Abstract:
This study was aimed at investigating the anti-inflammatory and anticholinesterase activity of six
naturally occurring flavonoids: (-) pinostrobin (1), 2’,4’-dihydroxy-3’,6’-dimethoxychalcone
(2), 6-8-diprenyleriodictyol (3), isobavachalcone (4), 4-hydroxylonchocarpin (5) and 6-
prenylapigenin (6). These compounds were isolated from Dorstenia and Polygonum species used
traditionally to treat pain. The anti-inflammatory activity was determined by using the Griess
assay and the 15-lipoxygenase inhibitory activity was determined with the ferrous oxidationxylenol
orange assay. Acetylcholinesterase (AChE) inhibition was determined by the Ellman’s
method. At the lowest concentration tested (3.12 μg/mL), compounds 2, 3 and 4 had significant NO inhibitory activity with 90.71%, 84.65 and 79.57% inhibition respectively compared to the
positive control quercetin (67.93%). At this concentration there was no significant cytotoxicity
against macrophages with 91.67%, 72.86 and 70.86% cell viability respectively, compared to
73.1% for quercetin. Compound 4 had the most potent lipoxygenase inhibitory activity (IC50 of
25.92 μg/mL). With the exception of (-) pinostrobin (1), all the flavonoids had selective
anticholinesterase activity with IC50 values ranging between 5.93 and 8.76 μg/mL compared to
the IC50 4.94 μg/mL of eserine the positive control. These results indicate that the studied
flavonoids especially isobavachalcone are potential anti-inflammatory natural products that may
have the potential to be developed as therapeutic agents against inflammatory conditions and
even Alzheimer’s disease.
