Early pharmacological profiling of isatin derivatives as potent and selective cytotoxic agents.

Isatin derivatives have attracted a lot of interest for their potential in the development of new anticancer drugs. A library of 38 isatin derivatives, created through an Ugi four-component reaction, underwent an initial screening in a panel of six human solid tumor cell lines. The four most active derivatives were then selected for further testing. These compounds showed selectivity towards the non-small cell lung cancer (NSCLC) cell line SW1573, whilst NSCLC A549 cells were barely affected. The combination of phenotypic assays, including wound healing, clonogenic and continuous live cell imaging provided a deeper understanding of the compounds' mode of action. In particular, the latter demonstrated that isatin derivatives were able to induce necroptosis in SW1573 cells. The kinetics of cell death showed that necroptosis appeared after 2.5 h of exposure, which could be delayed to 7 h when co-treated with necrostatin-1. Interaction between the isatin derivatives and the KRAS G12C protein variant was discarded after in silico studies. Further studies are warranted to identify the cellular target responsible for the observed selectivity among cell lines.

Novel Foscan®-derived ring-fused chlorins for photodynamic therapy of cancer.

Photodynamic therapy (PDT) is an established anticancer treatment that combines the use of a photosensitiser (PS) and a light source of a specific wavelength for the generation of reactive oxygen species (ROS) that are toxic to the tumour cells. Foscan® (mTHPC) is a clinically-approved chlorin used for the PDT treatment of advanced head and neck, prostate and pancreatic cancers but is characterized by being photochemically unstable and associated with prolonged skin photosensitivity. Herein, we report the synthesis of new 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins, having the meso-tetra(3-hydroxyphenyl)macrocycle core of mTHPC, by exploring the [8π + 2π] cycloaddition of a meso-tetra(3-hydroxyphenyl)porphyrin derivative with diazafulvenium methides. These chlorins have photochemical properties similar to Foscan® but are much more photostable. Among the novel compounds, two chlorins with a hydroxymethyl group and its azide derivative present in the 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused system, are promising photodynamic agents with activity in the 100 nM range against triple-negative breast cancer cells and, in the case of azidomethyl chlorin, a safer phototherapeutic index compared to Foscan®.

Solvent-Driven Self-Organization of Meso-Substituted Porphyrins: Morphological Analysis from Fluorescence Lifetime Imaging Microscopy.

A morphological analysis of different thin films of meso-tetra-p-(di-p-phenylamino)phenylporphyrin, H2T(TPA)4P, was made by fluorescence lifetime imaging microscopy (FLIM) and scanning electron microscopy (SEM). A comprehensive study of H2T(TPA)4P was undertaken through UV/vis absorption and fluorescence techniques in different solvents, solvent mixtures and in thin films. In solution, occurrence of intramolecular energy transfer from the triphenylamine (TPA) moieties to the porphyrin core, with quenching efficiencies in the order of 94-97%, is observed. The energy transfer rate constants are determined assuming Förster's dipole-dipole and Dexter's electron exchange mechanisms. In drop-cast-prepared thin films, from samples with different solvent mixtures, the photoluminescence (PL) quantum yield (ΦPL) decreases ∼1 order of magnitude compared to the solution behavior. FLIM and SEM experiments showed the self-organization and morphology of H2T(TPA)4P in thin films to be highly dependent on the solvent mixture used to prepare the film. In chloroform, the solvent's evaporation results in the formation of elongated and overlapped microrod structures. Introduction of a cosolvent, namely, a polar cosolvent, promotes changes in the morphology of the self-assembled structures, with the formation of three-dimensional spherical structures and hollow spheres. H2T(TPA)4P dispersed in a polymer matrix shows enhanced ΦPL values when compared to the drop-cast films. FLIM images showed coexistence of three different states or domains: aggregated, interface, and nonaggregated or less-aggregated states. This work highlights the importance of FLIM in the morphological characterization of heterogeneous films, together with the photophysical characterization of nano- and microdomains.

