advantages over the direct agonist approach. Nevertheless, the procognitive effects of α4ß2-nAChR positive allosteric modulators (PAMs) have not been extensively characterized. OBJECTIVES: The aim of the present study was to evaluate the procognitive efficacy of desformylflustrabromine (dFBr), a selective α4ß2-nAChR PAM. METHODS: Cognitive effects were investigated in the novel object recognition task (NORT) and the attentional set-shifting task (ASST) in rats. RESULTS: The results demonstrate that dFBr attenuated the delay-induced impairment in NORT performance and facilitated cognitive flexibility in the ASST. The beneficial effects of dFBr were inhibited by dihydro-ß-erythroidine, a relatively selective α4ß2-nAChR antagonist, indicating the involvement of α4ß2-nAChRs in cognitive processes. The tested α4ß2-PAM was also effective against ketamine- and scopolamine-induced deficits of object recognition memory. Moreover, procognitive effects were also observed after combined treatment with inactive doses of dFBr and TC-2403, a selective α4ß2-nAChR agonist. CONCLUSIONS: These findings indicate that dFBr presents procognitive activity, supporting the strategy based on α4ß2-nAChR potentiation as a plausible therapy for cognitive impairment.

A double-blind placebo-controlled randomized trial on the effect of hyosine n-butyl bromide for improving duration of labor in term pregnancies.

AIM: To compare the effectiveness of intramuscular hyocine n-butyl bromide (HBB) with placebo for shortening the duration of the first stage of labor in term pregnancies. METHODS: A double blind placebo-controlled randomized trial of parturients who presented at term in the active phase of labor was conducted. They were randomly (1:1 ratio) given intramuscular injection of either 40 mg (2 mL) of HBB or 2 mL of water for injection as a placebo. The primary outcome measures were the duration of first and second stages of labor. Subgroup analysis of primigravid and multigravid women were also performed for various outcomes. We did intention-to-treat analysis. RESULTS: Sixty-two women were randomized to each group and none were lost to follow-up. Baseline characteristics were similar between the HBB and placebo groups. The mean duration of first stage of labor was noted to be significantly shorter in the HBB group for both the primigravidas (246.6 ± 21.9 vs 391.8 ± 56.6 min for control; P < 0.001) and for multigravidas (205.9 ± 17.8 vs 323.8 ± 16.0 min for control;P < 0.001).There was also significantly shorter duration of second stage of labor in the HBB group (primigravida: P = 0.013; multigravida: P = 0.016). The duration of third stage of labor, mode of delivery and maternal and/or neonatal outcomes for both classes of parturients were not significantly different. CONCLUSION: HBB is effective in reducing the first and second stages of labor without adverse maternal or neonatal outcome. HBB does not significantly influence the duration of third stage of labor including mode of delivery. More evidence is needed to further explore the potential useful role of HBB in the active phase of labor.

Heme Oxygenase-1 and Carbon Monoxide Regulate Growth and Progression in Glioblastoma Cells.

In human glioma tumours, heme oxygenase-1 (HO-1) is overexpressed when compared with normal brain tissues and during oligodendroglioma progression. However, the molecular mechanisms mediated by HO-1 to promote glioblastoma remain unknown. We therefore aimed at investigating the effect of HO-1 expression and its selective enzymatic inhibition in two different cell lines (i.e. A172 and U87-MG). HO-1 was induced by hemin treatment (10 µM), and VP13/47 (100 µM) was used as a specific non-competitive inhibitor of HO-1 activity. Cell proliferation was measured by cell index measurement (xCelligence technology) and clonogenic assay, whereas cell migration was assessed by wound healing assay. Carbon monoxide-releasing molecules (CORMs) (i.e. CORM-3 and CORM-A1) were also used in a separate set of experiments to confirm the effect of HO-1 by-product in glioblastoma progression further. Our results were further validated using GSE4412 microarray dataset analysis and comparing biopsies overexpressing HO-1 with the rest of the cases. Our results showed that hemin was able to induce both HO-1 gene and protein expression in a cell-dependent manner being A172 more responsive to pharmacological upregulation of HO-1. Hemin, but not CORMs treatment, resulted in a significant increase of cell proliferation following 24 h of treatment as measured by increased cell index and colony formation capacity and such effect was abolished by VP13/47. Interestingly, both hemin and CORMs showed a significant effect on the wound healing assay also exhibiting cell specificity. Finally, our dataset analysis showed a positive correlation of HO-1 gene expression with ITGBI and ITGBII which are membrane receptors involved in cell adhesion, embryogenesis, tissue repair, immune response and metastatic diffusion of tumour cells. In conclusion, our data suggest that HO-1 and its by-product CO exhibit a cell-specific effect on various aspects of disease progression and are associated with a complex series of molecular mechanisms driving cell proliferation, survival and metastasis.

