Protective Effect of Natural Phenolic Acids, Rosmarinic Acid and Salvianolic Acid, Against Diabetic Atherosclerosis.

Cardiovascular disease (CVDs) and atherosclerosis remain a major causes of morbidity and mortality worldwide. Endothelial dysfunction is a central driver of atherosclerosis, which is significantly accelerated in diabetes mellitus through hyperglycemia-induced oxidative stress, oxidized low-density lipoprotein (oxLDL) accumulation, and NLRP3 inflammasome activation. Phenolic acids, a class of plant-derived polyphenols, have gained attention as vasoprotective agents due to their antioxidant and anti-inflammatory properties. Among them, rosmarinic acid and salvianolic acid have gained attention, yet no previous review has systematically compared their distinct molecular mechanisms. This review addresses the gap by summarizing the pathophysiological mechanisms linking endothelial dysfunction to atherosclerotic progression and comparing how rosmarinic acid and salvianolic acid modulate oxidative stress, nitric oxide signaling, inflammatory responses, and NLRP3 inflammasome activation. Rosmarinic acid primarily exerts its effects through the p38 MAPK-FOXO1-TXNIP and AMPK/eNOS pathways, while salvianolic acid mainly acts via the PKM2/PKR and NF-ĸB/NLRP3 signaling pathways. Despite these findings, clinical evidence remains limited, primarily limited to Phase 1 pharmacokinetic studies and mixed-extract trials, leaving compound-specific efficacy in humans unverified. This review highlights these translational gaps and suggests prioritizing clinical trials of purified compounds, bioavailability optimization, and dose-standardization studies to advance rosmarinic acid and salvianolic acid toward clinical application in diabetic atherosclerosis.