Garcinielliptone FC: Antiparasitic activity without cytotoxicity to mammalian cells

In vitro Evaluation of the Antileishmanial and Antischistosomal Activities of p-Coumaric Acid Prenylated Derivatives

We have evaluated eight p-coumaric acid prenylated derivatives in vitro for their antileishmanial activity against Leishmania amazonensis promastigotes and their antischistosomal activity against Schistosoma mansoni adult worms. Compound 7 ((E)-3,4-diprenyl-4-isoprenyloxycinnamic alcohol) was the most active against L. amazonensis (IC50=45.92 μM) and S. mansoni (IC50=64.25 μM). Data indicated that the number of prenyl groups, the presence of hydroxyl at C9, and a single bond between C7 and C8 are important structural features for the antileishmanial activity of p-coumaric acid prenylated derivatives.

Bacuri (Platonia insignis Mart.): Nutritional values, volatile compounds, rheological properties, health benefits, and potential products

The bacuri is one of the main Amazonian fruits, which is greatly appreciated by local inhabitants due to its characteristic flavor. It offers numerous potential applications in products such as juices, sweets, jams, and yogurts. This review discusses the nutritional values, physicochemical composition, volatile compounds, rheological properties, health benefits, and potential food products obtained from the pulp of bacuri, which contains considerable amounts of bioactive compounds, dietary fibers, minerals, amino acids, among other nutrients, as well as a potential for hypoglycemic compounds. The bacuri has an essentially floral aroma with fruity notes and an attractive exotic flavor. Its major aromatic compounds are linalool, cis-linalool, trans-linalool oxide, and hotrienol. Bacuri pulp presents itself as a non-Newtonian fluid of the pseudoplastic type. The bacuri fruit has not yet attained economic importance due to the lack of studies aimed at expanding the possibilities of post-harvest processing and commercialization.

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.

Total synthesis and structural reassignment of garcinielliptone FC, a polycyclic polyprenylated acylphloroglucinol with diverse bioactivity

Garcinielliptone FC (GFC) was assigned to be a type A polycyclic polyprenylated acylphloroglucinol (PPAP) and was found to exhibit diverse biological activities. Now we revise the structure of GFC to xanthochymol, a type B PPAP, via NMR and total synthesis methods. The total syntheses of (±)-xanthochymol and (±)-cycloxanthochymol were accomplished in 12 and 13 steps, respectively.

Neolignans isolated from Saururus cernuus L. (Saururaceae) exhibit efficacy against Schistosoma mansoni

Schistosomiasis, a parasitic disease caused by the blood fluke of the genus Schistosoma, affects over 230 million people, especially in developing countries. Despite the significant economic and public health consequences, only one drug is currently available for treatment of schistosomiasis, praziquantel. Thus, there is an urgent demand for new anthelmintic agents. Based on our continuous studies involving the chemical prospection of floristic biodiversity aiming to discover new bioactive compounds, this work reports the in vitro antiparasitic activity against Schistosoma mansoni adult worms of neolignans threo-austrobailignan-6 and verrucosin, both isolated from Saururus cernuus L. (Saururaceae). These neolignans showed a significant in vitro schistosomicidal activity, with EC₅₀ values of 12.6-28.1 µM. Further analysis revealed a pronounced reduction in the number of S. mansoni eggs. Scanning electron microscopy analysis revealed morphological alterations when schistosomes were exposed to either threo-austrobailignan-6 or verrucosin. These relevant antischistosomal properties were accompanied by low cytotoxicity potential against the animal (Vero) and human (HaCaT) cell lines, resulting in a high selectivity index. Considering the promising chemical and biological properties of threo-austrobailignan-6 and verrucosin, this research should be of interest to those in the area of neglected diseases and in particular antischistosomal drug discovery.

In Vitro Cercaricidal and Schistosomicidal Activities of the Raffia Wine and Hydroethanolic Extracts of Pedilanthus tithymaloides Linn (Poit). Stem Barks

