Therapeutic Potential of Natural Products in the Treatment of Schistosomiasis.

It is estimated that 250 million people worldwide are affected by schistosomiasis. Disease transmission is related to the poor sanitation and hygiene habits that affect residents of impoverished regions in tropical and subtropical countries. The main species responsible for causing disease in humans are Schistosoma Mansoni, S. japonicum, and S. haematobium, each with different geographic distributions. Praziquantel is the drug predominantly used to treat this disease, which offers low effectiveness against immature and juvenile parasite forms. In addition, reports of drug resistance prompt the development of novel therapeutic approaches. Natural products represent an important source of new compounds, especially those obtained from plant sources. This review compiles data from several in vitro and in vivo studies evaluating various compounds and essential oils derived from plants with cercaricidal and molluscicidal activities against both juvenile and adult forms of the parasite. Finally, this review provides an important discussion on recent advances in molecular and computational tools deemed fundamental for more rapid and effective screening of new compounds, allowing for the optimization of time and resources.

Anti-angiogenic and anti-proliferative activity of ziziphus leaf extract as a novel potential therapeutic agent for reducing hepatic injury in experimental hamster schistosomiasis.

BACKGROUND: Schistosomiasis is one of the most prevalent helminthic infections worldwide. Praziquantel (PZQ) resistance poses a possible danger to the disease's ability to be controlled. Little is known about the role of Ziziphus spina-christi leaf extract (ZLE) in the treatment of hepatic schistosomiasis. However, no study has explored ZLE's anti-angiogenic and anti-proliferative activity as a possible mechanism for reducing hepatic injury in this context. Therefore, this study aimed to evaluate the therapeutic potential of ZLE as an anti-angiogenic, and anti-proliferative agent in hamsters infected with S. mansoni. METHODS: Fifty hamsters were used and divided into 5 groups (10 hamsters each); noninfected untreated (controls), noninfected treated with ZLE, infected untreated, infected treated with PZQ- and infected treated with ZLE. Anti-angiogenic and anti-fibrotic effects of the drugs were assessed pathologically through the immunohistochemical expression of VEGF, Ki-67, and TGF ß1 in liver sections. Some oxidative stress parameters were measured in hepatic homogenates (NO, GSH, GST, and SOD), and serum liver enzymes were also assessed. RESULTS: A significant decrease in worm burden, granuloma size, granuloma area, and numbers in the ZLE- and PZQ-treated groups compared to the infected untreated group, and the decrease in granulomas number and tissue egg load was significantly lower in PZQ treated group compared to ZLE treated group (p<0.05). ZLE exhibited significant anti-angiogenic and anti-fibrotic effects on granulomas, illustrated by significantly lower expression of VEGF and TGF-ß1 than infected untreated and PZQ-treated groups. ZLE exhibits antiproliferative activity evidenced by a significant reduction of positive Ki-67 hepatocytes percentage compared to the infected untreated group. Moreover, ZLE exhibits potent antioxidant effects evidenced by a significantly lowered NO and conservation of hepatic GSH, GST, and SOD in hepatic homogenates compared to infected untreated and PZQ-treated groups (p<0.05). CONCLUSION: Our results point to ZLE as a promising hepatoprotective therapeutic tool in the treatment of schistosome hepatic fibrosis as it has anti-angiogenic, anti-proliferative, anti-fibrotic, and antioxidant effects in hamsters infected with S. mansoni, providing scientific support for its use in conventional medicine.

Antiparasitic properties of 4-nerolidylcatechol from Pothomorphe umbellata (L.) Miq. (Piperaceae) in vitro and in mice models with either prepatent or patent Schistosoma mansoni infections.

