First isolation of glutinol and a bioactive fraction with good anti-inflammatory activity from n-hexane fraction of Peltophorum africanum leaf.

OBJECTIVE

To investigate the anti-inflammatory activity of different fractions and glutinol (isolated compound), using nitric oxide synthase and cyclooxygenase (COX) inhibition as an indication of anti-inflammatory activity.

METHODS

Anti-inflammatory activity was evaluated using an in vitro assay determining the inhibition of the activity of pro-inflammatory enzyme model. Cyclooxygenases and inducible nitric oxide synthase are crucial enzymes involved in the pathogenesis of many chronic inflammatory conditions.

RESULTS

Sub-fraction F3.3 that was derived from n-hexane fraction of PA leaves significantly inhibited (P = 0.01) the catalytic activity of COX-2 (IC50 = 0.67 μg/mL) better than isolated compound, glutinol (IC50 = 1.22 μg/mL), compound 2 (CP2) (IC50 = 1.71 μg/mL) and sub-fraction F3.3.0 (IC50 = 1.30 μg/mL). A similar trend was observed in investigation of the inhibition of nitric oxide synthesis in RAW 264.7 cells by F3.3, glutinol, CP2 and F3.3.0. Inducible COX-2 and inducible nitric oxide synthase are among potent signalling enzymes that exacerbate inflammation.

CONCLUSIONS

Bioactive sub-fractions (F3.3 and F3.3.0) derived from the n-hexane fraction of PA had good anti-inflammatory activity, and the isolated compound, and glutinol may be useful as a template for the development of new anti-inflammatory drugs.