title: Evaluation of the in vitro trypanocidal activity of methylated flavonoid constituents of Vitex simplicifolia leaves.
abstract: BACKGROUND
  Trypanosomiasis is a neglected tropical disease with complex clinical manifestations, tedious diagnosis, and difficult treatments. The drugs available for the treatment of this endemic disease are old, expensive, and associated with other problems including safety and drug resistant parasites. Therefore, there is an urgent need for the development of new, effective, cheap, and safe drugs for its treatment. Plants are potentially rich sources of leads for new drugs against trypanosomiasis. Vitex simplicifolia (Verbenaceae) is used traditionally for the treatment of tooth ache, edema, skin diseases, gout and trypanosomiasis in Nigeria. In a preliminary study, the methanol extract of Vitex simplicifolia was shown to exhibit a pronounced trypanocidal activity against T. b. rhodesiense. The present study was undertaken to investigate the active component responsible for the acclaimed activity of the leaves of Vitex simplicifolia in the traditional treatment of trypanosomiasis in Nigeria and other African countries. Our investigations aim at assessing the plant as a new source of potential trypanocidal compounds.
  
  
  METHODS
  The crude extracts were prepared from the dried leaves using methanol, successive extraction with hexane, dichloromethane, ethylacetate and butanol was also done. The ethylacetate fraction was further fractionated and compounds isolated using preparative chromatographic technique and their structures were elucidated by NMR, mass spectrometry and comparison with literature data. Trypanocidal activities and cytotoxicity, using rat skeletal myoblast (L6) cells were investigated and their selectivity indices were determined.
  
  
  RESULTS
  The chromatographic separations of the methanol extracts gave rise to seven compounds. The isolated compounds 2, 3, 6 and 7 exhibited promising trypanocidal activity with IC50 values ranging from 4.7-12.3 μg/ml and cytotoxicity in the range of 1.58- 46.20 μg/ml. Compound 6, however, showed the most selective trypanocidal activity with a selectivity index of 9.8. This is the first report of trypanocidal activity of flavonoids from this plant genus.
  
  
  CONCLUSIONS
  The isolated compounds from Vitex simplicifolia exhibited noteworthy trypanocidal activities and hence may provide a source of new antitrypanosomal agents. These results also support the traditional use of Vitex simplicifolia in the treatment of trypanosomiasis. This is the first report of trypanocidal effect of flavonoids from this plant genus.
authors.affiliation: Department of Pharmaceutical and Medicinal Chemistry, University of Nigeria, Nsukka, Nigeria. nwodong@hotmail.com.|Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, D- 40225, Dusseldorf, Germany. nwodong@hotmail.com.
authors.forename: Ngozi
authors.initials: N
authors.lastname: Nwodo
authors.affiliation: Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, D- 40225, Dusseldorf, Germany. basdenc@yahoo.com.|Department of Pharmaceutical Chemistry, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria. basdenc@yahoo.com.
authors.forename: Festus
authors.initials: F
authors.lastname: Okoye
authors.affiliation: Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, D- 40225, Dusseldorf, Germany. laidaowan123@gmail.com.
authors.forename: Daowan
authors.initials: D
authors.lastname: Lai
authors.affiliation: Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, D- 40225, Dusseldorf, Germany. Abdessamad.debbab@uni-duesseldorf.de.
authors.forename: Abdesammed
authors.initials: A
authors.lastname: Debbab
authors.affiliation: Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland. marcel.kaiser@unibas.ch.|University of Basel, CH-4003, Basel, Switzerland. marcel.kaiser@unibas.ch.
authors.forename: Marcel
authors.initials: M
authors.lastname: Kaiser
authors.affiliation: Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, CH-4002, Basel, Switzerland. reto.brun@unibas.ch.|University of Basel, CH-4003, Basel, Switzerland. reto.brun@unibas.ch.
authors.forename: Reto
authors.initials: R
authors.lastname: Brun
authors.affiliation: Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, D- 40225, Dusseldorf, Germany. proksch@uni-duesseldorf.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Proksch
mesh_terms: D000818:Animals; D002460:Cell Line; D005419:Flavonoids / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D020128:Inhibitory Concentration 50; D008745:Methylation; D009549:Nigeria; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D014344:Trypanocidal Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016833:Trypanosoma brucei rhodesiense / Q000187:drug effects*; D014352:Trypanosomiasis / Q000188:drug therapy* / Q000469:parasitology; D020950:Vitex / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; D014344:Trypanocidal Agents