Viviane Dal-Souto Frescura

Biomonitoring genotoxicity and cytotoxicity of Microcystis aeruginosa (Chroococcales, Cyanobacteria) using the Allium cepa test

Water pollution caused by toxic cyanobacteria is a problem worldwide, increasing with eutrophication. Due to its biological significance, genotoxicity should be a focus for biomonitoring pollution owing to the increasing complexity of the toxicological environment in which organisms are exposed. Cyanobacteria produce a large number of bioactive compounds, most of which lack toxicological data. Microcystins comprise a class of potent cyclic heptapeptide toxins produced mainly by Microcystis aeruginosa. Other natural products can also be synthesized by cyanobacteria, such as the protease inhibitor, aeruginosin. The hepatotoxicity of microcystins has been well documented, but information on the genotoxic effects of aeruginosins is relatively scarce. In this study, the genotoxicity and ecotoxicity of methanolic extracts from two strains of M. aeruginosa NPLJ-4, containing high levels of microcystin, and M. aeruginosa NPCD-1, with high levels of aeruginosin, were evaluated. Four endpoints, using plant assays in Allium cepa were applied: rootlet growth inhibition, chromosomal aberrations, mitotic divisions, and micronucleus assays. The microcystin content of M. aeruginosa NPLJ-4 was confirmed through ELISA, while M. aeruginosa NPCD-1 did not produce microcystins. The extracts of M. aeruginosa NPLJ-4 were diluted at 0.01, 0.1, 1 and 10 ppb of microcystins; the same procedure was used to dilute M. aeruginosa NPCD-1 used as a parameter for comparison, and water was used as the control. The results demonstrated that both strains inhibited root growth and induced rootlet abnormalities. The strain rich in aeruginosin was more genotoxic, altering the cell cycle, while microcystins were more mitogenic. These findings indicate the need for future research on non-microcystin producing cyanobacterial strains. Understanding the genotoxicity of M. aeruginosa extracts can help determine a possible link between contamination by aquatic cyanobacteria and high risk of primary liver cancer found in some areas as well as establish water level limits for compounds not yet studied.

Influence of the type of vegetable oil on the drug release profile from lipid-core nanocapsules and in vivo genotoxicity study.

Abstract The use of rice bran (RB), soybean (SB) or sunflower seed (SF) oils to prepare lipid-core nanocapsules (LNCs) as controlled drug delivery systems was investigated. LNCs were prepared by interfacial deposition using the preformed polymer method. All formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 220–230 nm, polydispersity index < 0.20). The environmental safety was evaluated through an in vivo protocol (Allium cepa test) and LNCs containing RB, SB or SF oils did not present genotoxic potential. Clobetasol propionate (CP) was selected as a model drug to evaluate the influence of the type of vegetable oil on the control of the drug release from LNCs. Biphasic drug release profiles were observed for all formulations. After 168 h, the concentration of drug released from the formulation containing SF oil was lower (0.36 mg/mL) than from formulations containing SB (0.40 mg/mL) or RB oil (0.45 mg/mL). Good correlations between the consistency indices for the LNC cores and the burst and sustained drug release rate constants were obtained. Therefore, the type of the vegetal oil was shown as an important factor governing the control of drug release from LNCs.

Antiproliferative effect of the tree and medicinal species Luehea divaricata on the Allium Cepa cell cycle

The medicinal and tree species Luehea divaricata is known as ‘açoita-cavalo’ and widely used for wood, reclamation, and in popular medicine. The aim of this study was to evaluate the antiproliferative and genotoxic effects of infusions of two populations of this species on the Allium cepa cell cycle. Cells of root tips of Allium cepa were used as an in vivo test system for monitoring the genotoxicity of this medicinal plant. Leaves and bark of two populations of Luehea divaricata were collected during the vegetative stage and used to prepare infusions in two concentrations: for the leaves (6 g/L and 30 g/L) and two concentrations for the bark (32 g/L and 160 g/L), using distilled water as negative control and glyphosate 3% as positive control. For this study, 10 groups of four bulbs were utilized, with one group of bulbs for each treatment. The slides were prepared by the squashing technique, scoring 4000 cells for each group of bulbs. The mitotic index (MI) was calculated and then a statistical analysis was performed using chi-square (χ2). The results showed that Luehea divaricata infusions in both populations caused a reduction of MI compared to control, and in both analyzed concentrations there was no significant genotoxic effect in comparison to the negative control, however there was a significant difference in relation to the positive control for both populations. The antiproliferative effect of leaf extracts increased with a greater concentration and among bark extracts no significant difference occurred between the two concentrations. The studied populations did not show genetic variability regarding the antiproliferative effect.

Evaluation of the allelopathic, genotoxic, and antiproliferative effect of the medicinal species Psychotria brachypoda and Psychotria birotula (Rubiaceae) on the germination and cell division of Eruca sativa (Brassicaceae)

Biological assays are widely used to monitor toxic and allelopathic substances. The present study aimed to evaluate the allelopathic, genotoxic, and antiproliferative potential of aqueous extracts of Psychotria brachypoda (Müll. Arg.) Britton and Psychotria birotula Smith & Downs in two concentrations on the germination and cell division of Eruca sativa Hill. seeds. The biological assay was conducted in a controlled growth chamber. For monitoring the allelopathic effect, the following variables were evaluated: total number of germinated seeds, seedling root length, germination velocity index, and germination percentage. The means were compared using the Tukey test and orthogonal contrasts were undertaken to better compare the variables. To evaluate the antiproliferative and genotoxic effects, seedling roots were collected and the squashing technique was followed for preparation of slides. The results of the present study demonstrated that the medicinal species Psychotria brachypoda and Psychotria birotula inhibited root growth, germination velocity index, and germination percentage in seeds of arugula, in addition to inhibiting cell division and inducing chromosomal alterations in Eruca sativa. We conclude that the studied species have alellopathic, genotoxic, and antiproliferative effects on Eruca sativa in both concentrations studied.

