IN-VITRO SELECTIVE INHIBITION OF COX-2 ACTIVITY BY (3β)-LUP-20(29)-EN-3-OL A PENTACYCLIC TRITERPENE ISOLATED FROM C. ADANSONII STEM BARK EXTRACT

This study is aimed at investigating/elucidating the molecular structure and the biochemical mechanism of anti-inflammatory action of an isolated but yet unknown bioactive compound CA1 from Crateva adansonii stem bark extract. Qualitative phytochemical tests on the isolated bioactive anti-inflammatory compound gave positive reaction to terpenoid only, while the structural elucidation indicates that CA1 is (3β)-lup-20(29)-en-3-ol, a pentacyclic triterpene with molecular weight of 426.70 g, and molecular formular of C₃₀H₅₀O. The molecular structure of this pentacyclic triterpene was established using nuclear magnetic resonance (NMR), ultra-violet/visible spectrophotometer, infra-red, gas and mass spectrophotometers. The (3β)-lup-20(29)-en-3-ol was subjected to in-vivo anti-inflammatory activity study using egg-albumin induced rat hind paw edema method. However, (3β)-lup-20(29)-en-3-olwas investigated for its selective COX-1 and COX-2 inhibitory activities. An in-vitro model of inflammation using a colourimetric COX (ovine) inhibitor screening assay method was used as a model to investigate the effect of CA1 on PGE₂ production. (3β)-lup-20(29)-en-3-ol at the tested concentrations significantly (P < 0.05) and selectively inhibited the inducible form of cyclooxygenase, cyclooxygenase-2 enzyme, but exhibited no inhibitory activity against COX-1.