Discovery of (E)-3-(4-chlorophenyl)-N-(5-hydroxypentyl)acrylamide among N-substituted cinnamamide derivatives as a novel cosmetic ingredient for hyperpigmentation.

Hyperpigmentation disorders may result from inappropriate melanin deposition and/or excessive melanin synthesis. They are classified mainly as aesthetic problems, but they can significantly affect human health by decreasing self-esteem. There are available only limited treatment options for hyperpigmentation disorder, among others, cosmetic products applied topically. Depigmenting ingredients were found to be ineffective and characterized by various side effects. As a result, many efforts are made to discover novel, potent, and safe melanogenesis inhibitors for possible use in topical cosmetic depigmenting formulations. Cinnamic acid derivatives constitute a widely tested group for that purpose. This article reports research in the group of N-alkyl cinnamamide derivatives (un)substituted in phenyl ring. Among tested series, (E)-3-(4-chlorophenyl)-N-(5-hydroxypentyl)acrylamide (compound 21) showed the most promising inhibitory properties in mushroom tyrosinase assay (IC50 = 36.98 ± 1.07 µM for monophenolase activity, IC50 = 146.71 ± 16.82 µM for diphenolase activity) and melanin production inhibition in B16F10 mouse melanoma cell line at concentration 6.25 µM resulting probably from decreasing of Tyr, Mitf, Tyrp-1, and Tyrp-2 genes expression. This compound also showed melanin production inhibitory properties in pigmented reconstructed human epidermis when used in 1 % and 2 % solutions in 50 % PEG400. In vitro evaluation of its safety profile showed no cytotoxicity to human keratinocytes HaCaT, human skin fibroblasts BJ, and human primary epidermal melanocytes HEMa, no mutagenicity in the Ames test, no genotoxicity in micronucleus test, no phototoxicity, as well as no skin irritation potential tested in PEG400 solution. This compound was also shown to penetrate across the epidermis to reach the possible site of action. The performed research led to classify (E)-3-(4-chlorophenyl)-N-(5-hydroxypentyl)acrylamide as a novel potential depigmenting cosmetic ingredient.

In vitro safety evaluation of (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate (K-116) - the novel potential UV filter designed by means of a double chromophore strategy.

The use of topical photoprotection is necessary to reduce adverse effects caused by excessive exposure to ultraviolet radiation. Despite the high standards set for UV filters, many of them may contribute to the occurrence of adverse effects. The newly synthesised compound K-116, the (E)-cinnamoyl xanthone derivative, could be an alternative. We conducted extended in vitro safety evaluation of compound K-116. The research included assessment of irritation potential on skin tissue, evaluation of penetration through the epidermis, and assessment of phototoxicity, and mutagenicity. Additionally, the eco-safety of compound K-116 was evaluated, including an examination of its degradation pathway in the Cunninghamella echinulata model, as well as in silico simulation of the toxicity of both the parent compound and its degradation products. The research showed that compound K-116 tested in future application conditions is deprived of skin irritant potential additionally it does not penetrate through the epidermis. Results showed that K-116 concentrate is not phototoxic and not mutagenic. The eco-safety studies showed that it undergoes biodegradation in 27% in Cunninghamella echinulata model. The parent compound and formed metabolite are less toxic than reference UV filters (octinoxate and octocrylene).

Comparison of Bioactive Secondary Metabolites and Cytotoxicity of Extracts from Inonotus obliquus Isolates from Different Host Species.

Inonotus obliquus, a wood-decaying mushroom, has been used as a health-promoting supplement and nutraceutical for centuries. It is a source of bioactive compounds accumulated in both the conks (pseudosclerotia/sclerotia) and the biomass obtained in vitro. This study aimed to qualitatively and quantitatively analyze the bioelements and selected metabolites produced in mycelial cultures obtained from different host species. The mycochemical potential of mycelial cultures isolated from pseudosclerotia grown in Betula pendula, Alnus glutinosa, and Carpinus betulus was compared. Parent cultures were obtained in two types of medium (malt extract agar substrates without and with birch wood). Experimental cultures were developed in 2 L bioreactors for 10 days. The content of bioelements was determined using FAAS and FAES methods. Organic compounds were estimated using the RP-HPLC-DAD method. The cytotoxicity of the extracts was evaluated in human keratinocytes HaCaT, human skin fibroblasts BJ, human liver cancer HepG2, human melanoma A375, and mouse melanoma B16-F10. The extracts showed the presence of bioelements: sodium, potassium, magnesium, calcium, zinc, manganese, iron, and copper; phenolic acids: p-hydroxybenzoic, caffeic, p-coumaric, and protocatechuic; sterols: lanosterol, ergosterol, ergosterol peroxide; triterpene compounds: betulin, betulinic acid, inotodiol; indole compounds: L-tryptophan, tryptamine, 5-methyltryptamine, melatonin. The content of bioactive substances in the biomass was dependent on both the origin of the host species of the fungus isolate and the type of culture medium. Based on the results of this study, mycelial cultures can be proposed as a potential source of bioactive compounds and are promising naturally derived cytotoxic agents.