ETHNOPHARMACOLOGICAL RELEVANCE: Roots of Pothomorphe umbellata (L.) Miq. are used in traditional medicine of Africa and South America for the treatment of malaria and helminthiasis. However, neither P. umbellata nor its isolated compounds have been evaluated against Schistosoma species. AIMS OF THIS STUDY: To investigate the antischistosomal effects of P. umbellata root extracts and the isolated compound 4-nerolidylcatechol (4-NC) against Schistosoma mansoni ex vivo and in murine models of schistosomiasis. MATERIALS AND METHODS: The crude hydroalcoholic (PuE) and hexane (PuH) extracts of P. umbellata roots were prepared and initially submitted to an ex vivo phenotypic screening against adult S. mansoni. PuH was analyzed by HPLC-DAD, characterized by UHPLC-HRMS/MS, and submitted to chromatographic fractionation, leading to the isolation of 4-NC. The anthelmintic properties of 4-NC were assayed ex vivo against adult schistosomes and in murine models of schistosomiasis for both patent and prepatent S. mansoni infections. Praziquantel (PZQ) was used as a reference compound. RESULTS: PuE (EC50: 18.7 µg/mL) and PuH (EC50: 9.2 µg/mL) kill adult schistosomes ex vivo. The UHPLC-HRMS/MS analysis of PuH, the most active extract, revealed the presence of 4-NC, peltatol A, and peltatol B or C. After isolation from PuH, 4-NC presented remarkable in vitro schistosomicidal activity with EC50 of 2.9 µM (0.91 µg/mL) and a selectivity index higher than 68 against Vero mammalian cells, without affecting viability of nematode Caenorhabditis elegans. In patent S. mansoni infection, the oral treatment with 4-NC decreased worm burden and egg production in 52.1% and 52.3%, respectively, also reducing splenomegaly and hepatomegaly. 4-NC, unlike PZQ, showed in vivo efficacy against juvenile S. mansoni, decreasing worm burden in 52.4%. CONCLUSIONS: This study demonstrates that P. umbellata roots possess antischistosomal activity, giving support for the medicinal use of this plant against parasites. 4-NC was identified from P. umbellata roots as one of the effective in vitro and in vivo antischistosomal compound and as a potential lead for the development of novel anthelmintics.

Bioactivity of Trigonella foenum (Fenugreek) oil on immunological and biochemical response of Schistosoma mansoni infected mice.

The effect of fenugreek oil (FO) on some parasitological, immunological, and biochemical parameters in mice infected with Schistosoma mansoni were investigated. Chromatography mass spectrometry (GC/MS) analysis of FO revealed that linoleic acid, (E,E)-4-decadienal, and isopropyl myristate are the major constituents of FO. The results showed that treatment of S. mansoni-infected mice with 0.15 ml of FO daily for 10 successive days exhibited a significant reduction in the number of S. mansoni male worms, and coupled worms as compared to an infected control group (p < 0.05). Regarding total egg counts and oogram patterns, FO effectively reduced the percentage of hepatic and intestinal egg counts, and elevated immature and dead eggs in ratios closely to praziquantel (PZQ) treated mice. Meanwhile, FO significantly elevated the levels of glutathione and co-enzyme Q-10 (COQ-10) up to 0.33±0.02 ng/ml and 0.28±0.02 ng/ml, respectively. However, when accompanied with PZQ, COQ-10 level was closer to that of the normal control group (0.37 ± 0.021 ng/ml). The result also showed that FO significantly reduced levels of lipid per-oxidation (0.165±0.01 ng/ml) and vascular endothelial growth factor (0.25±0.02 pg/ml) as compared to the PZQ-treated group (0.234±0.02 ng/ml and 0.31±0.008 pg/ml, respectively). Moreover, FO recovered normal values of caspase-7, and when accompanied with PZQ, annexin-V was also significantly reduced. However, treatment of S. mansoni-infected mice with PZQ led to a significant increase in the level of annexin-V as compared to S. mansoni-infected mice group (p < 0.05). It can be concluded that FO may have a potential anti-schistosomal, antioxidant and anti-inflammatory activities. Also, it may have a recovering effect on apoptotic parameters toward the normal values.

Schistosomicidal and hepatoprotective activity of gamma-aminobutyric acid (GABA) alone or combined with praziquantel against Schistosoma mansoni infection in murine model.

OBJECTIVE: This study aimed to evaluate the efficacy of gamma-aminobutyric acid (GABA) alone or combined with praziquantel (PZQ) against Schistosoma (S) mansoni infection in a murine model. METHODS: Five groups, 8 mice each, were studied; GI served as normal controls; GII: S. mansoni-infected control group and the other three S. mansoni-infected groups received drug regimens for 5 consecutive days as follows GIII: Infected-PZQ treated group (200 mg/kg/day); GIV: Infected-GABA treated group (300 mg/kg/day) and GV: Infected-PZQ-GABA treated group (100 mg/kg/day for each drug). All animal groups were sacrificed two weeks later and different parasitological, histopathological and biochemical parameters were assessed. RESULTS: Combined GABA-PZQ treated group recorded the highest significant reduction in all parasitological, histopathological and biochemical parameters followed by PZQ and finally GABA groups. Combined GABA-PZQ treatment led to the complete disappearance of immature eggs and marked reduction of deposited eggs in liver tissues and improved liver pathology. Significant improvement in hepatic oxidative stress levels, serum albumin and total protein in response to GABA treatment alone or combined with PZQ. CONCLUSION: GABA had schistosomicidal, hepatoprotective and antioxidant activities against S. mansoni infection, GABA disrupted parasite pairing and activity, reduced the total number of worms recovered and the number of ova in the tissues. GABA may be considered an adjuvant therapy to potentiate PZQ antiparasitic activity and eradicate infection-induced liver damage and oxidative stress.

