title: Antioxidant activity and cytotoxicity of Cyrtosperma johnstonii extracts on drug sensitive and resistant leukemia and small cell lung carcinoma cells.
abstract: BACKGROUND
  The number of patients with cancer is increasing. New therapeutic agents to overcome drug-resistant tumors are urgently needed. Cyrtosperma johnstonii N.E. Br. (Araceae) is used for treatment of cancer in Thai traditional medicine. This study aimed to evaluate antioxidant activity and cytotoxicity of C. johnstonii extracts on human cancer cells.
  
  
  METHODS
  Dried powder of C. johnstonii rhizomes was extracted with several solvents. The 0.1 mg/ml extract solution was tested for antioxidant activity by 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP) assays. Color formation from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to determine cell viability. Standardization of the extract was performed by high-performance liquid chromatography (HPLC) with photodiode array detector at 254 and 360 nm. Cell cycle arrest was evaluated by flow cytometry after 5 min, 12 h and 24 h treated with 20 µg/ml of the acetone extract.
  
  
  RESULTS
  The acetone extract exhibited the highest phenolic content and antioxidant activity (TEAC and EC values = 19.2 ± 0.14 and 19.2 ± 0.31 mM/mg, respectively). The IC₅₀ values for leukemia ranged from 11 ± 1 to 29 ± 3 µg/ml and from 5 ± 2 to 6 ± 0 µg/ml for small cell lung carcinoma cells. Cell cycle arrest occurred at the G2/M phase followed by apoptosis. HPLC analysis revealed that rutin is the major constituents of the extract.
  
  
  CONCLUSIONS
  The acetone extract of C. johnstoni is a promising source of natural antioxidants and anticancer. The extract inhibits cancer cells effectively with less effect on normal cells.
authors.affiliation: Department of Pharmaceutical Science, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand. sirioko@chiangmai.ac.th
authors.forename: Siriporn
authors.initials: S
authors.lastname: Okonogi
authors.forename: Ruttiros
authors.initials: R
authors.lastname: Khonkarn
authors.forename: Samlee
authors.initials: S
authors.lastname: Mankhetkorn
authors.forename: Frank M
authors.initials: FM
authors.lastname: Unger
authors.forename: Helmut
authors.initials: H
authors.lastname: Viernstein
mesh_terms: D000096:Acetone / Q000737:chemistry; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000975:Antioxidants / Q000009:adverse effects / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D031061:Cyrtosperma / Q000737:chemistry*; D019008:Drug Resistance, Neoplasm; D020834:Ethnopharmacology; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D020128:Inhibitory Concentration 50; D004915:Leukemia, Erythroblastic, Acute / Q000188:drug therapy* / Q000378:metabolism; D010636:Phenols / Q000009:adverse effects / Q000032:analysis / Q000494:pharmacology; D010936:Plant Extracts / Q000009:adverse effects / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D027343:Rhizome / Q000737:chemistry; D012431:Rutin / Q000009:adverse effects / Q000032:analysis / Q000494:pharmacology; D055752:Small Cell Lung Carcinoma / Q000188:drug therapy* / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D013785:Thailand
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts; D012997:Solvents; D000096:Acetone; D012431:Rutin