title: Chemical form of metals in traditional medicines underlines potential toxicity in cell cultures.
abstract: BACKGROUND
  Mercury (Hg) and arsenic (As) are frequently found in traditional medicines as sulfides, such as cinnabar (HgS) and realgar (As(4)S(4)). There is a general perception that any medicinal use of such metal-containing remedies is unacceptable. An opposing opinion is that different chemical forms of arsenic and mercury have different toxic potentials.
  
  
  OBJECTIVE
  To clarify this question, cinnabar, realgar, and cinnabar- and realgar-containing traditional medicine An-Gong-Niu-HuangWan (AGNH), were compared to well-known mercurials (HgS, HgCl(2) and MeHg) and arsenicals (As(2)S(2), As(2)O(3), NaAsO(2), and Na(2)HAsO(4)) for their cytotoxicity in human and rodent cell lines.
  
  
  METHODS
  Cultured cells derived from target organs such as brain (HAPI) and liver (Hep3B, HepG2 and TRL1215) were treated with chemicals for 48 h and cytotoxicity was determined by the MTS assay.
  
  
  RESULTS
  MeHg was most toxic with LC(50) of 4-20μM, followed by NaAsO(2) (LC(50), 25-250 μM) and HgCl(2) (LC(50,) 50-100 μM), Na(2)HAsO(4)(LC(50), 60-400μM), As(2)O(3)(LC(50), 30-900 μM), and As(2)S(2) (LC(50), 100-500 μM). In comparison, the LC(50) of realgar ranged from 250 to1500 μM; whereas cinnabar or HgS were approximately 20,000 μM and the toxicity of AGNH was in the range of 1500-8000 μM. Approximately 5000-fold differences exist between MeHg and HgS, and over 10-fold differences exist between NaAsO(2) and As(4)S(4).
  
  
  CONCLUSIONS
  Chemical forms of metals are important factor in determining their toxicity in traditional medicines, both cinnabar and realgar are much less toxic than well-known mercurial and arsenicals.
authors.affiliation: Zunyi Medical College, Zunyi, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wu
authors.forename: Yuan-Fu
authors.initials: YF
authors.lastname: Lu
authors.forename: Jing-Zhen
authors.initials: JZ
authors.lastname: Shi
authors.forename: Shi-Xia
authors.initials: SX
authors.lastname: Liang
authors.forename: Jin-Shan
authors.initials: JS
authors.lastname: Shi
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
mesh_terms: D045744:Cell Line, Tumor; D002478:Cells, Cultured; D006801:Humans; D008519:Medicine, Traditional; D008670:Metals / Q000737:chemistry* / Q000633:toxicity; D008928:Mitochondria / Q000187:drug effects; D018384:Oxidative Stress
chemical_list: D008670:Metals