Multiple non-psychiatric effects of phenothiazines: A review

A hidden cysteine in Fis1 targeted to prevent excessive mitochondrial fission and dysfunction under oxidative stress

Fis1-mediated mitochondrial localization of Drp1 and excessive mitochondrial fission occur in human pathologies associated with oxidative stress. However, it is not known how Fis1 detects oxidative stress and what structural changes in Fis1 enable mitochondrial recruitment of Drp1. We find that conformational change involving α1 helix in Fis1 exposes its only cysteine, Cys41. In the presence of oxidative stress, the exposed Cys41 in activated Fis1 forms a disulfide bridge and the Fis1 covalent homodimers cause increased mitochondrial fission through increased Drp1 recruitment to mitochondria. Our discovery of a small molecule, SP11, that binds only to activated Fis1 by engaging Cys41, and data from genetically engineered cell lines lacking Cys41 strongly suggest a role of Fis1 homodimerization in Drp1 recruitment to mitochondria and excessive mitochondrial fission. The structure of activated Fis1-SP11 complex further confirms these insights related to Cys41 being the sensor for oxidative stress. Importantly, SP11 preserves mitochondrial integrity and function in cells during oxidative stress and thus may serve as a candidate molecule for the development of treatment for diseases with underlying Fis1-mediated mitochondrial fragmentation and dysfunction.

Targeted and non-targeted metabolic analysis of chlorpromazine in grass carp as well as the in-silico and metabolomics toxicity assessment

Chlorpromazine (CPZ) is an abused sedative that is extensively metabolized in organisms. However, the metabolic pathway of CPZ in aquatic organisms is still unclear. In this study, CPZ metabolites was analyzed in grass carp exposed to CPZ in the raising water using ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS). Thirteen CPZ metabolites were identified, including 11 previously reported and 2 newly identified metabolites (M9 and M13), and 5 known metabolites were confirmed using authentic standards. The molecular structures and transformation pathways of CPZ metabolites were putatively deduced, which mainly included oxygenation, demethylation, dechlorination and carboxylation reactions. Quantitative analysis of CPZ and its metabolites were also performed, and CPZ sulfoxide had a higher content as an important characteristic metabolite. In addition, in-silico toxicity prediction reminded that some metabolites possess ecotoxicity and developmental toxicities similar to, or even higher, than CPZ. Moreover, metabolomics results indicated that CPZ exposure could cause metabolic disorder in the endogenous metabolome of grass carp.

Ternary Metal (W-Ni-Sr) Oxide@Polypyrrole Nanotubes: A New Frontier in the Electrochemical Detection of Promethazine Hydrochloride (PMHC)

Promethazine hydrochloride (PMHC) is a vital drug that is used as an anticholinergic, antipsychotic, antihistaminic, analgesic, sedative, and neuroleptic. However, the overdosage of PMHC also causes reproductive variations, cardiac changes, hypotension, and endocrinal variations. Hence, the detection of PMHC is crucial. Therefore, in this work an electrochemical method for the detection of PMHC is reported. The fabrication for the modified electrode is built with tungsten (W), nickel (N), and strontium (S) ternary oxide (tWNSO). To the best of our knowledge, this tWNSO ternary oxide preparation is reported for the first time in the literature. The prepared ternary oxide is deposited on the polypyrrole nanotubes, and this nanocomposite that is formed is confirmed by various physical characterizations like XRD, SEM, TEM, UV-vis spectroscopy, FTIR spectroscopy, and also DFT studies for PMHC. Thus, the nanocomposite obtained is used as a working electrode for the detection of PMHC. The fabricated tWNSO/PPyNTs/GCE has an effective surface area of 0.0436 cm2. Also, no fouling was observed. The limit of detection of the analyte PMHC is 3.66 nM, the limit of quantification is 11.10 nM, and the sensitivity of the fabricated electrode in identifying the analyte is found to be 20.10 μA μM-1 cm-2. Thus, the modified working electrode effectively detects the analyte PMHC while demonstrating excellent stability and reproducibility.

Human Serum Albumin and Human Serum Albumin Nanoparticles as Carriers of 10-(2'-Pyrimidyl)-3,6-diazaphenothiazine: In Vitro Spectroscopic Studies

Human serum albumin (HSA) plays a fundamental role in the human body, including the transport of exogenous and endogenous substances. HSA is also a biopolymer with a great medical and pharmaceutical potential. Due to nontoxicity and biocompatibility, this protein can be used as a nanocarrier. 10-(2'-Pyrimidyl)-3,6-diazaphenothiazine (10-Pyr-3,6-DAPT) is a phenothiazine showing high anticancer potential in vitro against glioma, melanoma and breast cancer cells. Additionally, this compound is characterized by selectivity of action towards MCF-7 breast cancer and has low cytotoxicity towards normal cells. Considering the promising pharmacological potential of this compound and using spectroscopic techniques, HSA and human serum albumin nanoparticles (HSA-NP) were tested as carriers of this molecule. Based on the obtained data and the appropriate mathematical models (Stern-Volmer and Klotz models), it can be concluded that 10-Pyr-3,6-DAPT probably forms a weak (Ka = (5.24 ± 0.57) × 104 and Ka = (4.67 ± 0.59) × 104) for excitation wavelengths λex 275 nm and λex 295 nm, respectively) static complex (kq > 1010) with HSA (at Sudlow site II (subdomain IIIA), and the phenomenon of it having both strong therapeutic and toxic effects is possible. High encapsulation efficiency of 10-Pyr-3,6-DAPT into the HSA-NPs was obtained, and the changes in albumin secondary structure due to the presence of 10-Pyr-3,6-DAPT were registered. Based on the data presented, it can be concluded that due to the high toxic effects of 10-Pyr-3,6-DAPT, a better carrier may be HSA-NPs.

