Background: Due to its extensive arsenal of virulence factors and inherent resistance to antibiotics, Pseudomonas aeruginosa is a threat particularly in immunocompromised patients. Considering the central role of quorum sensing in the production of virulence factors, inhibition of bacterial communication mechanism constitute an opportunity to attenuate pathogenicity of bacteria resistant to available antibiotics. Our study aimed to assess the anti-quorum sensing activity of Anogeissus leiocarpus, traditionally used in Burkina Faso, for the treatment of infected burn wounds. Methods: Investigations were carried out on methanol extract from A. leiocarpus stem bark. The reporter strains Chromobacterium violaceum CV026 and P. aeruginosa PAO1 derivatives were used to evidence any interference with the bacterial quorum sensing and expression of related genes. P. aeruginosa PAO1 was used to measure the impact on pyocyanin production. Results: At a sub-inhibitory concentration (100 µg/mL), A. leiocarpus methanol extract quenched the quorum sensing mechanism of P. aeruginosa PAO1 by down-streaming the rhlR gene, with a subsequent reduction of pyocyanin production. Moreover, the antioxidant polyphenols evidenced are able to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-quorum sensing activities of A. leiocarpus stem bark could justify its traditional use in the treatment of infected burn wounds.

Objective: This current study was designed to investigate the ethno-medicinal uses of C. retusa and to learn about the knowledges of its toxicity. Methods: Questionnaires were administered to herbalists and traditional healers from Ouagadougou town in national language Mooré or Dioula. Data on the ethno-medicinal use of C. retusa, the plant part used, the modes of preparation and administration and the knowledges on its toxicity were collected for each interviewed respondents. Relative frequency of citation of each disease was calculated using Microsoft Excel software Results: C. retusa is mentioned by all the respondents to be used in the folklore system of medicine for the treat of various diseases including infectious and psychotropic diseases. Nine (09) diseases treated with C. retusa have been cited by respondents. The most diseases cited were congenital syphilis (72.5%) followed by malaria (7.5%) and hallucinations (7.5%). The whole plant is more used Original Research Article

Aims: The study aims to assess the ability of Acacia dudgeoni bark to antagonize quorum sensing system, expression of virulence factor and biofilm formation. Place and Duration of Study: The study was conducted at the Laboratory of Applied Biochemistry and Chemistry (LABIOCA), University Joseph KI-ZERBO between December 2018 to April 2019. Methodology: Methanol extract from A. dudgeoni stem bark, was used for the investigations. The reporters strain Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1 were used to measure the impact of extract on quorum sensing controlled violacein and pyocyanin production. P. aeruginosa PAO1 was used to measure the impact on biofilm formation. Results: At different concentrations (50-400 µg/mL) A. dudgeoni methanol extract quenched the quorum sensing mechanism. Significant inhibition of virulence factor, pyocyanin was recorded (66% of inhibition at 400 µg/mL) without affect negatively the growth of P. aeruginosa PAO1. The formation of biofilm was also affected with a reduction up to 59% at the concentration of 400 µg/mL. Conclusion: The anti-quorum sensing and anti-biofilm properties of this medicinal plant could serve as a source in the developpement of new effective anti- quorum sensing drugs.

Antiquorum-Sensing and Antibiofilm Activities of Balanites aegyptiaca (L.) Del. (Balanitaceae) and Terminalia macroptera Guill. and Perr. (Combretaceae).

Prosopis africana  (Guill. & Perr.) Taub. (Fabaceae) is used in the herbal medicine of Burkina Faso to treat dental caries. This study aims to contribute to the valorization of the said plant by investigating the antioxidant, anti-inflammatory and antibacterial properties of aqueous leaves and stems extracts. The inhibitory activity on lipoxygenase was used to evaluate the anti-inflammatory effect of the extracts. The antioxidant activity of bots extracts of the plant was assessed using DPPH radical scavenging, ABTS+ radical cation decolorization. The anti-biofilm effect of the extracts was evaluated on Streptococcus mutans ATCC 25175, Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa PAOI and the anti-Quorum sensing effect on Chromobacterium CV026. Aqueous extracts of Prosopis africana stems show the highest content of phenolic compounds (30,04± 0,59 mgAGE/100 mg extract) while those of the leaves show the highest content of total flavonoids (3.29 ± 0.53 mgQE/100mg extract). The aqueous extract of stem bark show the strongest antioxidant activity ( IC50 = 4.58±0.07µg/ml for the ABTS) , a best Inhibitory action on activity of lipoxygenase (IC50 = 13.42 ± 1.26 μg/mL ), a highest anti-biofilm activity ( 63.6%;  at the concentration of 100µg/ml) without affecting the bacterial growth. In addition, this extract has the strongest anti-quorum sensing activity with an percentage of inhibition 53,5%. These findings suggested that the aqueous extracts of stem bark and leaves of Prosopis africana contain promoted phytomolecules to combat dental caries infections. Keywords : Anti-biofilm, Anti-quorum sensing, Lipoxygenase, Prosopis africana