New 1,3-benzodioxole derivatives: Synthesis, evaluation of in vitro schistosomicidal activity and ultrastructural analysis

Effects of the probiotic Bacillus cereus GM on experimental schistosomiasis mansoni

Probiotics contribute to the integrity of the intestinal mucosa and preventing dysbiosis caused by opportunistic pathogens, such as intestinal helminths. Bacillus cereus GM obtained from Biovicerin® was cultured to obtain spores for in vivo evaluation on experimental schistosomiasis. The assay was performed for 90 days, where all animals were infected with 50 cercariae of Schistosoma mansoni on the 15th day. Three experimental groups were formed, as follows: G1-saline solution from the 1st until the 90th day; G2-B. cereus GM (105 spores in 300 μL of sterile saline) from the 1st until the 90th day; and G3-B. cereus GM 35th day (onset of oviposition) until the 90th day. G2 showed a significant reduction of 43.4% of total worms, 48.8% of female worms and 42.5% of eggs in the liver tissue. In G3, the reduction was 25.2%, 29.1%, and 44% of the total number of worms, female worms, and eggs in the liver tissue, respectively. G2 and G3 showed a 25% (p < 0.001) and 22% (p < 0.001) reduction in AST levels, respectively, but ALT levels did not change. ALP levels were reduced by 23% (p < 0.001) in the G2 group, but not in the G3. The average volume of granulomas reduced (p < 0.0001) 65.2% and 46.3% in the liver tissue and 83.0% and 53.2% in the intestine, respectively, in groups G2 and G3. Th1 profile cytokine (IFN-γ, TNF-α, and IL-6) and IL-17 were significantly increased (p < 0.001) stimulated with B. cereus GM in groups G2 and G3. IL-4 showed significant values when the stimulus was mediated by ConA. By modulating the immune response, B. cereus GM reduced the burden of worms, improved some markers of liver function, and reduced the granulomatous inflammatory reaction in mice infected with S. mansoni, especially when administered before infection.

Characterization and Investigation of Novel Benzodioxol Derivatives as Antidiabetic Agents: An In Vitro and In Vivo Study in an Animal Model

In this study, we synthesized benzodioxol carboxamide derivatives and investigated their antidiabetic potential. The synthesized compounds (Ia-Ic and IIa-IId) underwent characterization via HRMS, 1H-, 13CAPT-NMR, and MicroED. Their efficacy against α-amylase was assessed in vitro, while MTS assays were employed to gauge cytotoxicity across cancer and normal cell lines. Additionally, the antidiabetic impact of compound IIc was evaluated in vivo using a streptozotocin-induced diabetic mice model. Notably, IIa and IIc displayed potent α-amylase inhibition (IC50 values of 0.85 and 0.68 µM, respectively) while exhibiting a negligible effect on the Hek293t normal cell line (IC50 > 150 µM), suggesting their safety. Compound IId demonstrated significant activity against four cancer cell lines (26-65 µM). In vivo experiments revealed that five doses of IIc substantially reduced mice blood glucose levels from 252.2 mg/dL to 173.8 mg/dL in contrast to the control group. The compelling in vitro anticancer efficacy of IIc and its safety for normal cells underscores the need for further in vivo assessment of this promising compound. This research highlights the potential of benzodioxol derivatives as candidates for the future development of synthetic antidiabetic drugs.

In vitro activity, ultrastructural analysis and in silico pharmacokinetic properties (ADMET) of thiazole compounds against adult worms of Schistosoma mansoni

The present work aimed to carry out in vitro biological assays of thiazole compounds against adult worms of Schistosoma mansoni, as well as the in silico determination of pharmacokinetic parameters to predict the oral bioavailability of these compounds. In addition to presenting moderate to low cytotoxicity against mammalian cells, thiazole compounds are not considered hemolytic. All compounds were initially tested at concentrations ranging from 200 to 6.25 μM against adult worms of S. mansoni parasites. The results showed the best activity of PBT2 and PBT5 at a concentration of 200 μM, which caused 100% mortality after 3 h of incubation. While at 6 h of exposure, 100% mortality was observed at the concentration of 100 µM. Subsequent studies with these same compounds allowed classifying PBT5, PBT2, PBT6 and PBT3 compounds, which were considered active and PBT1 and PBT4 compounds, which were considered inactive. In the ultrastructural analysis the compounds PBT2 and PBT5 (200 µM) promoted integumentary changes with exposure of the muscles, formation of integumentary blisters, integuments with abnormal morphology and destruction of tubercles and spicules. Therefore, the compounds PBT2 and PBT5 are promising antiparasitics against S. mansoni.

