title: The Phototoxic Potential of the Flavonoids, Taxifolin and Quercetin.
abstract: Quercetin, one of the most abundant polyphenols in the plant kingdom has been shown to be photodegraded on exposure to UV light. Despite the fact, it is a component of several dermatological preparations. Its phototoxic potential has not been evaluated to date. The aim of this study was to assess whether photo-induced degradation of quercetin is linked to phototoxic effects on living cells. Its dihydro derivative, taxifolin, was included in the study. For evaluation, the 3T3 Neutral Red Uptake Phototoxicity Test according to OECD TG 432 was used. To better approximate human skin, HaCaT keratinocytes, normal human epidermal keratinocytes and dermal fibroblasts were used, apart from the Balb/c 3T3 cell line. Quercetin showed a dose-dependent photodegradation in aqueous and organic environments and a phototoxic effect on all used cells. Quercetin pretreatment and following UVA exposure resulted in increased reactive oxygen species production and intracellular glutathione level depletion in human dermal fibroblasts. Taxifolin was found completely nonphototoxic and photostable. As only in vitro methodology was used, further studies using 3D skin models and/or human volunteers are needed to confirm whether exposure to sunlight, tanning sunbeds and/or phototherapy in people using cosmetics containing quercetin is a health risk.
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Alena
authors.initials: A
authors.lastname: Rajnochová Svobodová
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Alena
authors.initials: A
authors.lastname: Ryšavá
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Michaela
authors.initials: M
authors.lastname: Psotová
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kosina
authors.affiliation: Department of Plastic and Aesthetic Surgery, University Hospital Olomouc, Olomouc, Czech Republic.
authors.forename: Bohumil
authors.initials: B
authors.lastname: Zálešák
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Ulrichová
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Vostálová
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000633:toxicity*; D012867:Skin / Q000166:cytology / Q000187:drug effects; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D011794:Quercetin; C003377:taxifolin