title: In vitro antiplasmodial activity and cytotoxicity of crude extracts and compounds from the stem bark of Kigelia africana (Lam.) Benth (Bignoniaceae).
abstract: In order to assess the potential of the stem bark of Kigelia africana (Lam.) Benth as source of new anti-malarial leads, n-hexane and ethyl acetate (EtOAc) extracts and four compounds isolated from the stem bark were screened in vitro against the chloroquine-resistant W-2 and two field isolates of Plasmodium falciparum using lactate dehydrogenase assay. The products were also tested for their cytotoxicity on LLC/MK2 monkey kidney cells. The EtOAc extract exhibited a significant antiplasmodial activity (IC(50) = 11.15 μg/mL on W-2; 3.91 and 4.74 μg/mL on field CAM10 and SHF4 isolates, respectively), whereas the n-hexane fraction showed a weak activity (IC(50) = 73.78 μg/mL on W-2 and 21.85 μg/mL on SHF4). Three out of the four compounds showed good activity against all the three different parasite strains (IC(50) <5 μM). Specicoside exhibited the highest activity on W-2 (IC(50) = 1.54 μM) followed by 2β, 3β, 19α-trihydroxy-urs-12-en-28-oic acid (IC(50) = 1.60 μM) and atranorin (IC(50) = 4.41 μM), while p-hydroxycinnamic acid was the least active (IC(50) =53.84 μM). The EtOAc extract and its isolated compounds (specicoside and p-hydroxycinnamic acid) were non-cytotoxic (CC(50) > 30 μg/mL), whereas the n-hexane extract and two of its products, atranorin and 2β, 3β, 19α-trihydroxy-urs-12-en-28-oic acid showed cytotoxicity at high concentrations, with the last one being the most toxic (CC(50) = 9.37 μg/mL). These findings justify the use of K. africana stem bark as antimalaria by traditional healers of Western Cameroon, and could constitute a good basis for further studies towards development of new leads or natural drugs for malaria.
authors.affiliation: Biotechnology Unit, University of Buea, P.O. Box 63 Buea, South West Region, Cameroon.
authors.forename: Denis
authors.initials: D
authors.lastname: Zofou
authors.forename: Archile Bernabe Ouambo
authors.initials: AB
authors.lastname: Kengne
authors.forename: Mathieu
authors.initials: M
authors.lastname: Tene
authors.forename: Moses N
authors.initials: MN
authors.lastname: Ngemenya
authors.forename: Pierre
authors.initials: P
authors.lastname: Tane
authors.forename: Vincent P K
authors.initials: VP
authors.lastname: Titanji
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D029402:Bignoniaceae; D002163:Cameroon; D002460:Cell Line; D000882:Haplorhini; D020128:Inhibitory Concentration 50; D007668:Kidney; D008517:Phytotherapy; D024301:Plant Bark; D010936:Plant Extracts / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D010936:Plant Extracts