Evaluation of Two Novel Hydantoin Derivatives Using Reconstructed Human Skin Model EpiskinTM: Perspectives for Application as Potential Sunscreen Agents.

This study aimed to assess two novel 5-arylideneimidazolidine-2,4-dione (hydantoin) derivatives (JH3 and JH10) demonstrating photoprotective activity using the reconstructed human skin model EpiskinTM. The skin permeability, irritation, and phototoxicity of the compounds was evaluated in vitro. Moreover, the in vitro genotoxicity and human metabolism of both compounds was studied. For skin permeation and irritation experiments, the test compounds were incorporated into a formulation. It was shown that JH3 and JH10 display no skin irritation and no phototoxicity. Both compounds did not markedly enhance the frequency of micronuclei in CHO-K1 cells in the micronucleus assay. Preliminary in vitro studies with liver microsomes demonstrated that hydrolysis appears to constitute their important metabolic pathway. EpiskinTM permeability experiments showed that JH3 permeability was lower than or close to currently used UV filters, whereas JH10 had the potential to permeate the skin. Therefore, a restriction of this compound permeability should be obtained by choosing the right vehicle or by optimizing it, which should be addressed in future studies.

Bioactivity and Mycochemical Profile of Extracts from Mycelial Cultures of Ganoderma spp.

Fungal mycelium cultures are an alternative to natural sources in order to obtain valuable research materials. They also enable constant control and adaptation of the process, thereby leading to increased biomass growth and accumulation of bioactive metabolites. The present study aims to assess the biosynthetic potential of mycelial cultures of six Ganoderma species: G. adspersum, G. applanatum, G. carnosum, G. lucidum, G. pfeifferi, and G. resinaceum. The presence of phenolic acids, amino acids, indole compounds, sterols, and kojic acid in biomass extracts was determined by HPLC. The antioxidant and cytotoxic activities of the extracts and their effects on the inhibition of selected enzymes (tyrosinase and acetylcholinesterase) were also evaluated. The total content of phenolic acids in the extracts ranged from 5.8 (G. carnosum) to 114.07 mg/100 g dry weight (d.w.) (G. pfeifferi). The total content of indole compounds in the extracts ranged from 3.03 (G. carnosum) to 11.56 mg/100 g d.w. (G. lucidum) and that of ergosterol ranged from 28.15 (G. applanatum) to 74.78 mg/100 g d.w. (G. adspersum). Kojic acid was found in the extracts of G. applanatum and G. lucidum. The tested extracts showed significant antioxidant activity. The results suggest that the analyzed mycelial cultures are promising candidates for the development of new dietary supplements or pharmaceutical preparations.

Synthesis and in vitro evaluation of anti-inflammatory, antioxidant, and anti-fibrotic effects of new 8-aminopurine-2,6-dione-based phosphodiesterase inhibitors as promising anti-asthmatic agents.