Schistosomiasis control remains a public health concern, and there is a need to evaluate new strategies for targeting larval and adult stages of the parasite. As Pedilanthus tithymaloides is empirically used to treat schistosomiasis, it becomes essential to know its effective action scientifically. This study assessed the cercaricidal and schistosomicidal activity of P. tithymaloides stem barks raffia wine extract (RwPt) and hydroethanolic extract (HePt). Different concentrations of these extracts were tested against cercariae (31.25–1000 μg/mL) and adult worms (62.5–2000 μg/mL) of Schistosoma mansoni. Niclosamide-olamine 5% (1 μg/mL) and praziquantel (10 μg/mL) were used as pharmacological controls. Cercariae viability was determined every 30 min for 180 min, and adult worms’ motor activity and viability after 24 and 48 h incubation. In addition, cytotoxicity and phytochemical analysis were performed. HePt was lethal to cercariae and adult worms with LC50 of 73.91 μg/mL after 60 min of incubation and 731.17 μg/mL after 48 h of incubation, respectively. Furthermore, a significant reduction of 94.44% in motor activity was observed in surviving worms at the concentration of 2000 μg/mL. RwPt was less effective on S. mansoni cercariae with an LC50 of 617.86 μg/mL after 180 min and on adult worms with a mortality rate of 9.83% at 2000 μg/mL for 48 h incubation. Both extracts showed a weak cytotoxicity profile with an IC50 of 983.50 μg/mL for HePt and more than 1000 μg/mL for RwPt. The LC-MS analysis of HePt allowed the detection of two annotated diterpenoids. Based on the selectivity index, the hydroethanolic extract of P. tithymaloides stem barks disclosed an intense cercaricidal activity and a moderate schistosomicidal effect with low cytotoxicity. These findings may support the potential use of Pedilanthus tithymaloides as a natural product or a source of natural-derived compounds for interrupting schistosomiasis transmission.

The ethnobotanical relevance of the tribe Symphonieae (Clusiaceae) around the world

ETHNOPHARMACOLOGICAL RELEVANCE

The tribe Symphonieae (Clusiaceae) encompasses 48 species accommodated in seven genera (Lorostemon, Montrouziera, Moronobea, Pentadesma, Platonia, Symphonia and Thysanostemon). Parts of these plants, mainly the exudates and the seeds oil are useful for different purposes, especially for treating dermatological conditions. In addition to the role in the folk medicine, some species are of great economic and cultural importance for native people from different continents.

AIM OF THE REVIEW

The goal of this review is to critically summarize the current knowledge on systematics, ethnobotanical, chemical and pharmacological aspects of species from the tribe Symphonieae, as well as to provide support for future taxonomic and phylogenetic studies on the Clusiaceae family.

MATERIALS AND METHODS

The available information was gathered from many different databases (Web of Science, ScienceDirect, Scopus, Pubmed, ChemSpider, SciFinder, ACS Publications, Wiley Online Library, Useful Tropical Plants Database, Google Scholar). Additional data from books, theses and dissertations were also included in this review.

RESULTS

Chemical studies of Symphonieae have demonstrated that the genera are a source of benzophenones, xanthones and biflavonoids. Components as sesquiterpenoids, triterpenoids, flavonoids, free fatty acids, among others, have also been reported. Extracts and compounds isolated from a variety of species have been exhibiting antimicrobial, cytotoxic and antiprotozoal activities, corroborating part of their medicinal uses. In addition, certain species produce edible fruits and a kind of "butter" with economic importance. All species produce exudate, which often has great relevance in the daily lives of local people.

CONCLUSION

Several species of Symphonieae have potential therapeutic applications and some of them have been investigated to scientifically validate their popular uses. In addition, a number of species have proved to be a rich source of promising pharmacologically active compounds. Finally, the value of fruits, exudate and butter, for instance, should serve as a stimulus for the sustainable development of products that aim to take advantage of these natural resources.

Amazonian Bacuri (Platonia insignis Mart.) Fruit Waste Valorisation Using Response Surface Methodology

Bacuri (Platonia insignis Mart) is a species from the Clusiaceae genus. Its fruit pulp is commonly used in South America in several food products, such as beverages, ice cream and candies. Only the pulp of the fruit is used, and the peels and seeds are considered waste from these industries. As a trioxygenated xanthone source, this species is of high interest for bioproduct development. This work evaluated the mesocarp and epicarp of bacuri fruits through different extraction methods and experimental conditions (pH, temperature and solvent) in order to determine the most effective method for converting this agro-industrial waste in a value-added bioproduct. Open-column procedures and HPLC and NMR experiments were performed to evaluate the chemical composition of the extracts, along with total phenols, total flavonoids and antioxidant activities (sequestration of the DPPH and ABTS radicals). A factorial design and response surface methodology were used. The best extraction conditions of substances with antioxidant properties were maceration at 50 °C with 100% ethanol as solvent for mesocarp extracts, and acidic sonication in 100% ethanol for epicarp extracts, with an excellent phenolic profile and antioxidant capacities. The main compounds isolated were the prenylated benzophenones garcinielliptone FC (epicarp) and 30-epi-cambogin (mesocarp). This is the first study analysing the performance of extraction methods within bacuri agro-industrial waste. Results demonstrated that shells and seeds of bacuri can be used as phenolic-rich bioproducts obtained by a simple extraction method, increasing the value chain of this fruit.

