Schizonepeta tenuifolia inhibits collagen stimulated platelet function via suppressing MAPK and Akt signaling
Abstract: The prevalence of cardiovascular diseases (CVDs) is increasing at a rapid pace in developed countries, and CVDs are the leading cause of morbidity and mortality. Natural products and ethnomedicine have been shown to reduce the risk of CVDs. Schizonepeta (S.) tenuifolia is a medicinal plant widely used in China, Korea, and Japan and is known to exhibit anti-inflammatory, antioxidant, and immunomodulatory activities. We hypothesized that given herbal plant exhibit pharmacological activities against CVDs, we specifically explored its effects on platelet function. Platelet aggregation was evaluated using standard light transmission aggregometry. Intracellular calcium mobilization was assessed using Fura-2/AM, and granule secretion (ATP release) was measured in a luminometer. Fibrinogen binding to integrin αⅡbβ3, was assessed using flow cytometry. Phosphorylation of mitogen-activated protein kinase (MAPK) signaling molecules and activation of the protein kinase B (Akt) was assessed using Western blot assays. S. tenuifolia, extract potently and significantly inhibited platelet aggregation, calcium mobilization, granule secretion, and fibrinogen binding to integrin αⅡbβ3. Moreover, all extracts significantly inhibited MAPK and Akt phosphorylation. S. tenuifolia extract inhibited platelet aggregation and granule secretion, and attenuated collagen mediated GPVI downstream signaling, indicating the potential therapeutic effects of these plant extracts on the cardiovascular system and platelet function. We suggest that S. tenuifolia extract may be a potent candidate to treat platelet-related CVDs and to be used as an antiplatelet and antithrombotic agent.