Nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (DCF), ibuprofen (IBU), and ketoprofen (KET) are commonly found in the environment and pose potential toxicological risks. This study investigates the microbial biotransformation of these NSAIDs by Cunninghamella spp. and evaluates the toxicity of the Cunninghamella-processed samples. The results demonstrate that Cunninghamella efficiently biotransformed DCF and IBU into multiple metabolites, whereas the biotransformation of KET was negligible. Microbial treatment reduced the ecotoxicity of IBU and DCF, as confirmed by Microtox® and algal growth inhibition assays. In vitro cytotoxicity tests using human hepatocytes (HepG2), neuroblastoma cells (SH-SY5Y), astrocytes, and rat cardiomyocytes (H9c2) showed lower toxicity of the biotransformation products compared to the parent compounds. The Ames assay revealed no mutagenicity for any of the samples. Endocrine disruption assays indicated a loss of antagonistic estrogenic and androgenic effects post-biotransformation, with minor estrogenic agonistic activity observed. In conclusion, fungal biotransformation by Cunninghamella appears to be a promising strategy for reducing the environmental toxicity of NSAIDs. However, the generation of transformation products with altered biological activity underscores the importance of combining analytical identification with comprehensive toxicological assessment.

Airway remodeling (AR) is a hallmark of chronic respiratory diseases (CRDs) and involves progressive structural alterations of the airway wall, leading to wall thickening and airway narrowing. Multiple cell types contribute to AR, including lung fibroblasts, which - under the influence of transforming growth factor type β (TGF-β) - upregulate pro-fibrotic markers, undergo phenotypic transition into myofibroblasts, and increase their contractile activity. Current treatment guidelines for CRDs lack effective therapies directly targeting AR. Recent reports suggest that the transient receptor potential ankyrin 1 (TRPA1) ion channel may be implicated in the mechanisms underlying AR. To explore this, we designed and synthesized 1,3,5-triazine-based derivatives (compounds 7 and 8), which exhibit agonistic activity towards TRPA1. In this study, we evaluated their pharmacological activity in TGF-β-stimulated human lung fibroblasts (MRC-5) by assessing calcium influx, pro-fibrotic markers expression, and contractile properties. Both compounds induced a robust calcium influx in MRC-5 cells, while the TRPA1 inhibitors and TGF-β stimulation attenuated this response. The tested 1,3,5-triazine-based TRPA1 activators decreased the expression of selected pro-fibrotic markers, such as α-smooth muscle actin (α-SMA), transgelin and collagen type I, reduced myofibroblasts number, and impaired the contractility of TGF-β-stimulated MRC-5 cells. Notably, the anti-fibrotic effects of the 1,3,5-triazine-based TRPA1 activators exceeded those of ASP-7663, a well-characterized TRPA1 agonist. Our findings expand current knowledge on TRPA1 modulation in AR and provide a novel perspective for drug development in CRDs.

As part of a project aimed at the pharmacological optimization of Contilisant, herein we describe molecular modelling studies that led to the identification of MBA-159 as a new polyfunctionalized, multitarget-directed ligand and a promising drug candidate for the treatment of Alzheimer's disease. We synthesized MBA-159 and conducted comprehensive in vitro and in vivo evaluations. In in vivo studies MBA-159 demonstrated favourable pharmacokinetics, anti-amnesic properties and significantly improved non-spatial memory (contextual and recognition memory) in a mouse model of scopolamine-induced amnesia. Additionally, MBA-159 showed a tendency to increase synaptic plasticity biomarkers and reduce neuroinflammatory trends (assessed by qPCR), as well as cognitive enhancement in a senescence-accelerated prone mouse 8 model.

