title: Isolation, identification, and quantification of roasted coffee antibacterial compounds.
abstract: 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 alpha-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 alpha-dicarbonyl compounds at the concentrations found in coffee demonstrated that caffeine synergistically enhances the antibacterial activity of alpha-dicarbonyl compounds and that glyoxal, methylglyoxal, and diacetyl in the presence of caffeine account for the whole antibacterial activity of roasted coffee.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Daglia
authors.forename: Adele
authors.initials: A
authors.lastname: Papetti
authors.forename: Pietro
authors.initials: P
authors.lastname: Grisoli
authors.forename: Camilla
authors.initials: C
authors.lastname: Aceti
authors.forename: Valentina
authors.initials: V
authors.lastname: Spini
authors.forename: Cesare
authors.initials: C
authors.lastname: Dacarro
authors.forename: Gabriella
authors.initials: G
authors.lastname: Gazzani
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000302:isolation & purification; D002110:Caffeine / Q000494:pharmacology; D040503:Coffea / Q000737:chemistry*; D003931:Diacetyl / Q000032:analysis / Q000494:pharmacology; D006037:Glyoxal / Q000032:analysis / Q000494:pharmacology; D006358:Hot Temperature; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D002110:Caffeine; D006037:Glyoxal; D003931:Diacetyl