In the present study, the hexane extract from branches of Drimys brasiliensis (Winteraceae) displayed potent activity against Schistosoma mansoni parasites (100% mortality of the worms at 200 μg/mL). Bioactivity-guided fractionation afforded, in addition to the previously reported bioactive sesquiterpene 3,6-epidioxy-bisabola-1,10-diene, two chemically related drimane sesquiterpenes—polygodial (1) and 9-deoxymuzigadial (2). The anti-S. mansoni effects for compounds 1 and 2 were determined in vitro, with compound 1 demonstrating significant potency (EC₅₀ value of 10 μM for both male and female worms), while 2 was inactive. Cytotoxicity assays against Vero cells revealed no toxicity for either compound (CC₅₀ > 200 μM). Additionally, an in silico analysis was conducted using the SwissADME platform for 1, revealing that this natural sesquiterpene exhibited adherence to several ADME parameters and no PAINS violations. Finally, in vivo studies with S. mansoni-infected mice treated with compound 1 demonstrated a 44.0% reduction in worm burden, accompanied by decreases in egg production of 71.8% in feces and 69.5% in intestines. These findings highlight the potential of polygodial (1) as a promising prototype for schistosomiasis treatment.

Schistosomiasis, a neglected tropical disease impacting over 250 million individuals globally, remains a major public health challenge due to its prevalence and significant impact on affected communities. Praziquantel, the sole available treatment, highlights the urgency of the need for novel anthelmintic agents to achieve the World Health Organization (WHO) goal of schistosomiasis elimination. Previous studies reported the promising antiparasitic activity of different terpenoids against Schistosoma mansoni Sambon (Diplostomida: Schistosomatidae). In the present work, the hexane extract from branches of Drimys brasiliensis afforded a diastereomeric mixture of endoperoxide sesquiterpenes, including 3,6-epidioxy-bisabola-1,10-diene (EDBD). This compound was evaluated in vitro and in vivo against S. mansoni. EDBD exhibited a significant reduction in S. mansoni viability in vitro, with an effective concentration (EC₅₀) value of 4.1 µM. Additionally, EDBD demonstrated no toxicity to mammalian cells. In silico analysis predicted good drug-likeness properties, adhering to pharmaceutical industry standards, including favorable ADME profiles. Furthermore, oral treatment of S. mansoni-infected mice with EDBD (400 mg/kg) resulted in a remarkable egg burden reduction (98% and 99% in tissues and feces, respectively) surpassing praziquantel’s efficacy. These findings suggest the promising potential of EDBD as a lead molecule for developing a novel schistosomiasis treatment.

Background: Schistosomiasis remains a major neglected tropical disease, with praziquantel (PZQ) as the only widely used treatment, despite its limitations. Parthenolide (PTL), a sesquiterpene lactone, exhibits potent in vitro antischistosomal activity; however, its poor aqueous solubility, low oral bioavailability, and chemical instability may limit its in vivo efficacy. Objective: This study investigated whether nanoencapsulation in nanostructured lipid carriers (NLC) could enable the in vivo antischistosomal activity of PTL. Methods: PTL was isolated from Tanacetum parthenium and incorporated into NLC using hot emulsification followed by ultrasonication. The resulting formulation (NLC-PTL) was physicochemically characterized, and its in vivo antischistosomal efficacy was evaluated in a murine model of Schistosoma mansoni infection. Results: NLC-PTL exhibited nanoscale size, low polydispersity, high encapsulation efficiency, and sustained drug release. In vivo, free PTL showed no significant effect on worm burden, whereas NLC-PTL achieved a marked reduction (77.9%) in adult worms and significantly decreased egg output compared to controls (p < 0.001). Blank NLC had no antiparasitic effect. Conclusions: Nanoencapsulation was associated with in vivo antischistosomal activity of PTL compared to the free compound. These findings suggest that formulation strategies may influence the in vivo performance of lipophilic natural products in schistosomiasis.

Introduction: Schistosomiasis, caused by trematodes of the genus Schistosoma, remains a major neglected tropical disease affecting over 240 million people, mainly in low-income regions