Phosphodiesterase (PDE) inhibitors are currently an extensively studied group of compounds that can bring many benefits in the treatment of various inflammatory and fibrotic diseases, including asthma. Herein, we describe a series of novel N'-phenyl- or N'-benzylbutanamide and N'-arylidenebutanehydrazide derivatives of 8-aminopurine-2,6-dione (27-43) and characterized them as prominent pan-PDE inhibitors. Most of the compounds exhibited antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)-induced murine macrophages RAW264.7. The most active compounds (32-35 and 38) were evaluated in human bronchial epithelial cells (HBECs) derived from asthmatics. To better map the bronchial microenvironment in asthma, HBECs after exposure to selected 8-aminopurine-2,6-dione derivatives were incubated in the presence of two proinflammatory and/or profibrotic factors: transforming growth factor type ß (TGF-ß) and interleukin 13 (IL-13). Compounds 32-35 and 38 significantly reduced both IL-13- and TGF-ß-induced expression of proinflammatory and profibrotic mediators, respectively. Detailed analysis of their inhibition preferences for selected PDEs showed high affinity for isoenzymes important in the pathogenesis of asthma, including PDE1, PDE3, PDE4, PDE7, and PDE8. The presented data confirm that structural modifications within the 7 and 8 positions of the purine-2,6-dione core result in obtaining preferable pan-PDE inhibitors which in turn exert an excellent anti-inflammatory and anti-fibrotic effect in the bronchial epithelial cells derived from asthmatic patients. This dual-acting pan-PDE inhibitors constitute interesting and promising lead structures for further anti-asthmatic agent discovery.

(+)-Usnic Acid as a Promising Candidate for a Safe and Stable Topical Photoprotective Agent.

The study aimed to examine whether usnic acid-a lichen compound with UV-absorbing properties-can be considered as a prospective photoprotective agent in cosmetic products. Moreover, a comparison of two usnic acid enantiomers was performed to preselect the more effective compound. To meet this aim, an in vitro model was created, comprising the determination of skin-penetrating properties via skin-PAMPA assay, safety assessment to normal human skin cells (keratinocytes, melanocytes, fibroblasts), and examination of photostability and photoprotective properties. Both enantiomers revealed comparable good skin-penetrating properties. Left-handed usnic acid was slightly more toxic to keratinocytes (IC50 80.82 and 40.12 µg/mL, after 48 and 72 h, respectively) than its right-handed counterpart. The latter enantiomer, in a cosmetic formulation, was characterized by good photoprotective properties and photostability, comparable to the UV filter octocrylene. Perhaps most interestingly, (+)-usnic acid combined with octocrylene in one formulation revealed enhanced photoprotection and photostability. Thus, the strategy can be considered for the potential use of (+)-usnic acid as a UV filter in cosmetic products. Moreover, the proposed model may be useful for the evaluation of candidates for UV filters.

Anticonvulsant and analgesic in neuropathic pain activity in a group of new aminoalkanol derivatives.

As part of the presented research, thirteen new aminoalkanol derivatives were designed and obtained by chemical synthesis. In vivo studies (mice, i.p.) showed anticonvulsant activity (MES) of nine compounds, and in the case of one compound (R,S-trans-2-((2-(2,3,5-trimethylphenoxy)ethyl)amino)cyclohexan-1-ol, 4) both anticonvulsant (ED50 MES = 15.67 mg/kg, TD50 rotarod = 78.30 mg.kg, PI = 5.00) and analgesic activity (OXA-induced neuropathic pain, active at 15 mg/kg). For selected active compounds additional in vitro studies have been performed, including receptor studies (5-HT1A), evaluation of antioxidant activity (DPPH assay), metabolism studies as well as safety panel (mutagenicity, safety in relation to the gastrointestinal flora, cytotoxicity towards astrocytes as well as impact on their proliferation and cell cycle).

The Involvement of Xanthone and (E)-Cinnamoyl Chromophores for the Design and Synthesis of Novel Sunscreening Agents.

Excessive UV exposure contributes to several pathological conditions like skin burns, erythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorption, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290-369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPFin vitro of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at concentrations up to 50 µM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Additionally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application.

S(+)-(2E)-N-(2-Hydroxypropyl)-3-Phenylprop-2-Enamide (KM-568): A Novel Cinnamamide Derivative with Anticonvulsant Activity in Animal Models of Seizures and Epilepsy.

