title: Antioxidant responses of damiana (Turnera diffusa Willd) to exposure to artificial ultraviolet (UV) radiation in an in vitro model; part ii; UV-B radiation.
abstract: BACKGROUND
  Ultraviolet type B (UV-B) radiation effects on medicinal plants have been recently investigated in the context of climate change, but the modifications generated by UV-B radiation might be used to increase the content of antioxidants, including phenolic compounds.
  
  
  OBJECTIVE
  To generate information on the effect of exposure to artificial UV-B radiation at different highdoses in the antioxidant content of damiana plants in an in vitro model.
  
  
  METHODS
  Damiana plantlets (tissue cultures in Murashige- Skoog medium) were irradiated with artificial UV-B at 3 different doses (1) 0.5 ± 0.1 mW cm-2 (high) for 2 h daily, (2) 1 ± 0,1 mW cm-2 (severe) for 2 h daily, or (3) 1 ± 0.1 mW cm-2 for 4 h daily during 3 weeks. The concentration of photosynthetic pigments (chlorophylls a and b, carotenoids), vitamins (C and E) and total phenolic compounds, the enzymatic activity of superoxide dismutase (SOD, EC 1.15.1.1) and total peroxidases (POX, EC 1.11.1), as well as total antioxidant capacity and lipid peroxidation levels were quantified to assess the effect of high artificial UV-B radiation in the antioxidant content of in vitro damiana plants.
  
  
  RESULTS
  Severe and high doses of artificial UV-B radiation modified the antioxidant content by increasing the content of vitamin C and decreased the phenolic compound content, as well as modified the oxidative damage of damiana plants in an in vitro model.
  
  
  CONCLUSIONS
  UV-B radiation modified the antioxidant content in damiana plants in an in vitro model, depending on the intensity and duration of the exposure.
authors.affiliation: Planeación Ambiental y Conservación.. tzenteno04@cibnor.mx.
authors.forename: Lluvia de Abril Alexandra
authors.initials: Lde A
authors.lastname: Soriano-Melgar
authors.affiliation: Agricultura en Zonas Áridas. Centro de Investigaciones Biológicas del Noroeste. S. C., Instituto Politécnico Nacional 195. Col. Playa Palo de Santa Rita Sur, La Paz, Baja California Sur. México..
authors.forename: Lilia
authors.initials: L
authors.lastname: Alcaraz-Meléndez
authors.affiliation: Planeación Ambiental y Conservación..
authors.forename: Lía C
authors.initials: LC
authors.lastname: Méndez-Rodríguez
authors.affiliation: Planeación Ambiental y Conservación..
authors.forename: María Esther
authors.initials: ME
authors.lastname: Puente
authors.affiliation: Laboratorio de Fisiología, Bioquímica y Biología Molecular de Plantas. Departamento de Ciencias de la Salud. Universidad Autónoma Metropolitana. Unidad Iztapalapa. Iztapalapa México D. F. México..
authors.forename: Fernando
authors.initials: F
authors.lastname: Rivera-Cabrera
authors.affiliation: Planeación Ambiental y Conservación.. tzenteno04@cibnor.mx.
authors.forename: Tania
authors.initials: T
authors.lastname: Zenteno-Savín
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D018384:Oxidative Stress; D010636:Phenols / Q000378:metabolism; D029647:Turnera / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D010636:Phenols