Me. Addy et Ml. Schwartzman, AN EXTRACT OF DESMODIUM ADSCENDENS ACTIVATES CYCLOOXYGENASE AND INCREASES PROSTAGLANDIN SYNTHESIS BY RAM SEMINAL-VESICLE MICROSOMES, PTR. Phytotherapy research, 9(4), 1995, pp. 287-293
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.