BACKGROUND:A number of rodent studies have investigated the effects of alcohol (ethanol) administration on the catecholaminergic neurotransmitters, norepinephrine (NE) and dopamine (DA). These studies suggest that presentation of alcohol to mice or rats can alter brain levels of NE and DA, in various subregions. Other studies have presented the hypothesis that there may be an unidentified pathway in rodents, and other organisms, that actually transforms ethanol to NE or DA. Here, this paper investigates the hypothesis in male CD-1 mice. METHODS:Experimental mice were systemically injected with an intoxicating dose of stable isotope-labeled carbon 13 (C13) ethanol (ethanol-1-13C, 20% v/v, 1.5 g/kg, ip), and brain samples (hippocampus and brainstem) were collected two hours post-injection. Two other groups of mice received normal unlabeled carbon 12 (C12) ethanol or a water (Control) injection, respectively. RESULTS:Although we had difficulty detecting the two neurotransmitters (especially C13 NE) due to their very low concentrations, high-resolution mass spectrometry analysis suggests that C12 ethanol selectively boosted hippocampal C12 NE, and C13 ethanol likewise boosted hippocampal C13 NE. We did not observe effects on DA. CONCLUSIONS:These data provide preliminary information on whether there is a novel biosynthetic pathway in mice that converts alcohol to catecholamines in select brain regions, where the ethanol molecule would presumably help form the ethanolamine side chain of NE. There are, however, alternative interpretations of these findings, including that acute alcohol administration modulates catecholamine release, reuptake, metabolism, or canonical biosynthesis.

Calcipotriol, a synthetic vitamin D3 analogue widely used in psoriasis treatment, requires a detailed stability assessment due to its topical application and potential exposure to UV radiation. As a drug applied directly to the skin, calcipotriol is particularly susceptible to photodegradation, which may affect its therapeutic efficacy and safety profile. The present study focuses on the analysis of calcipotriol photostability. An advanced UHPLC/MSE method was employed for the precise determination of calcipotriol and its degradation products. Particular attention was given to the effects of commonly used organic UV filters—approved for use in cosmetic products in both Europe and the USA (benzophenone-3, dioxybenzone, meradimate, sulisobenzone, homosalate, and avobenzone)—on the stability of calcipotriol. Unexpected degradation of calcipotriol was observed in the presence of sulisobenzone. Importantly, this effect was consistently detected in methanolic solution and in the pharmaceutical formulation containing calcipotriol and betamethasone, which is particularly significant from a practical perspective. This finding underscores the necessity of evaluating photostability under real-life conditions, as cosmetic ingredients, when co-applied with topical drugs on the skin, may substantially influence the stability profile of the pharmaceutical active ingredient. The research resulted in the first-time characterization of four degradation products of calcipotriol. The degradation process was found to primarily affect the E-4-cyclopropyl-4-hydroxy-1-methylbut-2-en-1-yl moiety, causing its isomerization to the Z isomer and the formation of diastereomers with either the R or S configuration. Computational analyses using the OSIRIS Property Explorer indicated that none of the five degradation products exhibit a toxicity effect, whereas molecular docking studies suggested possible binding of two of the five degradation products of calcipotriol with the VDR.

