In Vitro and In Silico of Cholinesterases Inhibition and In Vitro and In Vivo Anti-Melanoma Activity Investigations of Extracts Obtained from Selected Berberis Species.

Berberis species have a long history of use in traditional Chinese medicine, Ayurvedic medicine, and Western herbal medicine. The aim of this study was the quantification of the main isoquinoline alkaloids in extracts obtained from various Berberis species by HPLC, in vitro and in silico determination of anti-cholinesterase activity, and in vitro and in vivo investigations of the cytotoxic activity of the investigated plant extracts and alkaloid standards. In particular, Berberis species whose activity had not been previously investigated were selected for the study. In the most investigated Berberis extracts, a high content of berberine and palmatine was determined. Alkaloid standards and most of the investigated plant extracts exhibit significant anti-cholinesterase activity. Molecular docking results confirmed that both alkaloids are more favourable for forming complexes with acetylcholinesterase compared to butyrylcholinesterase. The kinetic results obtained by HPLC-DAD indicated that berberine noncompetitively inhibited acetylcholinesterase, while butyrylcholinesterase was inhibited in a mixed mode. In turn, palmatine exhibited a mixed inhibition of acetylcholinesterase. The cytotoxic activity of berberine and palmatine standards and plant extracts were investigated against the human melanoma cell line (A375). The highest cytotoxicity was determined for extract obtained from Berberis pruinosa cortex. The cytotoxic properties of the extract were also determined in the in vivo investigations using the Danio rerio larvae xenograft model. The obtained results confirmed a significant effect of the Berberis pruinosa cortex extract on the number of cancer cells in a living organism. Our results showed that extracts obtained from Berberis species, especially the Berberis pruinosa cortex extract, can be recommended for further in vivo experiments in order to confirm the possibility of their application in the treatment of neurodegenerative diseases and human melanoma.

Identification of the first-in-class dual inhibitors of human DNA topoisomerase IIα and indoleamine-2,3-dioxygenase 1 (IDO 1) with strong anticancer properties.

Molecular docking of a large set of thiosemicarbazide-based ligands resulted in obtaining compounds that inhibited both human DNA topoisomerase IIα and indoleamine-2,3-dioxygenase-1 (IDO1). To the best of our knowledge, these compounds are the first dual inhibitors targeting these two enzymes. As both of them participate in the anticancer response, the effect of the compounds on a panel of cancer cell lines was examined. Among the cell lines tested, lung cancer (A549) and melanoma (A375) cells were the most sensitive to compounds 1 (IC50=0.23 µg/ml), 2 (IC50=0.83 µg/ml) and 3 (IC50=0.25 µg/ml). The observed activity was even 90-fold higher than that of etoposide, with selectivity index values reaching 125. In-silico simulations showed that contact between 1-3 and human DNA topoisomerase II was maintained through aromatic moieties located at limiting edges of ligand molecules and intensive interactions of the thiosemicarbazide core with the DNA fragments present in the catalytic site of the enzyme.

Thiosemicarbazide Derivatives Targeting Human TopoIIα and IDO-1 as Small-Molecule Drug Candidates for Breast Cancer Treatment.

In 2020, breast cancer became the most frequently diagnosed type of cancer, with nearly 2.3 million new cases diagnosed. However, with early diagnosis and proper treatment, breast cancer has a good prognosis. Here, we investigated the effect of thiosemicarbazide derivatives, previously identified as dual inhibitors targeting topoisomerase IIα and indoleamine-2,3-dioxygenase 1 (IDO 1), on two distinct types of breast cancer cells (MCF-7 and MDA-MB-231). The investigated compounds (1-3) selectively suppressed the growth of breast cancer cells and promoted apoptosis via caspase-8- and caspase-9-related pathways. Moreover, these compounds caused S-phase cell cycle arrest and dose-dependently inhibited the activity of ATP-binding cassette transporters (MDR1, MRP1/2 and BCRP) in MCF-7 and MDA-MB-231 cells. Additionally, following incubation with compound 1, an increased number of autophagic cells within both types of the investigated breast cancer cells was observed. During preliminary testing of ADME-Tox properties, the possible hemolytic activities of compounds 1-3 and their effects on specific cytochrome P450 enzymes were evaluated.

