AN EXTRACT OF DESMODIUM ADSCENDENS ACTIVATES CYCLOOXYGENASE AND INCREASES PROSTAGLANDIN SYNTHESIS BY RAM SEMINAL-VESICLE MICROSOMES

Microsomes from ram seminal vesicles were used as a source of cyclooxy genase enzyme to evaluate the effect of an n-butanol fraction of Desmo dium adscendens (nBF) on prostaglandin (PG) synthesis. 1-C-14-arachido nic acid (C-14-AA) conversions into prostaglandin E(2) (PGE(2)), prost aglandin F-2 alpha (PGF(2a)) and the endoperoxide intermediate, prosta glandin H-2 (PGH(2)) were analysed radiometrically and compared among reaction mixtures with different concentrations of the cyclooxygenase enzyme, with and without GSH and with or without preincubation with nB F, tyramine and hordenine, phenolic compounds present in D. adscendens . The percentage of C-14-AA converted in the various reaction mixtures was used to indicate activation of cyclooxygenase enzyme (Cox). nBF a ctivated Cox at sub optimal enzyme concentrations and increased PG syn thesis at all enzyme concentrations used, shifting the increased produ ction in favour of PGE(2) under certain conditions. Tyramine was more effective than nBP in activating Cox. The results indicate that D. ads cendens contains compounds, other than phenolics, which modulate PG sy nthesis and could lead to production of relaxant prostanoids.