Lippia alba and Lippia gracilis essential oils affect the viability and oviposition of Schistosoma mansoni.

Schistosomiasis is a neglected tropical disease that affects millions of people around the world. Currently, the only drug available for the treatment of this disease is praziquantel, which has low efficacy against immature helminth stages and there are reports of drug resistance. In this study, the chemical composition and the in vitro effect of essential oils (EOs) and major compounds from Lippia gracilis and Lippia alba against schistosomula and adult Schistosoma mansoni worms were evaluated. Adult S. mansoni worms cultured for 8h in the presence of L. gracilis EO (50 and 100 µg/mL) or for 2h with its major compound, carvacrol (100 µg/mL), had a 100% reduction in viability. After interaction with L. alba EO (100µg/mL), there was a reduction of approximately 60% in the viability of adult worms after 24 hours of exposure; citral (50 and 100 µg/mL), its major compound, reduced the viability after 24 hours by more than 75%. Treatment of schistosomula with 100 µg/mL of L. gracilis or L. alba EOs for 6h led to a reduction in parasite viability of 80% and 16% respectively. Both EOs and their major compounds significantly reduced the oviposition of adult worms exposed to a non-lethal concentration (5 µg/mL). In addition, morphological changes such as the destruction of the tegument and disorganization of the reproductive system of male and female worms were visualized. Both EOs showed low cytotoxicity at a concentration of 50 µg/mL. The results encourage further investigation of these plants as a potential source of bioactive compounds against S. mansoni.

Evaluation of Antischistosomal Activities of Crude Aqueous Extracts of Artemisia annua, Nigella sativa, and Allium sativum against Schistosoma mansoni in Hamsters.

Schistosomiasis is a neglected disease, as the World Health Organization classified it in the second category after malaria. World Health Organization approved praziquantel (PZQ) as the only chemotherapy to treat schistosomiasis. Over the years, some problems have arisen with PZQ, as it showed poor efficacy in the early stages of infection as well as the emergence of some resistance to it. In searching for new alternative drugs to treat schistosomiasis, the researchers intensified their efforts to find a new drug. The present study focuses on evaluating the effect of three plant extracts Artemisia annua, Nigella sativa, and Allium sativum at different doses of 31.25, 62.5, 125, 250, and, 500 µg/ml; in vitro study was accomplished on the Schistosoma mansoni adult worms. The results declared that the concentration of 500, 250, and 125 of Artemisia annua was more effective on adult worms, and the same concentrations of Nigella sativa and Allium sativum gave less effect on the adult worms than the previous plant. In vivo study was accomplished on the hamster's tissue after exposing it to doses of the plants' extracts with different concentrations; it showed the presence of calcifications and damage to the worm eggs in the liver and spleen, as well as reducing the size of granulomas. After conducting many confirmatory studies Artemisia annua extract can be used as an effective and safe treatment for Schistosoma disease.

Dandelion (Taraxacum officinale) Improves the Therapeutic Efficiency of Praziquantel in Experimental Schistosomiasis.

PURPOSE: Although praziquantel (PZQ) has a wide use as an anti-schistosome agent, many of its imperfections and side effects have been reported in many studies. The current study aims to evaluate the curative effect of a natural dandelion extract (Taraxacum officinale) on schistosomiasis either alone or in combination with PZQ based on parasitological, immunological, histopathological and molecular investigations. METHODS: Mice were experimentally infected with Schistosoma mansoni cercariae and then divided into four groups, Schistosoma spp.-infected untreated group (IC group), Schistosoma spp.-infected group of mice treated with dandelion (I-Dn group), Schistosoma spp.-infected group of mice treated with PZQ (I-PZQ group), and Schistosoma spp.-infected group of mice treated with both PZQ and dandelion (I-PZQ + Dn group). Treatment started 45 days' post-infection. Besides, non-infected, non-treated mice served as the negative healthy control group (HC group). RESULTS: The present results indicated that dandelion administration significantly reduced the worm burden, ova number, and the number and diameter of hepatic granulomas as compared to the untreated infected group. The results also showed that the levels of IL-6 and TNF-α were significantly decreased in the combined treatment group (I-PZQ + Dn) as compared to the I-PZQ group. Administration of dandelion-only remarkably reduced AST and ALT activities associated with schistosomiasis. Moreover, hepatic DNA damage assessed by comet assay was significantly inhibited in the combined treated group compared to the infected untreated and PZQ treated groups. CONCLUSION: The results concluded that combined treatment of PZQ and dandelion extract improved immune response, decreased the number and diameter of granulomas, and inhibited DNA damage, indicating a reduction in liver fibrosis associated with schistosomiasis. The present study focused on the potential effect of dandelion as an adjunct medication for therapeutic properties of PZQ.