Combined In Silico and In Vitro Analyses to Assess the Anticancer Potential of Thiazolidinedione-Thiosemicarbazone Hybrid Molecules.

The number of people affected by cancer and antibiotic-resistant bacterial infections has increased, such that both diseases are already seen as current and future leading causes of death globally. To address this issue, based on a combined in silico and in vitro approach, we explored the anticancer potential of known antibacterials with a thiazolidinedione-thiosemicarbazone (TZD-TSC) core structure. A cytotoxicity assessment showed encouraging results for compounds 2-4, with IC50 values against T98G and HepG2 cells in the low micromolar range. TZD-TSC 3 proved to be most toxic to cancer cell lines, with IC50 values of 2.97 ± 0.39 µM against human hepatoma HepG2 cells and IC50 values of 28.34 ± 2.21 µM against human glioblastoma T98G cells. Additionally, compound 3 induced apoptosis and showed no specific hemolytic activity. Furthermore, treatment using 3 on cancer cell lines alters these cells' morphology and further suppresses migratory activity. Molecular docking, in turn, suggests that 3 would have the capacity to simultaneously target HDACs and PPARγ, by the activation of PPARγ and the inhibition of both HDAC4 and HDAC8. Thus, the promising preliminary results obtained with TZD-TSC 3 represent an encouraging starting point for the rational design of novel chemotherapeutics with dual antibacterial and anticancer activities.

TZD-Based Hybrid Molecules Act as Dual Anti-Mycobacterium tuberculosis and Anti-Toxoplasma gondii Agents.

Two distinct intracellular pathogens, namely Mycobacterium tuberculosis (Mtb) and Toxoplasma gondii (Tg), cause major public health problems worldwide. In addition, serious and challenging health problems of co-infections of Tg with Mtb have been recorded, especially in developing countries. Due to this fact, as well as the frequent cases of resistance to the current drugs, novel anti-infectious therapeutics, especially those with dual (anti-Tg and anti-Mtb) modes of action, are needed. To address this issue, we explored the anti-Tg potential of thiazolidinedione-based (TZD-based) hybrid molecules with proven anti-Mtb potency. Several TZD hybrids with pyridine-4-carbohydrazone (PCH) or thiosemicarbazone (TSC) structural scaffolds were more effective and more selective than sulfadiazine (SDZ) and trimethoprim (TRI). Furthermore, all of these molecules were more selective than pyrimethamine (PYR). Further studies for the most potent TZD-TSC hybrids 7, 8 and 10 and TZD-PCH hybrid molecule 2 proved that these compounds are non-cytotoxic, non-genotoxic and non-hemolytic. Moreover, they could cross the blood-brain barrier (BBB), which is a critical factor linked with ideal anti-Tg drug development. Finally, since a possible link between Tg infection and the risk of glioblastoma has recently been reported, the cytotoxic potential of TZD hybrids against human glioblastoma cells was also evaluated. TZD-PCH hybrid molecule 2 was found to be the most effective, with an IC50 of 19.36 ± 1.13 µg/mL against T98G cells.

Chitosan-Based Hydrogels for Controlled Delivery of Asiaticoside-Rich Centella asiatica Extracts with Wound Healing Potential.