Epilepsy is one of the most frequent neurological disorders affecting about 1% of the world's human population. Despite availability of multiple treatment options including antiseizure drugs, it is estimated that about 30% of seizures still remain resistant to pharmacotherapy. Searching for new antiseizure and antiepileptic agents constitutes an important issue within modern medicinal chemistry. Cinnamamide derivatives were identified in preclinical as well as clinical studies as important drug candidates for the treatment of epilepsy. The cinnamamide derivative presented here: S(+)-(2E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide (S(+)-N-(2-hydroxypropyl)cinnamamide, compound KM-568) showed anticonvulsant activity in several models of epilepsy and seizures in mice and rats. It was active in a genetic animal model of epilepsy (Frings audiogenic seizure-susceptible mouse model, ED50 = 13.21 mg/kg, i.p.), acute seizures induced electrically (maximal electroshock test ED50 = 44.46 mg/kg mice i.p., ED50 = 86.6 mg/kg mice p.o., ED50 = 27.58 mg/kg rats i.p., ED50 = 30.81 mg/kg rats p.o., 6-Hz psychomotor seizure model 32 mA ED50 = 71.55 mg/kg mice i.p., 44 mA ED50 = 114.4 mg/kg mice i.p.), chronic seizures induced electrically (corneal kindled mouse model ED50 = 79.17 mg/kg i.p., hippocampal kindled rat model ED50 = 24.21 mg/kg i.p., lamotrigine-resistant amygdala kindled seizure model in rats ED50 = 58.59 mg/kg i.p.), acute seizures induced chemically (subcutaneous metrazol seizure threshold test ED50 = 104.29 mg/kg mice i.p., ED50 = 107.27 mg/kg mice p.o., ED50 = 41.72 mg/kg rats i.p., seizures induced by picrotoxin in mice ED50 = 94.11 mg/kg i.p.) and the pilocarpine-induced status epilepticus model in rats (ED50 = 279.45 mg/kg i.p., ED97 = 498.2 mg/kg i.p.). The chemical structure of the compound including configuration of the chiral center was confirmed by NMR spectroscopy, LC/MS spectroscopy, elemental analysis, and crystallography. Compound KM-568 was identified as a moderately stable derivative in an in vitro mouse liver microsome system. According to the Ames microplate format mutagenicity assay performed, KM-568 was not a base substitution or frameshift mutagen. Cytotoxicity evaluation in two cell lines (HepG2 and H9c2) proved the safety of the compound in concentrations up to 100 µM. Based on the results of anticonvulsant activity and safety profile, S(+)-(2E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide could be proposed as a new lead compound for further preclinical studies on novel treatment options for epilepsy.

Discovery of Novel UV-Filters with Favorable Safety Profiles in the 5-Arylideneimidazolidine-2,4-dione Derivatives Group.

Effective protection from the harmful effects of UV radiation may be achieved by using sunscreens containing organic or inorganic UV filters. The number of currently available UV filters is limited and some of the allowed molecules possess limitations such as systemic absorption, endocrine disruption properties, contact and photocontact allergy induction, and low photostability. In the search for new organic UV filters we designed and synthesized a series consisting of 5-benzylidene and 5-(3-phenylprop-2-en-1-ylidene)imidazolidine-2,4-dione (hydantoin) derivatives. The photoprotective activity of the tested compounds was confirmed in methanol solutions and macrogol formulations. The most promising compounds possessed similar UV protection parameter values as selected commercially available UV filters. The compound diethyl 2,2'-((Z)-4-((E)-3-(4-methoxyphenyl)allylidene)-2,5-dioxoimidazolidine-1,3-diyl)diacetate (4g) was characterized as an especially efficient UVA photoprotective agent with a UVA PF of 6.83 ± 0.05 and favorable photostability. Diethyl 2,2'-((Z)-4-(4-methoxybenzylidene)-2,5-dioxo- imidazolidine-1,3-diyl)diacetate (3b) was the most promising UVB-filter, with a SPFin vitro of 3.07 ± 0.04 and very good solubility and photostability. The main photodegradation products were geometric isomers of the parent compounds. These compounds were also shown to be non-cytotoxic at concentrations up to 50 µM when tested on three types of human skin cells and possess no estrogenic activity, according to the results of a MCF-7 breast cancer model.

Anticonvulsant Activity of Enantiomeric N-trans-Cinnamoyl Derivatives of 2-Aminopropan-1-ols and 2-Aminobutan-1-ols.

