title: Determination of cytotoxicity of traditional Chinese medicine herbs, Rhizoma coptidis, Radix scutellariae, and Cortex phellodendri, by three methods.
abstract: BACKGROUND
  Many herbs are used in traditional Chinese medicine TCM) for treatment of infections but their properties, in particular, their effects on normal cells have received little attention. This study investigated the cytotoxic properties of three TCM herbs with potential use in prevention and treatment of ocular infections, including Acanthamoeba keratitis.
  
  
  METHODS
  The study investigated cytotoxic effects of the herbal extracts of Rhizoma coptidis, Radix scutellariae, and Cortex phellodendri on human corneal epithelial cells using trypan blue staining, MTT production, and flow cytometry. Differences between herbs were determined using repeated measures one-way analysis of variance, followed by paired t-tests where appropriate.
  
  
  RESULTS
  These three herbs appeared to lack cytotoxicity when tested with trypan blue and MTT, but flow cytometry revealed that R. coptidis led to cell membrane damage.
  
  
  CONCLUSIONS
  Lack of cytotoxicity of R. scutellariae and C. phellodendri extracts suggest that these are potentially suitable for use in ocular preparations. Only flow cytometry was able to accurately predict cytotoxic effects of extracts of TCM herbs on HCEC, demonstrating the importance of using a sensitive method of detection of cytotoxicity.
authors.affiliation: Squina Centre for Infection Control, School of Nursing, The Hong Kong Polytechnic University, Hong Kong. Electronic address: maureen.boost@polyu.edu.hk.
authors.forename: Maureen
authors.initials: M
authors.lastname: Boost
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Philip
authors.initials: P
authors.lastname: Yau
authors.affiliation: Squina Centre for Infection Control, School of Nursing, The Hong Kong Polytechnic University, Hong Kong; School of Optometry, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Maurice
authors.initials: M
authors.lastname: Yap
authors.affiliation: Squina Centre for Infection Control, School of Nursing, The Hong Kong Polytechnic University, Hong Kong; School of Optometry, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Pauline
authors.initials: P
authors.lastname: Cho
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D004396:Coloring Agents; D039323:Coptis / Q000737:chemistry*; D004365:Drugs, Chinese Herbal / Q000633:toxicity*; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D008516:Medicine, Chinese Traditional; D032102:Phellodendron / Q000737:chemistry*; D010936:Plant Extracts / Q000633:toxicity*; D031364:Scutellaria baicalensis / Q000737:chemistry*; D013194:Staining and Labeling; D013778:Tetrazolium Salts; D013844:Thiazoles; D018675:Toxicity Tests / Q000379:methods; D014343:Trypan Blue
chemical_list: D017304:Annexin A5; D004396:Coloring Agents; D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue; D014343:Trypan Blue
keywords: Cortex phellodendri; Cytotoxicity; Flow cytometry; Human corneal epithelial cells; Radix scutellariae; Rhizoma coptidis