In vitro antiplasmodial activity and cytotoxicity of crude extracts and compounds from the stem bark of Kigelia africana (Lam.) Benth (Bignoniaceae)

• Published in: Parasitology research (1987) Vol. 108; no. 6; pp. 1383 - 1390
• Main Authors: Zofou, Denis, Kengne, Archile Bernabe Ouambo, Tene, Mathieu, Ngemenya, Moses N., Tane, Pierre, Titanji, Vincent P. K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2011; Springer
• Subjects: Animals; Antimalarials - pharmacology; Bignoniaceae; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cameroon; Cell Line; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Haplorhini; Immunology; Inhibitory Concentration 50; Invertebrates; Kidney; Kigelia africana; Medical Microbiology; Microbiology; Original Paper; Phytotherapy; Plant Bark; Plant Extracts - pharmacology; Plasmodium falciparum; Plasmodium falciparum - drug effects; Cameroon; Africa; Malaria; Ethyl Acetate Extract; Artesunate; Field Isolate; Stem Bark; Dicotyledones; Angiospermae; Bark; Parasite; Activity; Cytotoxicity; Spermatophyta; Bignoniaceae; In vitro; Stem
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-011-2363-y

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.