Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy, and Department of Internal Medicine and Therapeutics, Faculty of Medicine, University of Pavia, Piazza Botta 10, 27100 Pavia, Italy
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 β-carotene−linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as TBA-reacting substances.
RS of Coffea robusta samples were found to be significantly higher when compared to those of Coffea arabica samples (p < 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 < 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 molecular mass protective fractions isolated indicate that they contain very strong protective agents.
Copyright © 2000 American Chemical Society
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The original text taken from a:
Daglia, Maria, et al. "In vitro antioxidant and ex vivo protective activities of green and roasted coffee." Journal of Agricultural and food chemistry 48.5 (2000): 1449-1454.