Synergistic Inhibitory Effect of Capsaicin and Dihydrocapsaicin on In Vitro Platelet Aggregation and Thromboxane Formation
Almaghrabi, S and Adams, MJ and Geraghty, DP and Ahuja, KDK, Synergistic Inhibitory Effect of Capsaicin and Dihydrocapsaicin on In Vitro Platelet Aggregation and Thromboxane Formation, Blood Coagulation and Fibrinolysis ISSN 0957-5235 (2018) [Refereed Article]
Capsaicinoids, including capsaicin (CAP) and dihydrocapsaicin (DHC), the pungent principles of pepper fruits, individually inhibit in vitro platelet aggregation. However, their effects when present in the relative proportions that they are found naturally in chilies, i.e., ~60% CAP and ~40% DHC, are not known. The aims of this study were to compare the effects of CAP and DHC alone, and in combination, on in vitro platelet aggregation, platelet count and thromboxane B2 formation (TXB2).
The effects of 12.5 and 6.25 μM CAP and DHC individually, and in combination (CAP:DHC, 60:40) on arachidonic acid (AA)-, ADP-, and collagen -induced aggregation, were investigated. Platelet count was determined pre- and post-incubation with CAP and DHC, and in combination. TXB2 formation from platelets treated with AA in the absence and presence of CAP and DHC individually, and in combination, was measured.
Compared to control, CAP and DHC (12.5 μM) inhibited AA-induced aggregation by 23.2% and 25.3%, respectively (both p<0.01). In combination, CAP and DHC exhibited further inhibition in AA-induced aggregation (CAP:DHC, 3.75:2.5 μM, 36.5%, p=0.01; 7.5:5 μM, 57.5%, p<0.001), compared to control. Incubation of platelets with CAP and DHC, and in combination did not significantly affect the platelet count. In addition, the CAP:DHC (7.5:5 uM) combination significantly inhibited (p<0.001) TXB2 formation, compared to the individual capsaicinoids.
The present study shows that thehe combination of CAP and DHC in the proportions they are usually present in pepper fruits, produces a significantly greater inhibitory effect on AA-induced platelet aggregation and subsequent TXB2 formation, compared to the individual capsaicinoids.