{"title":"Quorum Sensing Inhibition and Virulence Factor Attenuation in <i>Pseudomonas aeruginosa</i> by Camphor.","authors":"Farah Khader Al-Helo, Nasser El-Banna, Haitham Qaralleh, Muhamad O Al-Limoun, Khaled Khleifat","doi":"10.3831/KPI.2025.28.3.229","DOIUrl":null,"url":null,"abstract":"<p><strong>Objectives: </strong>This study aimed to assess the inhibitory effects of camphor on quorum sensing (QS), virulence factors, and biofilm formation in <i>Pseudomonas aeruginosa</i>, a multidrug-resistant pathogen.</p><p><strong>Methods: </strong><i>P. aeruginosa</i> was treated with sub-inhibitory concentrations of camphor (500, 250, and 125 µg/mL). Assays evaluated biofilm formation, surface hydrophobicity, swarming motility, cell aggregation, and exopolysaccharide (EPS) production. Inhibition of virulence factors-pyocyanin, rhamnolipid, protease, and chitinase-was also assessed. RT-PCR was used to quantify expression of QS-related genes (<i>LasR</i>, <i>LasI</i>, <i>RhlR</i>, and <i>RhlI</i>).</p><p><strong>Results: </strong>The minimum biofilm inhibitory concentration (MBIC50) ranged between 125 and 63 µg/mL. Camphor significantly reduced biofilm formation and virulence factor production at all tested concentrations. It also decreased EPS synthesis, swarming motility, hydrophobicity, and cell aggregation. Camphor suppressed acyl homoserine lactone (AHL) production and downregulated QS genes, reducing <i>LasR</i> and <i>LasI</i> expression by 5-fold and 4.6-fold, and <i>RhlR</i> and <i>RhlI</i> by 1.8-fold and 1.5-fold, respectively.</p><p><strong>Conclusion: </strong>Camphor demonstrates strong antibiofilm, antivirulence, and anti-QS activities against <i>P. aeruginosa</i> at concentrations as low as 125 µg/mL. These results suggest camphor is a promising candidate for alternative treatment strategies, warranting further investigation of its mechanisms and clinical safety.</p>","PeriodicalId":16769,"journal":{"name":"Journal of Pharmacopuncture","volume":"28 3","pages":"229-239"},"PeriodicalIF":1.8000,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12464080/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Pharmacopuncture","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3831/KPI.2025.28.3.229","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"INTEGRATIVE & COMPLEMENTARY MEDICINE","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives: This study aimed to assess the inhibitory effects of camphor on quorum sensing (QS), virulence factors, and biofilm formation in Pseudomonas aeruginosa, a multidrug-resistant pathogen.
Methods: P. aeruginosa was treated with sub-inhibitory concentrations of camphor (500, 250, and 125 µg/mL). Assays evaluated biofilm formation, surface hydrophobicity, swarming motility, cell aggregation, and exopolysaccharide (EPS) production. Inhibition of virulence factors-pyocyanin, rhamnolipid, protease, and chitinase-was also assessed. RT-PCR was used to quantify expression of QS-related genes (LasR, LasI, RhlR, and RhlI).
Results: The minimum biofilm inhibitory concentration (MBIC50) ranged between 125 and 63 µg/mL. Camphor significantly reduced biofilm formation and virulence factor production at all tested concentrations. It also decreased EPS synthesis, swarming motility, hydrophobicity, and cell aggregation. Camphor suppressed acyl homoserine lactone (AHL) production and downregulated QS genes, reducing LasR and LasI expression by 5-fold and 4.6-fold, and RhlR and RhlI by 1.8-fold and 1.5-fold, respectively.
Conclusion: Camphor demonstrates strong antibiofilm, antivirulence, and anti-QS activities against P. aeruginosa at concentrations as low as 125 µg/mL. These results suggest camphor is a promising candidate for alternative treatment strategies, warranting further investigation of its mechanisms and clinical safety.
期刊介绍：
The Journal of Pharmacopuncture covers a wide range of basic and clinical science research relevant to all aspects of the biotechnology of integrated approaches using both pharmacology and acupuncture therapeutics, including research involving pharmacology, acupuncture studies and pharmacopuncture studies. The subjects are mainly divided into three categories: pharmacology (applied phytomedicine, plant sciences, pharmacology, toxicology, medicinal plants, traditional medicines, herbal medicine, Sasang constitutional medicine, herbal formulae, foods, agricultural technologies, naturopathy, etc.), acupuncture (acupressure, electroacupuncture, laser acupuncture, moxibustion, cupping, etc.), and pharmacopuncture (aqua-acupuncture, meridian pharmacopuncture, eight-principles pharmacopuncture, animal-based pharmacopuncture, mountain ginseng pharmacopuncture, bee venom therapy, needle embedding therapy, implant therapy, etc.). Other categories include chuna treatment, veterinary acupuncture and related animal studies, alternative medicines for treating cancer and cancer-related symptoms, etc. Broader topical coverage on the effects of acupuncture, the medical plants used in traditional and alternative medicine, pharmacological action and other related modalities, such as anthroposophy, homeopathy, ayurveda, bioelectromagnetic therapy, chiropractic, neural therapy and meditation, can be considered to be within the journal’s scope if based on acupoints and meridians. Submissions of original articles, review articles, systematic reviews, case reports, brief reports, opinions, commentaries, medical lectures, letters to the editor, photo-essays, technical notes, and book reviews are encouraged. Providing free access to the full text of all current and archived articles on its website (www.journal.ac), also searchable through a Google Scholar search.
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