Uncovering the Formation of Color Gradients for Glucose Colorimetric Assays on Microfluidic Paper-Based Analytical Devices by Mass Spectrometry Imaging.

This study describes the use of mass spectrometry imaging with matrix-assisted laser desorption/ionization (MALDI) and desorption electrospray ionization (DESI) to understand the color gradient generation commonly seen in microfluidic paper-based analytical devices (µPADs). The formation of color gradients significantly impacts assay sensitivity and reproducibility with µPADs but the mechanism for formation is poorly understood. The glucose enzymatic assay using potassium iodide (KI) as a chromogenic agent was selected to investigate the color gradient generated across a detection spot. Colorimetric measurements revealed that the relative standard deviation for the recorded pixel intensities ranged between 34 and 40%, compromising the analytical reliability. While a variety of hypotheses have been generated to explain this phenomenon, few studies have attempted to elucidate the mechanisms associated with its formation. Mass spectrometry imaging using MALDI and DESI was applied to understand the nonuniform color distribution on the detection zone. MALDI experiments were first explored to monitor the spatial distribution of the glucose oxidase and horseradish peroxidase mixture, before and after lateral flow assay with and without KI. MALDI(+)-TOF data revealed uniform enzyme distribution on the detection spots. On the other hand, after the complete assay DESI(-) measurements revealed a heterogeneous shape indicating the presence of iodide and triiodide ions at the zone edge. The reaction product (I3-) is transported by lateral flow toward the zone edge, generating the color gradient. Mass spectrometry imaging has been used for the first time to prove that color gradient forms as result of the mobility small molecules and not the enzyme distribution on µPAD surface.

Molecular docking and pharmacological/toxicological assessment of a new compound designed from celecoxib and paracetamol by molecular hybridization.

Nonsteroidal anti-inflammatory drugs are commonly used worldwide; however, they have several adverse effects, evidencing the need for the development of new, more effective and safe anti-inflammatory and analgesic drugs. This research aimed to design, synthesize and carry out a pharmacological/toxicological investigation of LQFM-102, which was designed from celecoxib and paracetamol by molecular hybridization. To evaluate the analgesic effect of this compound, we performed formalin-induced pain, hot plate and tail flick tests. The anti-inflammatory effect of LQFM-102 was evaluated in carrageenan-induced paw oedema and pleurisy tests. The biochemical markers indicative of toxicity-AST, ALT, GSH, urea and creatinine-as well as the index of gastric lesion after prolonged administration of LQFM-102 were also analyzed. In addition, the interaction of LQFM-102 with COX enzymes was evaluated by molecular docking. In all experimental protocols, celecoxib or paracetamol was used as a positive control at equimolar doses to LQFM-102. LQFM-102 reduced the pain induced by formalin in both phases of the test. However, this compound did not increase the latency to thermal stimuli in the hot plate and tail flick tests, suggesting an involvement of peripheral mechanisms in this effect. Furthermore, LQFM-102 reduced paw oedema, the number of polymorphonuclear cells, myeloperoxidase activity and TNF-α and IL-1ß levels. Another interesting finding was the absence of alterations in the markers of hepatic and renal toxicity or lesions of gastric mucosa. In molecular docking simulations, LQFM-102 interacted with the key residues for activity and potency of cyclooxygenase enzymes, suggesting an inhibition of the activity of these enzymes.

Pharmacological and toxicological evaluations of the new pyrazole compound (LQFM-021) as potential analgesic and anti-inflammatory agents.

Chronic inflammation is a world health problem. There is a need to develop new anti-inflammatory and analgesic drugs with improved activity and reduced side effects. In this context, the aim of this study was to evaluate the antinociceptive and anti-inflammatory effects of the pyrazole compound LQFM-021 after acute and sub-chronic administration in rats submitted to a CFA-induced chronic arthritis model, as well as compare the toxicity of this compound to that of dipyrone, given throughout 7 days. Firstly, we observed that acute oral administration of the higher dose (130 µmol/kg) of LQFM-021 reduced paw lifting time (PET) and edema formation. These effects disappeared on the following day, requiring another dose to maintain the effects. This dose also promoted reduction of the polymorphonuclear recruitment in the synovial fluid. In another experiment, both treatments with LQFM-021, 65 µmol/kg twice a day and 130 µmol/kg once a day, produced a progressive and permanent reduction of the PET and edema, also reducing polymorphonuclear recruitment. However, the single treatment with 130 µmol/kg was more effective than the double treatment with 65 µmol/kg. LQFM-021 did not produce toxicity signs. However, dipyrone (130 µmol/kg once a day) promoted erosion of the epithelial cells and decreased mucus in the gastric mucosa. These data indicate that LQFM-021 produced antinociceptive and anti-inflammatory effects in CFA-induced arthritis in rats. These effects occurred in the absence of apparent toxic effects, indicating that the pyrazole compound LQFM-021 may be considered a good prototype for development of new analgesic/anti-inflammatory drug.