A Computational Study of Phenothiazine Derivatives as Acetylcholinesterase Inhibitors Targeting Alzheimer's Disease

BACKGROUND

Alzheimer's disease is a neurodegenerative disorder that affects learning, memory and behavioral turbulence in elderly patients. Acetylcholinesterase (AChE) inhibitors act as anti-Alzheimer's agents. Phenothiazine derivatives are considered momentous anti-Alzheimer's agents because of their AChE inhibitory activity. The elevated levels and increased expression of this protein have been associated with Alzheimer's disease. Coumarin-fused phenothiazines have emerged as significant anti-Alzheimer's agents due to their notable receptor inhibitory activity.

OBJECTIVE

Some unique phenothiazine analogs were designed, and computational studies were conducted to explore their inhibitory activity against the AChE enzyme (PDB id: 4EY7) by using the Schrodinger suite-2019-4.

METHODS

Docking studies were conducted by using the Glide module; binding free energies were calculated by means of the Prime MM-GBSA module, and Molecular dynamics (MD) simulation was performed by using the Desmond module of the Schrodinger suite. Glide scores were used to find out the binding affinity of the ligands with the target 4EY7.

RESULTS

The compounds exhibited enhanced hydrophobic interactions and formed hydrogen bonds, effectively impeding Acetylcholinesterase. The Glide scores for the compounds ranged from -13.4237 to -8.43439, surpassing the standard (Donepezil) with a score of -16.9898. Interestingly, a positive value was obtained for the MM-GBSA binding of the potent inhibitor. To gain insights into the dynamic behavior of the protein A8, molecular dynamics (MD) simulations were employed.

CONCLUSION

Based on the results, the study concludes that phenothiazine derivatives show promise as acetylcholinesterase inhibitors. Compounds with notable Glide scores are poised to exhibit significant anti-Alzheimer's activity, suggesting their potential therapeutic efficacy. Further in vitro and in vivo investigations are warranted to validate and explore the therapeutic potentials of these compounds.

Synthesis of new phenothiazine derivatives: Molecular docking, assessment of cytotoxic activity and oxidant-antioxidant properties on PCS-201-012, HT-29, and SH-SY5Y cell lines

Phenothiazine (PTZ) derivatives have been acknowledged as versatile compounds with significant implications across various areas of medicine, particularly, in cancer research. The cytotoxic effects of synthesized compounds on both normal and cancerous cells, along with their oxidant-antioxidant properties, are pivotal factors in cancer treatment strategies. In the current study, eight new PTZ derivatives were synthesized and the compounds' cytotoxic activities were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay while the oxidant-antioxidant properties were evaluated by oxidative stress index (OSI) calculation in SH-SY5Y (a human neuroblastoma cell line), HT-29 (a human colorectal adenocarcinoma cell line), and PCS-201-012 (a human primary dermal fibroblast cell line) cells. Consequently, the half-maximal inhibitory concentration (IC50) values of compound 3a were determined to be 218.72, 202.85, and 227.86 μM while the IC50 values of compound 3b were defined to be 227.42, 199.27, and 250.11 μM in PCS-201-012, HT-29, and SH-SY5Y cells, respectively. Additionally, it was determined that the synthesized compounds demonstrated the lowest OSI in PCS-201-012 cells as compared to the other cell lines.

Synthesis and Structure of 5-Methyl-9-(trifluoromethyl)-12H-quino[3,4-b][1,4]benzothiazinium Chloride as Anticancer Agent

In this work, the synthesis, structural analysis and anticancer properties of 5-methyl-9-trifluoromethyl-12H-quino[3,4-b][1,4]benzothiazinium chloride (3) are described. Compound 3 was synthesized by reacting 1-methyl-4-butylthio-3-(benzoylthio)quinolinium chloride with 4-(trifluoromethyl)aniline, respectively. The structure of the resulting product was determined using 1H-NMR and 13C-NMR spectroscopy as well as HR-MS spectrometry. The spatial geometry of agent 3 and the arrangement of molecules in the crystal (unit cell) were also confirmed using X-ray diffraction. The tetracyclic quinobenzothiazinium system is fairly planar because the dihedral angle between the planes formed by the benzene ring and the quinoline system is 173.47°. In order to obtain insight into the electronic charge distribution of the investigated molecule, electronic structure calculations employing the Density Functional Theory (DFT) were performed. Moreover, antiproliferative activity against a set of pancreatic cancer cell lines was tested, with compound 3 showing IC50 values against human primary pancreatic adenocarcinoma BxPC-3 and human epithelioid pancreatic carcinoma Panc-1 of 0.051 µM and 0.066 µM, respectively. The IC50 value of cytotoxicity/cell viability of the investigated compound assessed on normal human lung fibroblasts WI38 was 0.36 µM.

LETC inhibits α-Syn aggregation and ameliorates motor deficiencies in the L62 mouse model of synucleinopathy

Alpha-Synuclein (α-Syn) aggregation is a pathological feature of synucleinopathies, neurodegenerative disorders that include Parkinson's disease (PD). Here, we explored the efficacy of N,N,N',N'-tetraethyl-10H-phenothiazine-3,7-diamine dihydrochloride (LETC), a protein aggregation inhibitor, on α-Syn aggregation. In both cellular models and transgenic mice, α-Syn aggregation was achieved by the overexpression of full-length human α-Syn fused with a signal sequence peptide. α-Syn accumulated in transfected DH60.21 neuroblastoma cells and α-Syn aggregation was inhibited by LETC with an EC50 of 0.066 ± 0.047 μM. Full-length human α-Syn overexpressing Line 62 (L62) mice accumulated neuronal α-Syn that was associated with a decreased motor performance in the open field and automated home cage. LETC, administered orally for 6 weeks at 10 mg/kg significantly decreased α-Syn-positive neurons in multiple brain regions and this resulted in a rescue of movement deficits in the open field in these mice. LETC however, did not improve activity deficits of L62 mice in the home cage environment. The results suggest that LETC may provide a potential disease modification therapy in synucleinopathies through the inhibition of α-Syn aggregation.