The role of solvents and concentrations in the properties of oxime bearing A2B corroles.

A comprehensive study on the electronic spectral, photophysical and acid-base properties of phenyl- and methyl-oxime corrole derivatives and of triphenylcorrole (model corrole) has been performed, aiming to shed light on the existing species in the ground and excited states. Solvents and corrole concentration are found to govern the properties of the studied compounds and are determinants of their applicability in in vivo studies. In THF, the neutral corrole has two tautomeric forms (T1 and T2). In DMSO, the deprotonated form shows a characteristic long-wavelength Q band slightly shifted to blue when compared with the T1 tautomer and a higher fluorescence quantum yield. In ACN, with the increase of the corrole concentration formation of an aggregate due to homoconjugation (with dimer characteristics) is observed, and pioneeringly reported using UV-Vis and fluorescence studies and confirmed by carrying out titrations with TFA. The effect of the oxime group on the pK values of a corrole is found to influence the formation of a homoconjugate, namely by precluding its formation (at higher concentrations) when compared with the model corrole. TDDFT electronic quantum calculations support the experimental observations, namely the existence of tautomers and deprotonated species, with their respective electronic spectral features, further allowed proposing a structure for the homoconjugate complex in ACN. The characteristics of the oxime-corroles, namely a pK of ∼ 5, absorption and emission at ca. 650 nm and solvent dependent properties, make them good candidates for their use in biological systems either as probes, sensors, or as new sensitizers for photodynamic therapy.

Oral health status of 6- to 12-year-old children in Madrid, Spain: A cross-sectional study.

Based on the results of the 2015 oral health survey in Spain, the prevalence of untreated dental caries in temporary dentition, in the six-year cohort was 27,8%, and in the twelve-year cohort 14,6%. Due to the magnitude of the problem, the high health cost and the possibilities of prevention, monitoring the oral health status of the child population is extremely important, as it will allow the implementation of prevention and early care strategies. OBJECTIVES: To study the caries prevalence and malocclusion in the mixed dentition in children aged 6-12 years in Madrid, Spain. . MATERIALS AND METHODS: This is a descriptive, cross-sectional study carried out in the city of Madrid during the 2018-2019 school year. Fifth year students of the European University of Madrid through health surveys, calibrated and supervised by the two main researchers, collected the data. The schoolchildren assessed were students from different schools in the city of Madrid, between 6 and 12 years old. According to WHO standards, data were collected in 2 months. RESULTS: The total number of students examined was 303 students from 4 different schools in the community of Madrid. The prevalence of caries in our sample in the primary dentition was 45.21% with dmf> 0 and in the permanent dentition it was 23.7 % with a DMF> of 0. CONCLUSIONS: The oral health survey carried out in the sample shows a high prevalence of caries, as well as in the dmf and DMF indicators. Most of the children needed fluoride applications, so it would be interesting to evaluate which of them can be prevented with different public health projects.

Ring-Fused meso-Tetraarylchlorins as Auspicious PDT Sensitizers: Synthesis, Structural Characterization, Photophysics, and Biological Evaluation.

Novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused meso-tetraarylchlorins, with different degrees of hydrophilicity (with methyl ester, hydroxymethyl, and carboxylic acid moieties), have been synthesized and their photophysical characterization as well as in vitro photocytotoxicity assessment against human melanoma and esophageal and bladder carcinomas was carried out. An integrated analysis of the photosensitizers' performance, considering the singlet oxygen generation data, cell internalization, and intracellular localization, allowed to establish relevant structure-photoactivity relationships and the rationalization of the observed photocytotoxicity. In the diacid and monoalcohol series, chlorins derived from meso-tetraphenylporphyrin proved to be the most efficient photodynamic therapy agents, showing IC50 values of 68 and 344 nM against A375 cells, respectively. These compounds were less active against OE19 and HT1376 cells, the diacid chlorin with IC50 values still in the nano-molar range, whereas the monohydroxymethyl-chlorin showed significantly higher IC50 values. The lead di(hydroxymethyl)-substituted meso-tetraphenylchlorin confirmed its remarkable photoactivity with IC50 values below 75 nM against the studied cancer cell lines. Subcellular accumulation of this chlorin in the mitochondria, endoplasmic reticulum, and plasma membrane was demonstrated.

