Identification of Asiaticoside from Centella erecta (Apiaceae) as Potential Apyrase Inhibitor by UF-UHPLC-MS and Its In Vivo Antischistosomal Activity.

Schistosomiasis, caused by parasites of the genus Schistosoma, is a neglected disease with high global prevalence, affecting more than 240 million people in several countries. Praziquantel (PZQ) is the only drug currently available for the treatment. S. mansoni NTPDases (known as SmNTPDases, ATP diphosphohydrolases or ecto-apyrases) are potential drug targets for the discovery of new antischistosomal drugs. In this study, we screen NTPDases inhibitors from Centella erecta (Apiaceae) using an ultrafiltration combined UHPLC-QTOF-MS method and potato apyrase, identifying asiaticoside as one of the apyrase-binding compounds. After isolation of asiaticoside from C. erecta extract, we assessed its in vivo antischistosomal activities against Schistosoma mansoni worms and its in vitro enzymatic apyrase inhibition. Also, molecular docking analysis of asiaticoside against potato apyrase, S. mansoni NTPDases 1 and 2 were performed. Asiaticoside showed a significant in vitro apyrase inhibition and molecular docking studies corroborate with its possible actions in potato apyrase and S. mansoni NTPDases. In mice harboring a patent S. mansoni infection, a single oral dose of asiaticoside (400 mg/kg. p.o.) showed significantly in vivo antischistosomal efficacy, markedly decreasing the total worm load and egg burden, giving support for further exploration of apyrase inhibitors as antischistosomal agents.

Cardamonin Presents in Vivo Activity against Schistosoma mansoni and Inhibits Potato Apyrase.

Schistosomiasis, a neglected tropical disease caused by Schistosoma species, harms over 250 million people in several countries. The treatment is achieved with only one drug, praziquantel. Cardamonin, a natural chalcone with in vitro schistosomicidal activity, has not been in vivo evaluated against Schistosoma. In this work, we evaluated the in vivo schistosomicidal activities of cardamonin against Schistosoma mansoni worms and conducted enzymatic apyrase inhibition assay, as well as molecular docking analysis of cardamonin against potato apyrase, S. mansoni NTPDase 1 and S. mansoni NTPDase 2. In a mouse model of schistosomiasis, the oral treatment with cardamonin (400 mg/kg) showed efficacy against S. mansoni, decreasing the total worm load in 46.8 % and reducing in 54.5 % the number of eggs in mice. Cardamonin achieved a significant inhibition of the apyrase activity and the three-dimensional structure of the potato apyrase, obtained by homology modeling, showed that cardamonin may interact mainly through hydrogen bonds. Molecular docking studies corroborate with the action of cardamonin in binding and inhibiting both potato apyrase and S. mansoni NTPDases.

In Vitro Schistosomicidal Activity of the Alkaloid-Rich Fraction from Ruta graveolens L. (Rutaceae) and Its Characterization by UPLC-QTOF-MS.

Schistosomiasis is a neglected tropical disease that affects million people worldwide, mostly in developing countries. Ruta graveolens (Rutaceae) is a plant used in folk medicine to treat several diseases, including parasitic infections. In this study, we reported the in vitro schistosomicidal activity of the R. graveolens extract (Rg) and its active fraction (Rg-FAE). Also, the characterization of Rg-FAE by UPLC-ESI-QTOF-MS analysis and its in vitro antileishmanial activity against Leishmania braziliensis were also performed. In vitro schistosomicidal assays were assessed against adult worms of S. mansoni, while cell viability against peritoneal macrophages was measured by MTT assay. Rg (100 µg/mL) exhibited noticeable schistosomicidal activity, causing 100% mortality and decreasing motor activity of all adult male and female schistosomes, but with low activity against L. braziliensis. After chromatographic fractionation of Rg, fraction Rg-FAE was obtained, showing high activity against adult schistosomes. UPLC-ESI-QTOF-MS analysis of Rg-FAE revealed the presence of eleven alkaloids and one furanocoumarin. No significant antileishmanial activity was found for Rg, while Rg-FAE exhibited activity against L. braziliensis promastigotes. We demonstrated, for the first time, that the R. graveolens extract (Rg) and its alkaloid-rich fraction (Rg-FAE) are active against adult worms of S. mansoni, with no significant cytotoxicity on macrophages. Our findings open the route to further antiparasitic studies with the active fraction of R. graveolens and its identified compounds, especially alkaloids.

ATP-Diphosphohydrolases in Parasites: Localization, Functions and Recent Developments in Drug Discovery.

ATP-diphosphohydrolases (EC 3.6.1.5), also known as ATPDases, NTPases, NTPDases, EATPases or apyrases, are enzymes that hydrolyze a variety of nucleoside tri- and diphosphates to their respective nucleosides, being their activities dependent on the presence of divalent cations, such as calcium and magnesium. Recently, ATP-diphosphohydrolases were identified on the surface of several parasites, such as Trypanosoma sp, Leishmania sp and Schistosoma sp. In parasites, the activity of ATPdiphosphohydrolases has been associated with the purine recuperation and/or as a protective mechanism against the host organism under conditions that involve ATP or ADP, such as immune responses and platelet activation. These proteins have been suggested as possible targets for the development of new antiparasitic drugs. In this review, we will comprehensively address the main aspects of the location and function of ATP-diphosphohydrolase in parasites. Also, we performed a detailed research in scientific database of recent developments in new natural and synthetic inhibitors of the ATPdiphosphohydrolases in parasites.

Licochalcone A induces morphological and biochemical alterations in Schistosoma mansoni adult worms.

