title: Protective effect of Calendula officinalis extract against UVB-induced oxidative stress in skin: evaluation of reduced glutathione levels and matrix metalloproteinase secretion.
abstract: OBJECTIVE
  Calendula officinalis flowers have long been employed time in folk therapy, and more than 35 properties have been attributed to decoctions and tinctures from the flowers. The main uses are as remedies for burns (including sunburns), bruises and cutaneous and internal inflammatory diseases of several origins. The recommended doses are a function both of the type and severity of the condition to be treated and the individual condition of each patient. Therefore, the present study investigated the potential use of Calendula officinalis extract to prevent UV irradiation-induced oxidative stress in skin.
  
  
  METHODS
  Firstly, the physico-chemical composition of marigold extract (ME) (hydroalcoholic extract) was assessed and the in vitro antioxidant efficacy was determined using different methodologies. Secondly, the cytotoxicity was evaluated in L929 and HepG2 cells with the MTT assay. Finally, the in vivo protective effect of ME against UVB-induced oxidative stress in the skin of hairless mice was evaluated by determining reduced glutathione (GSH) levels and monitoring the secretion/activity of metalloproteinases.
  
  
  CONCLUSIONS
  The polyphenol, flavonoid, rutin and narcissin contents found in ME were 28.6 mg/g, 18.8 mg/g, 1.6 mg/g and 12.2mg/g, respectively and evaluation of the in vitro antioxidant activity demonstrated a dose-dependent effect of ME against different radicals. Cytoxicity experiments demonstrated that ME was not cytotoxic for L929 and HepG2 cells at concentrations less than or equal to of 15 mg/mL. However, concentrations greater than or equal to 30 mg/mL, toxic effects were observed. Finally, oral treatment of hairless mice with 150 and 300 mg/kg of ME maintained GSH levels close to non-irradiated control mice. In addition, this extract affects the activity/secretion of matrix metalloproteinases 2 and 9 (MMP-2 and -9) stimulated by exposure to UVB irradiation. However, additional studies are required to have a complete understanding of the protective effects of ME for skin.
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Yris Maria
authors.initials: YM
authors.lastname: Fonseca
authors.forename: Carolina Dias
authors.initials: CD
authors.lastname: Catini
authors.forename: Fabiana T M C
authors.initials: FT
authors.lastname: Vicentini
authors.forename: Auro
authors.initials: A
authors.lastname: Nomizo
authors.forename: Raquel Fernanda
authors.initials: RF
authors.lastname: Gerlach
authors.forename: Maria José Vieira
authors.initials: MJ
authors.lastname: Fonseca
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D020838:Calendula / Q000737:chemistry*; D003603:Cytotoxins; D003879:Dermatologic Agents / Q000032:analysis / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology; D035264:Flowers; D005978:Glutathione / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D051379:Mice; D008812:Mice, Hairless; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects; D010636:Phenols / Q000032:analysis / Q000494:pharmacology; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011837:Radiation-Protective Agents / Q000032:analysis / Q000494:pharmacology; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D003603:Cytotoxins; D003879:Dermatologic Agents; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D011837:Radiation-Protective Agents; D020782:Matrix Metalloproteinases; D005978:Glutathione