Monosubstituted Coumarins Inhibit Epinephrine-induced Platelet Aggregation

Area of Science:

• Pharmacology and Medicinal Chemistry
• Cardiovascular Research
• Drug Discovery

Background:

• Residual platelet reactivity to conventional antiplatelet drugs like aspirin and clopidogrel contributes to therapeutic failure.
• Platelet adrenoceptors are implicated in residual platelet reactivity, highlighting the need for new antiplatelet agents targeting epinephrine-induced aggregation.
• Limited data exists on the antiplatelet activity of coumarins, particularly their efficacy against epinephrine-induced platelet aggregation.

Purpose of the Study:

• To evaluate the in vitro antiplatelet activity of coumarin and its 15 derivatives against various agonists, with a focus on epinephrine.
• To establish the structure-activity relationship (SAR) of coumarin derivatives, identifying key structural features for antiplatelet efficacy.
• To utilize in silico studies to predict potential drug targets for coumarin derivatives, elucidating their mechanism of antiplatelet action.

Main Methods:

• Human platelet aggregation was measured using a Lumi-aggregometer.
• The inhibitory effects of 16 coumarin compounds were assessed against platelet aggregation induced by epinephrine (10 μM), collagen (2 μg/ml), or ADP (10 μM).
• In silico modeling was employed to investigate potential molecular targets of the active coumarin derivatives.

Main Results:

• Eleven coumarin derivatives demonstrated inhibitory activity against epinephrine-induced platelet aggregation, with 3-acetoxycoumarin and 7-methoxycoumarin showing the highest potency.
• Only coumarin itself inhibited collagen-induced platelet aggregation; no compounds affected ADP-induced aggregation.
• In silico analysis suggested that the most active coumarins may interact antagonistically with α2 and β2 adrenoceptors.

Conclusions:

• Coumarin derivatives, particularly 3-acetoxycoumarin and 7-methoxycoumarin, exhibit significant in vitro antiplatelet activity against epinephrine-induced aggregation.
• These findings suggest that coumarins could serve as a basis for developing novel antiplatelet agents to address residual platelet reactivity.
• The potential antagonistic interaction with α2 and β2 adrenoceptors provides a mechanistic insight into the antiplatelet effects of these coumarins, paving the way for future therapeutic applications.