Centella asiatica extract is a valued plant material with known anti-inflammatory and anti-microbiological properties. Using the Design of Experiment (DoE) approach, it was possible to obtain an optimized water/alcoholic extract from Centella asiatica, which allowed the preparation of the final material with biological activity in the wound healing process. Studies on the novel applications of Centella asiatica in conjunction with the multifunctional chitosan carrier have been motivated by the plant's substantial pharmacological activity and the need to develop new and effective methods for the treatment of chronic wounds. The controlled release of asiaticoside was made possible by the use of chitosan as a carrier. Based on the findings of investigations using the PAMPA skin assay, which is a model imitating the permeability of actives through skin, this compound, characterized by sustained release from the chitosan delivery system, was identified as being well able to permeate biological membranes such as skin. Chitosan and the lyophilized extract of Centella asiatica worked synergistically to block hyaluronidase, exert efficient microbiological activity and take part in the wound healing process, as proven in an in vitro model. A formulation containing 3% extract with 3% medium-molecular-weight chitosan was indicated as a potentially new treatment with high compliance and effectiveness for patients. Optimization of the chitosan-based hydrogel preparation ensured the required rheological properties necessary for the release of the bioactive from the chitosan delivery system and demonstrated a satisfactory antimicrobial activity.

Determination of Selected Isoquinoline Alkaloids from Chelidonium majus, Mahonia aquifolium and Sanguinaria canadensis Extracts by Liquid Chromatography and Their In Vitro and In Vivo Cytotoxic Activity against Human Cancer Cells.

The search for new substances with cytotoxic activity against various cancer cells, especially cells that are very resistant to currently used chemotherapeutic agents, such as melanoma cells, is a very important scientific aspect. We investigated the cytotoxic effect of Chelidonium majus, Mahonia aquifolium and Sanguinaria canadensis extracts obtained from different parts of these plants collected at various vegetation stages on FaDu, SCC-25, MCF-7, and MDA-MB-231 cancer cells. Almost all the tested extracts showed higher cytotoxicity against these cancer cells than the anticancer drug etoposide. The highest cytotoxicity against the FaDu, SCC-25, MCF-7 and MDA-MB-231 cancer cell lines was obtained for the Sanguinaria candensis extract collected before flowering. The cytotoxicity of extracts obtained from different parts of Chelidonium majus collected at various vegetation stages was also evaluated on melanoma cells (A375, G361 and SK-MEL-3). The highest cytotoxic activity against melanoma A375 cells was observed for the Chelidonium majus root extract, with an IC50 of 12.65 µg/mL. The same extract was the most cytotoxic against SK-MEL-3 cells (IC50 = 1.93 µg/mL), while the highest cytotoxic activity against G361 cells was observed after exposure to the extract obtained from the herb of the plant. The cytotoxic activity of Chelidonium majus extracts against melanoma cells was compared with the cytotoxicity of the following anticancer drugs: etoposide, cisplatin and hydroxyurea. In most cases, the IC50 values obtained for the anticancer drugs were higher than those obtained for the Chelidonium majus extracts. The most cytotoxic extract obtained from the root of Chelidonium majus was selected for in vivo cytotoxic activity investigations using a Danio rerio larvae xenograft model. The model was applied for the first time in the in vivo investigations of the extract's anticancer potential. The application of Danio rerio larvae xenografts in cancer research is advantageous because of the transparency and ease of compound administration, the small size and the short duration and low cost of the experiments. The results obtained in the xenograft model confirmed the great effect of the investigated extract on the number of cancer cells in a living organism. Our investigations show that the investigated plant extracts exhibit very high cytotoxic activity and can be recommended for further experiments in order to additionally confirm their potential use in the treatment of various human cancers.

Copper(II) Complexes with 1-(Isoquinolin-3-yl)heteroalkyl-2-ones: Synthesis, Structure and Evaluation of Anticancer, Antimicrobial and Antioxidant Potential.