This paper is the first report on the in vitro effects of licochalcone A, a chalcone isolated from Glycyrrhiza inflate Batalin (Leguminosae), on Schistosoma mansoni adult worms. In vitro, licochalcone A afforded lethal concentrations for 50% of parasites (LC50) of 9.12±1.1 and 9.52±0.9µM against female and male adult worms, respectively, at 24h. Additionally, the compound reduced the total number of S. mansoni eggs and affected the development of eggs produced by S. mansoni adult worms. Together, the results achieved after 24h showed that licochalcone A was 55.7- and 53.3-fold more toxic to S. mansoni female and male adult worms than to Chinese hamster ovary fibroblasts cells, respectively. Treatment with licochalcone A elicited drastic changes in the tegument of S. mansoni adult worms, as well as mitochondrial alteration and chromatin condensation. Licochalcone A also increased the superoxide anion level and decreased the superoxide dismutase activity in S. mansoni adult worms. Overall, our results indicated that licochalcone A displays in vitro schistosomicidal activity. This effect may result from increased production of reactive oxygen species (ROS) induced by the action of licochalcone A. The resulting ROS could act on the S. mansoni tegument and membranes and help induce the death of S. mansoni adult worms.

Parthenolide Modulates Immune Response in Cells from C57BL/6 Mice Induced with Experimental Autoimmune Encephalomyelitis.

Multiple sclerosis is a chronic inflammatory and autoimmune disease of the central nervous system that affects more than 2.5 million people worldwide. Experimental autoimmune encephalomyelitis is a murine autoimmune disease used to study multiple sclerosis. Parthenolide, a natural sesquiterpene lactone found in Tanacetum parthenium L., is known for its strong anti-inflammatory activity. Herein, we have investigated the in vitro immunomodulatory effects of parthenolide on cytokine production and nitric oxide in cultured cells from myelin oligodendrocyte glycoprotein 35-55 amino acid peptide mice. Experimental autoimmune encephalomyelitis was induced in C57BL/6 mice with myelin oligodendrocyte glycoprotein 35-55 amino acid peptide, and parthenolide was isolated from T. parthenium. Splenocytes and peritoneal cells were obtained from experimental autoimmune encephalomyelitis-induced mice and incubated with parthenolide (1, 5, and 20 µM). After in vitro treatment with parthenolide, supernatants were collected, and nitric oxide and cytokines were measured. The results suggested that parthenolide may regulate the activity of Th17 and Th1 cells, mainly by decreasing IL-17, TNF-α, and interferon gamma production. This modulation may be related to the lower levels of IL-12p40 and IL-6 after treatment with parthenolide. It was shown, for the first time, that parthenolide presents in vitro immunomodulatory effects on inflammatory mediators produced by cells from experimental autoimmune encephalomyelitis-induced mice.

Flavonoids and Sesquiterpene Lactones from Artemisia absinthium and Tanacetum parthenium against Schistosoma mansoni Worms.

Human schistosomiasis, caused by trematode worms of the genus Schistosoma, is one of the most significant neglected tropical diseases, affecting more than 200 million individuals worldwide and praziquantel is the only available drug to treat this disease. Artemisia absinthium L. and Tanacetum parthenium L. are species popularly used as anthelmintics. We investigated the in vitro schistosomicidal activity of crude extracts of A. absinthium (AA) and T. parthenium (TP) and their isolated compounds. AA and TP, at 200 µg/mL, were active, causing 100% mortality of all adult worms. Chromatographic fractionation of AA leads to isolation of artemetin and hydroxypelenolide, while santin, apigenin, and parthenolide were isolated from TP. Artemetin, hydroxypelenolide, santin, and apigenin, at 100 µM, were inactive against adult worms. Parthenolide (12.5 to 100 µM) caused 100% mortality, tegumental alterations, and reduction of motor activity of all adult worms of S. mansoni, without affecting mammalian cells. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms. This report provides the first evidence for the in vitro activity of parthenolide against adult worms of S. mansoni, opening the route to further schistosomicidal studies with this compound.

Immunomodulatory effects of licochalcone A on experimental autoimmune encephalomyelitis.

OBJECTIVES: Experimental autoimmune encephalomyelitis (EAE) is a murine autoimmune disease used to study multiple sclerosis. Herein, we have investigated the immunomodulatory effect of licochalcone A (LicoA) on NO, H2 O2 , tumour necrosis factor-alpha (TNF-α), interferon gamma (IFN-γ) and IL-17 production in cultured cells from EAE mice. METHODS: EAE was induced in C57Bl/6 mice with myelin oligodendrocyte glycoprotein peptide (MOG35-55 ). LicoA was isolated from the roots of Glycyrrhiza inflata. Splenocytes were obtained from EAE mice and incubated with LicoA (4, 20 and 40 µm). Peritoneal cells were obtained from EAE mice treated with LicoA (15 and 30 mg/kg/day. p.o.). H2 O2 , NO, IFN-γ, TNF-α and IL-17 production was determined in the presence or absence of concanavalin (ConA) or MOG35-55 stimulation. KEY FINDINGS: LicoA (40 µm) inhibited H2 O2 , NO, IFN-γ, TNF-α and IL-17 production in splenocytes spontaneously or after both ConA and MOG35-55 stimulation. LicoA (30 mg/kg/day) reduced clinical score and severity of EAE mice, and inhibited TNF-α, IFN-γ and IL-17 production in peritoneal cells. CONCLUSIONS: LicoA possesses immunomodulatory effects on H2 O2 , NO, IFN-γ, TNF-α and IL-17 production in cells from EAE mice. It is suggested that LicoA acts on the mechanism of development of EAE by IFN-γ, IL-17 and TNF-α inhibition, modulating the immune response on both Th1 and Th17 cells.