Understanding the behavioral pathways of xenobiotics in the environment allows for the assessment of the risk to humans resulting from their presence. The aim of the study was to assess whether photo-induced degradation of cefazolin is linked to phototoxic effects on living cells. Cefazolin solutions were exposed to UV-Vis radiation, and then quantitative analysis was performed using the validated UPLC-MS/MS method. The obtained data indicate that the photodegradation of cefazolin proceeds according to first-order kinetics and results in the formation of four main products. To understand the environmental modification on the toxicity of cefazolin and its photodegradation products to human health, we used a human skin culture and animal models. Both in vitro and in vivo studies help assess not only the toxicity of the original drug but also the potential ecological risks posed by its degradants. Considering the potential species-specific ecotoxicity of products for biota, it was necessary to use a set of organisms representing different trophic levels. The bioindication tests using Thamnocephalus platyurus and Daphnia magna as test organisms have shown similar EC50 values after 48 h of incubation (approximate to 40 mu g/mL). The luminescence inhibition test (LumiMara), based on the measurement of luminescence quenching of saltwater and freshwater bacterial strains, showed increased toxicity of the tested mixtures obtained during irradiation at different time. The highest toxicity was observed for saltwater strains #2 Photobacterium phosphoreum (NCIMB 30267) for all irradiated solutions (MTC=0.030 mu g/mL, after 8 h exposure), whereas in the case of non-irradiated solutions it was freshwater strain #11 Photorhabdus asymbiotica (NCIMB 30276), showing the lowest MTC values (12.913 mu g/mL). In vivo studies have shown that cefazolin and its photodegradation products have a pronounced effect on the development, motility and cardiac function of Zebrafish larvae, which is manifested by increased mortality (by approx. 10 % for a concentration of 1 mu g/mL; 2 h), body deformations (by approx. 0-10 % for a concentration 10 mu g/mL and by 0- 20 % for 50 mu g/mL compared to the control), and changes in heart rate (slowing of the heart rate by approx. 5-15 bpm noticeable with longer irradiation times, i.e. 6 and 8 h). Similarly, in vitro cytotoxicity studies using a cell proliferation assay showed increased cytotoxicity of the mixtures obtained after the longest exposure period compared to the non-irradiated antibiotic. The experimental results are consistent with the in silico data, which indicate increased toxicity of photodegradants, especially their cardiotoxic and cytotoxic potential. The performed analyses clearly indicate a higher toxicity of the tested mixtures compared to pure cefazolin in relation to living organisms.

Calenduloside E (CE) and chikusetsusaponin IVa (ChIVa) are triterpene saponins with multidirectional bioactivity. In this study, the contents of CE and ChIVa were determined in the roots, stems, leaves, and fruits of ten wild-growing species of Amaranthaceae. To achieve optimal extraction conditions for both saponins, maceration, shaking-assisted maceration, and ultrasound-assisted and heat reflux extraction were compared. A sensitive, specific, and rapid UPLC-MS/MS method was developed and validated for the simultaneous quantification of CE and ChIVa. The results showed that CE and ChIVa coexisted in most of the species analyzed, except for Ch. hybridum. For the first time, the presence of CE and ChIVa was noted in L. polysperma, A. patula, B. bonus-henricus, O. rubra, and O. glauca. Of the species analyzed, the highest ChIVa content was found in the fruit of A. sagittata (13.15 mg/g dw), L. polysperma (12.20 mg/g dw), and Ch. album (10.0 mg/g dw), and in the fruit and roots of Ch. strictum (5.52 and 7.77 mg/g dw, respectively). The highest amount of CE was determined in the fruit of A. sagittata (7.84 mg/g dw) and Ch. strictum (6.54 mg/g dw). These saponin-abundant plant parts of Amaranthaceae spp. may be considered convenient sources of these bioactive saponins.

The extensive use of organic UV filters (OUVFs) has led to these compounds being ubiquitously detected in the environment and considered a new kind of environmental pollutant. As OUVFs cannot be efficiently eliminated by conventional treatment processes, there is an urgent need to develop new innovative solutions for their removal. The present work investigates the efficacy of three Cunninghamella strains in the biodegradation of OUVFs: oxybenzone (BP-3) and 3-(4-methylbenzylidene)camphor (4-MBC). Moreover, a cytochrome P450 (CYP450) inhibition study was conducted, and Cunninghamella-processed samples in silico and in vitro toxicity were evaluated. Our results indicated the ability of Cunninghamella strains to utilize OUVFs. Among the tested Cunninghamella strains, both agents were the most efficiently removed by C. blakesleeana. These results were comparable with A. niger biodegradation capacity. In vitro studies of the fungi-processed samples confirmed no mutagenicity in the Ames test and the lack of cytotoxicity against HepG2 cell line. Moreover, Cunninghamella treatment positively influenced OUVFs SH-SY5Y neurotoxicity and ecotoxicity. After fungal treatment, BP-3 agonistic estrogenic activity was higher, whereas antagonistic androgenic effect was lower than before biotransformation. 4-MBC, after biotransformation, lost agonistic estrogenic activity, but gained antagonistic estrogenic properties. Additionally, this study confirmed the involvement of CYP450 enzymes in BP-3 and 4-MBC biotransformation, thus contributing to a better understanding of the detoxification pathways of OUVFs in fungi. In conclusion, these findings demonstrated, for the first time, that using environmental fungi Cunninghamella for the biodegradation of BP-3 and 4-MBC represents a potent approach for eliminating contaminants from the natural environment.

