Isolation, Identification, and Quantification of Roasted Coffee Antibacterial Compounds

• Published in: Journal of agricultural and food chemistry 2007-12, Vol.55 (25), p.10208-10213
• Main Authors: Daglia, Maria, Papetti, Adele, Grisoli, Pietro, Aceti, Camilla, Spini, Valentina, Dacarro, Cesare, Gazzani, Gabriella
• Format: Article
• Language: English
• Subjects: alpha-dicarbonyl compounds; Anti-Bacterial Agents - analysis; Anti-Bacterial Agents - isolation & purification; antibacterial activity; antibacterial properties; bioactive constituent; Biological and medical sciences; caffeine; Caffeine - pharmacology; carbonyl compounds; Coffea - chemistry; coffee beans; Coffee, tea and other stimulative beverage industries; Diacetyl - analysis; Diacetyl - pharmacology; diacetyl compounds; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; glyoxal; Glyoxal - analysis; Glyoxal - pharmacology; Hot Temperature; methylglyoxal; Plant Extracts - chemistry; Plant Extracts - pharmacology; Roasted coffee; roasting; Seeds - chemistry; Staphylococcus aureus; Staphylococcus aureus - drug effects; Streptococcus mutans; Streptococcus mutans - drug effects; α-dicarbonyl compounds
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0722607

Coffee brew is a widely consumed beverage with multiple biological activities due both to naturally occurring components and to the hundreds of chemicals that are formed during the roasting process. Roasted coffee extract possesses antibacterial activity against a wide range of microorganisms, including Staphylococcus aureus and Streptococcus mutans, whereas green coffee extract exhibits no such activity. The naturally occurring coffee compounds, such as chlorogenic acids and caffeine, cannot therefore be responsible for the significant antibacterial activity exerted by coffee beverages against both bacteria. The very low minimum inhibitory concentration (MIC) found for standard glyoxal, methylglyoxal, and diacetyl compounds formed during the roasting process points to these α-dicarbonyl compounds as the main agents responsible for the antibacterial activity of brewed coffee against Sa. aureus and St. mutans. However, their low concentrations determined in the beverage account for only 50% of its antibacterial activity. The addition of caffeine, which has weak intrinsic antibacterial activity, to a mixture of α-dicarbonyl compounds at the concentrations found in coffee demonstrated that caffeine synergistically enhances the antibacterial activity of α-dicarbonyl compounds and that glyoxal, methylglyoxal, and diacetyl in the presence of caffeine account for the whole antibacterial activity of roasted coffee.