Non-competitive heme oxygenase-1 activity inhibitor reduces non-small cell lung cancer glutathione content and regulates cell proliferation.

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related death mainly due to its high metastatic rate. Impairment of redox homeostasis mechanisms has been previously described in NSCLC and is associated with the disease itself as well as with comorbidities such as smoking. The aim of the present in vitro study was to evaluate the effect of selective and non-competitive inhibition of heme oxygenase-1 (HO-1) on cancer redox homeostasis with particular regards to glutathione (GSH) metabolism related enzymes. NSCLC cell line (A549) was treated with the HO-1 activity inhibitor VP13/47 (10 µM) and we further evaluated cell viability, apoptosis, mitochondrial dysfunction and oxidative stress. Our results showed that VP13/47 significantly reduced HO-1 expression and total HO activity thus, resulting in a significant reduction of cell viability, proliferation and increased apoptosis, mitochondrial dysfunction and oxidative stress. Consistently with increased oxidative stress, we also showed that reduced GSH was significantly decreased and such effect was also accompanied by a significant downregulation of the enzymes involved in its biosynthesis. Taken all together our results show that selective HO-1 inhibition significantly impairs NSCLC progression and may represent a possible pharmacological strategy for new chemotherapy agents.

Inhibition of UDP-glucuronosyltransferases (UGTs) by bromophenols (BPs).

Bromophenols (BPs) are important organic compounds which have become dominant pollutants during these years. Our present study investigated the potential inhibition behaviour of BPs on the activity of one of the most important phase II drug-metabolizing enzymes (DMEs), UDP-glucuronosyltransferases (UGTs). Recombinant UDP-glucuronosyltransferases (UGTs)-catalyzed glucuronidation of 4-methylumbelliferone (4-MU) was utilized as the probe reaction. 100 µM of BPs was utilized as the inhibition screening concentrations, and the complete inhibition profile of UGT isoforms by BPs was obtained. UGT1A7 was the most vulnerable UGT isoform towards BPs. Some structure-activity relationship for the inhibition of UGTs by BPs was found, and this relationship can be furtherly explained by the hydrophobic contacts of BPs with the activity cavity of UGTs using in silico docking method. The inhibition kinetics determination showed that the inhibition kinetic parameter Ki value was calculated to be 2.85, 3.99 and 31.00 µM for the inhibition of UGT1A3, UGT1A7, and UGT2B7 by representative BPs, 2,4,6-TBP. Combined with in vivo exposure concentration of 2,4,6-TBP, in vitro-in vivo extrapolation (IVIVE) was employed to demonstrate the moderate possibility for the inhibition of UGT1A3 and UGT1A7 by 2,4,6-TBP. In conclusion, our study gave the full description towards the inhibition of BPs towards UGT isoforms, which will provide a new perspective for elucidating the toxicity mechanism of bromophenols (BPs).

Development and Validation of an HPLC Method for the Quantitative Analysis of Bromophenolic Compounds in the Red Alga Vertebrata lanosa.

Bromophenols are a class of compounds occurring in red algae that are thought to play a role in chemical protection; however, their exact function is still not fully known. In order to investigate their occurrence, pure standards of seven bromophenols were isolated from a methanolic extract of the epiphytic red alga Vertebrata lanosa collected in Brittany, France. The structures of all compounds were determined by NMR and MS. Among the isolated substances, one new natural product, namely, 2-amino-5-(3-(2,3-dibromo-4,5-dihydroxybenzyl)ureido)pentanoic acid was identified. An HPLC method for the separation of all isolated substances was developed using a Phenomenex C8(2) Luna column and a mobile phase comprising 0.05% trifluoroacetic acid in water and acetonitrile. Method validation showed that the applied procedure is selective, linear (R2 0.999), precise (intra-day ≤ 6.28%, inter-day ≤ 5.21%), and accurate (with maximum displacement values of 4.93% for the high spikes, 4.80% for the medium spikes, and 4.30% for the low spikes). For all standards limits of detection (LOD) were lower than 0.04 µg/mL and limits of quantification (LOQ) lower than 0.12 µg/mL. Subsequently, the method was applied to determine the bromophenol content in Vertebrata lanosa samples from varying sampling sites and collection years showing values between 0.678 and 0.005 mg/g dry weight for different bromophenols with significant variations between the sampling years. Bioactivity of seven isolated bromophenols was tested in agar diffusion tests against Staphylococcus aureus and Escherichia coli bacteria. Three compounds showed a small zone of inhibition against both test organisms at a concentration of 100 µg/mL.

URC102, a potent and selective inhibitor of hURAT1, reduced serum uric acid in healthy volunteers.