Sprouts, rich in bioactive phytochemicals, are good candidates for functional food. This study brings novel evidence on the impact of microgravity and darkness conditions on the growth and bioactive compounds' synthesis in Brassica sprouts. In microgravity grown sprouts, the 50 to 80 % increase in abscisic acid (stress phytohormone) amount was noted, in comparison to control. Microgravity combined with darkness caused 2-fold increase in polyphenolics' synthesis in broccoli sprouts, and 3-fold increase in sulfur compounds' synthesis in kohlrabi sprouts. In contrast, kale showed the greatest response to microgravity alone, while Brussels sprouts responded the least. Kohlrabi sprouts revealed the best antioxidant effect (6.48 to 23.30 μM Fe2+/100 g dw), enhanced by microgravity and darkness conditions. The observed changes in polyphenolics' and glucosinolates' amounts in most cases correlated positively with the increase in the activity, of phenylalanine ammonia-lyase, and cytochrome P450 enzymes, being key drivers of biosynthesis of these compounds, respectively.

Two triterpene saponins, hederagenin glucosides, including a novel monodesmoside: 3-O-β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl] hederagenin (compound 1), were isolated from the fruits of Oxybasis rubra (L.) S.Fuentes, Uotila & Borsh (Amaranthaceae). These compounds, together with hederagenin itself (compound 4) and a commercially available 28-O-β-D-glucopyranosyl hederagenin ester (compound 3), were evaluated for cytotoxicity and selectivity across a wide panel of human cancer cell lines (skin, prostate, gastrointestinal, thyroid, and lung). All four compounds exhibited dose- and time-dependent effects, with varying potency depending on the specific cancer type. The isolated bidesmosidic saponin (3-O-β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl] hederagenin 28-O-β-D-glucopyranosyl ester—compound 2) showed the strongest activity and selectivity, with an IC50 = 6.52 μg/mL after 48 h incubation against WM793 melanoma, and almost no effect on normal HaCaT skin cells (IC50 = 39.94 μg/mL). Multivariate analysis of the obtained data using principal component analysis (PCA) and hierarchical cluster analysis (HCA) supported the assumption that cytotoxicity is influenced by the type of compound, its concentration, and the intrinsic sensitivity of the cell line. Structure-activity observations between closely related hederagenin derivatives are also briefly presented.

