Schinus terebinthifolius leaf extract causes midgut damage, interfering with survival and development of Aedes aegypti larvae

In this study, a leaf extract from Schinus terebinthifolius was evaluated for effects on survival, development, and midgut of A. aegypti fourth instar larvae (L4), as well as for toxic effect on Artemia salina. Leaf extract was obtained using 0.15 M NaCl and evaluated for phytochemical composition and lectin activity. Early L4 larvae were incubated with the extract (0.3–1.35%, w/v) for 8 days, in presence or absence of food. Polymeric proanthocyanidins, hydrolysable tannins, heterosid and aglycone flavonoids, cinnamic acid derivatives, traces of steroids, and lectin activity were detected in the extract, which killed the larvae at an LC50 of 0.62% (unfed larvae) and 1.03% (fed larvae). Further, the larvae incubated with the extract reacted by eliminating the gut content. No larvae reached the pupal stage in treatments at concentrations between 0.5% and 1.35%, while in the control (fed larvae), 61.7% of individuals emerged as adults. The extract (1.0%) promoted intense disorganization of larval midgut epithelium, including deformation and hypertrophy of cells, disruption of microvilli, and vacuolization of cytoplasms, affecting digestive, enteroendocrine, regenerative, and proliferating cells. In addition, cells with fragmented DNA were observed. Separation of extract components by solid phase extraction revealed that cinnamic acid derivatives and flavonoids are involved in larvicidal effect of the extract, being the first most efficient in a short time after larvae treatment. The lectin present in the extract was isolated, but did not show deleterious effects on larvae. The extract and cinnamic acid derivatives were toxic to A. salina nauplii, while the flavonoids showed low toxicity. S. terebinthifolius leaf extract caused damage to the midgut of A. aegypti larvae, interfering with survival and development. The larvicidal effect of the extract can be attributed to cinnamic acid derivatives and flavonoids. The data obtained using A. salina indicates that caution should be used when employing this extract as a larvicidal agent

Avaliação cinética e ecotoxicológica da degradação do corante têxtil direct orange 26 por processos Fenton e foto-Fenton/solar

The presence of color in textile effluents has been studied because of the need for more effective treatments. Therefore, advanced oxidative processes (AOP) have been used in the degradation of dyes, as well as in the conversion of organic matter. This study evaluated the degradation of the direct orange 26 textile dye by Fenton and photo-Fenton processes (with natural solar radiation). A statistical analysis, based on factorial 23 indicated the best working conditions, being: [H2O2] = 100 mg·L-1 and pH 3-4, for both AOP in that the [Fe] =  1 e 5 mg·L-1, for photo-Fenton and Fenton, respectively. The results of the kinetic studies demonstrated a good fit to the nonlinear kinetic model proposed by Chan and Chu, with values of R2 > 0,996 (photo-fenton) and R2 > 0,939 (Fenton). The tests performed to evaluate the chemical oxygen demand indicated conversions of 62.05% (Fenton) and 66.41% (photo-Fenton). Finally, the ecotoxicity study indicated that the post-treatment samples were non-toxic to the bacteria Escherichia coli and Proteus mirabilis but showed growth inhibition for Lactuca sativa (Fenton and photo-Fenton) seeds and for Brassica juncea and Portulaca grandiflora (Fenton).A presença de cor em efluentes têxteis tem sido alvo de estudo, devido a necessidade de tratamentos mais eficazes. Diante disso, processos oxidativos avançados (POA) têm sido utilizados na degradação de corantes, assim como na conversão da matéria orgânica. Este estudo avaliou a degradação do corante têxtil laranja direto 26 via processos Fenton e foto-Fenton (com radiação solar natural). Uma análise estatística, baseada em planejamentos fatoriais 23 indicaram as melhores condições de trabalho, sendo elas: [H2O2] = 100 mg·L-1 e pH 3-4, para ambos os POA em quanto que a [Fe] =  1 e 5 mg·L-1, para o foto-Fenton e o Fenton, respectivamente. Os resultados dos estudos cinéticos demonstraram um bom ajuste ao modelo cinético não-linear proposto por Chan e Chu apresentando R2 > 0,996 (foto-Fenton) e R2 > 0,939 (Fenton). Os ensaios realizados para avaliação da demanda química de oxigênio indicaram conversões de 62,05% (Fenton) e 66,41% (foto-Fenton). Por fim, o estudo de ecotoxicidade indicou que as amostras pós-tratamento não são tóxicas para as bactérias Escherichia coli e Proteus mirabilis, mas apresentou inibição do crescimento para sementes de Lactuca sativa (Fenton e foto-Fenton) e para Brassica juncea e Portulaca grandiflora (Fenton)

A trypsin inhibitor from Tecoma stans leaves inhibits growth and promotes ATP depletion and lipid peroxidation in Candida albicans and Candida krusei

