Extracts of Allium fistulosum Attenuates Pro-Inflammatory Action in the Lipopolysaccharide-Stimulated BV2 Microglia Cells

Abstract

Microglia are central nervous system (CNS)-resident professional macrophages that function as the principal immune cells responding to pathological stimulations in the CNS. Activation of microglia, induced by various pathogens, protects neurons and maintains homeostasis in the CNS, but severe activation causes inflammatory responses secreting various neurotoxic molecules such as nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines. Allium fistulosum, a member of the onion family, is mainly cultivated for consumption, as well as medicinal use in Oriental medicine. It has been reported that A. fistulosum has various biological effects such as anti-oxidant, anti-platelet aggregation, anti-fungus and anti-cholesterol synthesis, however there has been no research about the anti-inflammatory effects of A. fistulosum extracts. In this study, it was undertaken to explore the functions of A. fistulosum as a suppressor of neuronal inflammation by using BV2 microglia cells. As a result, it was found that four kinds of extracts of A. fistulosum effectively reduced the expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) at both mRNA and protein levels, and also attenuated pro-inflammatory cytokines such as tumor necrosis alpha (TNF-α), interleukin-1β (IL-1 β) and interleukin-6 (IL-6) at the mRNA level in BV2 stimulated by lipopolysaccharide (LPS). In addition, the extracts of A. fistulosum attenuated the release of NO markedly, as well as resulting in slight decreases of TNF-α and IL-6 production, the effects of which were most significant when treated with ethyl alcohol extract from the whole A. fistulosum. In conclusion, the data indicated that the anti-inflammatory actions of A. fistulosum against BV2 microglia cells is through the down-regulation of iNOS, COX2 and pro-inflammatory cytokines such as TNF-α and IL-6, and these effects are expected to help in the protection of nerve tissues by suppressions of neuronal inflammation in various neurodegenerative diseases.

Allium vegetables: Traditional uses, phytoconstituents, and beneficial effects in inflammation and cancer

“…In an MTT assay, all extracts except the ethanol extract of the root, effectively suppressed both the production of mRNA and the protein expression of iNOS and COX-2 enzymes at the concentrations of 50 µg/mL. The cellular concentrations of various pro-inflammatory cytokines, including TNF-α, IL-1ß and IL-6 were also significantly down regulated at the mRNA level (Park S-H et al 2011a).…”

Functional Perspective of Leeks: Active Components, Health Benefits and Action Mechanisms

“…iNOS↓, COX-2↓, TNF-α↓, IL-6↓, IL-1β↓ [38] Aqueous extracts of Welsh onion green leaves LPS-activated RAW 264.…”

“…Many studies have confirmed that, in the process of inflammation, the expression levels of NO, TNF-α, COX-2 and iNOS are increased. Another study explored the anti-inflammatory effect of leek extracts on LPS-stimulated BV2 microglia [38]. Four different extraction methods used to extract leeks were studied, and it was found that all four extracts could effectively inhibit the mRNA and protein expression levels of iNOS and COX-2 at the cellular level.…”

Anti-inflammatory Activity of Hizikia fusiformis Extracts Fermented with Lactobacillus casei in LPS-stimulated RAW 264.7 Macrophages

“…염증반응은 우리 몸을 보호하기 위 1 한 면역체계 반응이지만 지속적인 염증반응의 진행은 세포 조직의 손상을 초래하여 암, 뇌질환, 알츠하이머병, 관절염, 천식, 염증성 장질환 및 동맥경화 등 여러 질병뿐만 아니라 노화의 직·간접적 원인이 되는 것으로 알려져 있다 [2][3][4]. 대 식세포는 염증반응에 관여하는 주요 세포로 손상 부위로의 면역세포의 이동과 Tumor necrosis factor (TNF)-α, Interleukin (IL)-1β 및 IL-6 등의 pro-inflammatory cytokine 분비에 관여 하는 등 매우 중요한 역할을 한다 [1,3,[5][6][7].…”