An important problem is the impact of photodegradation on product toxicity in biological tests, which may be complex and context-dependent. Previous studies have described the pharmacology of cefepime, but the toxicological effects of its photodegradation products remain largely unknown. Therefore, photodegradation studies were undertaken in conditions similar to those occurring in biological systems in silico, in vitro, in vivo and ecotoxicological experiments. The structures of four cefepime photodegradation products were determined by UPLC-MS/MS method. The calculated in silico ADMET profile indicates that carcinogenic potential is expected for compounds CP-1, cefepime, CP-2 and CP-3. The Cell Line Cytomotovity Predictor 2.0 tool was used to predict the cytotoxic effects of cefepime and related compounds in non-transformed and cancer cell lines. The results indicate that possible actions include: non-small cell lung cancer, breast adenocarcinoma, prostate cancer and papillary renal cell carcinoma. OPERA models were used to predict absorption, distribution, metabolism and excretion (ADME) endpoints, and potential bioactivity of CP-2, cefepime and CP-4. The results obtained in silico show that after 96h of exposure, cefepime, CP-1, CP-2, and CP-3 are moderately toxic in the zebrafish model, while the CP-4 is highly toxic. On the contrary, cefepime is more toxic to T. platyurus (highly toxic) compared to the zebrafish model, similar to products CP-4, CP-3 and CP-2. In vitro cytotoxicity studies were performed by MTT assay, and in vivo acute embryo toxicity studies using Danio rerio embryos and larvae. In vitro showed an increase in the cytotoxicity of products with the longest exposure period i.e. for 8 h. Additionally, at a concentration of 200 μg/mL, statistically significant changes in metabolic activity were observed depending on the irradiation time. In vivo studies conducted with Zebrafish showed that both cefepime and its photodegradation products have only low toxicity. Assessment of potential ecotoxicity included Microbiotests on invertebrates (Thamnotoxkit F and Daphtoxkit F), and luminescence inhibition tests (LumiMara). The observed toxicity of the tested solutions towards both Thamnocephalus platyurus and Daphnia magna indicates that the parent substance (unexposed) has lower toxicity, which increases during irradiation. The acute toxicity (Lumi Mara) of nonirradiated cefepime solution is low for all tested strains (<10%), but mixtures of cefepime and its photoproducts showed growth inhibition against all tested strains (except #6, Photobacterium phoreum). Generally, it can be concluded that after UV–Vis irradiation, the mixture of cefepime phototransformation products shows a significant increase in toxicity.

In the pathogenesis of Alzheimer's disease, the overexpression of glycogen synthase kinase-3β (GSK-3β) stands out due to its multifaced nature, as it contributes to the promotion of amyloid β and tau protein accumulation, as well as neuroinflammatory processes. Therefore, in the present study, we have designed, synthesized, and evaluated a new series of GSK-3β inhibitors based on the N-(pyridin-2-yl)cyclopropanecarboxamide scaffold. We identified compound 36, demonstrating an IC50 of 70 nM against GSK-3β. Subsequently, through crystallography studies and quantum mechanical analysis, we elucidated its binding mode and identified the structural features crucial for interactions with the active site of GSK-3β, thereby understanding its inhibitory potency. Compound 36 was effective in the cellular model of hyperphosphorylated tau-induced neurodegeneration, where it restored cell viability after okadaic acid treatment and showed anti-inflammatory activity in the LPS model, significantly reducing NO, IL-6, and TNF-α release. In ADME-tox in vitro studies, we confirmed the beneficial profile of 36, including high permeability in PAMPA (Pe equals 9.4) and high metabolic stability in HLMs as well as lack of significant interactions with isoforms of the CYP enzymes and lack of considerable cytotoxicity on selected cell lines (IC50 > 100 μM on HT-22 cells and 89.3 μM on BV-2 cells). Based on promising pharmacological activities and favorable ADME-tox properties, compound 36 may be considered a promising candidate for in vivo research as well as constitute a reliable starting point for further studies.

Lipophilicity is a physicochemical parameter well known as a decisive factor for predicting the successful development of a drug. Thus, a balance between potency and physicochemical properties during medicinal chemistry optimization is needed. In this study, the lipophilicity of isoindole-1,3(2H)-dione derivatives designed as phosphodiesterase 10A (PDE10A) inhibitors was determined by chromatographic [reversed-phase thin-layer chromatography (RP-TLC) and ultra-performance liquid chromatography/mass spectrometry (UPLC/MS)] and in silico methods. To assess the correlation between the obtained lipophilicity parameters, principal component analysis (PCA) was performed. logP values obtained by chromatographic (logPRP-TLC and logPUPLC/MS) and in silico methods were compared using the PCA method. The results of PCA revealed that logPUPLC/MS and in silico clogP provided by the ChemDraw program were highly correlated. Compounds’ drug likeness was screened, and the pharmacokinetic properties were predicted. All the investigated compounds displayed drug-likeness properties, and they met the criteria of Lipinski’s rule of five, which predicted the oral bioavailability of drug candidates. Analysis of the influence of physicochemical properties on the biological activity showed that the compounds with increased potency on PDE10A had significantly higher topological polar surface area (TPSA) values. The blood‒brain barrier permeability and the hemolytic activity of model compound 18 were examined. The model compound 18 displayed no toxicity effect on erythrocytes in the hemolytic assay and good parallel artificial membrane permeability. The results showed that phthalimide compounds with benzimidazole moiety are a source of compound-targeted inhibition of PDE10A with balanced physicochemical and drug-likeness properties.