In Vitro Anthelminthic Activity and Ultrastructural Analysis of Barbatic Acid against Schistosomulae and Juvenile Worms of Schistosoma mansoni

Schistosomiasis affects about 260 million people worldwide and the search for new schistosomicidal compounds is urgent. In this study we evaluated the in vitro effect of barbatic acid against schistosomulae and young worms of Schistosoma mansoni. The barbatic acid was evaluated through the bioassay of motility and mortality, cellular viability and ultrastructural analysis of juvenile stages through Scanning Electron Microscopy. Barbatic acid showed a schistosomicidal effect against schistosomulae and young worms of S. mansoni after 3 h of exposure. At the end of 24 h, barbatic acid showed 100 %, 89.5 %, 52 % and 28.5 % of lethality for schistosomulae at the concentrations of 200, 100, 50 and 25 μM, respectively. For young worms, barbatic acid showed 100 % and 31.7 % of lethality at the concentrations of 200 and 100 μM, respectively. Motility changes were observed at all sublethal concentrations. There was a significant reduction in the viability of young worms after exposure to barbatic acid at 50, 100 and 200 μM. Extensive damage to the schistosomulae and young worm's tegument, was observed from 50 μM. This report provides data showing the schistosomicidal effect of barbatic acid on schistosomulae and young worms of S. mansoni, causing death, motility changes and ultrastructural damage to worms.

Synthesis, in vitro schistosomicidal activity and ultrastructural alterations caused by thiosemicarbazones and thiazolidinones against juvenile and adult Schistosoma mansoni worms (Sambon, 1907)

Schistosomiasis is a neglected disease that affects about 258 million people worldwide. Caused by Schistosoma mansoni, helminth which, in Brazil, it is present on 19 states and capital. Praziquantel (PZQ) treatment presents low efficacy and adverse effects in parasites juvenile stages. Thiosemicarbazones and thiazolidinones are rising as potent chemical groups that have biological activity wide spectrum, and with radical modifications, they may become more effective and selective. Aiming to evaluate the action of these molecules against S. mansoni, JF series thiosemicarbazones and thiazolidinones (LqIT/UFPE) were synthesized: JF30, JF31, JF33, JF34, JF35, JF36, JF38, JF39, JF42 and JF43. Several parameters were evaluated, such as: their cytotoxicity in VERO cells, in vitro schistosomicidal activity for juvenile and adult worms and their action on worms through ultrastructural changes. Cytotoxicity indices ranged from 272 µM to 725 µM. When evaluating mortality rate, adult and juvenile worms showed 100 % mortality rate within 24 h and 48 h, respectively, when exposed to the compounds JF31 and JF43 at a dose of 200 µM. Also, motility, mortality and oviposition parameters were evaluated: JF31 and JF43 presented a score of 0 in 24 h, meaning total absence of movement, whereas no eggs and soft tissue damage were observed under optical microscopy. Through scanning electron microscopy, integumentary alterations caused by the compounds JF31 and JF43 were observed, such as: exposure of the musculature, formation of integumentary bubbles, integuments with abnormal morphology and destruction of tubercles and spikes. The results shoerd that the compound JF31 was 2.39 times more selective for adult worms and JF43 was 3.74 times more selective for juvenile worms. Thus, the compounds JF43 and JF31 are the most promising for presenting schistosomicidal activity of S. mansoni.