Epilepsy, one of the most frequent neurological disorders, is still insufficiently treated in about 30% of patients. As a consequence, identification of novel anticonvulsant agents is an important issue in medicinal chemistry. In the present article we report synthesis, physicochemical, and pharmacological evaluation of N-trans-cinnamoyl derivatives of R and S-2-aminopropan-1-ol, as well as R and S-2-aminobutan-1-ol. The structures were confirmed by spectroscopy and for derivatives of 2-aminopropan-1-ols the configuration was evaluated by means of crystallography. The investigated compounds were tested in rodent models of seizures: maximal electroshock (MES) and subcutaneous pentetrazol test (scPTZ), and also in a rodent model of epileptogenesis: pilocarpine-induced status prevention. Additionally, derivatives of 2-aminopropan-1-ols were tested in benzodiazepine-resistant electrographic status epilepticus rat model as well as in vitro for inhibition of isoenzymes of cytochrome P450. All of the tested compounds showed promising anticonvulsant activity in MES. For R(-)-(2E)-N-(1-hydroxypropan-2-yl)-3-phenylprop-2-enamide pharmacological parameters were found as follows: ED50 = 76.7 (68.2-81.3) mg/kg (MES, mice i.p., time = 0.5 h), ED50 = 127.2 (102.1-157.9) mg/kg (scPTZ, mice i.p., time = 0.25 h), TD50 = 208.3 (151.4-230.6) mg/kg (rotarod, mice i.p., time = 0.25 h). Evaluation in pilocarpine status prevention proved that all of the reported compounds reduced spontaneous seizure activity and act as antiepileptogenic agents. Both enantiomers of 2-aminopropan-1-ols did not influence cytochrome P450 isoenzymes activity in vitro and are likely not to interact with CYP substrates in vivo. Chirality 28:482-488, 2016. © 2016 Wiley Periodicals, Inc.

Antidepressant pharmaceuticals in aquatic systems, individual-level ecotoxicological effects: growth, survival and behavior.

The growing consumption of antidepressant pharmaceuticals has resulted in their widespread occurrence in the environment, particularly in waterways with a typical concentration range from ng L-1 to µg L-1. An increasing number of studies have confirmed the ecotoxic potency of antidepressants, not only at high concentrations but also at environmentally relevant levels. The present review covers literature from the last decade on the individual-level ecotoxicological effects of the most commonly used antidepressants, including their impact on behavior, growth, and survival. We focus on the relationship between antidepressants physico-chemical properties and dynamics in the environment. Furthermore, we discuss the advantages of considering behavioral changes as sensitive endpoints in ecotoxicology, as well as some current methodological shortcomings in the field, including low standardization, reproducibility and context-dependency.

Mechanochemical synthesis and anticonvulsant activity of 3-aminopyrrolidine-2,5-dione derivatives.

A series of 3-aminopyrrolidine-2,5-dione derivatives was synthesized and tested for anticonvulsant activity. Succinimide derivatives were obtained from a simple solvent-based reaction and a mechanochemical aza-Michael reaction of maleimide or its N-substituted derivatives with selected amines. The structure of the compounds was confirmed by spectroscopic methods (NMR, FT-IR, HPLC, ESI-MS, EA and XRD for four compounds). The cytotoxic activity of the succinimide derivatives was evaluated using HepG2 cells for hepatocytotoxicity and SH-SY5Y cells for neurocytotoxicity. None of the studied compounds showed hepatocytotoxicity and two showed neurocytotoxicity. Initial anticonvulsant screening was performed in mice using the psychomotor seizure test (6 Hz, 32 mA). The selected compounds were evaluated in the following acute models of epilepsy: the maximal electroshock test, psychomotor seizure test (6 Hz, 44 mA), subcutaneous pentylenetetrazole seizure test, and acute neurotoxicity (rotarod test). The most active compound 3-((4-chlorophenyl)amino)pyrrolidine-2,5-dione revealed antiseizure activity in all seizure models (including pharmacoresistant seizures) and showed better median effective doses (ED50) and protective index values than the reference compound, ethosuximide. Furthermore, 3-(benzylamino)pyrrolidine-2,5-dione and 3-(phenylamino)pyrrolidine-2,5-dione exhibited antiseizure activity in the 6 Hz and MES tests, and 3-(butylamino)-1-phenylpyrrolidine-2,5-dione and 3-(benzylamino)-1-phenylpyrrolidine-2,5-dione exhibited antiseizure activity in the 6 Hz test. All active compounds demonstrated low in vivo neurotoxicity in the rotarod test and yielded favourable protective indices.

In silico and in vitro evaluation of a safety profile of a cosmetic ingredient: 4-methoxychalcone (4-MC).

