title: Comparison of cytotoxic activities of extracts from Selaginella species.
abstract: BACKGROUND
  Selaginella species are resurrection plants, which are known, possess various molecular bioactivities depending on species, but only a few species have been detailed observe in the advanced research.
  
  
  OBJECTIVE
  The objective of the following study is to compare the chemical profiles of different species of Selaginella and to investigate cytotoxicity and induction of apoptosis activities of some species of Selaginella.
  
  
  METHODS
  The high-performance liquid chromatography (HPLC) method was developed for chemical analysis. Ethyl acetate, ethanol and water-soluble extracts from seven Selaginella species were submitted to 3-(4,5-dimenthyl thizol-2-yl)-2,5-diphenyl tetrazolium bromide assay, flow cytometry, deoxyribonucleic acid (DNA) laddering analysis and caspase-3 expression using Bel-7402, HT-29 and HeLa cells.
  
  
  RESULTS
  The HPLC analysis revealed two major common peaks, which were identified as amentoflavone and robustaflavone and another three main peaks in their chromatograms. The results showed that S. labordei, Selaginella tamariscina and Selaginella uncinata had relatively stronger activities on Bel-7402 and HeLa cells and Selaginella moellendorfii had moderate antiproliferation activities, but Selaginella remotifolia and Selaginella pulvinata had almost no inhibitory activities. The main active components were in the ethyl acetate extracts which had abundant biflavonoids. The effects of these extracts on cell proliferation and apoptosis in different cells were not the same, they were more apparent on HeLa cells than on HT-29 cells. The assay of DNA laddering analysis and caspase-3 expression further confirmed that inducing cell apoptosis was one of antitumor mechanisms and antitumor activities of Selaginella species were related to apoptosis induced by caspase family.
  
  
  CONCLUSIONS
  S. labordei, S. tamariscina and S. uncinata would be potential antitumor agents.
authors.affiliation: Department of Identification and Assessment of TCM, Hubei College of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei Province and Ministry of Education, Wuhan 430065, Hubei Province, China ; Department of Phytochemistry, Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and the Chinese Academy of Sciences, Guilin 541006, Guangxi Province, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Identification and Assessment of TCM, Hubei College of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei Province and Ministry of Education, Wuhan 430065, Hubei Province, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Lei
authors.affiliation: Department of Identification and Assessment of TCM, Hubei College of Traditional Chinese Medicine, Key Laboratory of TCM Resource and TCM Compound Co-constructed by Hubei Province and Ministry of Education, Wuhan 430065, Hubei Province, China.
authors.forename: Ke-Li
authors.initials: KL
authors.lastname: Chen
keywords: Amentoflavone; Selaginella; antitumor; apoptosis