title: Evaluation of the use of Ocimum suave Willd. (Lamiaceae), Plectranthus barbatus Andrews (Lamiaceae) and Zanthoxylum chalybeum Engl. (Rutaceae) as antimalarial remedies in Kenyan folk medicine.
abstract: BACKGROUND
  Crude extracts from the leaves of Ocimum suave Willd (Lamiaceae) and the root barks of Plectranthus barbatus Andrews (Lamiaceae) and Zanthoxylum chalybeum Engl. (Rutaceae) were studied to ascertain the ethnopharmacological standing of their antimalarial usage in Kenyan folk medicine.
  
  
  METHODS
  Aqueous and Chloroform: Methanol (1:1) extracts of the plants were used in this study. Toxicity of the extracts was investigated by using brine shrimp lethality test and acute oral toxicity in mice. The antimalarial activity at a dose of 100 mg/kg was screened in Swiss albino mice against chloroquine sensitive Plasmodium berghei (D6) using Peters 4-day suppressive test. Chloroquine, at a dosage rate of 20 mg/kg was used as a reference drug.
  
  
  RESULTS
  The extracts showed some signs of acute toxicity in the brine shrimp lethality test. However, no signs of toxicity were observed in the mice at a dose of 2000 mg/kg of the crude extracts. The results revealed that all the tested crude extracts were safe. Z. chalybeum aqueous extract and P. barbatus organic extract showed chemosuppressive activities of 81.45% and 78.69%, respectively. This antimalarial activity was not significantly different from that of chloroquine (P<0.05).
  
  
  CONCLUSIONS
  The findings suggest that the Kenyan folkloric medicinal application of these plants has a pharmacological basis. Bioactivity guided fractionation and isolation of bioactive molecules from the two species could lead to new hits against Plasmodium falciparum malaria.
authors.affiliation: School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya. Electronic address: micheni.kiraithe@uonbi.ac.ke.
authors.forename: Micheni N
authors.initials: MN
authors.lastname: Kiraithe
authors.affiliation: Department of Public Health, Pharmacology & Toxicology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Nguta
authors.affiliation: Department of Public Health, Pharmacology & Toxicology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: James M
authors.initials: JM
authors.lastname: Mbaria
authors.affiliation: Department of Veterinary Anatomy, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Kiama
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology*; D001156:Artemia / Q000469:parasitology; D005260:Female; D007630:Kenya; D019686:Lamiaceae / Q000737:chemistry*; D008288:Malaria / Q000188:drug therapy*; D008297:Male; D016488:Medicine, African Traditional / Q000379:methods; D051379:Mice; D031339:Ocimum / Q000737:chemistry*; D008517:Phytotherapy / Q000379:methods; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D010962:Plasmodium berghei / Q000187:drug effects; D031346:Plectranthus / Q000737:chemistry*; D027821:Rutaceae / Q000737:chemistry*; D032106:Zanthoxylum / Q000737:chemistry*
chemical_list: D000962:Antimalarials; D010936:Plant Extracts
keywords: Antimalarial; Crude extract; Medicinal plants; Plasmodium berghei; Swiss albino mice; Toxicity