Chalcone is an important scaffold within medicinal and cosmetic chemistry. The structure enables multiple modifications which may result in obtaining compounds with desirable bioactivity. One of the chalcone derivatives, 4-methoxychalcone is a known cosmetic ingredient indexed in Cosing database as an antioxidant, bleaching, and skin conditioning substance. We investigated its in silico and in vitro safety profile. In silico study using Derek Nexus showed its potential of skin sensitisation, equivocal nature of chromosome damage in vitro in mammals, but also no mutagenic properties. In vitro research proved its activity as melanogenesis inhibitor in B16F10 cell line at the doses 12.5-3.125 µM. Evaluations performed in various cell lines showed that the cytotoxic doses were 50-25 µM. Tests in Episkin™ proved its ability to penetrate across epidermis and enabled classification of 2% formulation in PEG as non-irritant. In micronucleus tests it showed no genotoxicity. Studies in Cunninghamella echinulata model proved that 4-methoxychalcone was metabolised to less lipophilic products. 4-methoxychalcone showed phototoxic potential, its EC50(+UV) = 3.57 µg/mL, PIF = 10.19 and MPE = 0.428 were comparable to chlorpromazine. Moreover, 4-methoxychalcone showed ecotoxic potential in Microtox® assay with EC50(5 min) = 0.0047 mg/L and EC50(15 min) = 0.0033 mg/L. Although active doses were lower than toxic ones, some potential safety risks were noticed. Especially, due to the phototoxicity potential of 4-methoxychalcone, its use as depigmenting agent should involve avoidance of sunlight and use of appropriate photoprotection.

Synthesis and Evaluation of the Antidepressant-like Properties of HBK-10, a Novel 2-Methoxyphenylpiperazine Derivative Targeting the 5-HT1A and D2 Receptors.

The increasing number of patients reporting depressive symptoms requires the design of new antidepressants with higher efficacy and limited side effects. As our previous research showed, 2-methoxyphenylpiperazine derivatives are promising candidates to fulfill these criteria. In this study, we aimed to synthesize a novel 2-methoxyphenylpiperazine derivative, HBK-10, and investigate its in vitro and in vivo pharmacological profile. After assessing the affinity for serotonergic and dopaminergic receptors, and serotonin transporter, we determined intrinsic activity of the compound at the 5-HT1A and D2 receptors. Next, we performed behavioral experiments (forced swim test, tail suspension test) to evaluate the antidepressant-like activity of HBK-10 in naïve and corticosterone-treated mice. We also assessed the safety profile of the compound. We showed that HBK-10 bound strongly to 5-HT1A and D2 receptors and presented antagonistic properties at these receptors in the functional assays. HBK-10 displayed the antidepressant-like effect not only in naïve animals, but also in the corticosterone-induced mouse depression model, i.e., chronic administration of HBK-10 reversed corticosterone-induced changes in behavior. Moreover, the compound's sedative effect was observed at around 26-fold higher doses than the antidepressant-like ones. Our study showed that HBK-10 displayed a favorable pharmacological profile and may represent an attractive putative treatment candidate for depression.

Photostability Testing of a Third-Generation Retinoid-Tazarotene in the Presence of UV Absorbers.

Exposure of a drug to UV irradiation could affect its physicochemical properties. Hence, photostability testing is essential for topically administered drugs. Tazarotene, a receptor-selective, third-generation retinoid, is commonly used to treat acne vulgaris and psoriasis. In the present study, an in-depth analysis of the photostability of tazarotene in ethanolic solution in the presence of zinc oxide and/or titanium dioxide as well as benzophenone-type UV filters was performed. Eleven presumed products were derived from the photocatalytic degradation of tazarotene using ultra-performance liquid chromatography-tandem mass spectrometry, and transformation pathways were proposed. The degradation process mainly affected the 4,4-dimethyl-3,4-dihydro-2H-thiopyran moiety. The fragments most susceptible to oxidation were the methyl groups and the sulfur atom. Moreover, in the presence of sulisobenzone, under UV irradiation, tazarotene was subjected to a degradation process, which resulted in two photodecomposition products. In silico studies performed by OSIRIS Property Explorer demonstrated that five of the degradation products could be harmful in terms of the reproductive effects, which are associated with 3,4-dihydro-6-methyl-2H-1-benzothiopyran 1,1-dioxide, while one of them demonstrated potential irritant activity. The cytotoxic properties of the degradation products of tazarotene were assessed by MTT assay on a panel of human adherent cancer cells. Time- and concentration-dependent growth inhibition was evidenced in ovary (A2780) and breast (MDA-MB-231) cancer cell lines. The potential implication of the outcomes of the present research requires further studies mainly concerning the photostability of tazarotene in the topical formulations.