New phenothiazine conjugates as apoptosis inducing agents: Design, synthesis, In-vitro anti-cancer screening and 131I-radiolabeling for in-vivo evaluation

Phenothiazines (PTZs) are a group of compounds characterized by the presence of the 10H-dibenzo-[b,e]-1,4-thiazine system. PTZs used in clinics as antipsychotic drugs with other diverse biological activities. The current aim of the study is to investigate and understand the effect of potent PTZs compounds using a group of In-vitro and In-vivo assays. A total of seventeen novel phenothiazine derivatives have been designed, synthesized, and evaluated primarily in-vitro for their ability to inhibit proliferation activity against NCI-60 cancer cell lines, including several multi-drug resistant (MDR) tumor cell lines. Almost all compounds were active and displayed promising cellular activities with GI50 values in the sub-micromolar range. Four of the most promising derivatives (4b, 4h, 4g and 6e) have been further tested against two selected sensitive cancer cell lines (colon cancer; HCT-116 and breast cancer; MDA-MB231). The apoptosis assay showed that all the selected compounds were able to induce early apoptosis and compound 6e was able to induce additional cellular necrosis. Cell cycle assay showed all selected compounds were able to induce cell cycle arrest at sub-molecular phase of G0-G1 with compound 6e induced cell cycle arrest at G2M in HCT-116 cells. Accordingly, the apoptotic effect of the selected compounds was extensively investigated on genetic level and Casp-3, Casp-9 and Bax gene were up-regulated with down-regulation of Bcl-2 gene suggesting the activation of both intrinsic and extrinsic pathways. In-vivo evaluation of the antitumor activity of compound 4b in solid tumor bearing mice showed promising therapeutic effect with manifestation of dose and time dependent toxic effects at higher doses. For better evaluation of the degree of localization of 4b, its 131I-congener (131I-4b) was injected intravenously in Ehrlich solid tumor bearing mice that showed good localization at tumor site with rapid distribution and clearance from the blood. In-silico study suggested NADPH oxidases (NOXs) as potential molecular target. The compounds introduced in the current study work provided a cutting-edge phenothiazine hybrid scaffold with promising anti-proliferation action that may suggest their anti-cancer activity.

Fabrication of mixed-mode amphoteric β-cyclodextrin polymer for the simultaneous extraction of acidic and alkaline drugs

A multifunctional mixed-mode β-CD polymer adsorbent PNVCD-SIM containing amphoteric ions and multiple functional groups was prepared. Its physicochemical properties were characterized by scanning electron microscope (SEM), 1H nuclear magnetic resonance (1H NMR), 13C NMR, Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption-desorption test, elemental analysis (EA), and thermogravimetry and differential scanning calorimetry (TGA-DSC). The acidic indomethacin and alkaline promethazine were selected to evaluate the adsorption properties of PNVCD-SIM at different pH. Under optimal neutral pH conditions, the adsorption performance of PNVCD-SIM on acidic NSAIDs, alkaline phenothiazine, and neutral steroid hormone drugs was investigated. The results showed that PNVCD-SIM exhibited excellent diversified adsorption properties for acidic, alkaline, and neutral mixed drug components through the synergistic effects of β-CD inclusion, electrostatic interaction, hydrogen bond, π-π conjugation, and π-cation effect. The adsorption mechanism was consistent with the pseudo-second-order kinetic model and Langmuir isotherm model. Under the optimized conditions, a dispersive solid phase extraction method combined with high-performance liquid chromatography (dSPE-HPLC) using PNVCD-SIM as the adsorbent was established. The simultaneous extraction and detection of acidic-alkaline multi-component drugs in actual urine and lake water samples were successfully realized. This study provides new insight into the design and preparation of mixed-mode adsorption materials suitable for the rapid analysis and detection of multiple analytes.

14-Substituted Diquinothiazines as a New Group of Anticancer Agents

A series of novel double-angularly condensed diquinothiazines with aminoalkyl, amidoalkyl, sulfonamidoalkyl, and substituted phenyl groups was designed, synthesized, and evaluated for their anticancer activity against four selected human tumor cell lines (HTC116, SH-SY5Y, A549, and H1299). The cytotoxicity of the novel diquinothiazines was investigated against BEAS-2B cells. The activities of the compounds were compared to etoposide. Among them, compounds with aminoalkyl and phenyl groups showed excellent broad-spectrum anticancer activity. The most active 14-(methylthiophenyl)diquinothiazine, 3c, showed low cytotoxicity against BEAS-2B cells and high activity against tumor cell lines HTC116, SH-SY5Y, A549, and H1299, with IC50 values of 2.3 µM, 2.7 µM, 17.2 µM, and 2.7 µM, respectively (etopiside 8.6 µM, 3.9 µM, 44.8 µM, and 0.6, respectively). Live long-term microscopic observations of cell survival using the starting molecule M0 were also performed. Flow cytometry showed the proapoptotic effects of the studied diquinothiazines. Inhibition of the cell cycle in the S phase was observed, which is associated with damage to nucleic acids and connected to DNA replication arrest.

