Phenolic compounds in sugar cane (Saccharum officinarum L.) juice were identified and quantified by analytical high performance liquid chromatography and photodiode array detection, showing the predominance of flavones (apigenin, luteolin and tricin derivatives), among flavonoids, and of hydroxycinnamic, caffeic and sinapic acids, among phenolic acids, representing a total content of around 160 mg/L. A tricin derivative was present in the highest proportion (>10% of the total). The phenolic extract obtained from sugar cane juice showed a protective effect against in vivo MeHgCl intoxication and potent inhibition of ex vivo lipoperoxidation of rat brain homogenates, indicating a potential use for beneficial health effects and/or therapeutic applications.

Phenolic compounds are found in seaweed species together with other substances presenting antioxidant activity. The objective of this work was to evaluate the antioxidant activity of the free phenolic acids (FPA) fraction from the seaweed Halimeda monile, and its activity to protect the expression of hepatic enzymes in rats, under experimental CCl4 injury. The antioxidant activity was measured by the DPPH method. The FPA fraction (80 mg/kg, p.o.) was administered during 20 consecutive days to rats. The peroxidation was performed by thiobarbituric acid reactive substances (TBARS). The SOD and CAT enzymatic expressions were measured by RT/PCR. The histology technique was used to evaluate liver injuries. The expression of both, CAT and SOD genes, was more preserved by FPA. Only partial injury could be observed by histology in the liver of rats receiving FPA as compared with the control group; and CCl4 administration induced 60% more peroxidation as compared with the rats receiving FPA. These data suggest that FPA could modulate the antioxidant enzymes and oxidative status in the liver through protection against adverse effects induced by chemical agents

Hydrophilic and lipophilic fractions, obtained from the marine algae Halimeda incrassata (J.Ellis) J.V.Lamouroux, Halimedaceae, were studied by using the β-carotene-linoleate assay system. In case of hydrophilic fractions, the total phenolic compounds were quantified and two of their components were identified as salicylic and ferulic acids. From the lipophilic fraction, fatty acid composition was studied. The highest antioxidant activities values were found on the polar fractions containing phenolic acids. The total phenolics content on the hydrophilic fractions was 255 µg of gallic acid equivalents/g of fresh seaweed. To further characterize H. incrassata chemical composition, the total lipid content was quantified (7.4 mg per gram of dried algae) as well as the saturated and unsaturated fatty acids ratio (1:1.46). In summary, this paper adds more convincing evidences in support of the antioxidant abilities of the lyophilized aqueous extract of Halimeda incrassata and it also relates this bioactivity, for the first time, with particular phenolic components of the extract. Altogether, these results represent another step towards the use of this natural product as drug candidates.

OBJETIVO: Avaliar o efeito do extrato aquoso de alecrim sobre o estresse oxidativo em ratos diabéticos. MÉTODOS: O extrato aquoso de alecrim foi obtido por método sequencial. Os fenólicos totais foram determinados pelo método de Folin Ciocateau e a atividade antioxidante in vitro foi determinada através de três métodos: β-caroteno/ácido linoleico, varredura do radical 2,2 Difenil-1-Picril-hidrazil e oxigen radical absorbance capacity. Ratos Wistar machos foram distribuídos em 5 grupos: controle, diabético, e três grupos de animais diabéticos tratados com extrato aquoso de alecrim em concentrações diferentes: 25, 50 ou 100mg/kg por via oral durante 30 dias. O diabetes foi induzido por estreptozotocina e, no final do experimento, foi coletado sangue para avaliar o percentual de hemoglobina glicada e os tecidos hepático e cerebral para determinação das enzimas antioxidantes: superóxido dismutase, catalase, glutationa peroxidase e glutationa redutase. RESULTADOS: Constatou-se que o extrato aquoso de alecrim apresentou altos teores de compostos fenólicos totais e expressiva atividade antioxidante in vitro nos três métodos de avaliação. O extrato aquoso de alecrim na concentração de 50mg/kg diminuiu o percentual de hemoglobina glicada e aumentou a atividade das enzimas catalase e glutationa peroxidase no fígado, e da superóxido dismutase no cérebro de ratos diabéticos. No entanto, não foi observado efeito dose-resposta nas demais concentrações analisadas. CONCLUSÃO: O extrato aquoso de alecrim apresenta significativa capacidade antioxidante in vitro, atribuída à presença de compostos fenólicos em sua composição. E, quando administrado em ratos na concentração de 50mg/kg, demonstrou-se eficiente na atenuação do estresse oxidativo presente no diabetes experimental.

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