Cytogenotoxicity of rice crop water after application of the tricyclazole fungicide

Tricyclazole is currently one of the fungicides recommended for the treatment of diseases in irrigated rice. However, there is relatively little information on its cytotoxic and genotoxic potential. The objective of this study was to evaluate the cytotoxicity and genotoxicity of rice crop water after apllication of the tricyclazole fungicide through the Allium cepa L. test. The rice crop water samplings were collected before and 1, 15 and 30 days after application of the fungicide in rice plant shoots. The Allium cepa roots were placed in contact with the rice crop water to check for possible chromosomal abnormalities and mitotic index of the bioindicators meristematic cells. The data obtained by the Allium cepa test indicates that the application of the tricyclazole fungicide leads to an increase in the genotoxic activity in the rice crop water, through the appearance of chromosomal abnormalities, without, however, causing significant effects on the mitotic index. The major chromosomal alterations observed were anaphasic and telophasic bridges and laggard chromosomes.

Genotoxic and chromatographic analyses of aqueous extracts of Peltodon longipes Kunth ex Benth. (hortelã-do-campo)

Peltodon longipes e utilizada como estimulante e emenagoga. Objetivou-se realizar analises genotoxica e cromatografica dos extratos de duas amostras de P. longipes, coletadas nos municipios de Santa Maria e Tupancireta, RS, Brasil. O teste de Allium cepa foi utilizado para analise da genotoxicidade e a cromatografia liquida de alta eficiencia, para determinacao dos compostos fenolicos. O experimento de genotoxicidade constou de nove grupos de quatro bulbos de A. cepa. Os bulbos foram enraizados em agua destilada e apos transferidos para os tratamentos, por 24 horas, permanecendo o controle negativo em agua. Os tratamentos foram: extratos aquosos nas concentracoes de 5 e 15 g L-1 de cada amostra, alem de quatro grupos tratados com glifosato 1%, um deles usado como controle positivo e outros tres para testar a recuperacao de danos ao DNA, utilizando agua e os extratos de P. longipes da amostra de Santa Maria. Todos os extratos de P. longipes demonstraram potencial antiproliferativo, porem o efeito foi significativamente maior para os extratos da amostra de Tupancireta. Essa amostra tambem apresentou maior quantidade de acido rosmarinico e canferol, o que pode estar relacionado com os efeitos encontrados nesses extratos. Somente extratos da amostra de Santa Maria demonstraram potencial genotoxico.

Nutrient solution concentration and collection time in phytomass production, content, yield and chemical composition of essential oil of rosemary

ABSTRACT Rosmarinus officinalis L. (rosemary), is a medicinal and aromatic species used in the cosmetics and food processing industries. The present study aimed to evaluate the biomass production, content, yield and chemical composition of the essential oil of rosemary in cultivation out of soil with different concentrations of nutrient solution in both harvests. The cultivation of rosemary was conducted in a protected system off the ground, with concentrations of nutrient solutions of 1, 2, 3, 4 and 5 dS.m−1 for fertigation with collections of leaves 100 and 160 days after planting. Nutrient solution concentration influences phytomass production and the content and yield of essential oil of rosemary, though not its chemical composition. The collection time does not interfere in the content of essential oil; however, does interfere in the chemical composition; the production of phytomass and the yield of oil per plant are higher in collections at 160 days after planting.

Assessment of the antiproliferative and antigenotoxic activity and phytochemical screening of aqueous extracts of Sambucus australis Cham. & Schltdl. (ADOXACEAE)

The purpose of this study was to evaluate the antiproliferative and antigenotoxic activity of Sambucus australis Cham. & Schltdl. aqueous extracts on the cell cycle of Allium cepa L. as well as determine the phenolic compounds in such extracts. S. australis inflorescences and leaves of two accessions were used for aqueous extract preparation at concentrations: 0.003 g/ml and 0.012 g/ml. A. cepa bulbs were rooted in distilled water and, subsequently, placed in treatments for 24 hours. Rootlets were collected and fixed in modified Carnoys solution for 24 hours and kept. The squash technique was performed for slide preparation. Root tips were smashed and stained with 2% acetic orcein, and a total of 4000 cells per treatment were analyzed. The phenolic compounds were determined using high-performance liquid chromatography and data was analyzed using the Scott-Knott test. The results show that S. australis aqueous extracts have antiproliferative potential. Besides, the extracts prepared from S. australis leaves of both accessions at a concentration of 0.012 g/ml have shown antigenotoxic activity. The phytochemical analysis allowed us to determine the presence of flavonoids and phenolic acids, of which kaempferol and chrologenic acid were the most predominant compounds in the extracts from the inflorescences and leaves, respectively.