Phenothiazines Rapidly Induce Laccase Expression and Lignin-Degrading Properties in the White-Rot Fungus Phlebia radiata

Phlebia radiata is a widespread white-rot basidiomycete fungus with significance in diverse biotechnological applications due to its ability to degrade aromatic compounds, xenobiotics, and lignin using an assortment of oxidative enzymes including laccase. In this work, a chemical screen with 480 conditions was conducted to identify chemical inducers of laccase expression in P. radiata. Among the chemicals tested, phenothiazines were observed to induce laccase activity in P. radiata, with promethazine being the strongest laccase inducer of the phenothiazine-derived compounds examined. Secretomes produced by promethazine-treated P. radiata exhibited increased laccase protein abundance, increased enzymatic activity, and an enhanced ability to degrade phenolic model lignin compounds. Transcriptomics analyses revealed that promethazine rapidly induced the expression of genes encoding lignin-degrading enzymes, including laccase and various oxidoreductases, showing that the increased laccase activity was due to increased laccase gene expression. Finally, the generality of promethazine as an inducer of laccases in fungi was demonstrated by showing that promethazine treatment also increased laccase activity in other relevant fungal species with known lignin conversion capabilities including Trametes versicolor and Pleurotus ostreatus.

Antitumor Activity of PEGylated and TEGylated Phenothiazine Derivatives: Structure–Activity Relationship

The paper aims to investigate the antitumor activity of a series of phenothiazine derivatives in order to establish a structure–antitumor activity relationship. To this end, PEGylated and TEGylated phenothiazine have been functionalized with formyl units and further with sulfonamide units via dynamic imine bonds. Their antitumor activity was monitored in vitro against seven human tumors cell lines and a mouse one compared to a human normal cell line by MTS assay. In order to find the potential influence of different building blocks on antitumor activity, the antioxidant activity, the ability to inhibit farnesyltransferase and the capacity to bind amino acids relevant for tumor cell growth were investigated as well. It was established that different building blocks conferred different functionalities, inducing specific antitumor activity against the tumor cells.

Fabricating BiOCl/BiVO4 nanosheets wrapped in a graphene oxide heterojunction composite for detection of an antihistamine in biological samples

Antibiotics are essential medications for human and animal health, as they are used to battle urinary infections and bacterial diseases. Therefore, the rapid determination of antibiotic drugs in biological samples is necessary to address the current clinical challenge. Here, we developed a heterojunction ternary composite of BiOCl/BiVO₄ nanosheets enriched with graphene oxide (BiOCl/BiVO₄@GO) for accurate and minimal-level detection of an antihistamine (promethazine hydrochloride, PMZ) in urine samples. The BiOCl/BiVO₄ nanosheets were prepared by a wet chemical approach using a deep eutectic green solvent. The spectroscopic and analytical methods verified the formation and interaction of the BiOCl/BiVO₄@GO composite. Our results showed that the thoroughly exfoliated BiOCl/BiVO₄@GO composite retained good electrical conductivity and fast charge transfer toward the electrode-electrolyte interface in neutral aqueous media. In addition, the experimental conditions were accurately optimized, and the BiOCl/BiVO₄@GO composite showed excellent electrocatalytic activity toward the oxidation of PMZ. Indeed, the BiOCl/BiVO₄@GO composite demonstrated a good linear response range (0.01-124.7 μM) and a detection level of 3.3 nM with a sensitivity of 1.586 μA μM^-1 cm^-2. In addition, the BiOCl/BiVO₄@GO composite had excellent storage stability, good reproducibility, and reliable selectivity. Finally, the BiOCl/BiVO₄@GO displayed a desirable recovery level of PMZ in urine samples for real-time monitoring.

Potential of phenothiazines to synergistically block calmodulin and reactivate PP2A in cancer cells

Phenothiazines (PTZ) were developed as inhibitors of monoamine neurotransmitter receptors, notably dopamine receptors. Because of this activity they have been used for decades as antipsychotic drugs. In addition, they possess significant anti-cancer properties and several attempts for their repurposing were made. However, their incompletely understood polypharmacology is challenging. Here we examined the potential of the PTZ fluphenazine (Flu) and its mustard derivative (Flu-M) to synergistically act on two cancer associated targets, calmodulin (CaM) and the tumor suppressor protein phosphatase 2A (PP2A). Both proteins are known to modulate the Ras- and MAPK-pathway, cell viability and features of cancer cell stemness. Consistently, we show that the combination of a CaM inhibitor and the PP2A activator DT-061 synergistically inhibited the 3D-spheroid formation of MDA-MB-231 (K-Ras-G13D), NCI-H358 (K-Ras-G12C) and A375 (B-raf-V600E) cancer cells, and increased apoptosis in MDA-MB-231. We reasoned that these activities remain combined in PTZ, which were the starting point for PP2A activator development, while several PTZ are known CaM inhibitors. We show that both Flu and Flu-M retained CaM inhibitory activity in vitro and in cells, with a higher potency of the mustard derivative in cells. In line with the CaM dependence of Ras plasma membrane organization, the mustard derivative potently reduced the functional membrane organization of oncogenic Ras, while DT-061 had a negligible effect. Like DT-061, both PTZ potently decreased c-MYC levels, a hallmark of PP2A activation. Benchmarking against the KRAS-G12C specific inhibitor AMG-510 in MIA PaCa-2 cells revealed a higher potency of Flu-M than combinations of DT-061 and a CaM inhibitor on MAPK-output and a strong effect on cell proliferation. While our study is limited, our results suggest that improved PTZ derivatives that retain both, their CaM inhibitory and PP2A activating properties, but have lost their neurological side-effects, may be interesting to pursue further as anti-cancer agents.