Whole-organism phenotypic screening methods used in early-phase anthelmintic drug discovery

Diseases caused by parasitic helminths (worms) represent a major global health burden in both humans and animals. As vaccines against helminths have yet to achieve a prominent role in worm control, anthelmintics are the primary tool to limit production losses and disease due to helminth infections in both human and veterinary medicine. However, the excessive and often uncontrolled use of these drugs has led to widespread anthelmintic resistance in these worms - particularly of animals - to almost all commercially available anthelmintics, severely compromising control. Thus, there is a major demand for the discovery and development of new classes of anthelmintics. A key component of the discovery process is screening libraries of compounds for anthelmintic activity. Given the need for, and major interest by the pharmaceutical industry in, novel anthelmintics, we considered it both timely and appropriate to re-examine screening methods used for anthelmintic discovery. Thus, we reviewed current literature (1977-2021) on whole-worm phenotypic screening assays developed and used in academic laboratories, with a particular focus on those employed to discover nematocides. This review reveals that at least 50 distinct phenotypic assays with low-, medium- or high-throughput capacity were developed over this period, with more recently developed methods being quantitative, semi-automated and higher throughput. The main features assessed or measured in these assays include worm motility, growth/development, morphological changes, viability/lethality, pharyngeal pumping, egg hatching, larval migration, CO₂- or ATP-production and/or enzyme activity. Recent progress in assay development has led to the routine application of practical, cost-effective, medium- to high-throughput whole-worm screening assays in academic or public-private partnership (PPP) contexts, and major potential for novel high-content, high-throughput platforms in the near future. Complementing this progress are major advances in the molecular data sciences, computational biology and informatics, which are likely to further enable and accelerate anthelmintic drug discovery and development.

Neurolocomotor Behavior and Oxidative Stress Markers of Thiazole and Thiazolidinedione Derivatives against Nauphoeta cinerea

Thiazolidine compounds NJ20 {(E)-2-(2-(5-bromo-2-methoxybenzylidene)hydrazinyl)-4-(4-nitrophenyl)thiazole} and NW05 [(2-(benzo (d) (1,3) dioxol-4-ylmethylene)-N-(4-bromophenyl)-thiosemicarbazone] potentiated the effect of norfloxacin in resistant bacteria; however, there are no reports on their effects on Nauphoeta cinerea in the literature. The objective of this work was to evaluate the behavioral effects and oxidative markers of NW05 and NJ20 in lobster cockroach N. cinerea. To evaluate the behavioral study, a video tracking software was used to evaluate the locomotor points and the exploratory profile of cockroaches in the horizontal and vertical regions of a new environment. The total concentration of thiol and reduced glutathione (GSH), substances reactive to thiobarbituric acid (TBARS), free iron (II) content and mitochondrial viability were determined. The antioxidant potential was evaluated by the DPPH method. Both substances induced changes in the behavior of cockroaches, showing a significant reduction in the total distance covered and in the speed. In the cell viability test (MTT), there was a significant reduction for NJ20 (1 mM). NJ20 caused a significant increase in total levels of thiol and non-protein thiol (NPSH), although it also slightly increased the content of malondialdehyde (MDA). Both compounds (NW05 and NJ20) caused a significant reduction in the content of free iron at a concentration of 10 mM. In conclusion, the compound NJ20 caused moderate neurotoxicity (1 mM), but had good antioxidant action, while NW05 did not show toxicity or significant antioxidant activity in the model organism tested. It is desirable to carry out complementary tests related to the antioxidant prospection of these same compounds, evaluating them at different concentrations.

Route of intracellular uptake and cytotoxicity of sesamol, sesamin, and sesamolin in human melanoma SK-MEL-2 cells

