Fig 1.
Anti-inflammatory activity of mono-, di- and polyhydroxylated flavones on the LPS-induced NO production in rat kidney mesangial cells.
All of the hydroxylated flavones were abbreviated as the positions of hydroxyl groups followed by—HO. The total production of nitrite in the treatment media was measured with Griess assay at 48 h post 10 ng/mL LPS stimulation. The nitrile level in the LPS treatment alone was used as 100%, and IC50 values were obtained using the dose-response analysis provided by the Graphpad Prism software as shown in parenthesis. Compounds of group 5 with IC50 >200 μM were not shown in the figure.
Fig 2.
Structures of monohydroxylated and dihydroxylated flavones with IC50 against LPS-induced NO production.
Fig 3.
Direct NO radical quench study with selected monohydroxylated and polyhydroxylated flavones.
Spontaneous generation of NO was achieved by a freshly prepared sodium nitroprusside stock solution (5 mM) in water in Griess assay (top). The direct quench of NO radicals were assessed on the 3-, 7- and 6-hydroxyflavone and 3,3′,4′,5,5′,7-hexahydroxyflavone with vitamin C and resveratrol as the positive controls.
Fig 4.
The inhibition of LPS-induced NO production in kidney mesangial cells by 6-methoxyflavone, 6-acetoxyflavone and flavone 6-sulfate.
The total production of nitrite in the treatment media was measured with Griess assay at 48 h post 10 ng/mL LPS stimulation. IC50 values were obtained using the dose-response analysis provided by the Graphpad Prism software as shown in parenthesis.
Fig 5.
Western blot analysis of potential molecular targets by 6-methoxyflavone in kidney mesangial cells with LPS as the inflammatory stimuli.
Cells were pretreated with 6-methoxyflavone or resveratrol for 12 h and then LPS was added. Cell lysate were collected after 15 min and 24 h incubation for activated NF-κB pathway and iNOS protein, respectively.