Perphenazine and prochlorperazine decrease glioblastoma U‑87 MG cell migration and invasion: Analysis of the ABCB1 and ABCG2 transporters, E‑cadherin, α‑tubulin and integrins (α3, α5, and β1) levels

Glioblastoma multiforme is the most frequent type of malignant brain tumor, and is one of the most lethal and untreatable human tumors with a very poor survival rate. Therefore, novel and effective strategies of treatment are required. Integrins play a crucial role in the regulation of cellular adhesion and invasion. Integrins and α-tubulin are very important in cell migration, whereas E-cadherin plays a main role in tumor metastasis. Notably, drugs serve a crucial role in glioblastoma treatment; however, they have to penetrate the blood-brain barrier (BBB) to be effective. ABC transporters, including ATP binding cassette subfamily B member 1 (ABCB1) and ATP binding cassette subfamily G member 2 (ABCG2), are localized in the brain endothelial capillaries of the BBB, have a crucial role in the development of multidrug resistance and are modulated by phenothiazine derivatives. The impact of perphenazine and prochlorperazine on the motility of human Uppsala 87 malignant glioma (U87-MG) cells was evaluated using a wound-healing assay, cellular migration and invasion were assessed by Transwell assay, and the protein expression levels of ABCB1, ABCG2, E-cadherin, α-tubulin and integrins were determined by western blotting. The present study explored the effects of perphenazine and prochlorperazine on the levels of ABCB1, ABCG2, E-cadherin, α-tubulin and integrins (α3, α5, and β1), as well as on the migratory and invasive ability of U87-MG cells. The results suggested that perphenazine and prochlorperazine may modulate the expression levels of multidrug resistance proteins (they decreased ABCB1 and increased ABCG2 expression), E-cadherin, α-tubulin and integrins, and could impair the migration and invasion of U-87 MG cells. In conclusion, the decrease in migratory and invasive ability following treatment with phenothiazine derivatives due to the increase in ABCG2 and E-cadherin expression, and decrease in α-tubulin and integrins expression, may suggest that research on perphenazine and prochlorperazine in the treatment of glioblastoma is worth continuing.

Development of Phenothiazine Hybrids with Potential Medicinal Interest: A Review

The molecular hybridization approach has been used to develop compounds with improved efficacy by combining two or more pharmacophores of bioactive scaffolds. In this context, hybridization of various relevant pharmacophores with phenothiazine derivatives has resulted in pertinent compounds with diverse biological activities, interacting with specific or multiple targets. In fact, the development of new drugs or drug candidates based on phenothiazine system has been a promising approach due to the diverse activities associated with this tricyclic system, traditionally present in compounds with antipsychotic, antihistaminic and antimuscarinic effects. Actually, the pharmacological actions of phenothiazine hybrids include promising antibacterial, antifungal, anticancer, anti-inflammatory, antimalarial, analgesic and multi-drug resistance reversal properties. The present review summarizes the progress in the development of phenothiazine hybrids and their biological activity.

Psychologic Stress Drives Progression of Malignant Tumors via DRD2/HIF1α Signaling

Although it is established that the sustained psychologic stress conditions under which patients with tumors often reside accelerates malignant progression of tumors, the molecular mechanism behind this association is unclear. In this work, the effect of psychologic stress on tumor progression was verified using a stress-stimulated tumor-bearing mouse model (Str-tumor). Both D2 dopamine receptor (DRD2) and hypoxia-inducible factor-1α (HIF1α) were highly expressed in the nucleus of Str-tumors. Treatment with trifluoperazine (TFP), a DRD2 inhibitor, elicited better antitumor effects in Str-tumors than the control group. These results indicate that DRD2 may mediate stress-induced malignant tumor progression. DRD2 interacted with von Hippel-Lindau (VHL) in the nucleus, and competitive binding of DRD2 and HIF1α to VHL resulted in reduced ubiquitination-mediated degradation of HIF1α, enhancing the epithelial-mesenchymal transition of tumor cells. TFP acted as an interface inhibitor between DRD2 and VHL to promote the degradation of HIF1α. In conclusion, DRD2 may promote the progression of malignant tumors induced by psychologic stress via activation of the oxygen-independent HIF1α pathway, and TFP may serve as a therapeutic strategy for stress management in patients with cancer. SIGNIFICANCE: This work identifies DRD2 regulation of HIF1α as a mechanism underlying the progression of malignant tumors stimulated by psychologic stress and suggests that DRD2 inhibition can mitigate these stress conditions in patients.See related commentary by Bernabé, p. 5144.

Phenothiazines Modified with the Pyridine Ring as Promising Anticancer Agents

Azaphenothiazines are the largest and most perspective group of modified phenothiazines, and they exhibit variety of biological activities. The review sums up the current knowledge on the anticancer activity of isomeric pyridobenzothiazines and dipyridothiazines, which are modified azaphenothiazines with one and two pyridine rings, respectively, against 10 types of cancer cell lines. Some 10-substituted dipyridothiazines and even 10-unsubstituted parent compounds, such as 10H-1,9-diazaphenothiazine and 10H-3,6-diazaphenothiazine, exhibited very potent action with the IC50 values less than 1 µg/mL and 1 µM against selected cancer cell lines. The strength of the anticancer action depends both on the tricyclic ring scaffolds and the substituents at the thiazine nitrogen atom. The review discusses the kind of the substituents, nature of tricyclic ring scaffolds with the location of the azine nitrogen atoms, the types of the cancer cell lines, and the mechanism of action.

