Flavonoids from Acacia pennata and their cyclooxygenase (COX-1 and COX-2) inhibitory activities

Two new flavonoids quercetin 4'-O-alpha-L-rhamnopyranosyl-3-O-beta-allopyranoside (1) and apigenin 6-C-[2''-O-(E)-feruloyl-beta-D-glucopyranosyl]-8-C-beta-glucopyranoside (2), along with the known isorhamnetin 3-0-U-L-rhamnopyranoside (3), kaempferol 3-O-alpha-L-rhamnopyranosyl-(1 -> 4)-beta-D-glucopyranoside (4), and isovitexin (5) were isolated from the leaves of Acacia pennata Willd. (Mimosaceae) and tested for their anti-inflammatory activity. Their structures were determined by 1 D and 2D NMR and mass spectrometry. They were tested for an inhibitory effect on COX-1 and COX-2, showing 60-90% inhibition at 10(-4) g/mL and 5 - 14 % inhibition at 10(-4) g/mL, respectively.