Cardiovascular diseases (CVDs) remain the leading global cause of mortality, despite major advances in conventional pharmacotherapy. Limitations such as adverse drug reactions, incomplete risk reduction, and variable patient responses highlight the need for complementary therapeutic approaches. Plant-derived bioactive compounds have gained significant attention due to their multi-targeted actions, favorable safety profiles, and potential synergistic benefits alongside standard cardiovascular drugs. This review summarizes the cardiovascular therapeutic potential of key phytochemical classes, including flavonoids, polyphenols, alkaloids, terpenoids, saponins, and phenolic acids. These compounds exert protective effects through modulation of oxidative stress and inflammatory pathways (Nrf2 activation, NF-κB inhibition), improvement of endothelial function via enhanced nitric oxide bioavailability, regulation of lipid metabolism through LDL receptor and AMPK signaling, and suppression of atherosclerotic progression. Evidence from mechanistic studies, preclinical models, and emerging clinical trials supports the promise of compounds such as berberine, resveratrol, EGCG, and Salvia miltiorrhiza constituents. Challenges including poor bioavailability, extract variability, and clinical translation gaps are discussed to guide future research.