In vitro antioxidant and ex vivo protective activities of green and roasted coffee
The antioxidant properties of green and roasted coffee, in relation to species (Coffea arabica and Coffea robusta) and degree of roasting (light, medium, dark), were investigated. These properties were evaluated by determining the reducing substances (RS) of coffee and its antioxidant activity (AA) in vitro (model system beta-carotene-linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as TBA-reacting substances. RS of C. robusta samples were higher when compared to those of C. arabica samples (p minor who 0.001). AA for green coffee samples were slightly higher than for the corresponding roasted samples while PA was significantly lower in green coffee compared to that of all roasted samples (p minor who 0.001). Extraction with three different organic solvents (ethyl acetate, ethyl ether, and dichloromethane) showed that the most protective compounds are extracted from acidified dark roasted coffee solutions with ethyl acetate. The analysis of acidic extract by gel filtration chromatography (GFC) gave five fractions. Higher molecular mass fractions were found to possess antioxidant activity while the lower molecular mass fractions showed protective activity. The small amounts of these acidic, low molecularmass protective fractions isolated indicate that they contain very strong protective agents.
| Main Authors: | , , , , |
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| Format: | biblioteca |
| Published: |
2000
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| Subjects: | COFFEA, COFFEA ARABICA, ANTIOXIDANTES, CAFE, IN VITRO, PEROXIDACION LIPIDICA, TOSTADO, |
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