New evidence for tamoxifen as an antischistosomal agent: in vitro, in vivo and target fishing studies

Background: Praziquantel is the only drug available to treat schistosomiasis, and there is an urgent demand for new anthelmintic agents. Methodology & results: We conducted in-depth in vitro and in vivo studies and report a target fishing investigation. In vitro, tamoxifen was active against adult and immature worms at low concentrations (<5 μM). Tamoxifen at a single dose (400 mg/kg) or once daily for five consecutive days (100 mg/kg/day) in mice harboring either adult (patent infection) or juvenile (prepatent infection) significantly reduced worm burden (30-70%) and egg production (70-90%). Target fishing studies revealed propionyl-CoA carboxylase as a potential target for tamoxifen in Schistosoma mansoni and glucose uptake by S. mansoni was also significantly reduced. Conclusion: Our results provide news evidence of antiparasitic effect of tamoxifen and reveal propionyl-CoA carboxylase as a potential target.

Brazilian red propolis exhibits antiparasitic properties in vitro and reduces worm burden and egg production in an mouse model harboring either early or chronic Schistosoma mansoni infection

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis has been used in folk medicine for thousands of years and, in the past few decades, it has attracted renewed interest. Although propolis has been traditionally used in many communities worldwide against parasitic diseases, its effect against Schistosoma mansoni infection remains unclear.

AIM OF THE STUDY

To demonstrate the effects of Brazilian red propolis on Schistosoma mansoni ex vivo and in an animal model of schistosomiasis.

MATERIALS AND METHODS

In vitro, we monitored phenotypic and tegumental changes as well as the effects of the crude extract of propolis on pairing and egg production. In a mouse infected with either immature (early infection) or adult (chronic infection) worms, propolis was administered by oral gavage and we studied the influence of this natural product on worm burden and egg production.

RESULTS

Propolis 25 μg/mL reduced motility and caused 100% mortality of adult parasites ex vivo. Further analysis revealed a pronounced reduction in oviposition after exposure to propolis at sub-lethal concentrations. In addition, scanning electron microscopy showed morphological alterations in the tegument of schistosomes. In the animal model, propolis markedly reduced worm burden and egg production in both early and chronic S. mansoni infection when compared to untreated control animals.

CONCLUSIONS

The efficacy of Brazilian red propolis in both in vitro and in vivo studies suggests its potential anthelmintic properties against S. mansoni infection.

Antischistosomal properties of aurone derivatives against juvenile and adult worms of Schistosoma mansoni

Schistosomiasis is a neglected disease caused by helminth flatworms of the genus Schistosoma, affecting over 240 million people in more than 70 countries. The treatment relies on a single drug, praziquantel, making urgent the discovery of new compounds. Aurones are a natural type of flavonoids that display interesting pharmacological activities, particularly as chemotherapeutic agents against parasites. In pursuit of treatment alternatives, the present work conducted an in vitro and in vivo antischistosomal investigation with aurone derivatives against Schistosoma mansoni. After preparation of aurone derivatives and their in vitro evaluation on adult schistosomes, the three most active aurones were evaluated in cytotoxicity and haemolytic assays, as well as in confocal laser-scanning microscope studies, showing tegumental damage in parasites in a concentration-dependent manner with no haemolytic or cytotoxic potential toward mammalian cells. In a mouse model of schistosomiasis, at a single oral dose of 400 mg/kg, the selected aurones showed worm burden reductions of 35% to 65.0% and egg reductions of 25% to 70.0%. The most active thiophenyl aurone derivative 18, unlike PZQ, had efficacy in mice harboring juvenile S. mansoni, also showing significant inhibition of oviposition by parasites, giving support for the antiparasitic potential of aurones as lead compounds for novel antischistosomal drugs.