Laser-Irradiated Chlorpromazine as a Potent Anti-Biofilm Agent for Coating of Biomedical Devices

Nowadays, antibiotic resistance has become increasingly common, triggering a global health crisis, immediately needing alternative, including repurposed drugs with potent bactericidal effects. We demonstrated that chlorpromazine aqueous solutions exposed to laser radiation exhibited visible activity against various microorganisms. The aim of this study was to investigate the quantitative antimicrobial activity of chlorpromazine in non-irradiated and 4-h laser irradiated form. Also, we examined the effect of both solutions impregnated on a cotton patch, cannula, and urinary catheter against Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. In all experimental versions, the chlorpromazine antimicrobial activity was enhanced by laser exposure. Besides the experimental results, the in silico analyses using molecular docking proved that the improved antimicrobial activity of the irradiated compound was a result of the combined action of the photoproducts on the biological target (s). Our results show that laser radiation could alter the molecular structure of various drugs and their effects, proving to be a promising strategy to halt antibiotic resistance, by repurposing current medicines for new antimicrobial strategies, thereby decreasing the costs and time for the development of more efficient drugs.

Subnanomolar detection of promethazine abuse using a gold nanoparticle-graphene nanoplatelet-modified electrode

A simple, sensitive, and effective adsorptive stripping voltammetric sensor for the detection of trace-level promethazine was created based on a gold nanoparticle-graphene nanoplatelet-modified glassy carbon electrode (AuNP-GrNP/GCE). AuNP-GrNP nanocomposites were synthesized using an electroless deposition process, and the morphology was characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical behavior and detection of promethazine at the AuNP-GrNP/GCE were investigated utilizing cyclic voltammetry and adsorptive stripping voltammetry. The AuNP-GrNP/GCE showed outstanding synergistic electrochemical activity for promethazine oxidation, a highly active surface area, great adsorptivity, and outstanding catalytic properties. The electrolyte pH, amount of AuNP-GrNP nanocomposite, preconcentration potential (vs. Ag/AgCl), and time were optimized to obtain a high performance electrochemical sensor. Under optimal conditions, the proposed sensor displayed two linear concentration ranges from 1.0 nmol L^-1 to 1.0 μmol L^-1 and from 1.0 to 10 μmol L^-1. The limits of detection and quantitation were 0.40 and 1.4 nmol L^-1, respectively. This sensor displayed high sensitivity, a capability for rapid analysis, and excellent repeatability and reproducibility. The developed sensor was effective and practical for promethazine detection in biological fluids and forensic samples, and the obtained results exhibited excellent agreement with the results obtained using the method described in the British Pharmacopoeia. Graphical abstract.

Water soluble PEGylated phenothiazines as valuable building blocks for bio-materials

The paper reports a series of three new PEGylated phenothiazine derivatives which keep the potential of valuable building blocks for preparing eco-materials addressed to a large realm of fields, from bio-medicine to opto-electronics. They were synthetized by connecting the hydrophilic poly(ethylene glycol) to the hydrophobic phenothiazine via an ether, ester, or amide linking group. The successful synthesis of the targeted polymers and their purity were demonstrated by NMR and FTIR spectroscopy methods. Their capacity to self-assembly in water was studied by DLS and UV-vis techniques and the particularities of the formed aggregates were investigated by fluorescence spectroscopy, SEM, AFM, POM and UV light microscopy. The biocompatibility was assessed on normal human dermal fibroblasts and human cervical cancer cells. The synthetized compounds showed the formation of luminescent aggregates and proved excellent biocompatibility on normal cells. In addition, a concentration dependent cytotoxicity against HeLa cancer cells was noticed for the PEGylated phenothiazine containing an ester unit.

Influence of phenothiazine molecules on the interactions between positively charged poly-l-lysine and negatively charged DPPC/DPPG membranes

Phenothiazines are very effective antipsychotic drugs, which also have anticancer and antimicrobial activities. Despite being used in human treatment, the molecular mechanism of the biological actions of these molecules is not yet understood in detail. The role of the interactions between phenothiazines and proteins or lipid membranes has been much discussed. Herein, fourier-transform infrared (FTIR) spectroscopic studies were used to investigate the effect of three phenothiazines: fluphenazine (FPh); chlorpromazine (ChP); and propionylpromazine (PP) on the structures of a positively charged poly-l-lysine (PLL) peptide, a negatively charged dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol (DPPC/DPPG) membrane, and on the mutual interactions between electrostatically associated PLL molecules and DPPC/DPPG membranes. Phenothiazine-induced alterations in the secondary structure of PLL, the conformational state (trans/gauche) of the hydrocarbon lipid chains, and the hydration of the DPPC/DPPG membrane interface were studied on the basis of amide I' vibrations, antisymmetric and symmetric stretching vibrations of the CH₂ groups of the lipid hydrocarbon chains (ν_sCH₂), and stretching vibrations of the lipid C=O groups (νC = O), respectively. It was shown that in the presence of negatively charged DPPC/DPPG membranes, the phenothiazines were able to modify the secondary structure of charged PLL molecules. Additionally, the effect of PLL on the structure of DPPC/DPPG membranes was also altered by the presence of the phenothiazine molecules.

The interplay of conformations and electronic properties in N-aryl phenothiazines

Extra and intra conformations govern electronic properties of N-aryl phenothiazines as shown by combined experimental and computational structure–property relationships.

Structure–reactivity relationship of probes based on the H2S-mediated reductive cleavage of the CC bond

The structure–reactivity relationship of H₂S-mediated reductive cleavage of CC bond was studied and utilized to develop probes for detecting H₂S.

Phenothiazine and amide-ornamented novel nitrogen heterocyclic hybrids: synthesis, biological and molecular docking studies

The synthesis of phenothiazine and amide-ornamented nitrogen heterocycles (25–34) has been accomplished utilizing a multi-step synthetic protocol and the structures have been established based on physical and spectral techniques.

