The present study evaluated the toxicity of Microgramma vacciniifolia rhizome lectin (MvRL) to Artemia salina, human tumour cell lines (larynx epidermoid carcinoma Hep-2, NCI-H292 lung mucoepidermoid carcinoma, and chronic myelocytic leukaemia K562), and normal peripheral blood mononuclear cells (PBMCs), as well as to Biomphalaria glabrata embryos and adults. MvRL was toxic to A. salina (LC50=159.9 μg/mL), and exerted cytotoxic effects on NCI-H292 cells (IC50=25.23 μg/mL). The lectin (1-100 μg/mL) did not affect the viability of K562 and Hep-2 tumour cells, as well as of PBMCs. MvRL concentration of 1, 10, and 100 μg/mL promoted malformations (mainly exogastrulation) in 7.8%, 22.5%, and 27.7% of embryos, respectively, as well as delayed embryo development in 42.0%, 69.5%, and 54.7% of embryos, respectively. MvRL at a concentration of 100 μg/mL killed B. glabrata embryos (17.7%) and adults (25%). Further, MvRL damaged B. glabrata reproductive processes, which was evidenced by observations that snails exposed to the lectin (100 μg/mL) deposited fewer eggs than those in the control group, and approximately 40% of the deposited eggs exhibited malformations. Comparison of these results with that from A. salina assay indicates that MvRL is adulticidal at the concentration range which is toxic to environment. In conclusion, the cytotoxicity of MvRL on tumour cell and absence of toxicity to normal cell indicate its potential as chemotherapeutic drug. Also, the study revealed that the lectin is able to promote deleterious effects on B. glabrata embryos at environmentally safe concentrations.

This study evaluated the biological activity of an ether extract and barbatic acid (BAR) from Cladia aggregata on embryos and adult mollusks of Biomphalaria glabrata, cercariae of Schistosoma mansoni and the microcrustacean Artemia salina. The ether extract and BAR were obtained by successive extractions with diethyl ether. The obtained extracts were analyzed using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), proton nuclear magnetic resonance (1H-NMR) and infrared (IR) spectroscopy. The results demonstrated that the ether extract exerted embryotoxic effects at 50 and 100 µg/mL and molluscicidal effects at 20 and 25 µg/mL. BAR exhibited no embryotoxicity, and its molluscicidal concentration was equal to that of the ether extract. However, after 60 min of exposure, 1 µg/mL BAR presented cercaricidal activity against the parasite S. mansoni at the second larval stage. Neither substance induced toxicity against A. salina. These results indicate the potential molluscicidal activities of the ether extract and BAR against B. glabrata and S. mansoni cercariae. In addition to these effects, there was a lack of toxicity against the aquatic environment and no damage to the biota, indicating the potential of these products for large-scale control and/or eradication of schistosomiasis.

Evaluation of molluscicidal activity of Anadenanthera colubrina extracts on adult mollusc and embryos of the species Biomphalaria glabrata (Say, 1818) Avaliação da atividade moluscicida do extrato de Anadenanthera colubrina sobre moluscos adultos e embriões da espécie Biomphalaria glabrata (Say, 1818)

Background: Biomphalaria glabrata is an intermediate host for the larvae of Schistosoma mansoni, which is distributed widely in the tropics. B. glabrata control is important to minimize the spread of schistosomiasis and natural compounds have been sought for use against this disease. The Artemia salina bench-top bioassay has been used to investigate the ecotoxicity of many natural compounds, and its results also correlate well with the in vitro cytotoxicity of natural compounds to tumor cells. Aims: To evaluate deleterious effects of the Opuntia ficus-indica lectin (OfiL) on B. glabrata,          A. salina and human cancer cell lines. Methods: OfiL was isolated following a previously established protocol. The effects of OfiL on          B. glabrata were investigated by determining survival of adults as well as development and hatching of embryos. The concentration required to kill 50% (LC50) of A. salina nauplii was determined. The cytotoxicity was determined using the human cell lines Hep-2 (human larynx epidermoid carcinoma), NCI-H292 (human lung mucoepidermoid carcinoma) and K562 (chronic myelocytic leukemia). Results: The development of most embryos (92.5–97.5%) treated with 1, 10 and 100 µg/mL of OfiL was found to be delayed, and dead (2.2–3.3%) and malformed (0.3–5.2%) embryos were also observed. OfiL did not kill B. glabrata adults, but a high percentage (30–45%) of the embryos generated by snails incubated with the lectin exhibited malformations. OfiL exhibited toxicity against A. salina (LC50: 61.02 µg/mL) but did not display cytotoxicity against the tumor cell lines evaluated. Conclusion: In conclusion, this study showed that OfiL can be a tool for schistosomiasis control that acts by impairing the viability of B. glabrata eggs and the fecundity of adult snails.

Ionizing radiation can cause biological changes in different organisms such as mollusks from Biomphalaria glabrata species, in which alterations could be observed in the reproductive system of the specimens, prejudicing fertility and fecundity. As the changes may occur due to the lipid peroxidation caused by the action of free radicals on the gonads, the objective of this work was to evaluate the oxidative damage caused by the exposure of B. glabrata mollusks to different doses of 60 Co gamma radiation. In addition, efforts were carried out to standardize a sensitive and low-cost technique for detecting negative effects caused by high doses of ionizing radiation. For this, each mollusk group (n = 10) was submitted to 0 (control), 10, 15, 20 and 25 Gy (gammacell 60 Co, dose rate 3.53 kGy/h). The TBARS method was applied for the quantification of lipid peroxidation of the gonads of the mollusks after 24 and 48 h. ANOVA, followed by the mean comparison (Tukey) at the 5% of significance level (p<0.05), indicated high concentrations of TBARS in the gonads after 24 h. Otherwise, after 48 h, differences for TBARS concentrations were not significant, determining that the action of free radicals from ionizing radiation on cell membranes mainly occurred within 24 h after irradiation. Therefore, the TBARS assay could be applied for detecting oxidative stress caused by short exposure of B. glabrata to ionizing radiation.