Biological activities of arredoul jaune, a phytomedicine based ethanol extract from fresh roots of Pentadiplandra brazzeana baill. (Pentadiplandaceae) used as an antidiarrhoeal drug in Kisangani-Democratic Republic of Congo

Arredoul jaune, a phytomedicine based ethanol extract from the roots of Pentadiplandra brazzeana (Pentadiplandraceae), its soluble fractions, crude saponins and total alkaloids extract were submitted to a broad biological screening including antimicrobial, antiamoebic and spasmolytic activities which can justify its use as an antidiarrhoeal drug. Results indicated that all samples were significantly active in each assay with varying magnitudes. Arredoul jaune exhibited good antibacterial and bactericidal activities against all selected bacteria including Bacillus subtilis, Escherichia coli, Salmonella entertidis, Shigella dysenteria, Staphylococcus aureus, Shigella flexneri and Salmonella thyhimurium with MIC and MBC values < 100 μg/ml. It also displayed strong antiamoebic activity with minimal amoebicidal concentration (MAC) of 5.32 ± 0.02 μg/ml and produced more than 75% inhibition of acetylcholine (Ach) and depolarising solution rich in KCl-induced guinea-pig ileum contractions. Chroroform and ethylacetate soluble fractions from the partition of Arredoul jaune exhibited good antibacterial and bactericidal activities with MIC and MBC < 100 μg/ml, good and strong antiamoebic activity with MAC value of 15.21 ± 0.07 and 8.25± 0.12 μg/ml respectively. They produced more than 70% inhibition of both agonists- induced contractions of ileum guinea-pig. n-butanol fraction showed good antibacterial activity against Salmonella enteritidis, Shigella dysenria and S. flexneri (MIC and MBC < 100 μg/ml) while the residual aqueous phase exhibited moderate or low activity against selected bacteria according to the case (MIC or MBC = 15 or 250 μg/ml). They exhibited moderate antiamoebic activity (MAC > 10 μg/ml) and produced more than 64% inhibitions of both agonists-induced guinea-pig ileum contractions. Total alkaloids extract displayed good antibacterial and bactericidal activities with MIC and MBC < 100 μg/ml, strong antiamoebic activity with MAC value of 3.57 ± 0.05, μg/ml and produced more than 76% inhibition of both agonists-induced guinea-pig ileum contractions. Crude saponins showed only weak antimicrobial activity, moderate antiamoebic activity (MAC = 12.47 ± 0.47 μg/ml and produced more than 60% inhibition of both agonist-induced guinea-pig ileum contractions. These results can partly justify and support the use of Arredoul jaune in courant live for the treatment of diarrhoea whatever the origin of the disease.