Anti-neuroinflammatory effects of the KIOM -patented Polygonum multiflorum maximized root tuber against LPS-stimulated BV2 Cells

The main pathological mechanism of neurodegeneration is neuroinflammation. It is known that the persistent neuroinflammatory response is harmful by causing secondary nerve tissue damage. Meanwhile, P. multiflorum is a traditional oriental medicinal herb. It has been used as a hematopoietic agent and is used to treat a variety of diseases and conditions. The aim of the present study was to compare the anti-inflammatory efficacy between the commonly available P. multiflorum (C1) and the KIOM-patented in vitro-propagated P. multiflorum (K1), which had higher content of active ingredients and biomass, using culture and cultivation conditions of LPS-induced neuroinflammation. After stimulation with LPS and treatment with C1 and K1 in mouse microglial BV-2 cells, nitric oxide (NO) production, pro-inflammatory cytokine secretion, inducible NO synthase (iNOS) expression, MAPK phosphorylation and transcription factor activity were assessed. We examined the antioxidant effect using DPPH and production of nitric oxide (NO). C1 and K1 suppressed the expression of iNOS and COX-2 and the production of pro-inflammatory cytokines. Furthermore, we determined the levels of inflammatory mediators, such as interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and mitogen-activated protein kinases and IκBα via Western blotting to understand the regulating mechanisms. Additionally, C1 and K1 also inhibited the activation of p38 and nuclear factor-kappa B (NF-κB) in LPS-stimulated BV2 cells. In all experimental results, excellent anti-neuroinflammatory effects were confirmed at a lower dose in K1 than in C1, which is believed to be due to the increased biomass. Therefore, K1 is expected to be more effective than C1 and can be applied more broadly in the development of prevention and treatment of various inflammatory-mediated neurodegenerative diseases.