Identification of novel modulators of a schistosome transient receptor potential channel targeted by praziquantel.

Given the worldwide burden of neglected tropical diseases, there is ongoing need to develop novel anthelmintic agents to strengthen the pipeline of drugs to combat these burdensome infections. Many diseases caused by parasitic flatworms are treated using the anthelmintic drug praziquantel (PZQ), employed for decades as the key clinical agent to treat schistosomiasis. PZQ activates a flatworm transient receptor potential (TRP) channel within the melastatin family (TRPMPZQ) to mediate sustained Ca2+ influx and worm paralysis. As a druggable target present in many parasitic flatworms, TRPMPZQ is a promising target for a target-based screening campaign with the goal of discovering novel regulators of this channel complex. Here, we have optimized methods to miniaturize a Ca2+-based reporter assay for Schistosoma mansoni TRPMPZQ (Sm.TRPMPZQ) activity enabling a high throughput screening (HTS) approach. This methodology will enable further HTS efforts against Sm.TRPMPZQ as well as other flatworm ion channels. A pilot screen of ~16,000 compounds yielded a novel activator of Sm.TRPMPZQ, and numerous potential blockers. The new activator of Sm.TRPMPZQ represented a distinct chemotype to PZQ, but is a known chemical entity previously identified by phenotypic screening. The fact that a compound prioritized from a phenotypic screening campaign is revealed to act, like PZQ, as an Sm.TRPMPZQ agonist underscores the validity of TRPMPZQ as a druggable target for antischistosomal ligands.

Antischistosomal Activity of Origanum majorana, Ziziphus spina-christi, and Salvia fruticosa Plant Extracts on Hamster Infected with Schistosoma haematobium.

World Health Organization (WHO) has approved only one treatment for schistosomiasis, praziquantel (PZQ), but some poor efficacy was noticed in patients during the early stage of infection. Therefore, researchers have intensified their efforts to research new alternative medicines to treat schistosomiasis. In the present study, in vitro as well as in vivo studies have been accomplished to evaluate the effect of Origanum majorana, Ziziphus spina-christi, and Salvia fruticosa extracts in a different concentration 500, 250, 125, 62.5, and 31.25 µg/ml on golden hamster infected by Egyptian strains of schistosome (Schistosoma haematobium). In vitro, the adult worms and schistosomula of S. haematobium were investigated in RPMI-1640 medium for 48 hrs. The results showed that the concentration 500, 250, and 125 µg/ml of Origanum majorana, and Ziziphus spina-christi caused dead of 100% of Egyptian Schistosoma strains of adult worm and schistosomula of S. haematobium within 6 to 12 hrs of incubation. On the other hand, the extract of Salvia fruticosa at concentrations 500, 250, and 125 µg/ml showed death 100% parasites after 12 to 24 hrs of incubation. Inclusion, Origanum majorana, and Ziziphus spina-christi showed effectiveness against Egyptian Schistosoma strains (S. haematobium), a slight decrease in Salvia fruticosa was observed. Therefore, these medical plant extracts may be used as a safe and effective treatment for schistosomiasis.

Efficacy of Mebendazole and Praziquantel against Soil-Transmitted Helminths and Schistosoma mansoni Infections among Schoolchildren in Northwest Ethiopia.