10H-1,9-diazaphenothiazine and its 10-derivatives: synthesis, characterisation and biological evaluation as potential anticancer agents

10H-1,9-diazaphenothiazine was obtained in the sulphurisation reaction of diphenylamine with elemental sulphur and transformed into new 10-substituted derivatives, containing alkyl and dialkylaminoalkyl groups at the thiazine nitrogen atom. The 1,9-diazaphenothiazine ring system was identified with advanced 1H and 13C NMR techniques (COSY, NOESY, HSQC and HMBC) and confirmed by X-ray diffraction analysis of the methyl derivative. The compounds exhibited significant anticancer activities against the human glioblastoma SNB-19, melanoma C-32 and breast cancer MDA-MB-231 cell lines. The most active 1,9-diazaphenothiazines were the derivatives with the propynyl and N, N-diethylaminoethyl groups being more potent than cisplatin. For those two compounds, the expression of H3, TP53, CDKN1A, BCL-2 and BAX genes was detected by the RT-QPCR method. The proteome profiling study showed the most probable compound action on SNB-19 cells through the intrinsic mitochondrial pathway of apoptosis. The 1,9-diazaphenotiazine system seems to be more potent than known isomeric ones (1,6-diaza-, 1,8-diaza-, 2,7-diaza- and 3,6-diazaphenothiazine).

Antimelanoma activity of perphenazine and prochlorperazine in human COLO829 and C32 cell lines

Cutaneous melanoma is least common (only about 1% of skin cancers) but is the deadliest malignant tumor. Moreover, amelanotic types of melanoma are very difficult for clinical diagnosis. The standard therapy can cause a lot of side effects, e.g., nausea, vomiting, and headaches, which means that novel and effective strategies are required. Interestingly, phenothiazine derivatives possess sedative, antiemetic, and anticancer activity. Our goal was to determine the effect of perphenazine and prochlorperazine on cell viability, motility, microphthalmia-associated transcription factor (MITF) and tyrosinase content in melanotic and amelanotic melanoma cells. The viability of C32 and COLO829 melanoma cells was evaluated by the WST-1 colorimetric assay; impact on motility of human melanoma was performed by wound-healing assay, while tyrosinase and MITF content were determined by Western blot. In the present study, we explore the anticancer effect of perphenazine and prochlorperazine in human melanotic (COLO829) and amelanotic (C32) melanoma cells concluding that prochlorperazine inhibits cell viability in a concentration-dependent manner, impairs motility, and decreases tyrosinase and MITF amounts. Moreover, the analyzed drugs decrease/increase MITF amount depending on the type of melanoma. We demonstrated that the decrease of MITF and tyrosinase protein induces motility inhibition of C32 cells, which suggests the ability of those drugs to restore cancer cell sensitivity to treatment. The ability of prochlorperazine to contain the spread of the amelanotic melanoma in vivo may be helpful in the development of a new and effective antimelanoma therapies.

Effect of phenothiazine compounds on the secondary structure and fibrillogenesis of poly-l-lysine

Phenothiazine molecules are effective and commonly used antipsychotic drugs, especially in the treatment of schizophrenia. However, they produce strong extrapyramidal side-effects manifested by drug-induced parkinsonism. Because Parkinson's disease as a neurodegenerative illness is associated with the formation of amyloid fibrils in neuronal cells, it is postulated that the development of phenothiazine-induced parkinsonism may be related to the phenothiazine-induced formation of fibrillar aggregates. The effect of phenothiazine compounds (fluphenazine (FPh), chlorpromazine (ChP) and propionylpromazine (PP)) on the fibrillogenesis of poly-l-lysine (PLL) was studied using Fourier-transform infrared (FTIR) spectroscopy supported by principal component analysis (PCA), vibrational circular dichroism (VCD), transmission electron microscopy (TEM) and Congo red binding assay. The fibrillogenesis of PLL is accompanied by fibril formation with charged or uncharged polypeptides with PPII (polyproline-like extended helix), α-helix or β-sheet conformations. All of the phenothiazine molecules investigated effectively reduced the temperature required to induce the formation of β-sheet-rich fibrils from α-helix-rich fibrils of PLL.

The role of bracken fern illudanes in bracken fern-induced toxicities

Bracken fern is carcinogenic when fed to domestic and laboratory animals inducing bladder and ileal tumours and is currently classified as a possible human carcinogen by IARC. The carcinogenic illudane, ptaquiloside (PTQ) was isolated from bracken fern and is widely assumed to be the major bracken carcinogen. However, several other structurally similar illudanes are found in bracken fern, in some cases at higher levels than PTQ and so may contribute to the overall toxicity and carcinogenicity of bracken fern. In this review, we critically evaluate the role of illudanes in bracken fern induced toxicity and carcinogenicity, the mechanistic basis of these effects including the role of DNA damage, and the potential for human exposure in order to highlight deficiencies in the current literature. Critical gaps remain in our understanding of bracken fern induced carcinogenesis, a better understanding of these processes is essential to establish whether bracken fern is also a human carcinogen.

Synthesis, Anticancer Activity, and Apoptosis Induction of Novel 3,6-Diazaphenothiazines

New 10-substituted derivatives of 3,6-diazaphenothiazine, containing the triple bond linker terminated with tertiary cyclic and acyclic amine groups, were synthesized and screened for their anticancer action. The compounds exhibited varied anticancer activities against human glioblastoma SNB-19, melanoma C-32, and breast cancer MDA-MB231 cell lines, depending on the nature of the substituents. The most active 3,6-diazaphenothiazine, 4, was the derivative with the N,N-diethylamino-2-butynyl substituent against glioblastoma SNB-19, and was ten times more potent than cisplatin. For this compound, the expression of H3, TP53, CDKN1A, BCL-2, and BAX genes was detected by the RT-qPCR method. The gene expression ratio BAX/BCL-2 indicated the induction of mitochondrial apoptosis in cancer cell lines. The transformation of the propynyl substituent into amino-2-butynyl can be a method applicable to the search for more anticancer-active azaphenothiazines.