Cerebral Lipid Dynamics in Chronic Cerebral Hypoperfusion Model by DESI-MS Imaging.

Vascular dementia (VD) is a major cognitive disorder originated from a blood flow disruption in the brain. This process leads to chronic cerebral ischemia that deeply affects neuronal tissues and lipid homeostasis. The understanding of cerebral lipid dynamics during chronic ischemia can reveal biomarkers and novel pharmacological targets for the treatment of VD. In this study, we used the Desorption Electrospray Ionization - imaging mass spectrometry (DESI-IMS) technique to map lipids in the rat brain tissues after bilateral common carotid artery occlusion (BCCAO) rat model of chronic cerebral hypoperfusion. The brain imaging enabled the detection of differences in lipids from ischemic and non-ischemic brains. The analysis demonstrated that arachidonic acid (ARA), docosahexaenoic acid (DHA), dihomo-γ-linolenic acid, hydroxyeicosatetraenoic (HETE)-Ala and glycerophosphoethanolamine levels were significantly reduced in the hippocampus and cortex of animals submitted to BCCAO model when compared to control animals. Decanoic acid was increased after 30 days of BCCAO model. Partial least squares discriminant analysis (PLS-DA) could discriminate between BCCAO group and the control group, in which γ-linolenic acid (m/z 277) ion and stearic acid (m/z 283) had the highest discrimination potential. Taken together, these findings indicate that lipid dynamics are altered in chronic ischemia-induced by BCCAO in rats and indicate potential biomarkers and pharmacological targets for VD.

Pharmacological evaluation and molecular docking of new di-tert-butylphenol compound, LQFM-091, a new dual 5-LOX/COX inhibitor.

Dual 5-LOX/COX inhibitors are potential new dual drugs to treat inflammatory conditions. This research aimed to design, synthesis and to evaluate the anti-inflammatory and antinociceptive effects of the new compound, which is derived from nimesulide and darbufelone lead compounds. The new dual inhibitor 5-LOX/COX has the possible advantage of gastrointestinal safety. A voltammetric experiment was conducted to observe the drug's antioxidative effect. A formalin test, a hot plate test and carrageenan-induced mechanical hyperalgesia were employed to evaluate the analgesic nature of LQFM-091. To evaluate anti-inflammatory activity, we measured edema, leukocyte count, myeloperoxidase activity and cytokines levels in carrageenan-induced inflammation tests. We elucidated the underlying mechanisms by assessing the interaction the with COXs and LOX enzymes by colorimetric screening assay and molecular docking. The lethal dose (LD50) was estimated using 3T3 Neutral Red Uptake assay. Our results indicate that the LQFM-091 prototype is a powerful antioxidant, as well as able to inhibit COX-1, COX-2 and LOX activities. LQFM091 was classified in GHS category 4 (300

Design, synthesis and pharmacological evaluation of new anti-inflammatory compounds.

Inflammatory diseases and pain are among the main problems that significantly influence the lifestyle of millions of people and existing therapies are not always effective and can cause several adverse effects. In this context, the molecular modifications or synthesis of compounds continue being the best strategies for the identification of new compounds for the treatment of pain and inflammation. The aim of this study was to evaluate the analgesic and anti-inflammatory activities of new analogues of pyrazole compounds containing subunits N-phenyl-1-H-pirazoles and 1,3,4-oxadiazole-2(3H)-thione, LQFM-146, LQFM-147 and LQFM-148. In the acetic acid-induced abdominal writhing test, treatments with LQFM-146, LQFM-147 or LQFM-148 at doses 89, 178 and 356µmol/kg p.o. reduced the abdominal writhing in a dose-dependent manner. In the formalin test, these compounds at dose 178µmol/kg p.o. reduced the licking time only in inflammatory phase of this test, suggesting an antinociceptive effect dependent of the anti-inflammatory effect. The treatment with the three compounds in intermediate dose (178µmol/kg p.o.) reduced the edema at all tested time points in the carrageenan-induced paw edema test and reduced polymorphonuclears cell migration, activity myeloperoxidase and TNF-α levels in the carrageenan-induced pleurisy test. Our date suggest that the new compounds LQFM-146, LQFM-147 and LQFM-148 possess satisfactory anti-inflammatory and antinociceptive effects that involves the reduction of pro-inflammatory cytokines and inhibition of the myeloperoxidase enzyme.