Platelet Aggregation Inhibition: An Evidence-Based Systematic Review on the Role of Herbs for Primary Prevention Based on Randomized Controlled Trials

BACKGROUND: Platelet aggregation is a crucial mechanism in the progression of atherothrombotic events. This systematic review aims to introduce the plants studied in healthy people as the primary prevention to inhibit platelet aggregation. We also discuss possible mechanisms that are involved in the inhibition of platelet aggregation. METHODS: A systematic search on the electronic medical databases from 1970 to February 2020 was performed. The selected keywords were: “herb”, “plant”, “platelet aggregation”, “platelet activation”, “clinical trial”, “randomized” and “controlled”. RESULTS: The result of the initial search was a pool of 136 articles. After initial abstract reviewing, there were 55 relevant articles. Finally, 28 eligible records fulfilled our inclusion criteria to enter the qualitative synthesis process. CONCLUSION: Out of the 10 plants evaluated in the clinical trials, nine had inhibitory effects on platelet aggregation. Most of the reviewed plants, including tomato (Solanum lycopersicum L), garlic (Allium sativum), kiwifruit (Actinidia deliciosa), cacao (Theobroma cacao), grape (Vitis vinifera), ginkgo (Ginkgo biloba), flaxseed (Linum usitatissimum), sea buckthorn berry (Hippophae), and argan (Argania spinose) could be potential sources for the primary prevention of atherothrombotic events at an appropriate dosage. Finally, we do not consider phytoceuticals as a replacement for the guideline-directed medical treatment. Large randomized double-blind clinical trials are required to evaluate the anti-platelet characteristics of these plants for the adjuvant primary prevention of cardiovascular disease.