Suppression of lipopolysaccharide-induced expression of inflammatory indicators in RAW 264.7 macrophage cells by extract prepared from Ginkgo biloba cambial meristematic cells

Abstract

Context: Ginkgo biloba L. (Ginkgoaceae) leaves have been used as an herbal medicine that has a complex range of biological activities. However, when we consider that biological activity of plant extracts is highly variable according to the source, location, and harvest season, technology to obtain the natural products with homogeneity is extremely important.

Objective: We established the technology to obtain the cambial meristematic cells (CMCs) of Ginkgo biloba, which were expanded in vitro with homogeneity through a suspension culture and then determined the anti-inflammatory activity of fractionated samples prepared from the ethanol extract of CMCs.

Materials and methods: We determined the anti-inflammatory activity of samples using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Especially, influence of sample treatment on the expression of various indicators, such as nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, mitogen-activated protein (MAP) kinases, transcription factor, and cytokines, involved in inflammatory activity was assessed.

Results: A fractionated sample demonstrated 53.4% inhibition of LPS-induced NO production from the cells. Additionally, when fractionated samples were treated, iNOS and COX-2 expressions were almost completely suppressed. Fractionated samples also inhibited the phosphorylation of LPS-induced extracellular signal-regulated (ERK) and p38 MAP kinases more than 60%. IκB phosphorylation and subsequent nuclear factor (NF)-κB activation were also suppressed by fractionated samples. The expression of pro-inflammatory cytokines, IL-6 and tumor necrosis factor (TNF)-α, was significantly inhibited by the sample treatment.

Discussion and conclusion: Fractionated samples from the ethanol extract of Ginkgo biloba CMCs could potentially be the source of a powerful anti-inflammatory substance.

Keywords::

• Cytokine
• inflammation
• mitogen-activated protein kinase
• NF-κB
• nitric oxide

Acknowledgements

This work was supported by a grant from Ministry of Knowledge Economy, Republic of Korea (No. 70004355).

Declaration of interest

The authors report no declarations of interest.