Four copper(II) complexes, C1-4, derived from 1-(isoquinolin-3-yl)heteroalkyl-2-one ligands L1-4 were synthesized and characterized using an elemental analysis, IR spectroscopic data as well as single crystal X-ray diffraction data for complex C1. The stability of complexes C1-4 under conditions mimicking the physiological environment was estimated using UV-Vis spectrophotometry. The antiproliferative activity of both ligands L1-4 and copper(II) compounds C1-4 were evaluated using an MTT assay on four human cancer cell lines, A375 (melanoma), HepG2 (hepatoma), LS-180 (colon cancer) and T98G (glioblastoma), and a non-cancerous cell line, CCD-1059Sk (human normal skin fibroblasts). Complexes C1-4 showed greater potency against HepG2, LS180 and T98G cancer cell lines than etoposide (IC50 = 5.04-14.89 µg/mL vs. IC50 = 43.21->100 µg/mL), while free ligands L1-4 remained inactive in all cell lines. The prominent copper(II) compound C2 appeared to be more selective towards cancer cells compared with normal cells than compounds C1, C3 and C4. The treatment of HepG2 and T98G cells with complex C2 resulted in sub-G1 and G2/M cell cycle arrest, respectively, which was accompanied by DNA degradation. Moreover, the non-cytotoxic doses of C2 synergistically enhanced the cytotoxic effects of chemotherapeutic drugs, including etoposide, 5-fluorouracil and temozolomide, in HepG2 and T98G cells. The antimicrobial activities of ligands L2-4 and their copper(II) complexes C2-4 were evaluated using different types of Gram-positive bacteria, Gram-negative bacteria and yeast species. No correlation was found between the results of the antiproliferative and antimicrobial experiments. The antioxidant activities of all compounds were determined using the DPPH and ABTS radical scavenging methods. Antiradical tests revealed that among the investigated compounds, copper(II) complex C4 possessed the strongest antioxidant properties. Finally, the ADME technique was used to determine the physicochemical and drug-likeness properties of the obtained complexes.

Effect of Linker Elongation on the VGSC Affinity and Anticonvulsant Activity among 4-Alkyl-5-aryl-1,2,4-triazole-3-thione Derivatives.

The main aim of the current project was to investigate the effect of the linker size in 4-alkyl-5-aryl-1,2,4-triazole-3-thione derivatives, known as a group of antiepileptic drug candidates, on their affinity towards voltage-gated sodium channels (VGSCs). The rationale of the study was based both on the SAR observations and docking simulations of the interactions between the designed ligands and the binding site of human VGSC. HYDE docking scores, which describe hydrogen bonding, desolvation, and hydrophobic effects, obtained for 5-[(3-chlorophenyl)ethyl]-4-butyl/hexyl-1,2,4-triazole-3-thiones, justified their beneficial sodium channel blocking activity. The results of docking simulations were verified using a radioligand binding assay with [3H]batrachotoxin. Unexpectedly, although the investigated triazole-based compounds acted as VGSC ligands, their affinities were lower than those of the respective analogs containing shorter alkyl linkers. Since numerous sodium channel blockers are recognized as antiepileptic agents, the obtained 1,2,4-triazole derivatives were examined for antiepileptic potential using an experimental model of tonic-clonic seizures in mice. Median effective doses (ED50) of the compounds examined in MES test reached 96.6 ± 14.8 mg/kg, while their median toxic doses (TD50), obtained in the rotarod test, were even as high as 710.5 ± 47.4 mg/kg.

Determination of Some Isoquinoline Alkaloids in Extracts Obtained from Selected Plants of the Ranunculaceae, Papaveraceae and Fumarioideae Families by Liquid Chromatography and In Vitro and In Vivo Investigations of Their Cytotoxic Activity.