The intracellular uptake concentration determines drug absorption, drug activity, and toxicity. Sesamol, sesamin, and sesamolin are promising bioactive components from Sesame indicum L. Their respective intracellular uptake pathway and cytotoxicity were evaluated using melanoma and non-cancerous cells. Quantitative structure-activity relationship (QSAR) models were built to identify the molecular features affecting drug uptake in cells. The respective intracellular uptake pathway for sesamol vs. sesamin and sesamolin was carrier-mediated vs. passive transport. Topological polar surface area (PSA) and 2D autocorrections increase the intracellular concentration (C/M ratio) of these compounds. Sesamol has the lowest C/M ratio compared to sesamin and sesamolin, but only sesamol inhibits the cell viability of melanoma and provides an inhibition concentration at 50% (IC₅₀) against melanoma cells. The slightly aqueous solubility of sesamin and sesamolin, therefore, limits testing of their cytotoxicity. In conclusion, sesamol has the potential to inhibit melanoma cell growth, but requires improvement of the C/M ratio to increase its physicochemical properties. Thus, in order to investigate the cytotoxicity of sesamin and sesamolin against melanoma cells a solubility enhancer is needed.

Schistosomicidal effect of divaricatic acid from Canoparmelia texana (Lichen): In vitro evaluation and ultrastructural analysis against adult worms of Schistosoma mansoni

In this study we evaluated the in vitro effect of divaricatic acid against coupled worms of Schistosoma mansoni. The schistosomicidal effect was evaluated through the bioassay of motility and mortality, cellular viability of the worms and ultrastructural analysis through Scanning Electron Microscopy. To evaluate the cytotoxicity of divaricatic acid, a cell viability assay was performed with human peripheral blood mononuclear cells. Divaricatic acid proved effect against S. mansoni after 3 hours of exposure. At the end of 24 h the concentrations of 100 - 200 μM presented lethality to the worms. Motility changes were observed at sublethal concentrations. The IC₅₀ obtained by the cell viability assay for S. mansoni was 100.6 μM (96.24 - 105.2 μM). Extensive damage to the worm's tegument was observed such as peeling, erosion, bubbles, edema, damage and loss of tubercles and spines, fissures and tissue ruptures. No cytotoxicity was observed in human peripheral blood mononuclear cells. This report provides data showing the schistosomicidal effect of divaricatic acid on S. mansoni, causing death, motile changes and ultrastructural damage to worms. In addition, divaricatic acid was shown to be non-toxic to human peripheral blood mononuclear cells at concentrations effective on S. mansoni.

Molecular docking, chemo-informatic properties, alpha-amylase, and lipase inhibition studies of benzodioxol derivatives

Currently, available therapies for diabetes could not achieve normal sugar values in a high percentage of treated patients. In this research project, a series of 17 benzodioxole derivatives were evaluated as antidiabetic agents; that belong to three different groups were evaluated against lipase and alpha-amylase (α-amylase) enzymes. The results showed that 14 compounds have potent inhibitory activities against α-amylase with IC₅₀ values below 10 µg/ml. Among these compounds, 4f was the most potent compound with an IC₅₀ value of 1.11 µg/ml compared to the anti-glycemic agent acarbose (IC₅₀ 6.47 µg/ml). On the contrary, these compounds showed weak or negligible activities against lipase enzyme. However, compound 6a showed the best inhibitory anti-lipase activity with IC₅₀ 44.1 µg/ml. Moreover, all the synthesized compounds were undergone Molinspiration calculation, and the result showed that all compounds obeyed Lipinski's rule of five. Molecular docking studies were performed to illustrate the binding interactions between the benzodioxole derivatives and α-amylase enzyme pocket. Related to the obtained results it was clear that the carboxylic acid, benzodioxole ring, halogen or methoxy substituted aryl are important for the anti-amylase activities. The potent inhibitory results of some of the synthesized compounds suggest that these molecules should go further in vivo evaluation. It also suggests the benzodioxole derivatives as lead compounds for developing new drug candidates.