Tecoma stans (yellow elder) has shown medicinal properties and antimicrobial activity. Previous reports on antifungal activity of T. stans preparations and presence of trypsin inhibitor activity from T. stans leaves stimulated the investigation reported here. In this work, we proceeded to the purification and characterization of a trypsin inhibitor (TesTI), which was investigated for anti-Candida activity. Finally, in order to determine the potential of TesTI as a new natural chemotherapeutic product, its cytotoxicity to human peripheral blood mononuclear cells (PBMCs) was evaluated. TesTI was isolated from saline extract by ammonium sulphate fractionation followed by ion exchange and gel filtration chromatographies. Antifungal activity was evaluated by determining the minimal inhibitory (MIC) and fungicide (MFC) concentrations using fungal cultures containing only yeast form or both yeast and hyphal forms. Candida cells treated with TesTI were evaluated for intracellular ATP levels and lipid peroxidation. Cytotoxicity of TesTI to PBMCs was evaluated by MTT assay. TesTI (39.8 kDa, pI 3.41, Ki 43 nM) inhibited similarly the growth of both C. albicans and C. krusei culture types at MIC of 100 µg/mL. The MFCs were 200 µg/mL for C. albicans and C. krusei. Time-response curves revealed that TesTI (at MIC) was more effective at inhibiting the replication of C. albicans cells. At MIC, TesTI promoted reduction of ATP levels and lipid peroxidation in the Candida cells, being not cytotoxic to PBMCs. In conclusion, TesTI is an antifungal agent against C. albicans and C. krusei, without toxicity to human cells

<i>Aedes aegypti</i> L₄ larvae incubated for 12 h with <i>Schinus terebinthifolius</i> leaf extract (1.0%, w/v).

<p>(A) Larva eliminating the gut content covered by the peritrophic matrix. (B) Shrunken and pigmented midgut dissected from a larva incubated with the leaf extract. (C) Midgut dissected from a control larvae, after removal of gut content and peritrophic matrix, without apparent alterations. (D) Midgut dissected from a larva incubated with the leaf extract containing the 0.01 M phenylthiourea (PTU), a phenoloxidase inhibitor. (E) Midgut dissected from a larva incubated with 0.01 M PTU.</p

Toluidine Blue stained histological sections of the midgut of <i>Aedes aegypti</i> L4 from control (A) and incubated for 12 h with the <i>Schinus terebinthifolius</i> leaf extract (B).

<p>Midgut from control larva (A) showed a single-layered epithelium (ep) comprised of digestive (dc) and regenerative cells (rc) with preserved morphology (C). L, midgut lumen; m, muscle; n, digestive cell nuclei. Midgut from treated larva (B) showed intense disorganization of the epithelial layer (ep) with several spaces between cells (*) and some hypertrophied digestive cells (dc). Tissue/cell debris (arrowhead) is seen in the midgut lumen. m, muscle; n, digestive cell nucleus; pm, peritrophic matrix. Details of columnar digestive cells for control (C) and treated (D) larvae. Structure resembling vacuoles (v) are seen in D. n, cell nucleus; N, nucleolus; B, brush border.</p

Number of different cell types in the midgut of <i>Aedes aegypti</i> L₄ from control and those incubated for 12 h with the <i>Schinus terebinthifolius</i> leaf extract (1.0%, w/v).

<p>(A) Digestive, regenerative, and enteroendocrine cells from the midgut epithelium were counted under the fluorescence microscope. (B) Number of proliferating regenerative cells or cells with nuclear DNA damage (TUNEL positive) in the midgut epithelium were determined by fluorescence microscopy. (*) indicates significant difference (p < 0.05) in comparison to the control.</p

Electron micrographs of the midguts of <i>Aedes aegypti</i> L4 from control and those treated with <i>Schinus terebinthifolius</i> leaf extract at 1.0% (w/v).

<p>Mitochondria (arrowheads); microvilli (m); electron-lucent vacuoles (V); endoplasmic reticulum (ER); nucleus (n).</p

Proliferating regenerative cells or cells with nuclear DNA damage in the midgut of <i>Aedes aegypti</i> L₄ incubated for 12 h with distilled water (control) and <i>Schinus terebinthifolius</i> leaf extract at 1.0% (w/v).

<p>(A) Nuclei of proliferating (phosphohistone H3-positive) regenerative cells (arrow) at the posterior region of the midgut. (B) Nuclei of digestive and regenerative cells positive for DNA damage/fragmentation (arrowhead).</p

Development systems and revealers used for analysis by thin-layer chromatography of secondary metabolites in <i>S</i>. <i>terebinthifolius</i> leaf extract.

<p>Development systems and revealers used for analysis by thin-layer chromatography of secondary metabolites in <i>S</i>. <i>terebinthifolius</i> leaf extract.</p