Alkaloids are heterocyclic bases with widespread occurrence in nature. Plants are rich and easily accessible sources of them. Most isoquinoline alkaloids have cytotoxic activity for different types of cancer, including malignant melanoma, the most aggressive type of skin cancer. The morbidity of melanoma has increased worldwide every year. For that reason, developing new candidates for anti-melanoma drugs is highly needed. The aim of this study was to investigate the alkaloid compositions of plant extracts obtained from Macleaya cordata root, stem and leaves, Pseudofumaria lutea root and herb, Lamprocapnos spectabilis root and herb, Fumaria officinalis whole plant, Thalictrum foetidum root and herb, and Meconopsis cambrica root and herb by HPLC-DAD and LC-MS/MS. For determination of cytotoxic properties, human malignant melanoma cell line A375, human Caucasian malignant melanoma cell line G-361, and human malignant melanoma cell line SK-MEL-3 were exposed in vitro to the tested plant extracts. Based on the in vitro experiments, Lamprocapnos spectabilis herb extract was selected for further, in vivo research. The toxicity of the extract obtained from Lamprocapnos spectabilis herb was tested using an animal zebrafish model in the fish embryo toxicity test (FET) for determination of the LC50 value and non-toxic doses. Determination of the influence of the investigated extract on the number of cancer cells in a living organism was performed using a zebrafish xenograft model. Determination of the contents of selected alkaloids in different plant extracts was performed using high performance liquid chromatography (HPLC) in a reverse-phase system (RP) on a Polar RP column with a mobile phase containing acetonitrile, water and ionic liquid. The presence of these alkaloids in plant extracts was confirmed by LC-MS/MS. Preliminary cytotoxic activity of all prepared plant extracts and selected alkaloid standards was examined using human skin cancer cell lines A375, G-361, and SK-MEL-3. The cytotoxicity of the investigated extract was determined in vitro by cell viability assays (MTT). For in vivo determination of investigated extract cytotoxicity, a Danio rerio larvae xenograft model was used. All investigated plant extracts in in vitro experiments exhibited high cytotoxic activity against the tested cancer cell lines. The results obtained using the Danio rerio larvae xenograft model confirmed the anticancer activity of the extract obtained from Lamprocapnos spectabilis herb. The conducted research provides a basis for future investigations of these plant extracts for potential use in the treatment of malignant melanoma.

Inhibition of Toxoplasma gondii by 1,2,4-triazole-based compounds: marked improvement in selectivity relative to the standard therapy pyrimethamine and sulfadiazine.

A safer treatment for toxoplasmosis would be achieved by improving the selectivity profile of novel chemotherapeutics compared to the standard therapy pyrimethamine (PYR) and sulfadiazine (SDZ). We previously reported on the identification of the compounds with imidazole-thiosemicarbazide scaffold as potent and selective anti-Toxoplasma gondii (T. gondii) agents. In our current research, we report on the optimisation of this chemical scaffold leading to the discovery cyclic analogue 20 b with s-triazole core structure. This compound displayed prominent CC30 to IC50 selectivity index (SI) of 70.72, making it 160-fold more selective than SDZ, 11-fold more selective than PYR, and 4-fold more selective than trimethoprim (TRI). Additionally, this compound possesses prerequisite drug-like anti-Toxoplasma properties to advance into preclinical development; it showed ability to cross the BBB, did not induce genotoxic and haemolytic changes in human cells, and as well as it was characterised by low cellular toxicity.

Spectroscopic Evaluation of the Potential Neurotoxic Effects of a New Candidate for Anti-Seizure Medication-TP-315 during Chronic Administration (In Vivo).

The aim of this study was to investigate the potential neurotoxic effect of the new anti-seizure medication candidate-5-(3-chlorophenyl)-4-hexyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (TP-315), after chronic administration to mice. TP-315 was administered to mice intraperitoneally for 14 days. At 24 h post the last injection, animals were decapitated, their brains were acquired, flash-frozen in liquid nitrogen and cut into 10 µm slices. The FT-IR chemical imaging technique was used for the investigation of the potential neurotoxic effect in the cerebral cortex and hippocampus. The effect on the lipidomic and proteomic profile and on oxidative stress was investigated. The results showed no statistically significant changes in the above-mentioned parameters. TP-315 seems to pose no neurotoxic effect on the mouse brain after chronic use, therefore, its use should be safe.

Zinc Coordination Compounds with Benzimidazole Derivatives: Synthesis, Structure, Antimicrobial Activity and Potential Anticancer Application.

