title: Protective effect of a Phyllanthus orbicularis aqueous extract against UVB light in human cells.
abstract: BACKGROUND
  One approach to protect human skin against the dangerous effects of solar ultraviolet (UV) irradiation is the use of natural products, such as photoprotectors. Phyllanthus orbicularis Kunth (Euphorbiaceae) is a Cuban endemic plant used in popular medicine. Its antigenotoxicity effect against some harmful agents has been investigated. However, the effect in ultraviolet B (UVB)-irradiated human cells has not been previously assessed.
  
  
  OBJECTIVE
  The protective effect of a P. orbicularis extract against UVB light-induced damage in human cells was evaluated.
  
  
  METHODS
  DNA repair proficient (MRC5-SV) and deficient (XP4PA, complementation group XPC) cell-lines were used. Damaging effects of UVB light were evaluated by clonogenic assay and apoptosis induction by flow cytometry techniques. The extent of DNA repair itself was determined by the removal of cyclobutane pyrimidine dimers (CPDs). The CPDs were detected and quantified by slot-blot assay.
  
  
  RESULTS
  Treatment of UVB-irradiated MRC5-SV cells with P. orbicularis extract increased the percentage of colony-forming cells from 36.03 ± 3.59 and 4.42 ± 1.45 to 53.14 ± 8.8 and 14.52 ± 1.97, for 400 and 600 J/m(2), respectively. A decrease in apoptotic cell population was observed in cells maintained within the extract. The P. orbicularis extract enhanced the removal of CPD from genomic DNA. The CPDs remaining were found to be about 27.7 and 1.1%, while with plant extract, treatment these values decreased to 16.1 and 0.2%, for 3 and 24 h, respectively.
  
  
  CONCLUSIONS
  P. orbicularis aqueous extract protects human cells against UVB damage. This protective effect is through the modulation of DNA repair effectiveness.
authors.affiliation: Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Ciudad de la Habana, Cuba.
authors.forename: Marioly
authors.initials: M
authors.lastname: Vernhes
authors.forename: Maribel
authors.initials: M
authors.lastname: González-Pumariega
authors.forename: Luciana
authors.initials: L
authors.lastname: Andrade
authors.forename: Andre Passaglia
authors.initials: AP
authors.lastname: Schuch
authors.forename: Keronninn Moreno
authors.initials: KM
authors.lastname: de Lima-Bessa
authors.forename: Carlos Frederico Martins
authors.initials: CF
authors.lastname: Menck
authors.forename: Angel
authors.initials: A
authors.lastname: Sánchez-Lamar
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D003114:Colony-Forming Units Assay; D003462:Cuba; D004260:DNA Repair / Q000187:drug effects* / Q000528:radiation effects; D005434:Flow Cytometry; D006801:Humans; D029803:Phyllanthus / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D011740:Pyrimidine Dimers / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D010936:Plant Extracts; D011740:Pyrimidine Dimers