BACKGROUND: Soil-transmitted helminths (STHs) and Schistosoma mansoni are the main causes of morbidity among schoolchildren in the tropics. A school-based deworming program was launched to control and eliminate the infection in endemic countries including Ethiopia. Although periodic deworming is conducted in endemic areas, the prevalence of the infection is high in the country. In addition, periodic evaluation of the efficacy of the anthelminthic drug is limited. OBJECTIVE: This study is aimed at checking the efficacy of mebendazole and praziquantel with the respective STHs and Schistosoma mansoni parasites. METHODS: A longitudinal study was conducted from February to March 2018 among 422 schoolchildren. Stool samples were collected at baseline and at 2 and 4 weeks posttreatment and were processed using the Kato-Katz technique. Schoolchildren positive for STHs were treated with mebendazole and those positive for Schistosoma mansoni with praziquantel. After two weeks, a second round of stool was collected and examined, and then, single-dose redosing was given to each positive child. Lastly, the third stool sample was collected two weeks after the initiation of the redosing and checked for STHs and S. mansoni parasites. A close follow-up of students who were treated was done. All the data were entered and analyzed using SPSS version 20 for analysis. Descriptive statistics was used to compute the cure rate and egg reduction rate of mebendazole and praziquantel. RESULTS: Among 422 participants, the prevalence of STHs, hookworm, Ascaris lumbricoides, and S. mansoni was 44.7%, 35.1%, 21.1%, and 13.9%, respectively. The cure rate of mebendazole against A. lumbricoides increased from 60% in the single dose to 100% in redosing after two weeks. The cure rate of mebendazole against hookworm also increased from 32.4% in the single dose to 91.0% in the redosing. The cure rate of praziquantel against S. mansoni-infected children was 91.5% in the first round and 100% in the redosing phase. There was a 98.6-100% egg reduction rate in the redosing regimen of both drugs. CONCLUSION: The cure and egg reduction rates of single-dose mebendazole in the treatment of hookworm and A. lumbricoides are lower at week two than at redosing, while cure and egg reduction rates of single-dose praziquantel are satisfactory to treat S. mansoni. Therefore, single-dose praziquantel to S. mansoni and redosing of single-dose mebendazole to A. lumbricoides and hookworm infections can be used for treatment purposes.

The potent effect of silymarin combination with Praziquantel or mirazid for Schistosoma mansoni treatment in infected male swiss albino mice.

This work was carried out to investigate the effect of silymarin combination in the therapeutic plane of schistosomiasis with praziquantel or mirazid to enhance the liver and reduce fibrosis. Mice were divided into 2 main groups, the 1st uninfected group served as control and the 2nd group infected subcutaneously with 60 cercaria of S. mansoni per each. The infected group was subdivided into 5 subgroups, the 1st kept untreated, the 2nd and 3rd treated at the 7th week of infection with (600 mg/kg) of PZQ orally for 3 consecutive days, while the 3rd treated also orally with (150 mg/kg) of silymarin daily for 11 weeks. The 4th and 5th groups treated orally at the 7th week of infection with 600 mg/kg of MZ for 3 consecutive days, while the 5th group treated orally also with 150 mg/kg of silymarin daily for 11weeks. IgG determination showed high level in the untreated infected group. Furthermore, the infected groups treated with PZQ and PZQ with silymarin displayed the lower levels than treated with MZ. Additionally, the untreated infected group showed severe pathological changes as hyaline degeneration, inflammation, presence of worm burdens in dilated portal veins, granulomas as well as depositions of collagenous and reticular fibers indicated intense fibrosis. Treatment with PZQ alone resulted in reduction of pathological signs and decreasing of granulomas. Combination with silymarin to PZQ therapy revealed more improvement for liver besides to lowering of granulomas areas and volumes and decreasing of fibrosis. Whereas, treatment with MZ was less effective than PZQ to reduce granulomas areas, volumes and fibrosis. Although, combination of silymarin to MZ treatment resulted in more curative signs and reduction of granulomas areas, volumes and fibrosis. Furthermore, the present study concluded that PZQ still the more effective drug of schistosomiasis treatment than MZ. The silymarin is very useful in schistosomiasis treatment when combined with PZQ or MZ due to its anti-fibrotic effect.

In vivo assessment of the antischistosomal activity of curcumin loaded nanoparticles versus praziquantel in the treatment of Schistosoma mansoni.

Schistosomiasis is a serious parasitic infection affecting millions worldwide. This study aimed to explore the anti-schistosomal activity of curcumin and curcumin loaded gold-nanoparticles (Cur-GNPs) with or without praziquantel (PZQ). We used six groups of the C57BL/6 mice in which five groups were infected with Schistosoma Mansoni (S. mansoni) cercariae and exhibited, separately, to different treatment regimens of curcumin, curcumin loaded nanoparticle, and PZQ, in addition to one untreated group which acts as a control. Mice were sacrificed at the 8th week where both worms and eggs were counted in the hepatic and porto-mesenteric vessels in the liver and intestine, respectively, in addition to a histopathological examination of the liver granuloma. Curcumin caused a significant reduction in the worms and egg count (45.45%) at the 3rd week. A significant schistosomicidal effect of PZQ was found in all groups. Cur-GNPs combined with PZQ 97.4% reduction of worm burden in the 3rd week and the highest reduction in the intestinal and hepatic egg content, as well, besides 70.1% reduction of the granuloma size. The results suggested the curcumin in combination with PZQ as a strong schistosomicidal regimen against S. mansoni as it alters the hematological, biochemical, and immunological changes induced.