15β-Senecioyl-oxy-ent-kaur-16-en-19-oic Acid, a Diterpene Isolated from Baccharis lateralis, as Promising Oral Compound for the Treatment of Schistosomiasis

Praziquantel is the only available drug to treat schistosomiasis, and therefore, urgent studies must be performed to identify new anthelmintic agents. This study reports the anthelmintic evaluation of two related ent-kaurane diterpenes isolated from aerial parts of Baccharis lateralis (Asteraceae), ent-kaur-16-en-19-oic acid (1) and 15β-senecioyl-oxy-ent-kaur-16-en-19-oic acid (2) against Schistosoma mansoni in vitro and in a murine model of schistosomiasis. Both compounds exhibited in vitro activity with lethal concentration 50% (LC₅₀) values of 26.1 μM (1) and 11.6 μM (2) as well as reduced toxicity against human cell lines, revealing a good selectivity profile, mainly with compound 2 (selectivity index > 10). Compound 2 also decreased egg production and caused morphological alterations in the parasite reproductive system. In mice infected with S. mansoni, oral treatment with compound 2 at 400 mg/kg, the standard dose used in this model of schistosomiasis, caused a significant reduction in a total worm burden of 61.9% (P < 0.01). S. mansoni egg production, a key mechanism for both transmission and pathogenesis, was also markedly reduced. In addition, compound 2 achieved a significant reduction in hepatosplenomegaly. Therefore, the diterpene 15β-senecioyl-oxy-ent-kaur-16-en-19-oic acid (2) has an acceptable cytotoxicity profile and is orally active in a murine schistosomiasis model.

Therapeutic Effect of Diminazene Aceturate on Parasitic Blood Fluke Schistosoma mansoni Infection

Praziquantel is currently the only drug available to treat schistosomiasis, a disease of enormous public health significance caused by a blood fluke of the genus Schistosoma Diminazene, a drug approved by the FDA, has been successfully used to treat diseases caused by blood protozoan parasites. In this study, we evaluated the antiparasitic properties of diminazene against Schistosoma mansoni ex vivo and in mice harboring either chronic or early S. mansoni infections. In vitro, we monitored phenotypic and tegumental changes as well as the effects of the drug on pairing and egg production. In mice infected with either adult (chronic infection) or immature (early infection) worms, diminazene was administered intraperitoneally (10 to 100 mg/kg of body weight) or by oral gavage (100 to 400 mg/kg), and we studied the influence of the drug on worm burden and egg production. Liver and spleen pathologies and serum aminotransferase levels were also analyzed. In vitro, 50% effective concentrations (EC₅₀) and EC₉₀ revealed that diminazene is able to kill both immature and adult parasites, and its effect was time and concentration dependent. In addition, confocal laser scanning microscopy showed morphological alterations in the teguments of schistosomes. In an animal model, the influence of the drug on worm burden, egg production, hepatomegaly, and splenomegaly depended on the dosing regimen applied and the route of administration. Diminazene also caused a significant reduction in aminotransferase levels. Comparatively, diminazene treatment was more effective in chronic infection than in early infection. In tandem, our study revealed that diminazene possesses anthelmintic properties and inhibits liver injury caused by Schistosoma eggs.

Novel polyprenylated benzophenone derivatives from Clusia burle-marxii

Three new caged polyprenylated benzophenone derivatives named burlemarxiones D-F (1-3) were isolated from the hexane extract of Clusia burle-marxii trunks. Burlemarxione D (1) contains the tetracyclo[8.3.1.0^3,11.0^5,10]tetradecane core skeleton also observed for burlemarxione A, its probable immediate precursor. However, two additional rings are formed to produce an unprecedented complex-caged core skeleton. These additional rings could be formed by a radical cyclization reaction of one prenyl group at C-5 with C-1 and C-33, followed by oxidative dehydrogenation (rearomatization) or by an intramolecular [4 + 2] radical cycloaddition (Diels-Alder reaction), followed by an enolization reaction (rearomatization). Burlemarxiones E and F were isolated after methylation with diazomethane that was necessary to avoid the interconversion of the pair of β-diketones in tautomeric equilibrium. The proposed biosynthetic pathway for burlemarxiones D-F involves the condensation of either lavandulyl pyrophosphate or 2-(1-methylvinyl)-hexa-5-enyl pyrophosphate with the acylphloroglucinol derivative 6-benzoyl-5-hydroxy-5-cyclohexen-1,3-dione, followed by consecutive prenylation reactions. Therefore, Clusia burle-marxii reinforces the claim that the genus Clusia is an important source of sophisticated caged polyprenylated benzophenone derivatives.

H1-antihistamines as antischistosomal drugs: in vitro and in vivo studies

Background

Schistosomiasis is a socioeconomically devastating parasitic infection afflicting hundreds of millions of people and animals worldwide. It is the most important helminth infection, and its treatment relies solely on the drug praziquantel. Oral H1-antihistamines are available worldwide, and these agents are among the most widely used of all medications in children and adults. Given the importance of the drug repositioning strategy, we evaluated the antischistosomal properties of the H1-antihistamine drugs commonly used in clinical practices.

