Dual inhibitory activities of adhatoda vasica against cyclooxygenase and lipoxygenase

ABSTRACT

Adhatoda vasica [L.] Nees is a well-known plant drug in Ayurvedic and Unani medicine. It has been used for the treatment of various diseases, particularly for the treatment of inflammatory and cardiovascular diseases. However, the scientific rationale and mechanisms by which it functions in these diseases is not known. This study was designed to explore the inhibitory activity of Adhatoda vasica aqueous and butanolic fractions on arachidonic acid [AA] metabolism. For this purpose aqueous and butanolic fractions of Adhatoda vasica were screened for the presence of activities against arachidonic acid [AA] metabolites and their effectiveness was further evaluated by studying platelet aggregation induced by a AA, adenosine diphosphate [ADP], platelet activating factor [PAF], and collagen. AA metabolism was studied by thin layer chromatography system while platelet aggregation was measured by dual channel Lumi aggregometer. Aqueous fraction of Adhatoda vasica but not of butanolic fraction inhibited the AA metabolites through COX pathway [TXB[2]] and LOX pathway [LP1 and 12-HETE]. However, in platelet aggregation studies butanolic extract of Adhatoda vasica showed strong inhibition against AA, PAF and collagen induce aggregation but not against ADP. Aqueous fraction of Adhatoda vasica was active against none of the four aggregating agents. Adhatoda vasica possesses components which can inhibit AA metabolism and platelet aggregation. This may be one of the underlying mechanisms of their anti -inflammatory effects.