Developing new, smart drugs with the anticancer activity is crucial, especially for cancers, which cause the highest mortality in humans. In this paper we describe a series of coordination compounds with the element of health, zinc, and bioactive ligands, benzimidazole derivatives. By way of synthesis we have obtained four compounds named C1, C2, C4 and C4. Analytical analyses (elemental analysis (EA), flame atomic absorption spectrometry (FAAS)), spectroscopic (Fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS)) and thermogravimetric (TG) methods and the definition of crystal structures were used to explore the nature of bonding and to elucidate the chemical structures. The collected analytical data allowed the determination of the stoichiometry in coordination compounds, thermal stability, crystal structure and way of bonding. The cytotoxicity effect of the new compounds as a potential antitumor agent on the glioblastoma (T98G), neuroblastoma (SK-N-AS) and lung adenocarcinoma (A549) cell lines and human normal skin fibroblasts (CCD-1059Sk) was also determined. Cell viability was determined by the MTT assay. The results obtained confirmed that conversion of ligands into the respective metal complexes significantly improved their anticancer properties. The complexes were screened for antibacterial and antifungal activities. The ADME technique was used to determine the physicochemical and biological properties.

Aloe arborescens: In Vitro Screening of Genotoxicity, Effective Inhibition of Enzyme Characteristics for Disease Etiology, and Microbiological Activity.

The present study assessed the genotoxicity, the possibility of inhibiting selected enzymes, and the microbial activity of lyophilisate from 3-year-old A. arborescens leaves obtained from controlled crops. The lyophilisate from 3-year-old A. arborescens leaves was standardized for aloin A and aloenin A content. Moreover, concentrations of polyphenolic compounds and phenolic acids were determined. The first stage of the research was to determine genotoxicity using the comet test, which confirmed the safety of A. arborescens. Assays of enzymatic inhibition were performed for hyaluronidase (IC50 = 713.24 ± 41.79 µg/mL), α-glucosidase (IC50 = 598.35 ± 12.58 µg/mL), acetylcholinesterase and butyrylcholinesterase (1.16 vs. 0.34 µM of eserine/g d.m., respectively). The next stage of the research was to determine the ability of the healing properties using the scratch test, which showed a positive response using the extract. Microbial activity was evaluated and obtained against Gram-negative and Gram-positive bacteria and yeasts. We concluded that A. arborescens leaf gel meets the important conditions for plant raw materials to obtain semi-solid forms of herbal medicinal products.

Anticonvulsant Effectiveness and Neurotoxicity Profile of 4-butyl-5-[(4-chloro-2-methylphenoxy)methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) in Mice.

Protective (antiseizure) effects of 4-butyl-5-[(4-chloro-2-methylphenoxy)-methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) and acute neurotoxic effects were determined in the tonic-clonic seizure model and rotarod test in mice. The interaction profile of four classic antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) with TPL-16 was also determined in the tonic-clonic seizure model in mice. The protective effects of TPL-16 from tonic-clonic seizures (as ED50 values) and acute neurotoxic effects of TPL-16 (as TD50 values) were determined in 4 pretreatment times (15, 30, 60 and 120 min after its i.p. administration), in adult male albino Swiss mice. The interaction profile of TPL-16 with carbamazepine, phenobarbital, phenytoin and valproate in the tonic-clonic seizure model was determined with isobolographic analysis. Total concentrations of carbamazepine, phenobarbital, phenytoin and valproate were measured in the mouse brain homogenates. The candidate for novel antiepileptic drug (TPL-16) administered separately 15 min before experiments, has a beneficial profile with protective index (as ratio of TD50 and ED50 values) amounting to 5.58. The combination of TPL-16 with valproate produced synergistic interaction in the tonic-clonic seizure model in mice. The combinations of TPL-16 with carbamazepine, phenobarbital and phenytoin produced additive interaction in terms of protection from tonic-clonic seizures in mice. None of the total brain concentrations of classic AEDs were changed significantly after TPL-16 administration in mice. Synergistic interaction for TPL-16 with valproate and the additive interaction for TPL-16 with carbamazepine, phenobarbital and phenytoin in the tonic-clonic seizures in mice allows for recommending TPL-16 as the promising drug for further experimental and clinical testing.

