In vivo COX-2 modulation and metabolite profiling of Pandanus tectorius leaves extracts

The Pandanus tectorius methanolic (PTM) and P. tectorius aqueous (PTA) extracts were investigated for their potential in vivo anti-inflammatory activity using carrageenan-induced rat paw edema. Parameters including paw thickness measurement, histopathological, and immunohistochemical cyclooxygenase (COX)-2 expression analyses were measured and analyzed. PTA at 500 mg/kg significantly reduced inflammation after induction of carrageenan (Carr), with mean paw thickness change of 0.110 ± 0.024 mm at sixth hour post-induction and histopathological mean inflammatory grade of 1.80 ± 0.20. The reduced immunohistochemical COX-2 expression using PTA at 500 mg/kg was determined with mean final 3,3'-diaminobenzidine (DAB) intensity of 63.70 ± 2.08. The profiling of metabolites by liquid chromatography-mass spectrometry (LC-MS) revealed presence of ethyl caffeate and dihydroconiferyl alcohol as putative secondary metabolites of PTA which were the major peaks and have been reported to possess anti-inflammatory activities. This research has provided scientific insights of utilizing P. tectorius as a potential anti-inflammatory agent containing secondary metabolites which may be pharmacologically relevant.