<img src='/image/spc_char/beta.gif' border=0 >-Amyrin from <i>Ardisia elliptica</i> is more potent than aspirin in inhibiting collagen-induced platelet aggregation

Abstract

<i>Ardisia elliptica</i> Thunberg (Myrsinaceae) is a medicinal plant traditionally used for alleviating chest pains, treatment of fever, diarrhoea, liver poisoning and parturition complications. The objectives of the study were to investigate the effect of <i>A</i>. <i>elliptica</i> on collagen induced platelet aggregation and to isolate and purify potential antiplatelet components. Fresh <i>A. elliptica</i> leaves were extracted using methanol (70% v/v) by Soxhlet extraction and the extract was analysed for its inhibition of collagen-induced platelet aggregation. Inhibition of platelet aggregation was assessed by incubating the extracts with rabbit blood and collagen in a whole blood aggregometer and measuring the impedance. The leaf extract was found to inhibit platelet aggregation with an IC50 value of 167 <img src='/image/spc_char/micro.gif'> g/ml. Using bioassay guided fractionation, <img src='/image/spc_char/beta.gif'>-amyrin was isolated and purified. The IC50 value of <img src='/image/spc_char/beta.gif'>-amyrin was found to be 4.5 <img src='/image/spc_char/micro.gif'> g/ml (10.5 <img src='/image/spc_char/micro.gif'> <i>M</i>) while that of aspirin was found to be 11 <img src='/image/spc_char/micro.gif'> g/ml (62.7 <img src='/image/spc_char/micro.gif'> <i>M</i>), indicating that <img src='/image/spc_char/beta.gif'>-amyrin was six times as active as aspirin in inhibiting platelet aggregation. This paper is the first report that <img src='/image/spc_char/beta.gif'>-amyrin isolated from <i>A. elliptica</i> is more potent than aspirin in inhibiting collagen-induced platelet aggregation. In conclusion, <i>A. elliptica</i> leaves were found to inhibit collagen-induced platelet aggregation and one of the bioactive components responsible for the observed effect was determined to be <img src='/image/spc_char/beta.gif'>-amyrin.