Search Results (51)

Neurodegenerative and cardiovascular disorders share multifactorial origins, including oxidative stress, (neuro)inflammation, and lipid dysregulation—factors often addressed independently by single-target therapies. In this study, we report a rational multitarget approach through the design and synthesis of novel (benzo)thiazine derivatives that integrate antioxidant, anti-inflammatory, and antihyperlipidemic functionalities within a single molecular framework. The compounds were obtained in good yields via 3–7 step synthetic routes and evaluated through complementary in vitro and in vivo assays. Several derivatives displayed potent inhibition of lipoxygenase (IC₅₀ < 100 μM), significant reduction in carrageenan-induced edema (up to 60%), strong free radical scavenging and lipid peroxidation inhibition, as well as effective iron chelation. In vivo, most derivatives enhanced total antioxidant capacity (by 50–800%) and significantly improved plasma lipid profiles in mouse, while almost all compounds increased the plasma antiatherogenic index by more than 100% with selected compounds exceeding 600%. Notably, several molecules also showed moderate acetylcholinesterase inhibition, suggesting preliminary neuroprotective potential. Altogether, these multifunctional (benzo)thiazine derivatives represent promising lead structures for the development of agents targeting the complex interplay of oxidative, inflammatory, and metabolic pathways underlying neurodegenerative and cardiovascular diseases. Full article

There is an urgent need to develop new anti-inflammatory compounds due to the versatility of their applications and the side effects associated with currently used nonsteroidal anti-inflammatory drugs (NSAIDs). Compounds containing the 1,2-benzothiazine 1,1-dioxide moiety in their structure have demonstrated a broad range of pharmacological activities, among which the anti-inflammatory effect is the most well-documented. Numerous in vivo studies have confirmed the effectiveness of these compounds in alleviating pain and inflammation. In turn, in vitro studies have shown that 1,2-benzothiazine derivatives exhibit anti-inflammatory activity not only through the classical mechanism involving the inhibition of cyclooxygenase (COX) but also through modern, more complex mechanisms. These innovative mechanisms include inhibition of microsomal prostaglandin E₂ synthase-1 (mPGES-1) or 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), suppression of pro-inflammatory cytokines, and modulation of kinase activity involved in inflammatory processes. Importantly, many studies have shown that some new 1,2-benzothiazine 1,1-dioxide derivatives exhibit even stronger anti-inflammatory activity than traditional NSAIDs, making them promising candidates for new drugs targeting inflammation-related diseases. This paper presents a review of 1,2-benzothiazine 1,1-dioxide derivatives investigated for their anti-inflammatory activity in both in vivo and in vitro models, taking into account their various mechanisms of action and potential directions for further research. Full article

Although melanin is viewed as a natural sunscreen that protects pigmented cells against the adverse effects of solar radiation, recent studies have demonstrated that, under certain conditions, the pigment can actually contribute to light-induced oxidative damage of the cells. However, the main issue with such studies is finding natural pigments without photooxidative modifications. Recently, melanin obtained from melanocytes, generated from human induced pluripotent stem cells (hiPSC-Mel), was suggested as a promising source of the pigment without significant photooxidation. Although different studies have demonstrated the feasibility of the above-mentioned technique to obtain melanin-producing cells, no thorough analysis of the physicochemical properties of the pigment has been performed. To address this issue, we examined the key physicochemical parameters, including the aerobic photoreactivity of melanin isolated from hiPSC-Mel and compared them with those of melanin from other known sources of the pigment, such as bovine retinal pigment epithelium (bRPE) and phototype V (PT-V) hair. Electron paramagnetic resonance (EPR) spectroscopy, dynamic light scattering, UV–Vis absorption and HPLC analysis of melanin degradation products were used. The ability of the examined melanins to photogenerate reactive oxygen species was determined by employing EPR oximetry, EPR spin-trapping and time-resolved singlet oxygen phosphorescence. Although the results of such measurements demonstrated that melanin obtained from hiPSC-Mel exhibited the physicochemical properties typical for eumelanin, a contribution from pheomelanin with a substantial presence of benzothiazine subunits, was also evident. Importantly, the hiPSC-Mel pigment had significantly lower photoreactivity compared to bRPE melanin and PT-V hair melanin. Our findings indicate that hiPSC-Mel could be an excellent source of high-quality pigment for photoprotection studies. Full article

