Cryptocarya species - substitute plants for Ocotea bullata? A pharmacological investigation in terms of cyclooxygenase-1 and -2 inhibition

In response to the serious scarcity of Ocotea bullata (Burch.) Baillon (Lau raceae), an important medicinal plant in South Africa, Cryptocarya species (Lauraceae) are frequently used as substitute plants. Our investigation was aimed at a pharmacological comparison of O. bullata and the Cryptocarya sp ecies C. latifolia Sonder, C. myrtifolia Stapf., C. transvaalensis Burtt Da vy, C. woodii Engl. and C. wyliei Stapf, in terms of in vitro cyclooxygenas e-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibition, as an indication of O. bullatus' repute as a remedy against headache. Furthermore, we also compar ed bark and leaf extracts of the species investigated in order to address t he problem of destructive ring-barking. The utilization of leaves instead o f bark would help in the management of threatened medicinal plants. All Cry ptocareya species were superior to O. bullata with regard to bark extracts. C. woodii bark extracts showed outstanding equipotent activity towards COX -I and COX-2. The activity of extracts of fresh leaves was comparable to th e activity of the respective bark extracts. Drying the leaves before extrac tion resulted in a loss of activity, with the exception of C. wyliei. Extra cts of dried C. wyliei leaves exhibited high inhibitory activity, with a CO X-2/COX-1 ratio of 5.8. (C) 2000 Elsevier Science Ireland Ltd. All rights r eserved.