Use of kinase inhibitors against schistosomes to improve and broaden praziquantel efficacy.

Praziquantel (PZQ) is the drug of choice for schistosomiasis. The potential drug resistance necessitates the search for adjunct or alternative therapies to PZQ. Previous functional genomics has shown that RNAi inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) gene in Schistosoma adult worms significantly improved the effectiveness of PZQ. Here we tested the in vitro efficacy of 15 selective and non-selective CaMK inhibitors against Schistosoma mansoni and showed that PZQ efficacy was improved against refractory juvenile parasites when combined with these CaMK inhibitors. By measuring CaMK activity and the mobility of adult S. mansoni, we identified two non-selective CaMK inhibitors, Staurosporine (STSP) and 1Naphthyl PP1 (1NAPP1), as promising candidates for further study. The impact of STSP and 1NAPP1 was investigated in mice infected with S. mansoni in the presence or absence of a sub-lethal dose of PZQ against 2- and 7-day-old schistosomula and adults. Treatment with STSP/PZQ induced a significant (47-68%) liver egg burden reduction compared with mice treated with PZQ alone. The findings indicate that the combination of STSP and PZQ dosages significantly improved anti-schistosomal activity compared to PZQ alone, demonstrating the potential of selective and non-selective CaMK/kinase inhibitors as a combination therapy with PZQ in treating schistosomiasis.

Anthelmintic activity of praziquantel and Spilanthes acmella extract on an intestinal cestode parasite.

Spilanthes acmella Murr., popularised as toothache plant, is a well-known culinary and medicinal plant for different purposes, but its use as an anthelmintic is apparently exclusive to the Mizo people of India and Myanmar. A chloroform extract of Spilanthes acmella Murr. was analysed in a single quadrupole GC-MS system, from which it was found that the major compound was an alkylamide, N-isobutyl-(2E,4Z,8Z,10E)-dodecatetraenamide. A comparative study was performed on the anthelmintic activity of the plant extract and praziquantel (PZQ) against an intestinal cestode, Raillietina echinobothrida. In terms of efficacy, PZQ was more potent, but the plant extract was also effective at all concentrations tested. PZQ caused severe shrinkage and folds of the tegument, constriction of the suckers, dislocation of spines and erosion of microtriches. The plant extract caused shrinkage and folds on the main body but not on the scolex. Damage on the suckers is more pronounced than in PZQ-treated cestodes. The spines were completely removed. The current findings indicate that S. acmella is a good source of compounds with anthelmintic activity.

The antioxidants resveratrol and N-acetylcysteine enhance anthelmintic activity of praziquantel and artesunate against Schistosoma mansoni.

BACKGROUND: Treatment of schistosomiasis has relied on the anthelmintic drug praziquantel (PZQ) for more than a generation. Despite its celebrated performance for treatment and control of schistosomiasis and other platyhelminth infections, praziquantel has some shortcomings and the inability of this drug to counteract disease sequelae prompts the need for novel therapeutic strategies. METHODS: Using a host-parasite model involving Biomphalaria glabrata and Schistosoma mansoni we established mechanical transformation of S. mansoni cercariae into newly transformed schistosomula (NTS) and characterized optimal culture conditions. Thereafter, we investigated the antischistosomal activity and ability of the antioxidants N-acetylcysteine (NAC) and resveratrol (RESV) to augment the performance of praziquantel and/or artesunate (AS) against larval stages of the parasite. Drug effects were evaluated by using an automated microscopical system to study live and fixed parasites and by transmission electron microscopy (TEM). RESULTS: Transformation rates of cercariae to schistosomula reached ~ 70% when the manipulation process was optimized. Several culture media were tested, with M199 supplemented with HEPES found to be suitable for S. mansoni NTS. Among the antioxidants studied, RESV alone or combined with anthelminthic drugs achieved better results rather N-acetylcysteine (NAC). TEM observations demonstrated that the combination of AS + RESV induced severe, extensive alterations to the tegument and subtegument of NTS when compared to the constituent compounds alone. Two anthelmintic-antioxidant combinations, praziquantel-resveratrol [combination index (CI) = 0.74] and artesunate-resveratrol (CI = 0.34) displayed moderate and strong synergy, respectively. CONCLUSIONS: The use of viability markers including staining with propidium iodide increased the accuracy of drug screening assays against S. mansoni NTS. The synergies observed might be the consequence of increased action by RESV on targets of AS and PZQ and/or they may act through concomitantly on discrete targets to enhance overall antischistosomal action. Combinations of active agents, preferably with discrete modes of action including activity against developmental stages and/or the potential to ameliorate infection-associated pathology, might be pursued in order to identify novel therapeutic interventions.

