Antibacterial activity and mechanism of sanguinarine against Providencia rettgeri in vitro

PeerJ. 2020 Aug 11;8:e9543. doi: 10.7717/peerj.9543. eCollection 2020.


Background: Sanguinarine (SAG), a benzophenanthridine alkaloid, occurs in Papaveraceas, Berberidaceae and Ranunculaceae families. Studies have found that SAG has antioxidant, anti-inflammatory, and antiproliferative activities in several malignancies and that it exhibits robust antibacterial activities. However, information reported on the action of SAG against Providencia rettgeri is limited in the literature. Therefore, the present study aimed to evaluate the antimicrobial and antibiofilm activities of SAG against P. rettgeri in vitro.

Methods: The agar dilution method was used to determine the minimum inhibitory concentration (MIC) of SAG against P. rettgeri. The intracellular ATP concentration, intracellular pH (pHin), and cell membrane integrity and potential were measured. Confocal laser scanning microscopy (CLSM), field emission scanning electron microscopy (FESEM), and crystal violet staining were used to measure the antibiofilm formation of SAG.

Results: The MIC of SAG against P. rettgeri was 7.8 μg/mL. SAG inhibited the growth of P. rettgeri and destroyed the integrity of P. rettgeri cell membrane, as reflected mainly through the decreases in the intracellular ATP concentration, pHin and cell membrane potential and significant changes in cellular morphology. The findings of CLSM, FESEM and crystal violet staining indicated that SAG exhibited strong inhibitory effects on the biofilm formation of P. rettgeri and led to the inactivity of biofilm-related P. rettgeri cells.

Keywords: Antibiofilm; Antimicrobial; Providencia rettgeri; Sanguinarine.

Grant support

This work was supported by the National Natural Science Foundation of China (Nos. 81902067 and 81300028). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.