Metabolic stability and its role in the discovery of new chemical entities.

Determination of metabolic profiles of new chemical entities is a key step in the process of drug discovery, since it influences pharmacokinetic characteristics of therapeutic compounds. One of the main challenges of medicinal chemistry is not only to design compounds demonstrating beneficial activity, but also molecules exhibiting favourable pharmacokinetic parameters. Chemical compounds can be divided into those which are metabolized relatively fast and those which undergo slow biotransformation. Rapid biotransformation reduces exposure to the maternal compound and may lead to the generation of active, non-active or toxic metabolites. In contrast, high metabolic stability may promote interactions between drugs and lead to parent compound toxicity. In the present paper, issues of compound metabolic stability will be discussed, with special emphasis on its significance, in vitro metabolic stability testing, dilemmas regarding in vitro-in vivo extrapolation of the results and some aspects relating to different preclinical species used in in vitro metabolic stability assessment of compounds.

Microbial biotransformation of some novel hydantoin derivatives: Perspectives for bioremediation of potential sunscreen agents.

Having identified novel hydantoin derivatives (compounds 1-5) demonstrating promising photoprotective capacity against UV radiation, and understainding the problem of the biotic and abiotic degradation of UV filters, the aim of the study was to evaluate their metabolic fate with the environmental fungus Cunninghamella echinulata. In parallel, compound 1 in vitro microsomal metabolic pattern was evaluated. Finally, in silico toxicity of test compounds and their biotransformation products was estimated, and parent compounds photostability was assessed. The study demonstrated the capacity for C. echinulata to metabolize 1-5, which were biotransformed to a greater extent than the standard UV filter. O-dealkylation of the side chains attached to the phenyl or hydantoin rings, and hydroxylation of the phenyl ring occurred during microbial transformation. O-dealkylation product was a unique metabolite observed in microsomal biotransformation of 1, being its intrinsic clearance in the medium category range. In silico study demonstrated that compounds 1-5 have low toxicity risk. Among the resulting metabolites, four can increase the risk of reproductive effects as shown by OSIRIS prediction. Noteworthy, all indicated metabolites belong to minor metabolites, except for compound 3 major metabolite. Moreover, the results of the photostability study showed that 1-5 were considered to be photostable. To sum up, the obtained in vitro biotransformation, photostability, and in silico toxicity results encourage further studies on hydantoin derivatives as potential UV photoprotective agents. The presented biotransformation profile of compounds 1-5 by C. echinulata suggests that these compounds may follow a similar biodegradation fate when released into the environment.

Melanogenesis Inhibitors: Strategies for Searching for and Evaluation of Active Compounds.

Hyperpigmentation disorders constitute important medical and aesthetical conditions. Dark areas or dark spots on the skin result from inappropriate amount and/or deposition of skin pigments - melanins. Several depigmenting agents, such as kojic acid, arbutin, aloesin, ellagic acid, resveratrol, azelaic acid, niacinamide, tretinoin, glycolic acid, lactic acid, and citric acid, have already been identified and are used in topical drugs or cosmetic formulations for the treatment of hyperpigmentations. However, these compounds are characterized by insufficient effectiveness and multiple adverse effects. As a result, there is still a need for searching for new active substances. The current paper summarizes strategies for searching for novel melanogenesis inhibitors. In the review, they are divided according to approach, into in silico, in vitro and in vivo experiments. In silico research includes computational studies with models of tyrosinase and di-copper complexes. The in vitro approach is based on tests using tyrosinase (a key enzyme in melanin biosynthesis), cell cultures, cell co-cultures, pigmented human skin equivalents or Streptomyces bikiniensis model. In vivo studies involve zebrafish, rodents or humans. Examples of protocols and laboratory procedures are presented, with a focus on utilization of various models for evaluation of mechanisms of action of tested compounds. The potential limitations of the methods are also discussed, together with future perspectives in the field of searching for melanogenesis inhibitors.