Evaluation of the schistosomicidal, antioxidant and anti-inflammatory activities of the ethyl acetate fraction from Ozoroa pulcherrima Schweinf. Roots on Schistosoma mansoni-induced liver pathology in mice and its phytochemical characterization.

ETHNOPHARMACOLOGICAL RELEVANCE: Ozoroa pulcherrima Schweinf. (syn.: Heeria pulcherrrima Schweinf.) is a small shrub belonging to the family Anacardiaceae. In Africa, the stem and the leaves are used to treat dystocia, hyperthermia, and conjunctivitis, while the root is used to treat dysmenorrhea and intestinal helminthiasis. AIM OF THE STUDY: The aim of this study was to assess the schistosomicidal, antioxidant and anti-inflammatory effects of the ethyl acetate fraction from O. pulcherrima roots methanolic extract (EAOp) on S. mansoni- induced liver pathology in mice. Additionally, its phytochemical composition was elucidated. MATERIAL AND METHODS: The phytochemical characterization of EAOp was carried out by High-Performance Liquid Chromatography-Mass spectrometry (HPLC-MS). Total phenolic and flavonoid contents were also quantified in the fraction. S. mansoni-infected mice received daily and per os, for 28 days, EAOp at 200 or 400 mg/kg, starting from the 36th day post-infection. Praziquantel was used as reference drug. Uninfected-untreated, uninfected-treated and infected-untreated mice served as controls. At the 65th day post-infection mice were sacrificed and parasitological burden monitored. Transaminases, total bilirubin, and total proteins levels were determined in the plasma. Malondialdehyde (MDA), nitrites, superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) levels were measured in the liver as biomarkers of the oxidative stress. Liver histology and morphometric analysis of granulomas were also conducted. RESULTS: The HPLC-MS analysis data of EAOp revealed the presence of four triterpenes namely oleaterminaloic acid, hydroxyoleanolic acid, moronic acid, and oleanolic acid; a flavonoid dipentoxybenzoic acid and two alkaloids. Its total phenolic content was 76.46 ±â€¯0.01 mg GAE/g and total flavonoid content 6.26 ±â€¯0.31 mg rutin equivalent/g. The reductions of worm burden (48.89 and 75.56%), fecal egg count (77.76 and 69.52%) and egg load in the liver (65.33 and 77.18%) and intestine (78.06 and 84.63%) were significant after EAOp treatment. EAOp at all doses significantly (p < 0.001) reversed the increasing transaminases activities and total bilirubin level induced by the infection. A normalization of total proteins concentration was also recorded. Treatment of S. mansoni-infected mice with EAOp at 200 or 400 mg/kg resulted in a significant reduction (p < 0.001) of MDA concentration by 73.20% and 67.78% respectively. The level of nitrites which was reduced by the infection significantly increased after the treatment. EAOp significantly increased by 4.67 and 5.69-fold the CAT activity and by 126.67% the GSH level. Histologically, a significant reduction of the number (66.39 and 57.82%) and the volume (52.25 and 34.81%) of liver inflammatory granulomas was recorded after EAOp treatment at all doses. CONCLUSIONS: These results suggest that the liver pathology in S. mansoni infection is improved by EAOp which disclosed good schistosomicidal, antioxidant and anti-inflammatory activities. Its effects on the liver dysfunction and the hepatic oxidative stress were comparable to that of praziquantel. These findings justified the traditional use of O. pulcherrima for the treatment of intestinal helminthiasis. This fraction can be considered as a promising source for schistosomicidal agents.

Anthelmintic Potential of Cucurbita pepo Seeds on Hymenolepis nana.

