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| Author(s): |
Yara Severino de Queiroz
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR) |
| Defense date: | 2011-02-21 |
| Examining board members: |
Elizabeth Aparecida Ferraz da Silva Torres;
João Ernesto de Carvalho;
Maria Beatriz de Abreu Gloria;
Marcelo Macedo Rogero;
Geni Rodrigues Sampaio
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| Advisor: | Elizabeth Aparecida Ferraz da Silva Torres |
| Abstract | |
Introduction: The increased consumption of fruits and vegetables is associated with reduced risks of chronic diseases. This protective effect has been attributed particularly to the presence of several bioactive compounds such as phenolic and organosulfur compounds, likewise phytosterols present in garlic that may contribute to the antioxidant and lipid-lowering effects. However, the processing of garlic can cause changes in the quantity and effectiveness of bioactive compounds. This study aimed to evaluate whether the cooking and frying of garlic reduced the bioactive compounds concentrations, the antioxidant potential in vitro and in vivo in hypercholesterolemic hamsters. Methods: In vitro - were determined in raw garlic, fried and boiling: a) composition (protein, fat, ash, carbohydrates, dietary fiber, soluble and insoluble), b) fatty acid profile, c) total phenolic content, d ) content of quercetin, myricetin and apigenin, e) phytosterols, f) allicin, g) content of copper, zinc and selenium, h) Maillard reaction products, i) antioxidant potential using the ORAC test (Oxygen radical absorbance capacity), Rancimat® and system -caroteno/ácido linoleic. In vivo - male hamsters were divided into five groups with 10 animals each. 1 - control, 2 hypercholesterolemic, 3 - hypercholesterolemic and raw garlic, 4 - hypercholesterolemic and boiling garlic, group 5 - hypercholesterolemic and fried garlic. Samples of blood and liver were collected after a 4-week experimental period. In plasma were determined the antioxidant potential by the ORAC assay, the lipid profile (total cholesterol and fractions and triacylglycerols) and verified the activity of enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT). In liver tissue were evaluated the activity of liver enzymes (glutathione peroxidase, catalase and superoxide dismutase) and the antioxidant potential using two methods, ORAC and comet assay. Results: In vitro - The content of dietary fiber for raw garlic was 10.0per cent (71.6per cent is soluble and 28.4per cent is insoluble). The high content of trans fatty acids in fried garlic (14.9per cent ) is due to the frying process with 50per cent hydrogenated vegetable fat. The cooking did not alter the content of the minerals analyzed. The content of phenolic compounds in garlic samples ranged from 4.2 to 187.7 mg EAG/100g (dry matter), depending on the solvent (water, water / methanol, ethanol or acetone) and the extraction method used. Frying decreased the content of quercetin and allicin around 24per cent and 87per cent respectively. The phytosterols -sitosterol and campesterol are present in all samples, and the fried garlic showed the highest levels of these compounds in relation to raw and boiling garlic, besides presenting stigmasterol. Frying was the heat processing that contributed to the higher values of products of the Maillard reaction. The antioxidant potential by the ORAC assay (ethanol extracts, methanol/water and acetone) was reduced with the processing of garlic, and the reduction was greater for frying. The inhibition of lipid oxidation was better in methanol/water extracts. In vivo - The group of animals that received ration hyperlipidemic and raw garlic had less weight gain compared with groups that received garlic fried or boiling. Raw and boiling garlic were effective in reducing lipids in hamsters plasma. The antioxidant potential (measured by the ORAC and comet assay tests) of the groups hypercholesterolemic supplemented with raw or boiling garlic had higher values than the not supplemented group hypercholesterolemic. There was increased activity of antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase in all groups supplemented with garlic. In all groups there was no structural or functional damage in liver tissue. Conclusions: These results corroborate the expected and suggest that the raw and boiling garlic may lead to health benefits, given that these products have bioactive compounds, hypolipidemic effect and showed a high antioxidant potential in plasma and liver tissue, in addition to increased activity of antioxidant enzymes that are involved in mechanisms of health protection (AU) | |