In vitro and in vivo antiplasmodial activity and cytotoxicity of extracts from Vernonia amygdalina Del. Leaves

Abstract

Background This study evaluated the in vitro and in vivo antiplasmo-dial activity of extracts from V. amygdalina leaves. The plant was selected based on local claims on its efficacy as part of the treatment regimen in malarial infection in the southwestern region of Nigeria. Materials and methods Extracts of the plant (ethanolic, aqueous, and hydroetha-nolic (50:50) extracts) were prepared using standard procedures. Chemical profile of the extracts was performed through high performance thin layer chromatography (HPTLC) for quality control. The extracts were evaluated in vitro for antiplasmodial activity using a 3D7 chloroquine sensitive clone of NF-54 isolate of Plasmo-dium falciparum. The parasite growth inhibition was estimated based on the 48 hours microassay technique [1]. Cytotoxicity of these extracts was evaluated in vitro against non-cancerous vero cell lines (C-1008 kidney fibroblasts from African green monkey) by the neural red uptake method [2]. The in vivo antiplasmodial activity of the most active extract(s) was assessed based on the standard four days suppressive test on P. berghei (ANKA) infected male mice (six weeks old) of the Swiss strain [3]. Results Results from the in vitro study showed that the ethano-lic extract of the plant leaves had the highest (p<0.05) antiplasmodial activity (IC 50 = 9.83 ug/ml) and cytotoxi-city (IC 50 = 60.33) with moderate selectivity index of 6. 14 when compared with the other extracts. The ethanolic extract was also significantly active in vivo against P. berghei in a dose-dependent manner with maximum activity observed at 1000 mg/kg (% inhibition of 82.3 %). There was also a dose-dependent significant decrease (p<0.05) in some oxidative stress indices especially nitric oxide and malonaldehyde levels. The pro-inflammatory cytokines (TNF-a and IFN-g) levels were also considerably low relative to control values. Conclusions The results suggest that V. amygdalina possess moderate antiplasmodial activity both in vitro and in vivo. The immunomodulatory and antioxidant activities of this extract may be responsible for its antiplasmodial property. The study therefore confirms local claims on the use of the plant leaves as part of the treatment regimen in malarial infection.