Efficient synthesis of novel cyclic fused-phenothiazines via domino cyclization of 2-(benzo[b][1,4]thiazin-3-ylidene)acetate, aromatic aldehydes and cyclic 1,3-diketones

Novel fused and bridged phenothiazine derivatives were selectively synthesized via an acid-promoted reaction of alkyl 2-(benzo[b][1,4]thiazin-3-ylidene)acetate, aromatic aldehydes and cyclic diketones under different reaction conditions.

Phenothiazine and amide-ornamented dihydropyridinesviaa molecular hybridization approach: design, synthesis, biological evaluation and molecular docking studies

A series of novel phenothiazinyldihydropyridine dicarboxamides7a–7jwas synthesized by adopting a multi-step synthetic strategy and characterized through physical and spectral techniques.

Non-directed copper-catalyzed regioselective C–H sulfonylation of phenothiazines

A simple and general procedure for C3 sulfonylation of phenothiazines was developed by CuI/Li₂CO₃ catalyzed transformation of aryl/alkyl sulfonyl chlorides.

Lipophilicity of New Anticancer 1,6- and 3,6-diazaphenothiazines by of Use RP TLC and Different Computational Methods

The lipophilicity of new two series of anticancer active 10-substituted 1,6- and 3,6-diazaphenothiazines has been investigated using reversed-phase thin-layer chromatography. Their lipophilicity (RM0 and log PTLC) was determined with mixtures of acetone and Tris buffer as mobile phases. The relative lipophilicity parameter RM0 and specific hydrophobic surface area b were significantly intercorrelated showing congeneric classes of diazaphenothiazines. The parameter RM0 was transformed into parameter log PTLC by use of the calibration curve. The parameter log PTLC was compared with computationally calculated lipophilic parameters log Pcalcd. The lipophilicity was discussed with the structure elements and was correlated with molecular descriptors, ADME properties and in vitro anticancer activities.

Phospholipase A2 Inhibitors Modulate the Effect of Trifluoperazine on the Intracellular Ca2+ Concentration in Macrophages

Using Fura-2AM microfluorimetry, it was shown for the first time that phospholipase A₂ inhibitors 4-bromophenacyl bromide and glucocorticosteroids prednisolone and dexamethasone attenuate Ca²⁺ responses induced by neuroleptic trifluoperazine in macrophages. The results suggest the involvement of phospholipase A₂ and arachidonic acid metabolism cascade in the effect of trifluoperazine on intracellular Ca²⁺ concentration in macrophages.

Meet the relatives: a reintroduction to the clinical pharmacology of ‘typical’ antipsychotics (Part 1)

A number of pragmatic trials have cast doubt on the concept of ‘atypicality’ in relation to antipsychotic drugs, and some commentators have argued that the dichotomy between ‘typical’ (‘first-generation’) and ‘atypical’ ('second-generation’) compounds is artificial and should be abandoned, leaving the entire class of antipsychotics available for consideration in more individualised treatment planning. However, younger psychiatrists now gain little or no experience in the use of older antipsychotics. This is the first of two articles addressing practical issues for consideration in prescribing the older antipsychotics available in the UK. It covers background, including the fundamental clinical action of antipsychotics, the nature of drug licensing and identification of pharmacological parameters that may be of value in prescribing decisions, and discusses the phenothiazines: chlorpromazine, promazine, levomepromazine, pericyazine, perphenazine, trifluoperazine and prochlorperazine.

Synthesis of new hybrid 1,4-thiazinyl-1,2,3-dithiazolyl radicals via Smiles rearrangement

The condensation reaction of 2-aminobenzenethiols and 3-aminopyrazinethiols with 2-amino-6-fluoro-N-methylpyridinium triflate afforded thioether derivatives that were found to undergo Smiles rearrangement and cyclocondensation with sulphur monochloride to yield new hybrid 1,4-thiazine-1,2,3-dithiazolylium cations. The synthesized cations were readily reduced to the corresponding stable neutral radicals with spin densities delocalized over both 1,4-thiazinyl and 1,2,3-dithiazolyl moieties.

Therapeutic targeting of PP2A

Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase that regulates many cellular processes. Given the central role of PP2A in regulating diverse biological functions and its dysregulation in many diseases, including cancer, PP2A directed therapeutics have become of great interest. The main approaches leveraged thus far can be categorized as follows: 1) inhibiting endogenous inhibitors of PP2A, 2) targeted disruption of post translational modifications on PP2A subunits, or 3) direct targeting of PP2A. Additional insight into the structural, molecular, and biological framework driving the efficacy of these therapeutic strategies will provide a foundation for the refinement and development of novel and clinically tractable PP2A targeted therapies.

The effect of chlorpromazine on intracellular Ca2+ concentration in macrophages

Using Fura-2AM microfluorimetry, it was shown for the first time that neuroleptic chlorpromazine causes intracellular Ca²⁺ concentration increase in macrophages due to Ca²⁺ mobilization from intracellular Ca²⁺ stores and subsequent Ca²⁺ entry from the external medium. Chlorpromazine-induced Ca²⁺ entry is inhibited by La³⁺ and 2-aminoethoxydiphenyl borate and is associated with Ca²⁺ store depletion.