Effects of Bioinsecticidal Aegerolysin-Based Cytolytic Complexes on Non-Target Organisms.

Aegerolysin proteins ostreolysin A6 (OlyA6), pleurotolysin A2 (PlyA2) and erylysin A (EryA) produced by the mushroom genus Pleurotus bind strongly to an invertebrate-specific membrane sphingolipid, and together with a protein partner pleurotolysin B (PlyB), form transmembrane pore complexes. This pore formation is the basis for the selective insecticidal activity of aegerolysin/PlyB complexes against two economically important coleopteran pests: the Colorado potato beetle and the western corn rootworm. In this study, we evaluated the toxicities of these aegerolysin/PlyB complexes using feeding tests with two ecologically important non-target arthropod species: the woodlouse and the honey bee. The mammalian toxicity of the EryA/PlyB complex was also evaluated after intravenous administration to mice. None of the aegerolysin/PlyB complexes were toxic against woodlice, but OlyA6/PlyB and PlyA2/PlyB were toxic to honeybees, with 48 h mean lethal concentrations (LC50) of 0.22 and 0.39 mg/mL, respectively, in their food. EryA/PlyB was also tested intravenously in mice up to 3 mg/kg body mass, without showing toxicity. With no toxicity seen for EryA/PlyB for environmentally beneficial arthropods and mammals at the tested concentrations, these EryA/PlyB complexes are of particular interest for development of new bioinsecticides for control of selected coleopteran pests.

The LQB-223 Compound Modulates Antiapoptotic Proteins and Impairs Breast Cancer Cell Growth and Migration.

Drug resistance represents a major issue in treating breast cancer, despite the identification of novel therapeutic strategies, biomarkers, and subgroups. We have previously identified the LQB-223, 11a-N-Tosyl-5-deoxi-pterocarpan, as a promising compound in sensitizing doxorubicin-resistant breast cancer cells, with little toxicity to non-neoplastic cells. Here, we investigated the mechanisms underlying LQB-223 antitumor effects in 2D and 3D models of breast cancer. MCF-7 and MDA-MB-231 cells had migration and motility profile assessed by wound-healing and phagokinetic track motility assays, respectively. Cytotoxicity in 3D conformation was evaluated by measuring spheroid size and performing acid phosphatase and gelatin migration assays. Protein expression was analyzed by immunoblotting. Our results show that LQB-223, but not doxorubicin treatment, suppressed the migratory and motility capacity of breast cancer cells. In 3D conformation, LQB-223 remarkably decreased cell viability, as well as reduced 3D culture size and migration. Mechanistically, LQB-223-mediated anticancer effects involved decreased proteins levels of XIAP, c-IAP1, and Mcl-1 chemoresistance-related proteins, but not survivin. Survivin knockdown partially potentiated LQB-223-induced cytotoxicity. Additionally, cell treatment with LQB-223 resulted in changes in the mRNA levels of epithelial-mesenchymal transition markers, suggesting that it might modulate cell plasticity. Our data demonstrate that LQB-223 impairs 3D culture growth and migration in 2D and 3D models of breast cancer exhibiting different phenotypes.

Estudos pré-clínicos da pterocarpanoquinona LQB-118: toxicidade subaguda, eficácia em leishmaniose visceral experimental e mecanismo de ação / Preclinical studies of pterocarpanquinone lqb-118: subacute toxicity, efficacy in experimental visceral leishmaniasis and mechanism of action

A leishmaniose visceral (LV) é a forma mais severa de leishmaniose e é a segunda maior causa de mortes por doenças parasitarias depois da malária. O arsenal terapêutico contra a leishmaniose é pequeno, e cada um dos medicamentos disponíveis apresenta ao menos uma das desvantagens: toxicidade, eficácia, preço ou regime de tratamento. Nós temos concentrado esforços em estudar novos candidatos a fármacos como alternativas aos tratamentos atuais. A pterocarpanquinona LQB-118 foi desenhada e sintetizada com base em hibridação molecular e apresentou atividade em protozoários e linhagens celulares de leucemia. Resultados prévios demonstraram que a LQB-118 foi eficaz no tratamento da leishmaniose cutânea experimental e que o mecanismo de ação envolve a indução do estresse oxidativo com eventos característicos da morte celular por apoptose em Leishmania amazonensis. Neste estudo, foi observado que o tratamento com 10 mg/kg/dia por via oral de LQB- 118 inibiu o desenvolvimento de hepatoesplenomegalia em camundongos infectados com L. infantum, com uma redução de 99 por cento na carga parasitária. A análise toxicológica in vivo não apresentou nenhuma mudança nos parâmetros clínicos, bioquímicos ou hematológicos. A análise histológica evidenciou que os órgãos não apresentaram anormalidades, com a exceção do fígado, no qual foi observado focos de necrose com infiltração leucocitária com uma dose cinco vezes maior do que a dose terapêutica. Entretando, estas alterações não foram acompanhadas por aumento das transaminases. Para avaliar os eventos iniciais do mecanismo de ação da LQB- 118, promastigotas de L. amazonensis foram incubados com LQB-118 e antioxidantes. As perdas da viabilidade celular e do potencial de membrana mitocondrial não foram revertidas com os antioxidantes, embora a produção de EROs tenha sido prevenida, sugerindo que a produção de EROs não é a causa primária de morte do parasito...

Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is the second major cause of deaths byparasites after malaria. The arsenal of drugs against leishmaniasis is small, and each has a disadvantage in termsof toxicity, efficacy, price or treatment regimen. Our group has focused on studying new drug candidates asalternatives to current treatments. The pterocarpanquinone LQB-118 was designed and synthesized based onmolecular hybridization and exhibited antiprotozoal and anti-leukemic cell line activity. Our previous workdemonstrated that LQB-118 was an effective treatment of experimental cutaneous leishmaniasis and that themechanism of action involves induction of oxidative stress with characteristic events of cell death via apoptosisin Leishmania amazonensis. In this study, we observed that treatment with 10 mg/kg/day LQB-118 orallyinhibited the development of hepatosplenomegaly in L. infantum-infected mice, with a 99 percent reduction in parasiteload. The in vivo toxicological analysis showed no change in clinical, biochemical or hematological parameters.Histologically, all of the analyzed organs were normal with the exception of liver, in which focal points ofnecrosis with leukocyte infiltration were observed with a dose five times higher than the therapeutic dose.However, these changes were not accompanied by increase in transaminases. To assess the early effects of themechanism of action of LQB-118, promastigotes of L. amazonensis were incubated with LQB-118 andantioxidants. Cell viability and mitochondrial membrane potential were not reversed by the antioxidants,although the ROS production was, suggesting that ROS production is not the primary cause of parasite death...

Development and evaluation of a safe and effective sugar-free herbal lollipop that kills cavity-causing bacteria.

Dental caries (tooth decay) is caused by a specific group of cariogenic bacteria, like Streptococcus mutans, which convert dietary sugars into acids that dissolve the mineral in tooth structure. Killing cariogenic bacteria is an effective way to control or prevent tooth decay. In a previous study, we discovered a novel compound (Glycyrrhizol A), from the extraction of licorice roots, with strong antimicrobial activity against cariogenic bacteria. In the current study, we developed a method to produce these specific herbal extracts in large quantities, and then used these extracts to develop a sugar-free lollipop that effectively kills cariogenic bacteria like Streptococcus mutans. Further studies showed that these sugar-free lollipops are safe and their antimicrobial activity is stable. Two pilot human studies indicate that a brief application of these lollipops (twice a day for ten days) led to a marked reduction of cariogenic bacteria in oral cavity among most human subjects tested. This herbal lollipop could be a novel tool to promote oral health through functional foods.

Flavanoids and pterocarpans from the bark of Erythrina fusca.

Three new isomeric flavanones, fuscaflavanones A(1) (1), A(2) (2) and B (3), together with six known flavanones, lupinifolin (4), lonchocarpol A (5), a mixture of lonchocarpols C(1) and C(2) (6a, b), and a mixture of lonchocarpols D(1) and D(2) (7a, b), five pterocarpans, sandwicensin (8), phaseollidin (9), erythrabissin I (10), and a mixture of dolichins A and B (11a, b), one chalcone, isobavachalcone (12), and one isoflavone, wighteone (13), were isolated from the bark of Erythrina fusca LOUR. Their structures were elucidated on the basis of spectroscopic data. Some isolates were tested for antiplasmodial and cytotoxic activities and it was found that 5 and 9 exhibited moderate antiplasmodial activity against Plasmodium falciparum. For cytotoxicity, compounds 1, 4, 5, 9 and 12 showed moderate to weak activity against KB, BC and NCI-H187 cells, whereas 2 exhibited only weak activity against KB cells.

Pterocarpans phaseollin and neorautenol isolated from Erythrina addisoniae induce apoptotic cell death accompanied by inhibition of ERK phosphorylation.

The genus Erythrina (Leguminosae), consisting of over 100 different species, is distributed in tropical regions. In traditional medicine, Erythrina species are used to treat cancer, but little is known about the anticancer mechanisms. From the stem bark of Erythrina addisoniae Hutch. & Dalziel, six prenylated pterocarpans were isolated and analysed for pharmacological activity: While calopocarpin, cristacarpin, orientanol c, and isoneorautenol showed only a weak or moderate toxicity in H4IIE hepatoma cells (EC(50)-value> 25 microM), the toxicity of neorautenol and phaseollin was in the low micromolar range (EC(50)-value: 1 and 1.5 microM, respectively). We further focused on these two substances showing that both increased caspase 3/7 activity and nuclear fragmentation as markers for apoptotic cell death. Neorautenol (10 microM, 2h), but not phaseollin induced the formation of DNA strand breaks (comet assay). Both substances showed no effect on NF-kappaB signalling (SEAP assay: basal activity and stimulation with TNF-alpha), on the other hand both pterocarpans (10 microM, 2 h) decreased the activation of the ERK kinase (p44/p42), an mitogen activated protein kinase which is associated with cell proliferation. We conclude that the pterocarpans phaseollin and neorautenol may be responsible for the anticarcinogenic actions of the plant extract reported in the literature. Further analysis of these substances may lead to new pharmacons to be used in cancer therapy.