title: Antigenotoxic activity of Thai Sangyod red rice extracts against a chemotherapeutic agent, doxorubicin, in human lymphocytes by sister chromatid exchange (SCE) assay in vitro.
abstract: BACKGROUND
  Nowadays, anticarcinogenic potential of pigmented brown rice and rice bran varieties have been increasingly stated. However, their mechanisms of action are still inconclusive. One of which might be their antigenotoxic activity that no study in human cells was reported before.
  
  
  OBJECTIVE
  To evaluate the antigenotoxic activities of Thai Sangyod red rice extracts against a chemotherapeutic agent, doxorubicin, by sister chromatid exchange (SCE) assay in human lymphocytes in vitro.
  
  
  METHODS
  Two fractions of water-soluble of Sangyod rice extracts were used: (i) the washed water extract of brown rice (WWBR) and (ii) the water extract of rice bran (WERB). Human lymphocytes were pretreated with each extracts at concentrations of 6.2, 12.5, 25, 50 and 100 microg/ml for 2 h followed by a genotoxic agent, doxorubicin (DXR) (0.1 microg/ml) for 2 h. SCE level, mitotic index (MI) and proliferation index (PI) were evaluated. Statistical analysis by Dunnett's t-test was performed.
  
  
  RESULTS
  The results indicated that the pretreatment of WERB fraction only at concentration of 6.2 microg/ml could significantly decrease SCE level as compared to that of the DXR treated alone (p < 0.05). On the other hand, WERB fraction at other concentrations and all WWBR pretreatments could not. In addition, there was no significant difference in MI and PI levels between all pretreated extracts as compared to the DXR treated alone.
  
  
  CONCLUSIONS
  Our data revealed that WERB pretreatment only at specific low concentration of 6.2 microg/ml possessed the antigenotoxic potential against genotoxic damage but not anticytotoxic induced by DXR. Further work is still needed to clarify more the antigenotoxic and anticytotoxic potentials from other fractions of Sangyod rice extracts.
authors: Division of Biochemistry, Preclinical Science Department, Faculty of Medicine, Thammasat University, Pathumthani, Thailand. treetip2000@hotmail.com
authors: Treetip
authors: T
authors: Ratanavalachai
authors: Sumon
authors: S
authors: Thitiorul
authors: Sermkiat
authors: S
authors: Tanuchit
authors: Chalerm
authors: C
authors: Jansom
authors: Sakultala
authors: S
authors: Uttama
authors: Arunporn
authors: A
authors: Itharat
mesh_terms: D000328:Adult; D000903:Antibiotics, Antineoplastic / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004317:Doxorubicin / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects*; D008940:Mitotic Index; D009152:Mutagenicity Tests; D012275:Oryza; D010860:Pigments, Biological / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013785:Thailand
chemical_list: D000903:Antibiotics, Antineoplastic; D010860:Pigments, Biological; D010936:Plant Extracts; D004317:Doxorubicin