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.

A Review on Kigelia Africana

“…The LD50 was estimated from a log dosecurve to be 3,981.07 mg/kg. [29][30][31] In another study, 100mg/Kg aqueous extract was administered to rats induced with acetaminophen liver toxicity. The extract countered the effect of acetaminophen on the activities of as part atetransaminase (AST), alanine transaminase (ALT), superoxide dismutase (SOD), catalase (CAT), gluthathione peroxidase (GPx) and δ-aminolevulinate dehydrogenase (δ-ALA-D).…”

“…as well as certain CYP isozyme activities in rats, suggesting that ADD-199 had no overt organ specific toxicity and did not demonstrate a potential for drug interactions via CYPmediated metabolism in rats following sub-chronic administration [25] The protective effect of methanol extract of Kigelia africana fruit extract against cis-platin induced renal toxicity in male rats has been studied [29] The rats treated with cisplatin for 28 days, suffered loss in body weight, elevation in blood urea nitrogen and serum creatinine levels as well as tubular necrosis. Pre-treatment with Kigelia africana fruit methanol extract as a prophylaxis significantly prevented these changes.…”

“…Though post-treatment of animals with the extract after cisplatin treatment did not completely restore serum catalase activity, it caused some alleviating effects, suggesting that Kigelia africana fruit extract may protect against cisplatininduced renal toxicity, and hence might serve as a novel agent to limit renal injury. [29] Cytotoxic activity…”

Antimalarial drug interactions of compounds isolated from Kigelia africana (Bignoniaceae) and their synergism with artemether, against the multidrug-resistant W2mef Plasmodium falciparum strain

“…Benth (synonym: Kigelia pinnata (Jacq.) DC) was shown to be a potent source of antimalarial leads (Zofou et al 2011). The species is widely distributed in South, Central and West Africa, where it is known as cucumber or sausage tree because of huge fruits (average 0.6 m in length and 4 kg in weight).…”

Antineoplastic activity of a methanolic extract from Kigelia pinnata DC stem bark

“…This research interest is related to the traditional uses of bark and fruit extracts throughout Africa as remedies for treating sexually transmitted diseases, dysentery, leprosy, miscellaneous microbial and parasitic infections, skin ulcers, and neoplastic diseases [13,14,16,26]. Moreover, extracts from the plant, as well as isolated compounds, have been found to exert a constellation of other pharmacological effects, including antifungal [24], antiprotozoal (against Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense [23], and several, including multi-drug resistant, strains of Plasmodium falciparum [27][28][29]), antiinflammatory and analgesic [15,19], hepatoprotective [30], anti-fertility [31], CNS-stimulant, antidiarrheal, and antidiabetic [13,14,32], among others.…”