Biomphalaria glabrata snails constitute the main vector of schistosomiasis in Brazil, and Bauhinia monandra Kurz, the leaves of which contain BmoLL lectin with biocidal action, is a plant widely found on continents in which the disease is endemic. This work describes the composition of B. monandra preparations and the effect on embryos and adult snails, their reproduction parameters and hemocytes. We also describe the results of a comet assay after B. glabrata exposure to sublethal concentrations of the preparations. Additionally, the effects of the preparations on S. mansoni cercariae and environmental monitoring with Artemia salina are described. In the chemical evaluation, cinnamic, flavonoid and saponin derivatives were detected in the two preparations assessed, namely the saline extract and the fraction. Both preparations were toxic to embryos in the blastula, gastrula, trochophore, veliger and hippo stages (LC₅₀ of 0.042 and 0.0478; 0.0417 and 0.0419; 0.0897 and 0.1582; 0.3734 and 0.0974; 0.397 and 0.0970 mg/mL, respectively) and to adult snails (LC₅₀ of 6.6 and 0.87 mg/mL, respectively), which were reproductively affected with decreased egg deposition. In blood cell analysis, characteristic cells for apoptosis, micronucleus and binucleation were detected, while for comet analysis, different degrees of nuclear damage were detected. The fraction was able to cause total mortality of the cercariae and did not present environmental toxicity. Therefore, B. monandra preparations are promising in combating schistosomiasis since they can control both the intermediate host and eliminate the infectious agent, besides being safe to the environment.

Schistosomiasis, a potentially fatal chronic disease whose etiological agents are blood trematode worms of the genus Schistosoma spp., is one of the most prevalent and debilitating neglected diseases. The treatment of schistosomiasis depends exclusively on praziquantel (PZQ), a drug that has been used since the 1970s and that already has reports of reduced therapeutic efficacy, related with the development of Schistosoma-resistant or -tolerant strains. Therefore, the search for new therapeutic alternatives is an urgent need. Plumbagin (PLUM), a naphthoquinone isolated from the roots of plants of the genus Plumbago, has aroused interest in research due to its antiparasitic properties against protozoa and helminths. Here, we evaluated the in vivo schistosomicidal potential of PLUM against Schistosoma mansoni and the in silico pharmacokinetic parameters. ADMET parameters and oral bioavailability were evaluated using the PkCSM and SwissADME platforms, respectively. The study was carried out with five groups of infected mice and divided as follows: an untreated control group, a control group treated with PZQ, and three groups treated orally with 8, 16, or 32 mg/kg of PLUM. After treatment, the Kato–Katz technique was performed to evaluate a quantity of eggs in the feces (EPG). The animals were euthanized for worm recovery, intestine samples were collected to evaluate the oviposition pattern, the load of eggs was determined on the hepatic and intestinal tissues and for the histopathological and histomorphometric evaluation of tissue and hepatic granulomas. PLUM reduced EPG by 65.27, 70.52, and 82.49%, reduced the total worm load by 46.7, 55.25, and 72.4%, and the female worm load by 44.01, 52.76, and 71.16%, for doses of 8, 16, and 32 mg/kg, respectively. PLUM also significantly reduced the number of immature eggs and increased the number of dead eggs in the oogram. A reduction of 36.11, 46.46, and 64.14% in eggs in the hepatic tissue, and 57.22, 65.18, and 80.5% in the intestinal tissue were also observed at doses of 8, 16, and 32 mg/kg, respectively. At all doses, PLUM demonstrated an effect on the histopathological and histomorphometric parameters of the hepatic granuloma, with a reduction of 41.11, 48.47, and 70.55% in the numerical density of the granulomas and 49.56, 57.63, and 71.21% in the volume, respectively. PLUM presented itself as a promising in vivo antiparasitic candidate against S. mansoni, acting not only on parasitological parameters but also on hepatic granuloma. Furthermore, in silico, PLUM showed good predictive pharmacokinetic profiles by ADMET.

Background: Schistosomiasis affects more than 250 million people, and praziquantel remains the only drug available for treatment; however, its activity is restricted to adult worms. Previously, our group evaluated six thiazole derivatives (PBT1–PBT6) in vitro against adult Schistosoma mansoni, identifying PBT2, PBT5, and PBT6 as the most active compounds. The present study aimed to evaluate the in vitro activity of PBT2, PBT5, and PBT6 against schistosomula and juvenile worms, as well as their in vivo efficacy against adult S. mansoni. Methods: Mechanically transformed schistosomula and juvenile worms recovered from mice (21 days post-infection) were incubated with the compounds (12.5–200 μM). Cytotoxicity was assessed using murine splenocytes and peritoneal macrophages exposed to the same concentration range. For in vivo evaluation, infected mice were orally treated with compounds (50, 100, or 200 mg/kg) for five consecutive days. Results: All compounds induced 100% mortality in schistosomula and juvenile worms within 3 h of exposure at 100 and 200 μM. Parasite cell viability was markedly reduced (>90%) at concentrations between 50 and 200 μM. The LC₅₀ values ranged from 15.3 to 30.9 μM for schistosomula and from 27.8 to 34.9 μM for juvenile worms, with low cytotoxicity observed in mammalian cells (CC₅₀ ≥ 193.9 μM). In vivo treatment resulted in significant reductions in fecal egg counts (~80% at 200 mg/kg), total worm burden (~60%), and egg loads in liver and intestinal tissues, in addition to an increased proportion of dead eggs in the intestine. Conclusions: The evaluated thiazole derivatives demonstrated potent in vitro activity against immature stages of S. mansoni and significant in vivo efficacy against adult parasites, accompanied by favorable changes in key parasitological parameters. These findings reinforce the potential of thiazole-based compounds as promising multistage schistosomicidal candidates.