Antibacterial effects of Nanyang Kiwifruit extract toothpaste on common oral pathogens

Tao Liu; Hongmei Wang; Hua Li; Lidan Shi; Panpan Meng; Lin Feng; Rui Xiao

Abstract：Objective Oral diseases exhibit a multifactorial etiology. Plant-derived antimicrobial agents have gained recognition in daily personal care because of their eco-friendly, natural, and biodegradable properties. This study aimed to investigate the antibacterial efficacy of Nanyang kiwifruit extract toothpaste against common oral pathogens, in comparison with four commercially available toothpastes, to identify effective strategies for controlling pathogenic microorganisms and preventing oral diseases. Methods Five toothpaste formulations (grape probiotic, white, grape-flavored, peach-flavored, and kiwifruit extract) were prepared as gradient dilutions via two-fold serial dilution. Each dilution series was mixed 1:1 with standardized suspensions of Candida albicans, Staphylococcus aureus, Escherichia coli, or Proteus vulgaris (0.5×106 CFU/ml), followed by overnight incubation at 37℃. Minimum inhibitory concentrations (MICs) were determined spectrophotometrically at OD600. Minimum bactericidal concentrations (MBCs) were subsequently assessed by plate spreading of 100 μl aliquots of the overnight cultures onto LB agar, with bactericidal activity confirmed as a ≥99.9% CFU reduction. Results The kiwifruit extract toothpaste demonstrated comprehensive antibacterial activity against all four tested pathogens, exhibiting broader-spectrum inhibitory effects compared with commercial toothpastes. Conclusion The Nanyang kiwifruit extract toothpaste demonstrated broad-spectrum antimicrobial activity against both bacterial and fungal pathogens, exhibiting superior efficacy and broader coverage compared with single-target commercial toothpastes. Its multi-pathogen inhibitory capacity addresses a critical limitation of conventional antibacterial toothpastes that primarily target specific microbial subsets, thereby providing greater microbial control for oral ecological balance.