The design of novel anti-inflammatory drugs remains a critical area of research in the development of effective treatments for inflammatory diseases. In this study, a series of 1,2-benzothiazine was evaluated through a multifaceted approach. In particular, we investigated the potential interactions of the potential drugs with lipid bilayers, an important consideration for membrane permeability and overall pharmacokinetics. In addition, we evaluated their ability to inhibit cyclooxygenase 1 and cyclooxygenase 2 activity and selectivity using both a cyclooxygenase inhibition assay and molecular docking simulations. To evaluate their therapeutic potential, we performed in vitro assays to measure cytokine mRNA expression in inflamed cells. The antioxidant activity was evaluated using both in vitro assays, such as 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid scavenging, to determine the compounds’ capacity to neutralize free radicals and reduce oxidative stress. Theoretical calculations, including density functional theory, were used to predict the reactivity profiles of the compounds. Full article

The aim of this study was to obtain new, safe, and effective compounds with anticancer activity since cancer is still the leading cause of mortality worldwide. The rational design of new compounds was based on the introduction of differentially substituted phenylpiperazines into the 1,2-benzothiazine scaffold as a reference for the structures of recent topoisomerase II (Topo II) inhibitors such as dexrazoxane and XK-469. The newly designed group of 1,2-benzothiazine derivatives was synthesized and tested on healthy (MCF10A) and cancer (MCF7) cell lines, alone and in combination with doxorubicin (DOX). In addition, molecular docking studies were performed both to the DNA-Topo II complex and to the minor groove of DNA. Most of the tested compounds showed cytotoxic activity comparable to doxorubicin, a well-known anticancer drug. The compound BS230 (3-(4-chlorobenzoyl)-2-{2-[4-(3,4-dichlorophenyl)-1-piperazinyl]-2-oxoethyl}-4-hydroxy-2H-1,2-benzothiazine 1,1-dioxide) showed the best antitumor activity with lower cytotoxicity towards healthy cells and at the same time stronger cytotoxicity towards cancer cells than DOX. Moreover, molecular docking studies showed that BS230 has the ability to bind to both the DNA-Topo II complex and the minor groove of DNA. Binding of the minor groove to DNA was also proven by fluorescence spectroscopy. Full article

Climate change forces agriculture to face the rapidly growing virulence of biotrophic fungal pathogens, which in turn drives researchers to seek new ways of combatting or limiting the spread of diseases caused by the same. While the use of agrochemicals may be the most efficient strategy in this context, it is important to ensure that such chemicals are safe for the natural environment. Heterocyclic compounds have enormous biological potential. A series of heterocyclic scaffolds (1,3,4-thiadiazole, 1,3-thiazole, 1,2,4-triazole, benzothiazine, benzothiadiazine, and quinazoline) containing 2,4-dihydroxylaryl substituents were investigated for their ability to inhibit the growth and development of biotrophic fungal pathogens associated with several important cereal diseases. Of the 33 analysed compounds, 3 were identified as having high inhibitory potential against Blumeria and Puccinia fungi. The conducted research indicated that the analysed compounds can be used to reduce the incidence of fungal diseases in cereals; however, further thorough research is required to investigate their effects on plant–pathogen systems, including molecular studies to determine the exact mechanism of their activity. Full article

1,4-Benzothiazines are the main building blocks of the naturally occurring pheomelanin pigments, and their chromophoric properties have been strongly related to the well-known phototoxicity of these pigments, partly responsible for the high incidence of melanoma and other skin cancers in red-haired people. However, some peculiar features of the 1,4-benzothiazine chromophore could be functionally exploited in several sectors. Within this context, in this perspective, an overview of the very recently reported applications of the 1,4-benzothiazine chromophore in pH sensing, filter permeability control, smart packaging, electrochromic device fabrication, bioimaging, photocatalysis, and HPLC detection systems is provided, together with a brief presentation of recently developed synthetic approaches to the 1,4-benzothiazine scaffold, with the aim of emphasizing the still-undervalued multifunctional opportunities offered by this class of compounds. Full article

