Estragole Exhibits Anti-inflammatory Activity with the Regulation of NF-κB and Nrf-2 Signaling Pathways in LPS-induced RAW 264.7 cells

Estragole is a naturally occurring phenylpropanoid obtained from essential oils found in a broad diversity of plants. Although the phenylpropanoids show many biological activities, clear regulation of the inflammatory signaling pathways has not yet been determined. Here, we scrutinized the anti-inflammatory effect of estragole. The anti-inflammatory effect of estragole was determined through the inhibitory mechanisms of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinases (MAPK) pathways and the activation of nuclear factor erythroid 2-related factor 2 (Nrf-2)/heme oxygenase (HO)-1 pathways in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Estragole significantly inhibited NO production, iNOS and COX-2 expression as well as LPS-induced NF-κB and MAPK activation. Furthermore, estragole suppressed LPS-induced intracellular ROS production but up-regulated the stress response gene HO-1 via the activation of transcription factor Nrf-2. These findings demonstrate that estragole inhibits the LPS-induced expression of inflammatory mediators via the down-regulation of iNOS, COX-2, NF-κB, and MAPK pathways, as well as the up-regulation of the Nrf-2/HO-1 pathway, indicating that this phenylpropanoid has potential therapeutic and preventive applications in various inflammatory diseases.

Studies on volatile oils compounds of Acorus macrospadiceus based on GC-MS, an ethnomedicinal and food plant used by local people in southwest China / 中国中药杂志

Acorus macrospadiceus is a common medicinal and food plant used different ethnic groups in Guizhou and surrounding areas. In this paper, the leaf and rhizome tissues of A. macrospadiceus were hydro-distilled to extract the volatile oils. The chemical constituents of these oils were analyzed by GC-MS and identified using the NIST 14.0 & NIST 14.0s mass spectral libraries. The relative contents of chemical constituents from the different plant parts were determined by area normalization. The analysis of A. macrospadiceus volatile oils resulted in the identification of 25 compounds from the leaf and 36 compounds from the rhizome. The identified compounds accounted for 97.85% of the leaf essential oil content and 97.18% of the rhizome essential oil content. The main volatile constituent of A. macrospadiceus was identified as estragole (93.56% of total oil content in leaf and 71.62% of total oil content in rhizome). Fourteen compounds were found to be common to essential oils of both leaf and rhizome. However, the relative amounts of these compounds were significantly different between the plant parts; the remaining identified compounds were unique to each part. This comparison of volatile oils from the different parts of A. macrospadiceus can serve as a reference for future development. Because of the higher estragole content and better harvesting sustainability of the leaves compared to rhizomes, the leaves of A. macrospadiceus deserve consideration for sustainable development. However, when we use it as a medical plant, we should draw a distinction between it with A. tatarinowii.

Estragole blocks neuronal excitability by direct inhibition of Na+ channels

Estragole is a volatile terpenoid, which occurs naturally as a constituent of the essential oils of many plants. It has several pharmacological and biological activities. The objective of the present study was to investigate the mechanism of action of estragole on neuronal excitability. Intact and dissociated dorsal root ganglion neurons of rats were used to record action potential and Na+ currents with intracellular and patch-clamp techniques, respectively. Estragole blocked the generation of action potentials in cells with or without inflexions on their descendant (repolarization) phase (Ninf and N0 neurons, respectively) in a concentration-dependent manner. The resting potentials and input resistances of Ninf and N0 cells were not altered by estragole (2, 4, and 6 mM). Estragole also inhibited total Na+ current and tetrodotoxin-resistant Na+ current in a concentration-dependent manner (IC50 of 3.2 and 3.6 mM, respectively). Kinetic analysis of Na+ current in the presence of 4 mM estragole showed a statistically significant reduction of fast and slow inactivation time constants, indicating an acceleration of the inactivation process. These data demonstrate that estragole blocks neuronal excitability by direct inhibition of Na+ channel conductance activation. This action of estragole is likely to be relevant to the understanding of the mechanisms of several pharmacological effects of this substance.