4-Aminoquinolines Bearing a 1,3-Benzodioxole Moiety: Synthesis and Biological Evaluation as Potential Antifungal Agents

In search of new environmentally friendly and effective antifungal agents, a series of 4-aminoquinolines bearing a 1,3-benzodioxole moiety were prepared and their structures were fully elucidated by spectroscopic analyses. The antifungal activities of all the target compounds against five phytopathogenic fungi were evaluated in vitro. The results revealed that most of the newly synthesized compounds exhibited obvious inhibitory activities at the concentration of 50 μg/mL. Among them, 6-(furan-2-yl)-N-(4-methylphenyl)-2H-[1,3]dioxolo[4,5-g]quinolin-8-amine hydrochloride (7m) displayed more promising antifungal potency with EC₅₀ values of 10.3 and 14.0 μg/mL against C. lunata and A. alternate, respectively. Particularly, the EC₅₀ value of 7m against C. lunata was 7.3-fold as potent as the standard azoxystrobin. There were some significant morphological alterations in the mycelia of C. lunata when treated with 7m at 50 μg/mL. Additionally, the preliminary structure-activity relationships (SARs) were also discussed. Thus, this study suggests that 4-aminoquinolines bearing a 1,3-benzodioxole moiety are interesting scaffolds for the development of novel antifungal agents.

Anti-inflammatory activity of novel thiosemicarbazone compounds indole-based as COX inhibitors

BACKGROUND

In this article, a series of 20 new thiosemicarbazone derivatives containing indole were synthesized and evaluated for their anti-inflammatory potential.

METHODS

The compounds were obtained through a synthetic route of only two steps, with yields that varied between 33.6 and 90.4%, and characterized by spectroscopic and spectrometric techniques.

RESULTS

An initial screening through the lymphoproliferation assay revealed that compounds LT76, LT81, and LT87 were able to inhibit lymphocyte proliferation, with CC₅₀ of 0.56 ± 0.036, 0.9 ± 0.01 and 0.5 ± 0.07 µM, respectively, better results than indomethacin (CC₅₀ > 12 µM). In addition, these compounds were able to suppress the in-vitro production of TNF-α and NO, in addition to stimulating the production of IL-4. Reinforcing in-vitro assays, the compounds were able to inhibit COX-2 similar to Celecoxib showing greater selectivity for this isoform (LT81 SI: 23.06 versus Celecoxib SI: 11.88). Animal studies showed that compounds LT76 (64.8% inhibition after 6 h), LT81 (89% inhibition after 6 h) and LT87 (100% inhibition after 4 h) were able to suppress edema in mice after inoculation carrageenan with greater potency than indomethacin, and immunohistochemistry revealed that the groups treated with LT76, LT81 and LT87 reduced the expression of COX-2, similar or better results when compared to indomethacin. Complementarily, in-silico studies have shown that these compounds have a good pharmacokinetic profile, for respecting the parameters of Lipinski and Veber, showing their good bioavailability.

CONCLUSIONS

These results demonstrate the potency of thiosemicarbazone derivatives containing indole and confirm their importance as scaffolds of molecules with notorious anti-inflammatory activity.

Chemotherapy for human schistosomiasis: how far have we come? What's new? Where do we go from here?

Globally, schistosomiasis threatens more than 700 million lives, mostly children, in poor localities of tropical and sub-tropical areas with morbidity due to acute and chronic pathological manifestations of the disease. After a century since the first antimonial-based drugs were introduced to treat the disease, anti-schistosomiasis drug development is again at a bottleneck with only one drug, praziquantel, available for treatment purposes. This review focuses on promising chemotypes as potential starting points in a drug discovery effort to meet the urgent need for new schistosomicides.

In vitro activity of usnic acid potassium salt against different developmental stages of Schistosoma mansoni: An ultrastructural study