Acyl(imidoyl)ketenes are highly reactive heterocumulenes that enable diversity-oriented synthesis of various drug-like heterocycles. Such ketenes, bearing heterocyclic substituents, afford angularly fused pyridin-2(1H)-ones in their [4+2]-cyclodimerization reactions. We have utilized this property for the development of a new synthetic approach to pharmaceutically interesting pyrido[2,1-b][1,3]benzothiazol-1-ones via the [4+2]-cyclodimerization of acyl(1,3-benzothiazol-2-yl)ketenes generated in situ. The thermal behaviors of 3-aroylpyrrolo[2,1-c][1,4]benzothiazine-1,2,4-triones and 3-benzoylpyrrolo[2,1-b][1,3]benzothiazole-1,2-dione (two new types of [e]-fused 1H-pyrrole-2,3-diones reported by us recently) have been studied by thermal analysis and HPLC to elucidate their capability to be a source of acyl(1,3-benzothiazol-2-yl)ketenes. As a result, we have found that only 3-aroylpyrrolo[2,1-c][1,4]benzothiazine-1,2,4-triones are suitable for this. The experimental results are supplemented with computational studies that demonstrate that thermolysis of 3-aroylpyrrolo[2,1-c][1,4]benzothiazine-1,2,4-triones proceeds through an unprecedented cascade of two thermal decarbonylations. Based on these studies, we discovered a novel mode of thermal transformation of [e]-fused 1H-pyrrole-2,3-diones and developed a new pot, atom, and step economic synthetic approach to pyrido[2,1-b][1,3]benzothiazol-1-ones. The synthesized drug-like pyrido[2,1-b][1,3]benzothiazol-1-ones are of interest to pharmaceutics, since their close analogs show significant antiviral activity. Full article

In this study, we report the synthesis of unsubstituted 1,2-benzothiazines through a redox-neutral Rh(III)-catalyzed C–H activation and [4+2]-annulation of S–aryl sulfoximines with vinylene carbonate. Notably, the introduction of an N-protected amino acid ligand significantly enhances the reaction rate. The key aspect of this redox-neutral process is the utilization of vinylene carbonate as an oxidizing acetylene surrogate and an efficient vinylene transfer agent. This vinylene carbonate enables the cyclization with the sulfoximine motifs, successfully forming a diverse array of 1,2-benzothiazine derivatives in moderate to good yields. Importantly, this study highlights the potential of Rh(III)-catalyzed C–H activation and [4+2]-annulation reactions for the synthesis of optically pure 1,2-benzothiazines with high enantiomeric purity. Full article

A new series of 4H-1,3-benzothiazine dyes were prepared and fully characterized in an aqueous medium. Benzothiazine salts were synthesized either through the classical synthetic pathway using Buchwald–Hartwig amination or through economical and environmentally friendly electrochemical synthesis. The latest synthetic approach employs successful electrochemical intramolecular dehydrogenative cyclization of N-benzylbenzenecarbothioamides to form 4H-1,3-benzothiazines. 4H-1,3-Benzothiazines were evaluated as novel DNA/RNA probes. Through the use of several methods such as UV/vis spectrophotometric titrations, circular dichroism and thermal melting experiments, the binding of four benzothiazine-based molecules to polynucleotides was examined. Compounds 1 and 2 acted as DNA/RNA groove binders, thus suggesting the potential of these compounds as novel DNA/RNA probes. This is a proof-of-concept study and will be expanded to include SAR/QSAR studies. Full article

The purpose of the present paper was to assess the ability of five newly designed and synthesized meloxicam analogues to interact with phospholipid bilayers. Calorimetric and fluorescence spectroscopic measurements revealed that, depending on the details of the chemical structure, the studied compounds penetrated bilayers and affected mainly their polar/apolar regions, closer to the surface of the model membrane. The influence of meloxicam analogues on the thermotropic properties of DPPC bilayers was clearly visible because these compounds reduced the temperature and cooperativity of the main phospholipid phase transition. Additionally, the studied compounds quenched the fluorescence of prodan to a higher extent than laurdan, what pointed to a more pronounced interaction with membrane segments close to its surface. We presume that a more pronounced intercalation of the studied compounds into the phospholipid bilayer may be related to the presence of the molecule of a two-carbon aliphatic linker with a carbonyl group and fluorine substituent/trifluoromethyl group (compounds PR25 and PR49) or the three-carbon linker together with the trifluoromethyl group (PR50). Moreover, computational investigations of the ADMET properties have shown that the new meloxicam analogues are characterized by beneficial expected physicochemical parameters, so we may presume that they will have a good bioavailability after an oral administration. Full article

