COX-1 inhibitory activity in extracts from Eucomis L'Herit. species

Non-steroidal anti-inflammatory compounds can relieve pain and inflammation associated with elevated levels of prostaglandins in the body and are prop osed to be the agents responsible for the action of traditional herbal reme dies associated with the reduction of pain, fever and inflammation. Primari ly the bulbs and in some instances the leaves and roots, of Eucomis L 'Heri t. species are widely utilized in South African traditional medicine for th is purpose. A measure of the anti-inflammatory activity of plant extracts c an be generated using the cyclooxygenase (COX-I) assay. High levels of COX- 1 inhibitory activity were detected in crude extracts prepared from the lea ves, bulbs and roots of Euconis species. Of the 11 species tested, 9 specie s exhibited moderate COX-1 inhibitory activity (40-70%) for the aqueous bul b extracts. All 11 species showed COX-1 inhibitory activity of +/- 70% or h igher, for the ethanol bulb extracts. The bulb and root extracts (ethanol) showed, in general, the highest levels of COX-1 inhibitory activity, but mo st species exhibited no significant difference in activity between plant pa rts. Generally (for 7 of the 11 species), these levels did not differ signi ficantly in specimens harvested in summer and in winter. IC50 values were c alculated to be 72 mug ml(-1) for the bulb extract of E. autumnalis autumna lis, and 27 mug ml(-1) for the root extracts. The corresponding IC50 value for the leaf extract was estimated to be 15 mug ml(-1). The COX-1 inhibitor s were relatively stable over time, both in solution (ethanol) and in the d ried plant material. Extracts tested over a period of three years did not d iffer significantly in COX-1 inhibitory activity. These experimental result s validate the extensive use of this plant in southern African traditional medicine. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.