Curry Leaf Triggers Cell Death of P. gingivalis with Membrane Blebbing

• Published in: Pathogens (Basel) Vol. 10; no. 10; p. 1286
• Main Authors: Nakao, Ryoma, Ikeda, Tsuyoshi, Furukawa, Soichi, Morinaga, Yasushi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 06.10.2021; MDPI
• Subjects: Antibacterial activity; Antibiotics; Antimicrobial agents; antimicrobials/antimicrobial resistance; Apoptosis; Atomic force microscopy; Bacteria; Bactericidal activity; Biofilms; Cell death; Cinnamon; curry leaf; Depolarization; E coli; Health services; Heat treatment; Heat treatments; herbal medicine; Leaves; Membrane potential; Membranes; Minimum inhibitory concentration; Natural products; Pathogens; Periodontal disease; periodontal disease/periodontitis; Periodontal diseases; Permeability; Plant extracts; Porphyromonas gingivalis; Public health; Teeth
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens10101286

Periodontal disease has become a serious public health problem, as indicated by accumulating evidence that periodontal disease is not only a major cause of tooth loss but is also associated with various systemic diseases. The present study assessed the anti-bacterial activities of three herbal products (curry leaf, clove, and cinnamon) against Porphyomonas gingivalis, a keystone pathogen for periodontal diseases. The curry leaf extract (CLE) showed the strongest growth inhibitory activity among them, and the activity was maintained even after extensive heat treatment. Of note, while clove and cinnamon extracts at sub-minimum inhibitory concentrations (sub-MICs) significantly enhanced the biofilm formation of P. gingivalis, CLE at sub-MIC did not have any effect on the biofilm formation. The MIC of CLE against P. gingivalis was higher than those against a wide range of other oral bacterial species. P. gingivalis cells were completely killed within 30 min after treatment with CLE. Spatiotemporal analysis using high-speed atomic force microscopy revealed that CLE immediately triggered aberrant membrane vesicle formation on the bacterial surface. Bacterial membrane potential assay revealed that CLE induced depolarization of the bacterial membrane. Taken together, these findings suggest the mechanism behind early bactericidal activity of CLE and its therapeutic applicability in patients with periodontal diseases.