title: Limited stability in cell culture medium and hydrogen peroxide formation affect the growth inhibitory properties of delphinidin and its degradation product gallic acid.
abstract: In the present study we investigated the stability of anthocyanidins under cell culture conditions and addressed the question whether degradation products might contribute to the cellular effects assigned to the parent compounds. Substantial degradation was found already after 30 min, measured by HPLC/DAD. However, the decrease of detectable anthocyanidins exceeded by far the formation of the respective phenolic acids. From the formed phenolic acids only gallic acid (GA) exhibited growth inhibitory properties. However, also GA was found to be degraded rapidly. Furthermore, the incubation with delphinidin (DEL) or GA resulted in a substantial formation of hydrogen peroxide. The suppression of hydrogen peroxide accumulation by catalase modified significantly the growth inhibitory effects of DEL and GA, indicating that hydrogen peroxide formation might generate experimental artefacts. In summary, the results show that the phenolic acids formed by the degradation of cyanidin (CY), pelargonidin (PG), peonidin (PN) and malvidin (MV) do not contribute to the growth inhibitory effect of the parent compound. The degradation of DEL generates a phenolic acid with substantial growth inhibitory properties (GA). However, taken into account the small proportion of generated GA and its lacking stability, the contribution of GA to the growth inhibitory properties of DEL might be limited.
authors.affiliation: Institute of Applied Biosciences, Section of Food Toxicology, University of Karlsruhe TH, Karlsruhe, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Kern
authors.forename: Diana
authors.initials: D
authors.lastname: Fridrich
authors.forename: Julia
authors.initials: J
authors.lastname: Reichert
authors.forename: Susanne
authors.initials: S
authors.lastname: Skrbek
authors.forename: Anja
authors.initials: A
authors.lastname: Nussher
authors.forename: Sabine
authors.initials: S
authors.lastname: Hofem
authors.forename: Sandra
authors.initials: S
authors.lastname: Vatter
authors.forename: Gudrun
authors.initials: G
authors.lastname: Pahlke
authors.forename: Corinna
authors.initials: C
authors.lastname: Rüfer
authors.forename: Doris
authors.initials: D
authors.lastname: Marko
mesh_terms: D000872:Anthocyanins / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D003470:Culture Media / Q000737:chemistry*; D004355:Drug Stability; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005707:Gallic Acid / Q000737:chemistry / Q000494:pharmacology*; D006131:Growth Inhibitors / Q000494:pharmacology*; D019073:HT29 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors
chemical_list: D000872:Anthocyanins; D003470:Culture Media; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D005707:Gallic Acid; D006861:Hydrogen Peroxide; D002374:Catalase; D011505:Protein-Tyrosine Kinases; C017185:delphinidin