Acetyl eugenol, a component of oil of cloves (Syzygium aromaticum L.) inhibits aggregation and alters arachidonic acid metabolism in human blood platelets.
In continuation of our studies with the oil of cloves--a common kitchen spice and a crude drug for home medicine--we have isolated yet another active component identified as acetyl eugenol (AE); the earlier reported active component being eugenol. The isolated material (IM) was found to be a potent platelet inhibitor; IM abolished arachidonate (AA)-induced aggregation at ca. 12 microM, a concentration needed to abolish the second phase of adrenaline-induced aggregation. Chemically synthesized acetyl eugenol showed similar effects on AA- and adrenaline-induced aggregation. A dose-dependent inhibition of collagen-induced aggregation was also observed. AE did not inhibit either calcium ionophore A23187- or thrombin-induced aggregation. Studies on aggregation and ATP release were done using whole blood (WB). AA-induced aggregation in WB was abolished at 3 micrograms/ml (14.6 microM) which persisted even after doubling the concentration of AA. ATP release was inhibited. Inhibition of aggregation appeared to be mediated by a combination of two effects: reduced formation of thromboxane and increased generation of 12-lipoxygenase product (12-HPETE). These effects were observed by exposing washed platelets to (14C)AA or by stimulating AA-labelled platelets with ionophore A23187. Acetyl eugenol inhibited (14C)TxB2 formation in AA-labelled platelets on stimulation with thrombin. AE showed no effect on the incorporation of AA into platelet phospholipids.
Srivastava
K C
KC
Department of Environmental Medicine, ISH, Odense C, Denmark.
Malhotra
N
N
D000215:Acylation / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000378:metabolism; D001092:Arachidonate 12-Lipoxygenase / Q000378:metabolism; D001095:Arachidonic Acids / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002250:Carbon Radioisotopes; D002855:Chromatography, Thin Layer; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005054:Eugenol / Q000494:pharmacology*; D006801:Humans; D010743:Phospholipids / Q000097:blood; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology; D013929:Thromboxane B2 / Q000097:blood
D001095:Arachidonic Acids; D002250:Carbon Radioisotopes; D010743:Phospholipids; D010975:Platelet Aggregation Inhibitors; D000001:Calcimycin; D005054:Eugenol; D013929:Thromboxane B2; D000255:Adenosine Triphosphate; D003094:Collagen; D001092:Arachidonate 12-Lipoxygenase; D013917:Thrombin; D004837:Epinephrine