Abstract
The anti-inflammatory activity of a coumarin and nine anthraquinone derivatives, 3-hydroxy-1-methoxy-2-methylanthraquinone
(1), 2-hydroxymethyl anthraquinone (2), schimperiquinone B (3), cleomiscosin A (4), damnacanthal (5), 1,2-dihydroxy anthraquinone (6), damnacanthol (7), 3-hydroxy-2-hydroxymethyl anthraquinone (8), 1-hydroxy-2-methoxyanthraquinone (9), and 2-hydroxymethyl-3-O-prenylanthraquinone (10), isolated from the roots of Pentas schimperi were determined. The anti-15-lipoxygenase activity and nitric oxide production inhibition
on lipopolysaccharide-activated macrophages RAW 264.7 cells were determined as indicators
of anti-inflammatory activity. The Griess assay was used to measure nitric oxide production
and the ferrous oxidation-xylenol orange assay was used to determine the 15-lipoxygenase
inhibitory activity. All the compounds significantly decreased nitrite + nitrate accumulation
in lipopolysaccharide-stimulated RAW 264.7 cells in a concentration-dependent manner
with 85.67 % to 119.75 % inhibition of nitrite + nitrate production at 20 µg/mL. Most
of the compounds had a moderate inhibitory effect on 15-lipoxygenase activity. Compounds
8 and 10 were the most potent inhibitor both in nitrite + nitrate production with respective
IC50 values of 1.56 µM and 6.80 µM. Compounds 2, 7, and 8 had good anti-15-lipoxygenase activity with respective IC50 values of 13.80 µM, 14.80 µM, and 15.80 µM compared to quercetin, which was used
as a standard lipoxygenase inhibitor (IC50 of 16.80 µM). Our study revealed 3-hydroxy-2-hydroxymethyl anthraquinone and damnacanthol
as potent inhibitors of both 15-lipoxygenase activity and nitric oxide production.
Further studies are needed in order to envisage its possible future use as a therapeutic
alternative against inflammatory diseases.
Key words
Pentas schimperi
- Rubiaceae - anthraquinones - nitric oxide - lipoxygenase