OBJECTIVE: The main drug used against Hymenolepis nana is praziquantel (PZQ), which causes side effects and toxicity. In contrast, natural extracts have limited side effects and are safer. Past researches have proved that pumpkin seeds are effective as natural antimicrobial and antiparasitic treatment. The present study investigates a natural alternative and less expensive treatment against H. nana using pumpkin seeds. MATERIALS AND METHODS: Healthy female albino mice were divided into four groups: normal control, infected control with H. nana, infected and treated with PZQ, and lastly, the group infected and treated with pumpkin seeds' extract. RESULTS: Pumpkin seeds aqueous extract showed a significant reduction (P < 0.05) in the number and length of H. nana adult worms, number and viability of eggs in comparison to the infected control group and PZQ group. Pumpkin seed aqueous extract is proven to be an effective anthelmintic against H. nana. CONCLUSION: We recommend pumpkin seed extract as a natural alternative, less expensive and safe therapy for H. nana. This is the first study in Saudi Arabia to investigate the therapeutic effect of pumpkin seeds' extract on H. nana.

A novel cell-free method to culture Schistosoma mansoni from cercariae to juvenile worm stages for in vitro drug testing.

BACKGROUND: The arsenal in anthelminthic treatment against schistosomiasis is limited and relies almost exclusively on a single drug, praziquantel (PZQ). Thus, resistance to PZQ could constitute a major threat. Even though PZQ is potent in killing adult worms, its activity against earlier stages is limited. Current in vitro drug screening strategies depend on newly transformed schistosomula (NTS) for initial hit identification, thereby limiting sensitivity to new compounds predominantly active in later developmental stages. Therefore, the aim of this study was to establish a highly standardized, straightforward and reliable culture method to generate and maintain advanced larval stages in vitro. We present here how this method can be a valuable tool to test drug efficacy at each intermediate larval stage, reducing the reliance on animal use (3Rs). METHODOLOGY/PRINCIPAL FINDINGS: Cercariae were mechanically transformed into skin-stage (SkS) schistosomula and successfully cultured for up to four weeks with no loss in viability in a commercially available medium. Under these serum- and cell-free conditions, development halted at the lung-stage (LuS). However, the addition of human serum (HSe) propelled further development into liver stage (LiS) worms within eight weeks. Skin and lung stages, as well as LiS, were submitted to 96-well drug screening assays using known anti-schistosomal compounds such as PZQ, oxamniquine (OXM), mefloquine (MFQ) and artemether (ART). Our findings showed stage-dependent differences in larval susceptibility to these compounds. CONCLUSION: With this robust and highly standardized in vitro assay, important developmental stages of S. mansoni up to LiS worms can be generated and maintained over prolonged periods of time. The phenotype of LiS worms, when exposed to reference drugs, was comparable to most previously published works for ex vivo harvested adult worms. Therefore, this in vitro assay can help reduce reliance on animal experiments in search for new anti-schistosomal drugs.

Paeoniflorin in experimental BALB/c mansoniasis: A novel anti-angiogenic therapy.

Chronic hepatic schistosomiasis causes portal hypertension, fibrosis and lethal hepatosplenic complications. Previous studies focused mainly on schistosomicidal drugs and neglected the therapeutic approaches against the vascular complications after portal hypertension. Investigating a novel anti-angiogenic therapy is an urgent. The current study is to evaluate the performance of Paeoniflorin (PAE) as an anti-angiogenic therapy, being a powerful anti-fibrotic, compared to artemether (ART) and praziqantel (PZQ) in schistosomiasis mansoni BALB/c mice. Thirty two laboratory bred male BALB/c Swiss albino mice. The mice were classified into four groups (8 mice each), control infected (CI), PZQ (300 mg/kg/12 h), ART (0.1 ml/mg/d) and PAE (50 mg/kg/d) treated groups for one month. All mice groups were sacrificed 15 weeks post infection for assessment of the drugs' efficacy by parasitological, histopathological and immunohistochemical studies. Our results in PAE group showed marked reduction in the mean egg count/gram stool, worm burden, egg count/gram liver tissue, granuloma diameter and pro-angiogenic factors as vascular endothelial growth factor (VEGF), Proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (α-SMA) and CD34; conversely, there was an augmentation of the tissue inhibitor metalloproteinases-2 (TIMP-2) as an anti-angiogenic expression that was exceeded ART and PZQ treated groups compared to CI group (p˂0.001). Conclusively, PAE has an anti-angiogenic impact with no vascular proliferative activity or recanalization, no micro-vessel density (MVD) changes, granuloma resolution and fibrosis regression. PAE is predicted to be a potential therapy for chronic hepatic diseases associated with fibrosis and angiogenesis, hopeful in protecting from advanced serious complications; cancer and metastasis.