Currently, the control of schistosomiasis is based on a single drug, praziquantel, which is effective against all species of Schistosoma but only in the adult stage, presenting a schistosomicidal deficit at the other developmental stages of the parasites. Recently our research group has demonstrated that the potassium salt of usnic acid (PS-UA) presented schistosomicidal property against couples of adult worms of S. mansoni. Thus, the present study seeks to report for the first time the in vitro activity of PS-UA against different developmental stages of S. mansoni (schistosomules and young worms). As schistosomicide parameters, we evaluated motility, mortality, cell viability of the worms and tegument changes by scanning electron microscopy (SEM). After 3 h exposure, PS-UA was lethal to schistosomules at concentrations of 100 and 50 μM, whereas for concentrations 25 and 12.5 μM, 38 and 18% of mortality and 62 and 24% changes in motility, respectively, were reached. Yet for schistosomules, concentration of 25 μM caused 90 and 100% of death after 6 and 12 h, respectively. In the concentration of 12.5 μM at intervals of 12 and 24 h mortality was 68 and 100%, respectively. For young worms, after 3 h of exposure at concentrations of 200 and 100 μM caused 57 and 27% mortality, respectively. After 12 and 24 h, these concentrations caused mortality of 90 and 100% and 47 and 60% respectively. After 24 h, concentrations of 50 and 25 μM caused 80 and 30% change in motility, respectively. However, at the 12.5 μM concentration no change was observed. In addition, PS-UA reduced the cellular viability of young worms by 50.98% and 85.87% at concentrations of 100 and 200 μM, respectively. In both stages of worms and at different exposure intervals, PS-UA caused alterations such as: dorsoventral contraction, peeling, swelling, blisters, erosion, exposure of subtegumental tissue and disintegration of tegument. According to the results, changes in motility and mortality caused by PS-UA against schistosomules and young worms were concentration and time-dependents, also PS-UA even at low concentration, was able to cause profound ultrastructural changes in the integument of the worms. PS-UA is a promising candidate as prophylactic agent in the control of schistosomiasis mansoni.

In vitro activity, ultrastructural studies and in silico pharmacokinetic properties of indol-3-yl-thiosemicarbazones derivatives and analogues against juvenile and adult worms of S. mansoni

The present work aimed to carry out in vitro biological assays of indol-3-yl derivatives thiosemicarbazones (2a-e) and 4-thiazolidinones (3a-d) against juvenile and adult worms of S. mansoni, as well as the in silico determination of pharmacokinetic parameters for the prediction of the oral bioavailability of these derivatives. All compounds were initially screened at a concentration of 200 μM against S. mansoni adult worms and the results evidenced the good activity of compounds 2b, 2d and 3b, which caused 100% mortality after 24, 48 and 72 h, respectively. Subsequent studies with these same compounds revealed that compound 2b was able to reduce the viability of the parasites by 85% and 83% at concentrations of 200 and 100 μM, respectively. In relation to the juvenile worms, all compounds (2b, 2d and 3b) were able to cause mortality, but compound 2b demonstrated better activity causing 100% mortality in 48 h. Additionally, it was possible to observe reduction in the viability of juvenile worms of 85%, 81% and 64% at concentrations of 200, 100 and 50 μM, respectively. Several ultrastructural damages were observed when adult and juvenile S. mansoni worms were exposed to compound 2b (200 μM) that was characterized by extensive destruction by the integument, which may justify the mortality rate of cultured parasites. In the DNA interaction assay, fragmentation of the genetic material of adult worms when treated with compound 2b (200 μM) was evidenced, indicating the apoptosis process as mechanism of parasite death. Regarding pharmacokinetic properties, all derivatives are according to the required parameters, predicting good oral bioavailability for the studied compounds. The results presented in this study reveal the good activity of compound 2b in both adult and juvenile worms of S. mansoni, pointing this compound as promising in the development of further studies on schistosomicidal activity.

In vitro and in vivo activities of DW-3-15, a commercial praziquantel derivative, against Schistosoma japonicum

Background

Schistosomiasis is a debilitating neglected tropical disease that affects approximately 190 million people around the world. Praziquantel (PZQ) is the only drug available for use against all Schistosoma species. Although PZQ has a high efficacy, recognized concerns have prompted the development of new, alternative drugs for repeated use in endemic areas where PZQ efficacy against strains of Schistosoma is reduced. A hybrid drug containing different pharmacophores within a single molecule is a promising strategy. Our earlier in vivo studies showed the significant antiparasitic activity of a praziquantel derivative, DW-3-15, against Schistosoma japonicum. In the present study, DW-3-15 was synthesized in large amounts by a pharmaceutical company and its schistosomicidal efficacy and stability were further confirmed. Parameters such as parasite viability, pairing and oviposition were evaluated in vitro. An in vivo study was conducted to assess the effect of commercial DW-3-15 on worm burden, egg production and diameter of granulomas. Additionally, to gain insight into the mechanism of action for DW-3-15, morphological changes in the tegument of S. japonicum were also examined.