Applications of Photodynamic Therapy in Endometrial Diseases.

Photodynamic therapy (PDT) is a medical procedure useful for several benign conditions (such as wound healing and infections) and cancer. PDT is minimally invasive, presents few side effects, good scaring, and is able to minimal tissue destruction maintaining organ anatomy and function. Endoscopic access to the uterus puts PDT in the spotlight for endometrial disease treatment. This work systematically reviews the current evidence of PDT's potential and usefulness in endometrial diseases. Thus, this narrative review focused on PDT applications for endometrial disease, including reports regarding in vitro, ex vivo, animal, and clinical studies. Cell lines and primary samples were used as in vitro models of cancer, adenomyosis and endometrioses, while most animal studies focused the PDT outcomes on endometrial ablation. A few clinical attempts are known using PDT for endometrial ablation and cancer lesions. This review emphasises PDT as a promising field of research. This therapeutic approach has the potential to become an effective conservative treatment method for endometrial benign and malignant lesions. Further investigations with improved photosensitisers are highly expected.

Isolation and Identification of Cytotoxic Compounds Present in Biomaterial Life®.

Direct pulp capping consists of a procedure in which a material is directly placed over the exposed pulp to maintain dental vitality. Although still widely used in clinical practice, previous in vitro studies found that the biomaterial Life® presented high cytotoxicity, leading to cell death. This study aimed to identify the Life® constituents responsible for its cytotoxic effects on odontoblast-like cells (MDPC-23). Aqueous medium conditioned with Life® was subjected to liquid-liquid extraction with ethyl acetate. After solvent removal, cells were treated with residues isolated from the organic and aqueous fractions. MTT and Trypan blue assays were carried out to evaluate the metabolic activity and cell death. The organic phase residue promoted a significant decrease in metabolic activity and increased cell death. On the contrary, no cytotoxic effects were observed with the mixture from the aqueous fraction. Spectroscopic and spectrometric methods allowed the identification of the toxic compounds. A mixture of the regioisomers ortho, para, and meta of N-ethyl-toluenesulfonamide was identified as the agent responsible for the toxicity of biomaterial Life® in MDPC-23 cells. These findings contribute to improving biomaterial research and development.

Tryptanthrin derivatives as efficient singlet oxygen sensitizers.

Halogenated tryptanthrin and aminotryptanthrin were synthesized from indigo or isatin precursors. Dibromo- and tetrabromo-tryptanthrin were obtained from indigo dyes following green chemistry procedures, through microwave-assisted synthesis in mild oxidation conditions. Spectral and photophysical properties of the compounds, including quantitative determination of all the different deactivation pathways of S1 and T1, were obtained in different solvents and temperatures. The triplet state (T1) has a dominant role on the photophysical properties of these compounds, which is further enhanced by the halogens at the fused-phenyl rings. Substitution with an amino group, 2-aminotryptanthrin (TRYP-NH2), leads a dominance of the radiative decay channel. Moreover, with the sole exception of TRYP-NH2, S1 ~ ~ > T1 intersystem crossing constitutes the dominant route, with internal conversion playing a minor role in the deactivation of S1 in all the studied derivatives. In agreement with tryptanthrin, emission of the triplet state of tryptanthrin derivatives (with exception of TRYP-NH2), was observed together with an enhancement of the singlet oxygen sensitization quantum yield: from 70% in tryptanthrin to 92% in the iodine derivative. This strongly contrasts with indigo and its derivatives, where singlet oxygen sensitization is found inefficient.

