Bio-guided isolation of anti-salmonellae compounds of Thonningia sanguinea, an Ivorian medicinal plant

Salmonella enterica ssp. enterica is a leading cause of bacterial food-borne outbreaks in developed countries and is also a public-health concern in developing countries. Diarrhoea, a common symptom of human salmonellosis, kills 3-million children each year in developing countries [1]. The emergence of strains of S. enterica with multiple drug resistance is of great concern worldwide. Our preliminary work showed that the aqueous extract of Thonningia sanguinea (Balanophoraceae), an Ivorian plant used traditionally for the treatment of diarrhoea [2] demonstrate growth inhibitory effect in vitro against different strains of Salmonella such as S. Typhi (CMI=4.16mg/mL), S. Typhimurium (CMI=4,16mg/mL), S. Hadar (CMI=3.33mg/mL), S. Essen (CMI=4.16mg/mL).

In order to isolate the antibacterial compounds, the aqueous extract was successively fractionated with cyclohexane, ethyl actetate and butanol. All these fractions were evaluated for their antibacterial activity using the disc-diffusion assays. The butanolic extract (5mg/disc) was the most active extract according to the inhibition zone diameter (12±0.8mm). Fractionation of the butanolic extract lead to the isolation of two polyphenolic derivates which structure elucidation is under process.

References: 1. White, P.L. et al. (1997), Rev. Sci. Tech. 16: 525–541. 2. Vangah-Manda, M. et al. (1994), Rev. Med. Pharm. Afr. 8: 154–157.