Inhibition of LDL-oxidation and antioxidant properties related to polyphenol content of hydrophilic fractions from seaweed Halimeda Incrassata (Ellis) Lamouroux

Abstract

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.

Anti-atherogenic properties associated with the antioxidant activity from the hydrophilic extracts of Halimeda incrassata (Chlorophyta, Bryopsidales)

“…Yeh and Yen (2006) suggested that these three phenolic acids, including ferulic acid, modulate the phase II antioxidant enzymes and the phase II sulphate conjugative enzymes; and they seem to selectively induce hepatic mRNA transcripts for CAT, probably through the up-regulation of gene transcription, as well as the Nrf2 transcription factor. In previous results from our group, Mancini-Filho et al (2009) reported an over-expression of CAT genes by treatment with FPA from Halimeda monile; while de Oliveira e Silva et al (2012) showed that by using (RT/PCR) analysis increased the catalase (CAT) gene expression in the group treated with free phenolic acid (FPA) fractions from Halimeda opuntia, suggesting inducing effects on the enzyme.…”

“…Several lines of results have documented the ability of a hydrophilic extract from this seaweed to target free-radical mediated processes in vitro cell culture and in vivo experimental models (Rivero et al, 2003;Fallarero et al, 2003;Linares et al, 2004;Mancini-Filho et al, 2009;de Oliveira e Silva et al, 2012). In previous studies, in vitro Halimeda spp seaweeds have been described as having a relationship between antioxidant activity and antiatherogenic properties (Costa-Mugica et al, 2012).…”

Effect of Natural Food Antioxidants Against LDL and DNA Oxidative Changes

“…The functional groups of flavonoids attached to the three ring system of flavonoids has been reported to trigger a positive impact against LDL oxidation [21]. In a study by Naderi et al Costa-Mugica et al [71] reported that lyophilized aqueous extracts and phenolic-rich fractions of seaweed (H. Incrassata) significantly inhibited LDL oxidation when evaluated by using heparinprecipitated LDL exposed to Cu2+ ions with AAPH as the free radical generator. The authors claimed that the observed effect could be related to the antioxidant potential of the polar phenolic fractions.…”

Evaluation of Genotoxic and DNA Photo-Protective Activity of Bryothamnion triquetrum and Halimeda incrassata Seaweeds Extracts

“…The aqueous extracts from Halimeda incrassata and Bryothamnion triquetrum seaweeds have been reported as antiatherogenic [7] and antinociceptive and anti-inflammatory [8,9], respectively. Additionally, both extracts contain neuroprotective and antioxidant capacities [10][11][12] and some experimental works have been carried out in order to evaluate their toxic properties, by means of in vitro assays [13][14][15]. The present study was designed to test the genotoxic potential of these aqueous extracts in the primary structure of DNA molecule.…”