Aggregation-Induced Emission Leading to White Light Emission in Diphenylbenzofulvene Derivatives.

The search for a unique molecular system able to efficiently emit in the total visible range of the electromagnetic spectra, i. e., white light emission (WLE), is a topic of intense research. We here show that aggregates formed by diphenylbenzofulvene (DPBF) derivatives are from two to four orders of magnitude more emissive than their monomers. From a simple strategy, involving structural modification of a DPBF propelled shape core, a close match with the pure white light emission coordinates is obtained with a combination of two derivatives in films, with featured solid-state emission, without involvement of D-A groups or energy transfer processes.

Ugi Reaction Synthesis of Oxindole-Lactam Hybrids as Selective Butyrylcholinesterase Inhibitors.

Molecular hybridization is a valuable approach in drug discovery. Combining it with multicomponent reactions is highly desirable, since structurally diverse libraries can be attained efficiently in an eco-friendly manner. In this work, isatin is used as the key building block for the Ugi 4-center 3-component reaction synthesis of oxindole-lactam hybrids, under catalyst-free conditions. The resulting oxindole-ß-lactam and oxindole-γ-lactam hybrids were evaluated for their potential to inhibit relevant central nervous system targets, namely cholinesterases and monoamine oxidases. Druglikeness evaluation was also performed, and compounds 4eca and 5dab exhibited great potential as selective butyrylcholinesterase inhibitors, at the low micromolar range, with an interesting predictive pharmacokinetic profile. Our findings herein reported suggest oxindole-lactam hybrids as new potential agents for the treatment of Alzheimer's disease.

Modern Methods for the Sustainable Synthesis of Metalloporphyrins.

Metalloporphyrins are involved in many and diverse applications that require the preparation of these compounds in an efficient manner, which nowadays, also involves taking into consideration sustainability issues. In this context, we use ball milling mechanochemistry and sonochemistry for the rational development of synthetic strategies for the sustainable preparation of metalloporphyrins. Zinc, copper, cobalt and palladium complexes of hydrophobic porphyrins were obtained in high yields and under mechanical action with a moderate excess of the metal salt, without any solvent or additive. Sonochemistry prove to be a good alternative for the preparation of metal complexes of water-soluble porphyrins in good yields and short reaction times. Both strategies have good sustainability scores, close to the ideal values, which is useful in comparing and helping to choose the more adequate method.

Novel fluorinated ring-fused chlorins as promising PDT agents against melanoma and esophagus cancer.

Investigation of novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins, derived from 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, as PDT agents against melanoma and esophagus cancer is disclosed. Diol and diester fluorinated ring-fused chlorins, including derivatives with 2-(2-hydroxyethoxy)ethanamino groups at the phenyl rings, were obtained via a two-step methodology, combining SNAr and [8π + 2π] cycloaddition reactions. The short-chain PEG groups at the para-position of the phenyl rings together with the diol moiety at the fused pyrazole ring promote a red-shift of the Soret band, a decrease of the fluorescence quantum yield and an increase of the singlet oxygen formation quantum yield, improving the photophysical characteristics required to act as a photosensitizer. Introduction of these hydrophilic groups also improves the incorporation of the sensitizers by the cells reaching cellular uptake values of nearly 50% of the initial dose. The rational design led to a photosensitizer with impressive IC50 values, 13 and 27 nM against human melanoma and esophageal carcinoma cell lines, respectively.

Red-Purple Photochromic Indigos from Green Chemistry: Mono-tBOC or Di-tBOC N-Substituted Indigos Displaying Excited State Proton Transfer or Photoisomerization.