Kynurenic acid and cancer: facts and controversies.

Kynurenic acid (KYNA) is an endogenous tryptophan metabolite exerting neuroprotective and anticonvulsant properties in the brain. However, its importance on the periphery is still not fully elucidated. KYNA is produced endogenously in various types of peripheral cells, tissues and by gastrointestinal microbiota. Furthermore, it was found in several products of daily human diet and its absorption in the digestive tract was evidenced. More recent studies were focused on the potential role of KYNA in carcinogenesis and cancer therapy; however, the results were ambiguous and the biological activity of KYNA in these processes has not been unequivocally established. This review aims to summarize the current views on the relationship between KYNA and cancer. The differences in KYNA concentration between physiological conditions and cancer, as well as KYNA production by both normal and cancer cells, will be discussed. The review also describes the effect of KYNA on cancer cell proliferation and the known potential molecular mechanisms of this activity.

A New Insight into the Potential Role of Tryptophan-Derived AhR Ligands in Skin Physiological and Pathological Processes.

The aryl hydrocarbon receptor (AhR) plays a crucial role in environmental responses and xenobiotic metabolism, as it controls the transcription profiles of several genes in a ligand-specific and cell-type-specific manner. Various barrier tissues, including skin, display the expression of AhR. Recent studies revealed multiple roles of AhR in skin physiology and disease, including melanogenesis, inflammation and cancer. Tryptophan metabolites are distinguished among the groups of natural and synthetic AhR ligands, and these include kynurenine, kynurenic acid and 6-formylindolo[3,2-b]carbazole (FICZ). Tryptophan derivatives can affect and regulate a variety of signaling pathways. Thus, the interest in how these substances influence physiological and pathological processes in the skin is expanding rapidly. The widespread presence of these substances and potential continuous exposure of the skin to their biological effects indicate the important role of AhR and its ligands in the prevention, pathogenesis and progression of skin diseases. In this review, we summarize the current knowledge of AhR in skin physiology. Moreover, we discuss the role of AhR in skin pathological processes, including inflammatory skin diseases, pigmentation disorders and cancer. Finally, the impact of FICZ, kynurenic acid, and kynurenine on physiological and pathological processes in the skin is considered. However, the mechanisms of how AhR regulates skin function require further investigation.

UVB Radiation and Selected Tryptophan-Derived AhR Ligands-Potential Biological Interactions in Melanoma Cells.

Excessive UV exposure is considered the major environmental factor in melanoma progression. Human skin is constantly exposed to selected tryptophan-derived aryl hydrocarbon receptor (AhR) ligands, including kynurenine (KYN) and kynurenic acid (KYNA), as they are endogenously produced and present in various tissues and body fluids. Importantly, recent studies confirmed the biological activity of KYN and KYNA toward melanoma cells in vitro. Thus, in this study, the potential biological interactions between UVB and tryptophan metabolites KYN and KYNA were studied in melanoma A375, SK-MEL-3, and RPMI-7951 cells. It was shown that UVB enhanced the antiproliferative activity of KYN and KYNA in melanoma cells. Importantly, selected tryptophan-derived AhR ligands did not affect the invasiveness of A375 and RPMI-7951 cells; however, the stimulatory effect was observed in SK-MEL-3 cells exposed to UVB. Thus, the effect of tryptophan metabolites on metabolic activity, cell cycle regulation, and cell death in SK-MEL-3 cells exposed to UVB was assessed. In conclusion, taking into account that both UVB radiation and tryptophan-derived AhR ligands may have a crucial effect on skin cancer formation and progression, these results may have a significant impact, revealing the potential biological interactions in melanoma cells in vitro.

Effect of Chronic Administration of 5-(3-chlorophenyl)-4-Hexyl-2,4 -Dihydro-3H-1,2,4-Triazole-3-Thione (TP-315)-A New Anticonvulsant Drug Candidate-On Living Organisms.