OBJECTIVE: URC102, a novel and potent inhibitor of human uric acid transporter 1 (hURAT1), is currently under clinical development to treat patients with gout. We performed a randomized, double-blind, placebo-controlled, phase I study to evaluate the safety, tolerability, pharmacodynamic, and pharmacokinetic profiles of URC102 after single and multiple oral administration in healthy male subjects. METHODS: Thirty-one Koreans and 23 Caucasians received a single dose of URC102 at 1-30 mg and 1-10 mg, respectively, while 44 Koreans received URC102 once-daily for 7 days at 1-20 mg. We evaluated safety and tolerability throughout the study, and serially determined serum uric acid, the fractional excretion of uric acid and URC102 concentrations. RESULTS: URC102 was well tolerated over the dose range of 1-10 mg after single and multiple administration. URC102 rapidly reduced serum uric acid, which was maintained over the entire treatment period. Furthermore, URC102 increased the area-under-the-effect curve over 168 h for fractional excretion of uric acid in a dose-dependent manner. The maximum plasma concentration and the area under the plasma concentration-time curve of URC102 increased dose-proportionally. The pharmacokinetic and pharmacodynamics characteristics of URC102 were similar in Koreans and Caucasians. CONCLUSION: URC102 was safe and effectively lowered serum uric acid, which should be tested and confirmed in patients with hyperuricaemia and/or gout through further studies. TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01953497 and NCT02524678.

Acute Administration of Desformylflustrabromine Relieves Chemically Induced Pain in CD-1 Mice.

Neuronal nicotinic acetylcholine receptors are cell membrane-bound ion channels that are widely distributed in the central nervous system. The α4ß2 subtype of neuronal nicotinic acetylcholine receptor plays an important role in modulating the signaling pathways for pain. Previous studies have shown that agonists, partial agonists, and positive allosteric modulators for the α4ß2 receptors are effective in relieving pain. Desformylflustrabromine is a compound that acts as an allosteric modulator of α4ß2 receptors. The aim of this study was to assess the effects of desformylflustrabromine on chemically induced pain. For this purpose, the formalin-induced pain test and the acetic acid-induced writhing response test were carried out in CD-1 mice. Both tests represent chemical assays for nociception. The results show that desformylflustrabromine is effective in producing an analgesic effect in both tests used for assessing nociception. These results suggest that desformylflustrabromine has the potential to become a clinically used drug for pain relief.

Synthesis and Structure-Activity Relationship of Omaezallene Derivatives.

Omaezallene derivatives (nor-bromoallene, nor-bromodiene, and bromoenynes) were successfully synthesized. Their antifouling activity and toxicity to the cypris larvae of the barnacle Amphibalanus amphitrite and ecotoxicity to the marine crustacean Tigriopus japonicus were studied. It was revealed that the two side chains of omaezallene were essential to its antifouling activity because the activities of nor-bromoallene and nor-bromodiene were significantly diminished. The bromoenyne was found to exhibit potent antifouling activities comparable to omaezallene with low toxicity and ecotoxicity. Preparation of bromoenyne framework is much easier than that of bromodiene moiety in omaezallene. Based on the antifouling activities of the bromoenynes, the synthesis of fluorescent probes and evaluation of their biological activities were also carried out.

Fusogens: Chemical Agents That Can Rapidly Restore Function After Nerve Injury.

BACKGROUND: Restoring function after nerve injury remains one of medicine's greatest challenges. The current approach of epineurial coaptation does not address the fundamental insult at the molecular level: a discontinuity in the axonal membranes. Membrane fusion is possible through agents collectively called chemical fusogens, which are heterogeneous in structure and mechanism of action. We sought a unifying system for classifying fusogens to better understand their role in cell fusion. MATERIALS AND METHODS: We conducted a comprehensive literature review to identify the most commonly cited chemical fusogens, their structures, mechanisms of actions, and clinical applications to date. We identified seven chemical fusogens (polyethylene glycol, chitosan, dextran sulfate, n-nonyl bromide, calcium, sodium nitrate, and H-α-7), which have each been studied to different extents in protoplasts, animals, and humans. RESULTS: Chemical fusogens achieve cell fusion by one of two ways: bringing cells in close enough proximity to each other so the inherent fluidity of the phospholipid membrane allows for their rearrangement or modifying the surface charges of the membranes to diminish repellent charges. Sowers initially put forth a classification system that identified these agents as cell aggregators and membrane modifiers, respectively. We adapted this classification system in the setting of axonal membrane fusion and hypothesized that the most effective approach to axonal membrane repair is likely combination of both. CONCLUSIONS: Chemical fusogens could be grouped into two mechanistic categories-cell aggregators and membrane modifiers. For axonal membrane fusion, a combination of both mechanisms can significantly contribute to advancing outcomes in peripheral nerve repair via a chemical-surgical intervention.