Results

The in vitro study showed the antiparasitic activity of DW-3-15 against S. japonicum, with significant reductions in viability of adult and juvenile worms, worm pairings and egg output. Compared to PZQ, DW-3-15 induced similar ultrastructural changes and evident destruction of the tegument surface in male worms. In vivo, the oral administration of DW-3-15 at a dose of 400 mg/kg per day for five consecutive days in mice significantly reduced the total worm burden and number of eggs in the liver. Histological analysis of the livers showed a marked reduction in the average diameter of the egg granuloma.

Conclusions

Our findings suggest that DW-3-15, a PZQ derivative with the prospect of commercial production, can be developed as a potential promising schistosomicide.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3442-7) contains supplementary material, which is available to authorized users.

SAR Studies and Biological Characterization of a Chromen-4-one Derivative as an Anti-Trypanosoma brucei Agent

Chemical modulation of the flavonol 2-(benzo[d][1,3]dioxol-5-yl)-chromen-4-one (1), a promising anti-Trypanosomatid agent previously identified, was evaluated through a phenotypic screening approach. Herein, we have performed structure-activity relationship studies around hit compound 1. The pivaloyl derivative (13) showed significant anti-T. brucei activity (EC₅₀ = 1.1 μM) together with a selectivity index higher than 92. The early in vitro ADME-tox properties (cytotoxicity, mitochondrial toxicity, cytochrome P450 and hERG inhibition) were determined for compound 1 and its derivatives, and these led to the identification of some liabilities. The 1,3-benzodioxole moiety in the presented compounds confers better in vivo pharmacokinetic properties than those of classical flavonols. Further studies using different delivery systems could lead to an increase of compound blood levels.

Usnic acid potassium salt from Cladonia substellata (Lichen): Synthesis, cytotoxicity and in vitro anthelmintic activity and ultrastructural analysis against adult worms of Schistosoma mansoni

We report for the first time the in vitro effect of Potassium Salt, derived from Usnic Acid (PS-UA), isolated from the lichen Cladonia substellata Vanio, on couples of Schistosoma mansoni. As schistosomicide parameters, we evaluated mortality, motility, cell viability of the worms and tegument changes by scanning electron microscopy (SEM). Exposure to a concentration of 100 μM caused 75% mortality after 3 h. After 6 h, changes in motility in concentrations of 50 and 25 μM are evidenced. After 12 h and 24h, the concentrations of 50 and 100 μM caused 6.25% and 87.5% and 50% and 100% mortality, respectively. PS-UA reduced the cell viability of the worms by 27.36% and 52.82% at concentrations 50 and 100 μM, respectively. Through SEM we observed progressive dose-and time-dependent, alterations such as swelling, blisters, dorsoventral contraction, erosion until disintegration of the tubercles in the tegument of male and female. PS-UA did not alter the viability of human peripheral blood mononuclear cells and showed high selectivity indices (IC₅₀ > 200 μM). Our results indicate that PS-UA represents a possible candidate for a new anthelmintic drug in the control of schistosomiasis.

In Vitro and in Vivo Antischistosomal Activities of Chalcones

In this study, we evaluated the in vitro and in vivo schistosomicidal activities of chalcones against Schistosoma mansoni worms. In vitro assays revealed that chalcones 1 and 3 were the most active compounds, without affecting significantly mammalian cells. Confocal laser scanning microscopy and scanning electron microscopy studies revealed reduction on the numbers of tubercles and morphological alterations in the tegument of S. mansoni worms after in vitro incubation with chalcones 1 and 3. In a mouse model of schistosomiasis, the oral treatment (400 mg/kg) with chalcone 1 or 3 significantly caused a total worm burden reduction in mice. Chalcone 1 showed significant inhibition of the S. mansoni ATP diphosphohydrolase activity, which was corroborated by molecular docking studies. The results suggested that chalcones could be explored as lead compounds with antischistosomal properties.