Methods

Twenty-one antihistamine drugs were initially screened against adult schistosomes ex vivo. Subsequently, we investigated the anthelmintic properties of these antihistamines in a murine model of schistosomiasis for both early and chronic S. mansoni infections at oral dosages of 400 mg/kg single dose or 100 mg/kg daily for five consecutive days. We also demonstrated and described the ability of three antihistamines to induce tegumental damage in schistosomes through the use of scanning electron microscopy.

Results

From phenotypic screening, we found that desloratadine, rupatadine, promethazine, and cinnarizine kill adult S. mansoni in vitro at low concentrations (5–15 µM). These results were further supported by scanning electron microscopy analysis. In an animal model, rupatadine and cinnarizine revealed moderate worm burden reductions in mice harboring either early or chronic S. mansoni infection. Egg production, a key mechanism for both transmission and pathogenesis, was also markedly inhibited by rupatadine and cinnarizine, and a significant reduction in hepatomegaly and splenomegaly was recorded. Although less effective, desloratadine also revealed significant activity against the adult and juvenile parasites.

Conclusions

Although the worm burden reductions achieved are all only moderate, comparatively, treatment with any of the three antihistamines is more effective in early infection than praziquantel. On the other hand, the clinical use of H1-antihistamines for the treatment of schistosomiasis is highly unlikely.

Antiparasitic activity of piplartine (piperlongumine) in a mouse model of schistosomiasis

Schistosomiasis is one of the most important parasitic infections in terms of its negative effects on public health and economics. Since praziquantel is currently the only drug available to treat schistosomiasis, there is an urgent need to identify new anthelmintic agents. Piplartine, also known as piperlongumine, is a biologically active alkaloid/amide from peppers that can be detected in high amounts in the roots of Piper tuberculatum. Previously, it has been shown to have in vitro schistosomicidal effects. However, its anthelmintic activity in an animal host has not been reported. In the present work, in vivo antischistosomal properties of isolated piplartine were evaluated in a mouse model of schistosomiasis infected with either adult (patent infection) or juvenile (pre-patent infection) stages of Schistosoma mansoni. A single dose of piplartine (100, 200 or 400 mg/kg) or daily doses for five consecutive days (100 mg/kg/day) administered orally to mice infected with schistosomes resulted in a reduction in worm burden and egg production. Treatment with the highest piplartine dose (400 mg/kg) caused a significant reduction in a total worm burden of 60.4% (P < 0.001) in mice harbouring adult parasites. S. mansoni egg production, a process responsible for pathology in schistosomiasis, was also significantly inhibited by piplartine. Studies using scanning electron microscopy revealed substantial tegumental alterations in parasites recovered from mice. Since piplartine has well-characterized mechanisms of toxicity, is easily available, and is cost-effective, our results indicate that this bioactive molecule derived from medicinal plants could be a potential lead compound for novel antischistosomal agents.

Toxicity, cytotoxicity, mutagenicity and in vitro antioxidant models of 2-oleyl-1,3-dipalmitoyl-glycerol isolated from the hexane extract of Platonia insignis MART seeds

2-oleyl-1,3-dipalmitoyl-glycerol (ODG) was obtained from Platonia insignis (bacurizeiro) seeds. There are no studies on its toxicity and protective activities against oxidative stress. This study was aimed to evaluate antioxidant effects in vitro, as well as to evaluate the toxicological and mutagenic effects of the ODG. ODG showed a median lethal dose (LD₅₀) greater than 1200 μg mL^-1 in A. salina. In the assay of A. cepa (0.2-0.002 mg mL^-1) the ODG compound at the highest concentration was slightly cytotoxic with decrease in the size of roots and mitotic indexes, but did not induce chromosomal alterations. ODG (8.75-140.00 μg mL^-1) was found to reduce nitric oxide production by 41.6 %, while the antioxidant standard ascorbic acid (AA) reduced 54.14 %. ODG (15.625-250.00 μg mL^-1) promoted removal of the hydroxyl radical by 35.69 % at the highest concentration and was able to prevent lipid peroxidation induced by 2,2'-azobis-2-amidinopropane (AAPH), inhibiting the amount of TBARS formed, up to 35.69 %, a result close to that obtained with AA. Thus, ODG moderately reduced the levels of hydroxyl radicals, nitric oxide, and TBARS in vitro and was nontoxic at low concentrations.

