title: Cytotoxicity of 91 Kenyan indigenous medicinal plants towards human CCRF-CEM leukemia cells.
abstract: BACKGROUND
  Plants from Kenyan flora are traditionally used against many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. Recently there are recommendations that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants that treat cancer.
  
  
  OBJECTIVE
  The present study was aimed at investigating the cytotoxicity of a plethora of 145 plant parts from 91 medicinal plants, most of which are used in the management of cancer and related diseases by different communities in Kenya, against CCRF-CEM leukemia cell line.
  
  
  METHODS
  Extracts from different plant parts (leaves, stems, stem bark, roots, root barks, aerial parts and whole herb) were obtained by cold percolation using different solvent systems, such as (1:1v/v) dichloromethane (CH2Cl2) and n-hexane (1), methanol (MeOH) and CH2Cl2 (2); neat MeOH (3), 5% H2O in MeOH (4) and with ethanol (EtOH, 5); their cytotoxicities were determined using the resazurin reduction assay against CCRF-CEM cells.
  
  
  RESULTS
  At a single concentration of 10μg/mL, 12 out of 145 extracts exhibited more than 50% cell inhibition. These include samples from the root bark of Erythrina sacleuxii (extracted with 50% n-hexane-CH2Cl2), the leaves of Albizia gummifera, and Strychnos usambarensis, the stem bark of Zanthoxylum gilletii, Bridelia micrantha, Croton sylvaticus, and Albizia schimperiana; the root bark of Erythrina burttii and E. sacleuxii (extracted with 50% CH2Cl2-MeOH), the stem bark of B. micrantha and Z. gilletii (extracted using 5% MeOH-H2O) and from the berries of Solanum aculeastrum (extracted with neat EtOH). The EtOH extract of the berries of S. aculeastrum and A. schimperiana stem bark extract displayed the highest cytotoxicity towards leukemia CCRF-CEM cells, with IC50 values of 1.36 and 2.97µg/mL, respectively. Other extracts having good activities included the extracts of the stem barks of Z. gilletii and B. micrantha and leaves of S. usambarensis with IC50 values of 9.04, 9.43 and 11.09µg/mL, respectively.
  
  
  CONCLUSIONS
  The results of this study provided information related to the possible use of some Kenyam medicinal plants, and mostly S. aculeastrum, A. schimperiana, C. sylvaticus, Z. gilletii, B. micrantha and S. usambarensis in the treatment of leukemia. The reported data helped to authenticate the claimed traditional use of these plants. However, most plants are used in combination as traditional herbal concoctions. Hence, the cytotoxicity of corresponding plant combinations should be tested in vitro to authenticate the traditional medical practitioners actual practices.
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya; Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany. Electronic address: lkerubo@uonbi.ac.ke.
authors.forename: Leonidah K
authors.initials: LK
authors.lastname: Omosa
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.
authors.forename: Jacob O
authors.initials: JO
authors.lastname: Midiwo
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Masila
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.
authors.forename: Boniface M
authors.initials: BM
authors.lastname: Gisacho
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.
authors.forename: Renee
authors.initials: R
authors.lastname: Munayi
authors.affiliation: Department of Chemistry, School of Physical Sciences, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.
authors.lastname: Francisca-Kamakama
authors.affiliation: Department of Chemistry, Kisii University, P. O. Box 408-40200, Kisii, Kenya.
authors.forename: Kitur Phylis
authors.initials: KP
authors.lastname: Chemutai
authors.affiliation: Department of Biochemistry, Faculty of Medicine, University of Khartoum, P. O. Box 321-11115, Khartoum, Sudan.
authors.forename: Gihan
authors.initials: G
authors.lastname: Elhaboob
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany.
authors.forename: Mohamed E M
authors.initials: ME
authors.lastname: Saeed
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany.
authors.forename: Sami
authors.initials: S
authors.lastname: Hamdoun
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany; Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors.forename: Victor
authors.initials: V
authors.lastname: Kuete
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz, Germany. Electronic address: efferth@uni-mainz.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Efferth
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D007630:Kenya; D007938:Leukemia / Q000473:pathology*; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D006131:Growth Inhibitors; D010936:Plant Extracts
keywords: Albizia schimperiana; Cancer; Kenyan flora; Leukemia; Solanum aculeastrum; Traditional medicine