Guava leaf extract and topical haemostasis

The effects of guava leaf extract on the bleeding time and the three main m echanisms of haemostasis: vasoconstriction, platelet aggregation and blood coagulation, were investigated. The water extract of guava leaves did not s horten bleeding times in rats. Guava leaf extract potentiated the vascular muscle contraction induced in rabbits by phenylephrine, and when given alon e it stimulated human platelet aggregation in vitro in a dose-dependent man ner. On the other hand, it significantly prolonged blood coagulation; activ ated partial thromboplastin time (APTT) test (p < 0.05), The higher the con centration of the extract, the longer APTT was observed. Thus, a water extr act of guava leaves showed ambiguous effects on the haemostatic system. Gua va leaf extract did not affect bleeding times, it stimulated vasoconstricti on and platelet aggregation but it inhibited blood coagulation, Therefore, guava leaf extract is not recommended as a haemostatic agent. Copyright (C) 2000 John Wiley & Sons, Ltd.