Diabetic foot ulcers represent a major complication driven by chronic inflammation, oxidative stress, impaired angiogenesis, and defective extracellular matrix remodeling. This integrative review synthesizes mechanistic evidence from 51 preclinical studies evaluating plant-derived interventions in diabetic animal models. Database searches (PubMed, Embase, Scopus) identified species modulating discrete molecular targets across healing phases. In the inflammatory phase, extracts suppressed NF-κB-dependent cytokine production (IL-1β, TNF-α, IL-6), reduced oxidative stress via Nrf2/HO-1 activation, and disrupted AGE-RAGE signaling, facilitating neutrophil resolution and macrophage reprogramming. During proliferation, interventions upregulated angiogenic factors (VEGF, bFGF, IGF-1) through ERK1/2 and PI3K/Akt-eNOS pathways, stimulated fibroblast proliferation, and enhanced collagen deposition. In the remodeling phase, extracts improved tensile strength by modulating MMP-2/9 and TIMP-2 balance, promoting type I collagen maturation and organized fiber architecture. Polyphenol-rich species (Punica granatum, Quercus infectoria, Polygonatum kingianum) demonstrated the most robust multi-target activity. However, translational gaps persist due to extract heterogeneity, limited phytochemical standardization, and overreliance on young male rodent models. Future development requires standardized bioactive quantification, dose–response characterization, advanced delivery systems (hydrogels, nanofibers), and validation in aged animals with comorbidities. These mechanistic insights support plant-based therapies as multi-component adjuvants targeting the complex pathophysiology of diabetic ulcers.