Methanol Extract from Anogeissus leiocarpus (DC) Guill. et Perr. (Combretaceae) Stem Bark Quenches the Quorum Sensing of Pseudomonas aeruginosa PAO1

Abstract

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.

Leveraging Phytochemicals: The Plant Phylogeny Predicts Sources of Novel Antibacterial Compounds

“…Combretaceae is a relatively small family with 10 genera and 530 species [15]. Extracts containing the flavonoids catechin and naringenin [37] from Combretum spp., ellagic acid derivatives from Terminalia chebula [38] and from Anogeissus leiocarpus [39] have been linked to inhibition of the QS-dependent virulence factors in Pseudomonas aeruginosa . One study [40] has noted that extracts of T. chebula were even more inhibitory to the gram-negative bacteria Klebsiella pneumoniae compared with Gram-positive S. aureus .…”

Antioxidant, Antiquorum-Sensing and Antibiofilm Activities of <i>Balanites aegyptiaca</i> (L.) Del. (Balanitaceae) and <i>Terminalia macroptera</i> Guill. and Perr. (Combretaceae)

“…The microdilution method was used to determined MIC values on P. aeruginosa PAO1 and C. violaceum CV026 according to [13]. An appropriately diluted bacterial culture was added to each well containing test extracts in order to obtain a final concentration range of 5 mg/mL to 0.15625 mg/mL.…”

“…and Perr. (Combretaceae) traditionally used to treat respiratory diseases and wound, reduces the production of QS-controlled factors and gene expression [13]. These preliminary results lead to select some medicinal plants of Burkina faso flora for screening their anti-QS activity.…”

Anti-quorum quenching activity of methyl gallate isolated from galls of Guiera senegalensis J. F. Gmel (Combretaceae)

“…The production of a purple pigment, violacein, controlled by QS system in Chromobacterium violaceum making this strain an excellent biomonitor for the research of anti-QS compounds (Yong and Zhong, 2012). Thus, many plants have been widely screened for their anti-QS activity (Adonizio et al, 2008a;Ouedraogo and Kiendrebeogo, 2016;Vandeputte et al, 2010). Phenolic compounds isolated from Combretaceae exhibited anti-QS activity and reduced the production of QS-controlled virulence factors of P. aeruginosa (Adonizio et al, 2008b;Taganna et al, 2011;Vandeputte et al, 2010).…”