To better understand the impact of solar light exposure on human skin, the chemical characterization of native melanins and their structural photo-modifications is of central interest. As the methods used today are invasive, we investigated the possibility of using multiphoton fluorescence lifetime (FLIM) imaging, along with phasor and bi-exponential fitting analyses, as a non-invasive alternative method for the chemical analysis of native and UVA-exposed melanins. We demonstrated that multiphoton FLIM allows the discrimination between native DHI, DHICA, Dopa eumelanins, pheomelanin, and mixed eu-/pheo-melanin polymers. We exposed melanin samples to high UVA doses to maximize their structural modifications. The UVA-induced oxidative, photo-degradation, and crosslinking changes were evidenced via an increase in fluorescence lifetimes along with a decrease in their relative contributions. Moreover, we introduced a new phasor parameter of a relative fraction of a UVA-modified species and provided evidence for its sensitivity in assessing the UVA effects. Globally, the fluorescence lifetime properties were modulated in a melanin-dependent and UVA dose-dependent manner, with the strongest modifications being observed for DHICA eumelanin and the weakest for pheomelanin. Multiphoton FLIM phasor and bi-exponential analyses hold promising perspectives for in vivo human skin mixed melanins characterization under UVA or other sunlight exposure conditions. Full article

Echinacea is a widely used plant medicine, valued especially for its well-documented ability to stimulate the immune system. It has been suggested that melanin could be one of the bioactive factors responsible for the immunostimulatory properties of the plant. The biological functions of melanin pigments are closely related to their chemical composition and structural features. The aim of this study was to characterize the melanin from Echinacea purpurea based on the analysis of thermal degradation products of the well-purified pigment extracted from the dried herb. The melanin was pyrolyzed, and the resulting products were separated by gas chromatography and identified using a triple quadrupole mass spectrometer operating in full scan and multiple reaction monitoring modes. Three groups of marker products were detected in the melanin pyrolysate: polyphenol derivatives, nitrogen-containing heterocycles devoid of sulfur, and benzothiazines/benzothiazoles. This suggests that E. purpurea produces three structurally different melanin pigments: allomelanin, eumelanin, and pheomelanin, which in turn may affect the biological activity of the herb. Our results provide the first-ever evidence that plants are capable of synthesizing pheomelanin, which until now, has only been described for representatives of the animal and fungal kingdoms. Full article

The modified 1,2-benzothiazine analogues designed as new drug candidates and discussed in this paper are oxicam derivatives. Oxicams are a class of non-steroidal anti-inflammatory drugs (NSAIDs). Their biological target is cyclooxygenase (COX), a membrane protein associated with the phospholipid bilayer. In recent decades, it has been proven that the biological effect of NSAIDs may be closely related to their interaction at the level of the biological membrane. These processes are often complicated and the biological membranes themselves are very complex. Therefore, to study these mechanisms, simplified models of biological membranes are used. To characterize the interaction of six oxicam derivatives with DPPC, DMPC and EYPC, artificial models of biological membranes (multi-bilayers or liposomes), differential scanning calorimetry (DSC) and fluorescence spectroscopy techniques were applied. In spectroscopic measurements, two fluorescent probes (Laurdan and Prodan) localized in different membrane segments were used. All tested oxicam derivatives interacted with the lipid bilayers and may penetrate the artificial models of biological membranes. They intercalated into the lipid bilayers and were located in the vicinity of the polar/apolar membrane interface. Moreover, a good drug candidate should not only have high efficiency against a molecular target but also exhibit strictly defined ADMET parameters, therefore these activities of the studied compounds were also estimated. Full article