Figure 1 Phytochemicals in the treatment of periodontitis. (A) Phytochemicals inhibit periodontal pathogenic microorganisms. Phytochemicals exert multifaceted antimicrobial activity against periodontal pathogens by inhibiting the bacterial proliferation, eliminating free-floating periodontal pathogen, downregulating virulence-factor expression, and disrupting dental plaque biofilms. (B) Phytochemicals alleviate inflammation in periodontal tissue. Phytochemicals mitigate periodontal inflammation by modulating key signaling pathways, including NF-κB, JAK-STAT, MAPK, Nrf2/HO-1, PI3K/Akt, and Wnt/β-catenin, effectively suppressing inflammatory mediator release and maintaining tissue homeostasis. (C) Phytochemicals promote periodontal tissue regeneration. Phytochemicals enhance tissue regeneration, encompassing both bone and soft-tissue repair. For bone regeneration, NPs improve the inflammatory, hyperoxic, and hyperglycemic microenvironment, suppress osteoclast activity, and promote stem cell differentiation and osteoblast function. For soft-tissue regeneration, phytochemicals primarily modulate macrophage and fibroblast activity to facilitate repair. ROS – reactive oxygen species; AGES – advanced glycation end products. The image was created using Adobe Photoshop 2020.