In this work, in vitro and in vivo antioxidant properties of the marine algae Halimeda monile were assessed and the levels of some of its compounds likely to be responsible for such properties were determined. The estimated contents of total polyphenols, chlorophylls a and b and carotenoids were 179.5, 356.3, 452.8 and 42.2 mg/g dry weight seaweed, respectively. The presence of terpenoids and flavonoids was also observed. The antioxidant activity of two polar fractions from H. monile (lyophilized aqueous extract and free phenolic acid fraction) was evaluated using three antioxidant assays: ferric reducing antioxidant power, 1,1-diphenyl-2-picrylhydrazyl and lipid peroxidation. Treatment of CCl4-induced liver damage in rats with extracts resulted in lower serum thiobarbituric acid-reactive substances levels and higher hepatic glutathione concentrations compared to those observed in the CCl4-treated group. Also, a significant increase in catalase activity was detected after treatment with the extracts. These results suggest that the seaweed H. monile could be a potential source for natural antioxidants. PRACTICAL APPLICATIONSSeaweeds have a broad chemical composition, consisting of bioactive molecules as chlorophyll, carotenoids, mycosporine-like amino acids, terpenoids, carbohydrates, vitamins and phenolic compounds. Different seaweed extracts have received increased attention, due to their pharmacological effects, particularly in vivo hypolipidemic, antioxidant, immunological and antitumoral activities. The phenolic compounds are powerful antioxidant molecules, and fractions rich in these compounds may be use as antioxidant complement in health states where oxidative state is damage. Results of this research with Halimeda monile L. fractions showed in experiments in vitro and in vivo the presence of different phenolic compounds and that the antioxidant activity is related to them. Therefore, the H. monile L. seaweed fractions have the potential to be developed into new health foods.

Antioxidant activity and hepatoprotective properties of the aqueous extract and tetrahydrofuran-extracted phenolic fractions of Halimeda opuntia (Linnaeus) Lamouroux were investigated in rats with chemically induced liver injury. Total polyphenols were determined by using the Folin-Ciocalteau reagent. Liver damage was induced by CCl(4) and assessed by a histological technique. Reverse transcription/polymerase chain reaction (RT/PCR) analysis showed increased superoxide dismutase (SOD) and catalase (CAT) gene expression and activities in the group treated with free phenolic acid (FPA) fractions of H. opuntia, suggesting inducing effects on both enzymes. In addition, rats treated with FPA fractions displayed lower liver thiobarbituric acid reactive substance (TBARS) levels than those observed for rats in the CCl(4)-treated group. These data suggest that the phenolic fractions from H. opuntia may protect the liver against oxidative stress-inducing effects of chemicals by modulating its antioxidant enzymes and oxidative status.

LDL oxidation and oxidative stress are closely related to atherosclerosis. Therefore, natural antioxidants have been studied as promising candidates. In the present study, the LDL oxidation inhibition activity of bioactive compounds from Halimeda incrassata seaweed. associated to antioxidant capacity, was evaluated in vitro. Experimental work was conducted with lyophilized aqueous extract and phenolic-rich fractions of the seaweed and their effect on LDL oxidation was evaluated using heparin-precipitated LDL (hep-LDL) with exposure to Cu 2+ ions and AAPH as the free radical generator. H. incrassata had a protective effect for hep-LDL in both systems and the presence of phenolic compounds contributed to the activity where phenolic-rich fractions showed significant capacity for inhibition of oxidation mediated by Cu 2+ ions. The observed effect could be related to the antioxidant potential of polar fractions evidenced by reducing activity and DPPH• radical scavenging. The results obtained in vitro further support the antioxidant and LDL oxidation inhibition properties of H. incrassata and further knowledge toward future phytotherapeutic application of the seaweed. Uniterms:Halimeda incrassata/antioxidant properties. Antioxidants. Polyphenols. Lipoproteins/ oxidation inhibition.A oxidação da LDL e o estresse oxidativo estão intimamente relacionados com a aterosclerose. Por isso, os antioxidantes naturais têm sido estudados como candidatos promissores. No presente trabalho foi avaliada in vitro a capacidade de inibição da oxidação da LDL pelos compostos bioativos da alga Halimeda incrassata em associação à capacidade antioxidante. O trabalho experimental foi conduzido com extratos polares (extrato aquoso liofilizado e frações ricas em fenólicos) e seu efeito na oxidação da LDL foi avaliado usando LDL precipitada com heparina (hep-LDL), oxidada com íons de Cu 2+ e AAPH, como geradores de radicais livres. A H. incrassata apresentou efeito protetor para hep-LDL em ambos sistemas e a presença de compostos fenólicos contribuiu para a atividade em que as frações ricas em fenólicos demonstram capacidade significativa em inibir a oxidação mediada pelos íons de Cu 2+. O efeito observado deve estar relacionado com o potencial antioxidante das frações polares medido pela atividade redutora e varredura do radical DPPH. Os resultados obtidos demonstram as propriedades antioxidantes e de inibição da oxidação da LDL da H. incrassata e podem contribuir para as evidências de futuras aplicações fitoterapêuticas desta alga. Unitermos:Halimeda incrassata/propriedades antioxidantes. Antioxidantes. Polifenóis. Lipoproteínas/ inibição da oxidação.

The aim of this research was to compare the efficiency of different murine lines for genotoxicity assays. Rats and mice of different murine lines were used. The spontaneous and induced indexes were evaluated according to alkaline comet assay of peripheral blood leukocytes, micronucleus and chromosomic aberration assay of bone marrow cell, and sperm head morphology assay. In most of the evaluated assays the line of Balb/c mice turned out to be the ideal biomodel, with less spontaneous indexes and high induced indexes to the mutagen used; allowing to detect in a narrow error margin those substances that are classified of very low genotoxicity. These results demonstrate that genetically the line of Balb/c mice in both sexes is more stable than the other ones evaluated. This suggests the use of the Balb/c line on in vivo genotoxicity assay will increase sensibility and robustness.

Objective: The seed oil extract of Carapa guianensis has various biomedical applications. Recently this extract was evaluated for expressing great potential as antioxidant on in vivo assays. Besides its safety has been evaluated in several genotoxicity assays, not being toxic in different models of DNA damage. The aim of this research was to evaluate the genotoxic potential of seed oil extract of C.guianensis on peripheral blood leukocytes of Sprague-Dawley rats using the comet assay. Methods: Five experimental groups were formed consisting of five male and five female Sprague-Dawley rats in each group. A placebo group (2% Tween 65), three dose levels of the extract (400, 1000 and 2000 mg/kg) administered orally for 14 days, and a positive control group treated with cyclophosphamide (CP) at a dose of 50 mg/kg intraperitoneally 48 and 24 h before euthanasia were established. After the experimental period the animals were anesthetized and a blood drop was extracted for performing the comet assay of peripheral blood leukocytes; then the rats were euthanized under ether atmosphere. Results: The results presented no differences between controls and extract-treated animals of both sexes in the percentage of nucleoids at different levels, arbitrary units and length of DNA migration. However, validating our result, the CP-treated animals showed significant DNA damage. Conclusion: The seeds oil extract of C.guianensis did not exert genotoxic effect as measured through the comet assay on peripheral blood leukocytes of male as well as female Sprague-Dawley rats. [J Exp Integr Med 2013; 3(3.000): 231-236