About 70 million people suffer from epilepsy-a chronic neurodegenerative disease. In most cases, the cause of the disease is unknown, but epilepsy can also develop as the result of a stroke, trauma to the brain, or the use of psychotropic substances. The treatment of epilepsy is mainly based on the administration of anticonvulsants, which the patient must most often use throughout their life. Despite significant progress in research on antiepileptic drugs, about 30% of patients still have drug-resistant epilepsy, which is insensitive to pharmacotherapy used so far. In our recent studies, we have shown that 4-alkyl-5-aryl-1,2,4-triazole-3-thiones act on the voltage-gated sodium channels and exhibit anticonvulsant activity in an MES (maximal electroshock-induced seizure) and 6Hz test in mice. Previous studies have shown their beneficial toxic and pharmacological profile, but their effect on a living organism during chronic use is still unknown. In the presented study, on the basis of the previously conducted tests and the PAMPA (parallel artificial membrane permeability assay) BBB (blood-brain barrier) test, we selected one 1,2,4-triazole-3-thione derivative-TP-315-for further studies aimed at assessing the impact of its chronic use on a living organism. After long-term administration of TP-315 to Albino Swiss mice, its effect on the functional parameters of internal organs was assessed by performing biochemical, morphological, and histopathological examinations. It was also determined whether the tested compound inhibits selected isoforms of the CYP450 enzyme system. On the basis of the conducted tests, it was found that TP-315 does not show nephrotoxic nor hepatotoxic effects and does not cause changes in hematological parameters. In vitro tests showed that TP-315 did not inhibit CYP2B6, CYP2D6, CYP3A4, or CYP3A5 enzymes at the concentration found in the serum of mice subjected to long-term exposure to this compound.

Determination of Cytotoxic Activity of Sanguinaria canadensis Extracts against Human Melanoma Cells and Comparison of Their Cytotoxicity with Cytotoxicity of Some Anticancer Drugs.

Melanoma is an enormous global health burden, and should be effectively addressed with better therapeutic strategies. Therefore, new therapeutic agents are needed for the management of this disease. The aim of this study was the investigation of cytotoxic activity of some isoquinoline alkaloid standards and extracts obtained from Sanguinaria canadensis-collected before, during, and after flowering-against three different human melanoma cells (A375, G361, SK-MEL-3). The cytotoxicity of these extracts was not previously tested on these melanoma cell lines. Determination of alkaloid contents was performed by HPLC-DAD using Polar RP column and mobile phase containing acetonitrile, water, and 1-butyl-3-methylimidazolium tetrafluoroborate. The cytotoxicity of alkaloid standards was investigated by determination of cell viability and calculation of IC50 values. Significant differences were observed in the alkaloids content and cytotoxic activity of the extracts, depending on the season of collection of the plant material. In the Sanguinaria canadensis extracts high contents of sanguinarine (from 4.8543 to 9.5899 mg/g of dry plant material) and chelerythrine (from 42.7224 to 6.8722 mg/g of dry plant material) were found. For both of these alkaloids, very high cytotoxic activity against the tested cell lines were observed. The IC50 values were in the range of 0.11-0.54 µg/mL for sanguinarine and 0.14 to 0.46 µg/mL for chelerythrine. IC50 values obtained for Sanguinaria canadensis extracts against all tested cell lines were also very low (from 0.88 to 10.96 µg/mL). Cytotoxic activity of alkaloid standards and Sanguinaria canadensis extracts were compared with the cytotoxicity of anticancer drugs-etoposide, cisplatin, and hydroxyurea. In all cases except the one obtained for cisplatin against A375, which was similar to that obtained for Sanguinaria canadensis after flowering against the same cell line, IC50 values obtained for anticancer drugs were higher than the IC50 values obtained for sanguinarine, chelerythrine, and Sanguinaria canadensis extracts. Our results showed that Sanguinaria canadensis extracts and isoquinoline alkaloids, especially sanguinarine and chelerythrine, could be recommended for further in vivo experiments in order to confirm the possibility of their application in the treatment of human melanomas.