Cyanobacteria are known for producing a wide array of secondary metabolites, including non-ribosomally synthesized oligopeptides, whose functions remain to be determined. Woronichinia naegeliana, a common component of freshwater blooms, represents an under-explored resource of bioactive oligopeptides. Among these oligopeptides are cyanopeptolin 1081 and anabaenopeptin 899, which have been shown to have adverse effects on zooplankton. The absolute amino acid configuration of these peptides appears typical relative to other cyanopeptolins and anabaenopeptins. To understand their toxic mechanisms, enzyme assays were conducted. The inhibitory activity of cyanopeptolin 1081 and anabaenopeptin 899 was tested against proteases such as chymotrypsin, trypsin, elastase, thrombin, and carboxypeptidase A, resulting in different activities against these enzymes. Cyanopeptolin 1081 inhibited both chymotrypsin and elastase, while anabaenopeptin 899 inhibited carboxypeptidase A but failed to inhibit the other tested enzymes at a concentration of 37 μM. The inhibitory concentration values determined here highlight that these compounds are among the most potent enzyme inhibitors in freshwater-derived cyanopeptides.

Helicobacter pylori (H. pylori) cause chronic inflammation of the gastric mucosa which can lead to epithelial atrophy and metaplasia resulting in peptic ulcer disease and gastric cancer. The increasing resistance of H. pylori to antibiotics and chemotherapeutics used to treat the infection is a serious problem. However, it has been confirmed that the introduction of effective anti-H. pylori therapy can prevent the progression to cancerous changes. This problem calls for the search for new and effective therapies. Xanthones are a group of compounds with extensive biological activities, including antibacterial activity, also against H. pylori. Addressing this issue, the aim of the study was to evaluate the potential of a group of 13 xanthone derivatives against susceptible and resistant H. pylori strains. Moreover, our objective was to conduct tests aimed at determining their ability to inhibit biofilm formation. The antimicrobial evaluation revealed that benzylpiperazine coupled at the C-2 position to xanthone (compounds C11 and C12) had good selective bacteriostatic activity against reference and clinical H. pylori strains (MBC/MIC ratio >4) but with no activity against other bacteria such as Staphylococcus aureus, Escherichia coli, and Lactobacillus paracasei. Analysis of the activity of compounds C11 and C12 against the biofilm formed by H. pylori strain ATCC 700684, and the clinical strain showed that these compounds caused a significant reduction in the amount of biofilm produced (5-20×). Moreover, cell viability analysis confirmed a 3-4× reduction in the viability of cells forming biofilm after treatment with C11 and C12. Finally,both compounds did not impair human fibroblast viability at tested concentrations and were not mutagenic in the Ames test. Therefore, they could be promising leads as antibacterial candidates for multidrug-resistant strains of H. pylori.

