<i>ent</i>-Kaurane and <i>ent</i>-Pimarane Diterpenes from <i>Siegesbeckia pubescens</i> Inhibit Lipopolysaccharide-Induced Nitric Oxide Production in BV2 Microglia

Abstract

The extract of Siegesbeckia pubescens herb and its chemical constituents were tested for the ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 microglia. The methanol extract and the 90% MeOH fraction of S. pubescens effectively attenuated lipopolysaccharide-induced nitric oxide production. Several steps of chromatography yielded eight ent-kaurane diterpenes (1-8) and one ent-pimarane diterpene (9) from the 90% MeOH fraction. Among these compounds, compounds 2-9 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia. Compounds 3 and 9 concentration-dependently decreased the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), supported by quantitative real time polymerase chain reaction (PCR) and Western blot analysis. These results suggest that ent-kaurane and ent-pimarane diterpenes isolated from S. pubescens are expected to be potential candidates against neuroinflammation-related disease.

Quercetin 3,7-O-dimethyl ether from Siegesbeckia pubescens suppress the production of inflammatory mediators in lipopolysaccharide-induced macrophages and colon epithelial cells

“…For searching the anti-inflammatory natural products employing RAW 264.7 cells and HT-29 cells as an in vitro assay system, we further investigated S. pubescens herbs, which was previously reported that extract, fractions, its isolated diterpenes have the anti-neuroinflammatory activities. 14) Moreover, we have attempted to isolate another phtyochemicals, targeting for the treatment of IBD. This methanolic extract was then suspended in DW and successively partitioned with CH 2 Cl 2 and DW.…”

“…11) In pharmacological studies, it was reported that S. pubescens has shown cartilage protective and analgesic activities, and an inhibitory activity on immediate hypersensitivity. [12][13][14] Also, it was reported that entkaurane and ent-pimarane diterpenenes from S. pubescens and flavonoids from S. glabrescens have the anti-inflammatory effects on the LPS-stimulated BV2 microglials. 14,16) QDE was isolated from Croton schiedeanus and showed the vasorelaxant activity with the NO/cyclic guanosine monophosphate pathway.…”

“…[12][13][14] Also, it was reported that entkaurane and ent-pimarane diterpenenes from S. pubescens and flavonoids from S. glabrescens have the anti-inflammatory effects on the LPS-stimulated BV2 microglials. 14,16) QDE was isolated from Croton schiedeanus and showed the vasorelaxant activity with the NO/cyclic guanosine monophosphate pathway. 15) However, there is limited evidence to indicate that QDE can attenuate intestinal inflammatory disease.…”

“…11) In pharmacological studies, it was reported that S. pubescens has shown cartilage protective and analgesic activities, and an inhibitory activity on immediate hypersensitivity. [12][13][14] Recent reports have been issued on diterpenes, major compounds derived from S. pubescens, for its antiinflammatory activity or mode of action. 14) Therefore, as a part of our ongoing screening program to evaluate the anti-inflammatory potentials of natural compounds, we investigated the in vitro anti-inflammatory activities of S. pubescens.…”

“…[12][13][14] Recent reports have been issued on diterpenes, major compounds derived from S. pubescens, for its antiinflammatory activity or mode of action. 14) Therefore, as a part of our ongoing screening program to evaluate the anti-inflammatory potentials of natural compounds, we investigated the in vitro anti-inflammatory activities of S. pubescens. This led to the isolation of a flavonoid, quercetin 3,7-O-dimethyl ether (QDE), which was subjected to anti-inflammatory in LPS-stimulated macrophage cells, RAW 264.7 cells and colon epithelial cells, HT-29 cells.…”