Phytochemical study and evaluation of the antiviral activity of aqueous extracts of three medicinal plants; Xylopia aethiopica, Gliricidia sepium and Ocimum gratissimum used in Cote d’Ivoire

*1Bouagnon, J. J. R., 2Bolou, G. E. K., 3Guédé, K. B., 4Sanga, D., 4Koffi, L. R., 4N’Guessan, C. D. R., 5Konan, Y., 5Adjogoua, E. V., 4N’Guessan, J. D.,
4Djaman, A. J., and 1,3Dosso, M.

1Biological Resources Center/Biobank, Institut Pasteur, Côte d’Ivoire

2National Floristic Center, Felix Houphouët-Boigny University, Côte d’Ivoire

3Department of Bacteriology-Virology, Institut Pasteur, Côte d’Ivoire

4Laboratory of Biology and Health, UFR Biosciences, Felix Houphouët-Boigny University, Côte d’Ivoire

5Department of epidemic viruses, Institut Pasteur, Côte d’Ivoire
*Correspondence to:

Background: The present work is part of the exploration of new antiviral molecules to combat antimicrobial resistance. In purpose, this study determined the phytochemical analysis, cytotoxicity and antiviral activity of extracts from three Ivorian medicinal plants; Gliricidia sepium, Ocimum gratissimum and Xylopia aethiopica against poliovirus 1, a non-enveloped RNA virus.

Methodology: Aqueous extract of the three plants, which were identified at the herbarium of National Floristic Center Abidjan, was done using a previously described method. The precipitation or staining technique was used to highlight the chemical groups in the three extracts while the polyphenol content of each extract was assessed by the colorimetric method. Cytotoxicity and antiviral activity tests were performed in 96-well plates. Cytotoxicity of each extract on L20B (a genetically engineered mouse cell line) was determined by observation of the cell line carpet. Antiviral activity of three extracts against poliovirus type I was determined after 72 hours using an assay that measures inhibition of the cytopathic effect on cell culture. Continue reading “Phytochemical study and evaluation of the antiviral activity of aqueous extracts of three medicinal plants; Xylopia aethiopica, Gliricidia sepium and Ocimum gratissimum used in Cote d’Ivoire”

Invasive behaviour and depolarization effect of Pseudomonas fluorescens on rat cerebellar granule neurons

S Mezghani-Abdelmoula, A Khemiri, O Lesouhaitier, S Chevalier, L Cazin



Previous studies have shown that Pseudomonas fluorescens exerts cytotoxic effects on neurons and glial cells. In the present work, we investigated the time course effect of Pseudomonas fluorescens MF37 and of its lipopolysaccharide (LPS) on cultured rat cerebellar granule neurons. The kinetics of binding of P. fluorescens to cerebellar granule neurons is identical to that of cortical neurons but the binding index is lower, suggesting the presence of a reduced number of binding sites. As demonstrated by measurement of the concentration of nitrites in the culture medium, P. fluorescens induces a rapid stimulation (3 h) of the nitric oxide synthase (NOS) activity of the cells. In contrast, LPS extracted from P. fluorescens requires a long lag phase (24 h) before observation of an activation of NOS. Measurement of the resting membrane potential of granule neurons showed that within 3 h of incubation, there was no difference of effect between the action of P. fluorescens and that of its LPS endotoxin. Two complementary approaches allowed us to demonstrate that P. fluorescens MF37 presents a rapid invasive behaviour, suggesting a mobilisation of calcium in its early steps of action. The present study reveals that P. fluorescens induces the sequential activation of a constitutive calcium dependent NOS and that of an inducible NOS activated by LPS. Ours results also suggest that P. fluorescens cytotoxicity and invasion are not mutually exclusive events.

Key Words: Cytotoxicity, Lipopolysaccharide, Patch-clamp, Invasion, Pseudomonas fluorescens

Afr. J. Clin. Exper. Microbiol. Vol.6(1) 2005: 1-13