Plants from the Amaranthaceae family are a source of oleanolic acid (OA)-type saponins with cytotoxic activity. Two known OA-type saponins, calenduloside E and chikusetsusaponin IVa, were isolated from the roots of Chenopodium strictum Roth. Their structures were confirmed using MS and NMR techniques. This constitutes the inaugural report of the saponins in Ch. strictum. Both the isolated saponins and structurally similar compounds, momordin Ic and OA, were compared for their cytotoxicity against various cancer and normal cell lines (including skin, breast, thyroid, gastrointestinal, and prostate panels). Their effects were dose- and time-dependent, varying with the specific cell line and compound structure. A chemometric approach demonstrated the effects of the compounds on the cell lines. The study discusses the structure–activity observations. The key structural elements for potent cytotoxic activity included the free carboxyl group 28COOH in the sapogenin structure (OA) and the presence of a sugar moiety. The monodesmosides with glucuronic acid (GlcA) at the C3 position of OA were generally more cytotoxic than bidesmosides or OA alone. The addition of xylose in the sugar chain modified the activity towards the cancer cells depending on the specific cell line. OA-type saponins with GlcA (particularly calenduloside E and momordin Ic) represent a promising avenue for further investigation as potential anticancer agents.

Selective enhancement of synaptic GABA signaling mediated by GABA-A receptors has been previously reported to promote functional recovery after ischemic stroke, while tonic GABA signaling has been detrimental. To identify agents that enhance synaptic signaling, we synthesized GABA-A ligands based on three chemotypes with affinity values pK i= 6.44-8.32. Representative compounds showed a preference in functional responses toward synaptic type of GABA-A receptors, compared to the extrasynaptic ones. In a cellular ischemia model (OGD), selected compounds showed the potential to improve neuronal recovery. The selected lead, compound 4, demonstrated the ability to reduce mitochondrial dysfunction, regulate intracellular calcium levels, decrease caspase 3 levels, and promote neurite outgrowth in in vitro assays. In an animal model, compound 4 enhanced motor recovery and showed neuroprotective activity by reducing infarct volume and decreasing poststroke acidosis. These findings underscore the value of selective ligands modulating synaptic GABA-A receptors in promoting recovery from ischemic stroke.

Cyanobacterial harmful algal blooms (CyanoHABs) are observed in many regions worldwide with increasing frequency. The massive development of cyanobacteria is a severe problem for the water environment due to negative changes in water parameters, the introduction of toxic metabolites (cyanotoxins) into the water, and the resulting disruption of ecological relations in the ecosystem. Knowledge regarding CyanoHABs in aquatic reservoirs is increasing. However, information about cyanobacteria development in other, untypical habitats like deserts, open soils, or polar regions is still insufficient. Similarly, data regarding the distribution of cyanotoxins are extensive for some regions (for example, in Europe or North America), whereas, in other localities, such as those in South America, the data are scarce. In this paper, we investigated if phototrophic microbial communities collected from open soil (La Paz department, Sud Yungas province, Bolivia) contained cyanobacteria described as cyanotoxin producers. We performed qualitative and quantitative analysis of typical cyanotoxins found in aquatic reservoirs – anatoxin-a (ATX-a), cylindrospermopsin (CYN), and microcystin-LR (MC-LR). The obtained results showed a relatively high biodiversity of the studied microbial phototrophic community, which consists of several cyanobacterial and algal genera. Analyses of cyanotoxins showed that CYN and MC-LR were not present in the studied samples. However, despite the lack of cyanobacteria described as ATX-a producers, high-performance liquid chromatography (HPLC) chromatograms were revealed, and mass spectrometry (MS) spectra confirmed the presence of the toxin in the studied material. The results presented in this paper are, to the best of our knowledge, the first confirmation of the presence of ATX-a in open soil habitats, as well as the first record of cyanotoxin occurrence in Bolivia. The identification of anatoxin-producing cyanobacteria in open soil environments presents a novel finding that necessitates further work to elucidate their prevalence, abundance, and associated potential hazards, as well as the taxonomic classification of the specific cyanobacterial species able for anatoxin synthesis within these soil habitats. Future studies should focus on the distribution of cyanotoxins in cyanobacterial communities in untypical habitats and in localities for which, to date, the information on cyanotoxin occurrence is not currently available.