title: In vitro antifungal effect of black cumin seed quinones against dairy spoilage yeasts at different acidity levels.
abstract: The antiyeast activity of the black cumin seed (Nigella sativa) quinones dithymoquinone, thymohydroquinone (THQ), and thymoquinone (TQ) were evaluated in vitro with a broth microdilution method against six dairy spoilage yeast species. Antifungal effects of the quinones were compared with those of preservatives commonly used in milk products (calcium propionate, natamycin, and potassium sorbate) at two pH levels (4.0 and 5.5). THQ and TQ possessed significant antiyeast activity and affected the growth of all strains tested at both pH levels, with MICs ranging from 8 to 128 μg/ml. With the exception of the antibiotic natamycin, the inhibitory effects of all food preservatives against the yeast strains tested in this study were strongly affected by differences in pH, with MICs of ≥16 and ≥512 μg/ml at pH 4.0 and 5.5, respectively. These findings suggest that HQ and TQ are effective antiyeast agents that could be used in the dairy industry as chemical preservatives of natural origin.
authors.affiliation: Department of Crop Sciences and Agroforestry, Institute of Tropics and Subtropics, Nutrition and Dietetics, Faculty of Agrobiology, Food and Nature Resources, Czech University of Life Sciences Prague, Kamycka 129, Prague 6-Suchdol, 165 21, Czech Republic.
authors.forename: Katerina
authors.initials: K
authors.lastname: Halamova
authors.forename: Ladislav
authors.initials: L
authors.lastname: Kokoska
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Flesar
authors.forename: Olga
authors.initials: O
authors.lastname: Sklenickova
authors.forename: Blanka
authors.initials: B
authors.lastname: Svobodova
authors.forename: Petr
authors.initials: P
authors.lastname: Marsik
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000382:microbiology*; D031881:Nigella sativa / Q000737:chemistry*; D011809:Quinones / Q000494:pharmacology*; D015003:Yeasts / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000935:Antifungal Agents; D005520:Food Preservatives; D011809:Quinones