Garcinielliptone FC: Selective anti-amastigote and immunomodulatory effects on macrophages infected by Leishmania amazonensis

The present study was directed to the in vitro antileishmanial, cytotoxic and immunomodulatory effects of Garcinielliptone FC (GFC) against promastigote and macrophage-internalized amastigote forms of Leishmania amazonensis. GFC showed in vitro cytotoxicity against BALB/c peritoneal macrophages with CC₅₀ of 74.90 μM. The hemolytic activity against sheep erythrocytes only demonstrated a decrease of 20.42% in cell viability at the highest tested concentration tested (1326.0 μM). GFC promoted in vitro growth inhibition of both promastigote and intracellular amastigotes with IC₅₀ values of 14.06 and 1.91 μM, respectively, with 7.3-fold higher Selectivity Index (SI) for intracellular amastigotes (SI = 39.21) than for promastigotes (SI = 5.33). Interestingly, the pre-treatment of macrophages or promastigotes with GFC promoted decrease of infected macrophages and number of recovered amastigotes, respectively. Also, GFC was able to markedly promote macrophages activation by increase of phagocytic capability and nitrite production at concentrations able to solve infection of macrophages by L. amazonensis, suggesting the possible involvement of immunomodulatory modulation of macrophages leading to solve the infection. GFC is an emerging and promising chemical compound for the studies focused on the assessment of its therapeutic potential on in vivo experimental models of leishmaniasis.

Vanillin-Related N-Acylhydrazones: Synthesis, Antischistosomal Properties and Target Fishing Studies

Background:

Schistosomiasis is a neglected disease, which affects millions of people in developing countries. Its treatment relies on a single therapeutic alternative, the praziquantel. This situation may lead to drug resistance which, in turn, made urgent the need for new antischistosomal agents. Nacylhydrazones are usually explored as good antimicrobial agents, but the vanillin-related N-acylhydrazones have never been tested by their antiparasitic potential.

Objective:

Herein, we report the synthesis of seven analogues, three of them unpublished, their biological investigation against Schistosoma mansoni and Target Fishing studies.

Methods:

The compounds were synthesized following classical synthetical approaches. The anthelmintic potential was assessed as well as their cytotoxicity profile. Confocal laser scanning microscopy and target fishing study were performed to better understand the observed antischistosomal activity.

Results:

Compound GPQF-407 exhibited good antischistosomal activity (47.91 µM) with suitable selectivity index (4.14). Confocal laser scanning microscopy revealed that it triggered severe tegumental destruction and tubercle disintegration. Target fishing studies pointed out some probable targets, such as the serine-threonine kinases, dihydroorotate dehydrogenases and carbonic anhydrase II.

Conclusion:

The GPQF-407 was revealed to be a promising antischistosomal agent which, besides presenting the N-acylhydrazone privileged scaffold, also could be easily synthesized on large scales from commercially available materials.

Phenotypic screening of nonsteroidal anti-inflammatory drugs identified mefenamic acid as a drug for the treatment of schistosomiasis

Background

Treatment and control of schistosomiasis, one of the most insidious and serious parasitic diseases, depend almost entirely on a single drug, praziquantel. Since the funding for drug development for poverty-associated diseases is very limited, drug repurposing is a promising strategy. In this study, 73 nonsteroidal anti-inflammatory drugs (NSAIDs) commonly used in medical and veterinary fields were evaluated for their anti-schistosomal properties.

Methods

The efficacy of NSAIDs was first tested against adult Schistosoma mansoni ex vivo using phenotypic screening strategy, effective drugs were further tested in a murine model of schistosomiasis. The disease parameters measured were worm and egg burden, hepato- and splenomegaly.

Findings

From 73 NSAIDs, five (mefenamic acid, tolfenamic acid, meclofenamic acid, celecoxib, and diclofenac) were identified to effectively kill schistosomes. These results were further supported by scanning electron microscopy analysis. In addition, the octanol-water partition coefficient, both for neutral and ionized species, revealed to be a critical property for the ex vivo activity profile. Compounds were then tested in vivo using both patent and a prepatent S. mansoni infection in a mouse model. The most effective NSAID was mefenamic acid, which highly reduced worm burden, egg production, and hepato- and splenomegaly.

Interpretation

The treatment regimen used in this study is within the range for which mefenamic acid has been used in clinical practice, thus, it is demonstrated the capacity of mefenamic acid to act as a potent anti-schistosomal agent suitable for clinical repurposing in the treatment of schistosomiasis.