In indigo, excited state proton transfer (ESPT) is known to be associated with the molecular mechanism responsible for highly efficient radiationless deactivation. When this route is blocked (partially or totally), new deactivation routes become available. Using new green chemistry procedures, with favorable green chemistry metrics, monosubstitution and disubstitution of N group(s) in indigo, by tert-butoxy carbonyl groups, N-(tert-butoxycarbonyl)indigo (NtBOCInd) and N,N'-(tert-butoxycarbonyl)indigo (N,N'tBOCInd), respectively, were synthetically accomplished. The compounds display red to purple colors depending on the solvent and substitution. Different excited-state deactivation pathways were observed and found to be structure- and solvent-dependent. Trans-cis photoisomerization was found to be absent with NtBOCInd and present with N,N'tBOCInd in nonpolar solvents. Time-resolved fluorescence experiments revealed single-exponential decays for the two compounds which, linked to time-dependent density functional theory (TDDFT) studies, show that with NtBOCInd ESPT is extremely fast and barrierless-predicted to be 1 kJ mol-1 in methylcyclohexane and 5 kJ mol-1 in dimethylsulfoxide-, which contrasts with ∼11 kJ mol-1 experimentally obtained for indigo. An alternative ESPT, competitive with the N-H···O═C intramolecular pathway, involving dimer units is also probed by TDDFT and found to be consistent with the experimentally observed time-resolved data. N,N'tBOCInd, where ESPT is precluded, shows solvent-dependent trans-cis/cis-trans photoisomerization and is surprisingly found to be more stable in the nonemissive cis conformation, whose deactivation to S0 is found to be solvent-dependent.

The application of isatin-based multicomponent-reactions in the quest for new bioactive and druglike molecules.

Oxindole derivatives are known for their great interest in the field of Medicinal Chemistry, as they display vast biological activities. Recent efforts concerning the preparation of oxindole derivatives using isatin-based multicomponent reactions (MCRs) constitute a great advance in generating druglike libraries fast and with wide scaffold diversity. In this review, we address those recent developments, exploring the synthetic pathways and biological activities described for these compounds, namely antitumor, antibacterial, antifungal, antiparasitic, antiviral, antioxidant, anti-inflammatory and central nervous system (CNS) pathologies. To add new depth to this work, we used a well-established web-based free tool (SwissADME) to evaluate the most promising scaffolds in what concerns their druglike properties, namely by evaluating their compliance with some of the most valuable rules applied by medicinal chemists in both academia and industrial settings (Lipinski, Ghose, Veber, Egan, Muegge). The aim of this review is to endorse isatin-based MCRs as a valuable synthetic approach to attain new hit compounds bearing the oxindole privileged structure, while critically exploring these scaffolds' druglike properties.

Sulfonated tryptanthrin anolyte increases performance in pH neutral aqueous redox flow batteries.

Aqueous organic redox flow batteries (AORFBs) hold great promise as low-cost, environmentally friendly and safe alternative energy storage media. Here we present aqueous organometallic and all-organic active materials for RFBs with a water-soluble active material, sulfonated tryptanthrin (TRYP-SO3H), working at a neutral pH and showing long-term stability. Electrochemical measurements show that TRYP-SO3H displays reversible peaks at neutral pH values, allowing its use as an anolyte combined with potassium ferrocyanide or 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate as catholytes. Single cell tests show reproducible charge-discharge cycles for both catholytes, with significantly improved results for the aqueous all-organic RFB reaching high cell voltage (0.94 V) and high energy efficiencies, stabilized during at least 50 working cycles.

A water-soluble bithiophene with increased photoluminescence efficiency and metal recognition ability.

