en Other Other Original Article Original Article <span style="font-family:Tahoma;"><span style="font-size:12px;"><span style="unicode-bidi:embed"><span style="line-height:107%">Gallic acid (GA) is a powerful antioxidant extracted from plants of the Brazilian Cerrado. Oxidative stress plays an important role in the occurrence of radiation-induced osteonecrosis in patients treated for head and neck cancer. There is a need to develop research aimed at developing complementary therapies to prevent or reverse bone damage. The aim of the present study was to investigate the effect of GA in preosteoblasts exposed to therapeutic ionizing radiation. MC3T3-E1 preosteoblast cells were treated with 10 &micro;M GA and exposed to 6 Gy ionizing radiation. We performed in vitro assays of cell proliferation, oxidative stress analysis by detection of reactive oxygen species, and alkaline phosphatase assay. GA at lower concentrations was able to significantly increase proliferation and inhibit radiation-induced generation of reactive oxygen species in osteoblast precursor cells, despite ionizing radiation-induced injury. Furthermore, GA significantly increased alkaline phosphatase at a dose of 6 Gy. The findings suggested that GA could attenuate ionizing radiation-induced injuries in osteoblast precursor cells. Moreover, in vivo studies are needed to better investigate the role of GA in osteonecrosis, especially in cancer patients undergoing radiotherapy or taking antiresorptive drugs.</span></span></span></span> Antioxidant, Gallic acid, ionizing radiation, osteonecrosis, osteoradion-ecrosis, radiotherapy 19 28 http://ijmcmed.org/browse.php?a_code=A-10-931-3&slc_lang=en&sid=1 Renata Sousa Leite renatasl.doutorado@gmail.com 100319475328460030046 0009-0006-5267-3137 No Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Rogério Gonçalves da Rocha rogerio.g.rocha@gmail.com 100319475328460030047 100319475328460030047 No Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Angeliny Tamiarana Lima Tabosa angel.tabosa@yahoo.com.br 100319475328460030048 100319475328460030048 No Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Emisael Stênio Batista Gomes stenio.tena@gmail.com 100319475328460030049 100319475328460030049 No Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Laís Santiago lais-santiago2011@hotmail.com 100319475328460030050 100319475328460030050 No Oncological Radiology Center, Hospital Dilson Godinho, Montes Claros, Minas Gerais, Brazil. Danillo Costa Rodrigues danillocr0507@gmail.com 100319475328460030051 100319475328460030051 No Department of Dentistry, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Sérgio Henrique Sousa Santos sergiosousas@hotmail.com 100319475328460030052 100319475328460030052 No Institute of Agricultural Sciences, Food Engineering College, Universidade Federal de Minas Gerais, Montes Claros, Minas Gerais, Brazil. André Luiz Sena Guimarães andre.guimaraes@unimontes.br 100319475328460030053 100319475328460030053 No Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil. Lucyana Conceição Farias lucyana.farias@unimontes.br 100319475328460030054 100319475328460030054 Yes Laboratory of Health Science, Postgraduate Program in Health Sciences, Universidade Estadual de Montes Claros, Minas Gerais, Brazil.