In Vitro and In Vivo Studies of Spironolactone as an Antischistosomal Drug Capable of Clinical Repurposing

Schistosomiasis is a parasitic flatworm disease that infects over 200 million people worldwide, especially in poor communities. Treatment and control of the disease rely on just one drug, praziquantel. Since funding for drug development for poverty-associated diseases is very limited, drug repurposing is a promising strategy. In this study, from a screening of 13 marketed diuretics, we identified that spironolactone, a potassium-sparing diuretic, had potent antischistosomal effects on Schistosoma mansoni in vitro and in vivo in a murine model of schistosomiasis. In vitro, spironolactone at low concentrations (<10 µM) is able to alter worm motor activity and the morphology of adult schistosomes, leading to parasitic death. In vivo, oral treatment with spironolactone at a single dose (400 mg/kg) or daily for five consecutive days (100 mg/kg/day) in mice harboring either patent or prepatent infections significantly reduced worm burden, egg production, and hepato- and splenomegaly (P < 0.05 to P < 0.001). Taken together, with the safety profile of spironolactone, supported by its potential to affect schistosomes, these results indicate that spironolactone could be a potential treatment for schistosomiasis and make it promising for repurposing.

Structure⁻Activity Relationship of Piplartine and Synthetic Analogues against Schistosoma mansoni and Cytotoxicity to Mammalian Cells

Schistosomiasis, caused by helminth flatworms of the genus Schistosoma, is an infectious disease mainly associated with poverty that affects millions of people worldwide. Since treatment for this disease relies only on the use of praziquantel, there is an urgent need to identify new antischistosomal drugs. Piplartine is an amide alkaloid found in several Piper species (Piperaceae) that exhibits antischistosomal properties. The aim of this study was to evaluate the structure–function relationship between piplartine and its five synthetic analogues (19A, 1G, 1M, 14B and 6B) against Schistosoma mansoni adult worms, as well as its cytotoxicity to mammalian cells using murine fibroblast (NIH-3T3) and BALB/cN macrophage (J774A.1) cell lines. In addition, density functional theory calculations and in silico analysis were used to predict physicochemical and toxicity parameters. Bioassays revealed that piplartine is active against S. mansoni at low concentrations (5⁻10 µM), but its analogues did not. In contrast, based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, piplartine exhibited toxicity in mammalian cells at 785 µM, while its analogues 19A and 6B did not reduce cell viability at the same concentrations. This study demonstrated that piplartine analogues showed less activity against S. mansoni but presented lower toxicity than piplartine.

A 28-day Sub-acute Genotoxic and Behavioural Assessment of Garcinielliptone FC

Garcinielliptone FC (GFC) is a polyisoprenylated benzophenone isolated from Platonia insignis Mart (Clusiaceae) with promising anticonvulsant properties. However, its safe use and other effects on the central nervous system require assessment. This study assessed the toxicological effects of GFC using the comet assay and the micronucleus test in mice treated for 28 days. A behavioural model was employed to detect possible injuries on the central nervous system. Mice treated with GFC (2, 10 and 20 mg/kg; i.p.) daily for 28 days were submitted to rotarod test, open-field test and tail suspension test (TST). After the behaviour tasks, biological samples were assessed to evaluate genotoxic and mutagenic effects using the comet assay and the micronucleus test. Garcinielliptone FC did not impair the performance of the animals in the rotarod and open-field tests, with no antidepressant-like effect in TST. No genotoxic effects in blood and cerebral cortex were observable in the comet assay; however, there was a significant increase in index and frequency of damage in liver after treatment with GFC 20 mg/kg. Garcinielliptone FC did not increase micronucleus frequency in bone marrow. At the tested doses, GFC was not toxic to the CNS and did not induce genotoxic damage to blood or bone narrow cells. DNA damage to liver tissue was caused only by the highest dose, although no mutagenic potential was observed.

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.