A new water-soluble tri-tert-butyl-bithiophenesulfonamide (α2-tbS) was synthesized and a comprehensive spectroscopic and photophysical study was undertaken in organic solvents and water at different pH values. In contrast to the behaviour found for the parent (and un-substituted) α,α'-bithiophene (α2), in which radiationless decay processes are the main excited-state deactivation channels, the tert-butylsulfonamide derivative presents a significant fluorescence quantum yield (φF) (ca. one order of magnitude higher than that of α2). The high φF allowed further exploring α2-tbS as a selective fluorimetric sensor for metal ions. A strong selectivity towards Cu(ii) is observed at neutral pH values, whereas at pH = 9.5 a strong quenching upon the addition of Hg(ii) is observed. An additional high sensitivity of 0.64 ± 0.02 ppm towards Cu(ii) was observed, well below 1.25 ppm (∼20 µM), the maximum value allowed in drinking water by the EPA.

Corroles and Hexaphyrins: Synthesis and Application in Cancer Photodynamic Therapy.

Corroles and hexaphyrins are porphyrinoids with great potential for diverse applications. Like porphyrins, many of their applications are based on their unique capability to interact with light, i.e., based on their photophysical properties. Corroles have intense absorptions in the low-energy region of the uv-vis, while hexaphyrins have the capability to absorb light in the near-infrared (NIR) region, presenting photophysical features which are complementary to those of porphyrins. Despite the increasing interest in corroles and hexaphyrins in recent years, the full potential of both classes of compounds, regarding biological applications, has been hampered by their challenging synthesis. Herein, recent developments in the synthesis of corroles and hexaphyrins are reviewed, highlighting their potential application in photodynamic therapy.

Iron Deposits in Periaqueductal Gray Matter Are Associated with Poor Response to OnabotulinumtoxinA in Chronic Migraine.

Previous studies have reported increased brain deposits of iron in patients with chronic migraine (CM). This study aims to determine the relation between iron deposits and outcome after treatment with OnabotulinumtoxinA (OnabotA). Demographic and clinical data were collected for this study through a prospective cohort study including 62 CM patients treated with OnabotA in the Hospital Clínico Universitario de Santiago de Compostela (Spain). Demographic and clinical variables were registered. Selected biomarkers in plasma during interictal periods (calcitonin gene-related peptide (CGRP) and pentraxin-3 (PTX3)) and neuroimaging changes (iron deposits in the red nucleus (RN), substantia nigra (SN), globus pallidus (GP), and periaqueductal gray matter (PAG), and white matter lesions (WML)) were determined. Subjects were classified in responders (≥50% reduction in headache days) or non-responders (<50%). Responders to treatment were younger (mean age difference = 12.2; 95% confidence interval (CI): 5.4-18.9, p = 0.001), showed higher serum levels of CGRP (≥50 ng/mL) and PTX3 (≥1000 pg/mL) and smaller iron deposits in the GP and PAG (mean difference = 805.0; 95% CI: 37.9-1572.1 µL, p = 0.040 and mean difference = 69.8; 95% CI: 31.0-108.6 µL, p = 0.008; respectively). Differences in PAG iron deposits remained significant after adjusting for age (mean difference = 65.7; 95% CI: 22.8-108.6 µL, p = 0.003) and were associated with poor response to OnabotA after adjustment for clinical and biochemical variables (odds ratio (OR) = 0.963; 95% CI: 0.927-0.997, p = 0.041). We conclude that larger PAG iron deposits are associated with poor response to OnabotA in CM.

Platinum(II) ring-fused chlorins as efficient theranostic agents: Dyes for tumor-imaging and photodynamic therapy of cancer.

The discovery of Pt-chlorin-type theranostic agents is described. Luminescent Pt(II) 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins, with different degrees of hydrophilicity, have been synthesized and their in vitro photocytotoxicity against human melanoma, oesophageal and bladder carcinomas was studied. A di(hydroxymethyl)-substituted chlorin was identified as a privileged molecule to explore imaging-guided photodynamic therapy. In addition to the high activity as PDT agent and absence of cytotoxicity per se, this molecule showed the ideal photophysical and photochemical properties. In vivo studies using a A375 melanoma mouse model, proved the extraordinary properties of this chlorin as a luminescent probe and the ability to impair tumor growth, making image guided treatment and follow up a possibility.