Anti-virulence Activity of Three Medicinal Plants: Cassia occidentalis L., Crossopteryx febrifuga (Afzel ex G. Don) Benth. and Zanthoxylum zanthoxyloides (Lam) Zep. and Timl

Aims: This current study was designated to assess the ability of Cassia occidentalis, Crossopteryx febrifuga and Zanthoxylum zanthoxyloides traditionally used for the treatment of infectious diseases, to reduce the production of virulence factors. Place and Duration of Study: The study was conducted at the Laboratory of Applied Biochemistry and Chemistry (LABIOCA), University Ouaga 1 Pr Joseph KI-ZERBO between September 2018 to January 2019. Methodology: Methanol extracts from C. occidentalis (leaves and stem), C. febrifuga (leaves and stem) and Z. zanthoxyloides (Stem bark) were used for the investigations. The reporter strain Pseudomonas aeruginosa PAO1 was used to measure the impact of extracts on elastase and pyocyanin production. Antioxidant activity was measured through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Results: All extracts at the concentration of 100 µg/mL inhibited significantly the production of pyocyanin without affect negatively the growth of P. aeruginosa PAO1 with a reduction of 39%, 52% and 28% respectively for C. occidentalis, C. febrifuga and Z. zanthoxyloides. C. febrifuga showed the highest inhibition level on the production of elastase with a rate of 48%. The results demonstrated varying level of reduction of pyocyanin and elastase production in the reporter strain.  Moreover, the antioxidant polyphenols evidenced are capable to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-virulence properties of these medicinal plants could justify their traditional use in the treatment of infectious diseases.