Cyclohexene-fused 1,3-oxazines with selective antibacterial and antiparasitic action and low cytotoxic effects

Oxazine derivatives, a class of heterocyclic compounds, exhibit a variety of biological properties, such as anticonvulsant and antitumor activities. In this study, we evaluated the effect of two cyclohexene-fused 1,3-oxazines (cis‑1-benzyl-N-phenyl-1,4,4a,5,8,8a-hexahydro-3,1-benzoxazin-2-imine (1) and trans‑N-phenyl-1,4,4a,5,8,8a-hexahydro-3,1-benzoxazin-2-imine (2)) in cultures of Bacillus cereus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Serratia marcescens, Shigella flexneri and Staphylococcus aureus by the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Additionally, the ex vivo antiparasitic activity of oxazines was assessed against Schistosoma mansoni, a helminth that is one of the major agents of the disease schistosomiasis Also, oxazines were evaluated on three tumor cell lines, NCI-H292 (human lung carcinoma), MCF-7 (human breast adenocarcinoma) and HEp-2 (human cervix carcinoma), and two normal cell lines (Vero and red blood cells). Bioassays revealed that oxazine 2 is more effective against bacteria than oxazine 1, with the lowest MIC and MBC values of 3.91 and 32.5μg/mL, respectively. Similarly, compound 2 demonstrated higher antiparasitic activity than 1, and scanning electron microscopy analysis showed several morphological alterations in the tegument of worms in a concentration-dependent manner. In contrast, both oxazines exhibited low cytotoxic effects on cancer and normal cell lines. These results indicated that oxazines exerted direct effects on bacteria and parasite schistosomes. More importantly, since schistosomiasis control programs rely on one drug, praziquantel, oxazines may have the potential to become new antischistosomal agents.

Synergistic effects of in vitro combinations of piplartine, epiisopiloturine and praziquantel against Schistosoma mansoni

Schistosomiasis is a world health problem, and praziquantel is the only drug currently used for the treatment. There is some evidence that extensive monotherapy of praziquantel may be leading to drug resistance in the parasite. In order to find alternative treatments, the effects of the combination of epiisopiloturine (EPI), piplartine (PPT) and praziquantel (PZQ) were evaluated. Similarity analysis of these compounds was performed using optimized molecular structures to compare the shape and the charge modeling of combinations between PZQ and EPI or PPT. Supported by this data, in vitro association of PZQ-PPT, PZQ-EPI, and EPI-PPT was carried out, and the activity of these combinations against Schistosoma mansoni was assessed. The results showed synergistic activity with a combination index (CI) of 0.42 for the treatment with PZQ-PPT. Both PZQ-EPI and EPI-PPT combinations also showed synergistic effects, with CI values of 0.86 and 0.61, respectively. Surface alterations in the tegument of adult schistosomes after the treatments were observed using laser confocal microscopy and scanning electron microscopy. Additionally, the association of EPI-PPT decreased the cytotoxicity when compared with both isolated compounds in three different lines of mammalian cells. Thus, synergistic combinations of PZQ-PPT, PZQ-EPI, and EPI-PPT create the possibility of reduced doses to be used against Schistosoma mansoni.

ULTRASTRUCTURAL CHANGES IN Schistosoma mansoni MALE WORMS AFTER in vitro INCUBATION WITH THE ESSENTIAL OIL OF Mentha x villosa Huds

INTRODUCTION

The essential oil Mentha x villosa (MVEO) has a wide range of actions, including antibacterial, antifungal, antiprotozoal and schistosomicidal actions. The present study aimed to investigate the ultrastructural changes of MVEO on the tegument of adult Schistosoma mansoni.

MATERIALS AND METHODS

Different concentrations of MVEO were tested on S. mansoni adult worms in vitro. Ultrastructural changes on the tegument of these adult worms were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

The MVEO caused the death of all worms at 500 μg mL(-1) after 24 h. After 24h of 500 μg mL(-1) MVEO treatment, bubble lesions were observed over the entire body of worms and they presented loss of tubercles in some regions of the ventral portion. In the evaluation by TEM, S. mansoni adult worms treated with MVEO, 500 μg mL(-1), presented changes in the tegument and vacuoles in the syncytial matrix region. Glycogen granules close to the muscle fibers were visible.

CONCLUSION

The ability of MVEO to cause extensive ultrastructural damage to S. mansoni adult worms correlates with its schistosomicidal effects and confirms earlier findings with S. mansoni.

Antischistosomal Activity of Oxindolimine-Metal Complexes

In recent years, a class of oxindole-copper and -zinc complex derivatives have been reported as compounds with efficient proapoptotic activity toward different tumor cells (e.g., neuroblastomas, melanomas, monocytes). Here we assessed the efficacy of synthesized oxindole-copper(II), -zinc(II), and -vanadyl (VO(2+)) complexes against adult Schistosoma mansoni worms. The copper(II) complexes (50% inhibitory concentrations of 30 to 45 μM) demonstrated greater antischistosomal properties than the analogous zinc and vanadyl complexes regarding lethality, reduction of motor activity, and oviposition.