2023 Volume 77 Issue 2 Pages 76-82
Pseudomonas aeruginosa (P. aeruginosa) has low virulence, but causes opportunistic infections in susceptible individuals. Owing to the emergence of drug-resistant bacteria, there is a need for alternative drugs and active ingredients as antimicrobial agents. In a previous study, we found that the Chinese herbal medicine ‘Maoto’ had an inhibitory effect on P. aeruginosa PAO1. Although Maoto is composed of four kinds of herbal medicines, there are few reports on the effects of each herbal medicine on its virulence factors. In this study, we investigated whether herbal medicines contained in Maoto could inhibit virulence in P. aeruginosa. P. aeruginosa standard strain PAO1 was used as the bacterial strain, and Ephedrae herba (E. herba), Armeniacae semen (A. semen), Cinnamomi cortex (C. cortex), and Glycyrrhizae radix (G. radix) were used as herbal medicines. As the effects of each herbal medicine on PAO1, bacterial growth rate, pyocyanin production assay, biofilm formation assay and three types of motility (swimming, swarming and twitching) were examined. E. herba and C. cortex inhibited growth rate and biofilm formation. Only swimming motility was inhibited by C. cortex. Pyocyanin production was inhibited by E. herba, C. cortex, and G. radix. In this study, we reveal the potential of treatment against P. aeruginosa infection by C. cortex.
