## 1 Introduction  
The _Epiolobium_ genus (Onagracee) consists of approximately 200 species that are distributed worldwide (e.g., Europe, America, Africa, and northern Asia). _Epiolobium_ species were used in folk medicine in Europe and North America. Because of its demolient and embilient properties, _Epiolobium_ herbs have been used for the treatment of diarrhea, infection, irritation, and inflammation. Additionally, the extract of _Epiolobium parviform_ and _Epiolobium roseum_ possess radical scavenging activity, which indicates the antioxidant effects of _Epiolobium_ herbs [1]. This evidence suggests that _Epiolobium_ herbs are potential anti-inflammatory agents. _Epiolobium amurensse_ subsp. _cephalostigma_ ([PERSON].) [PERSON], [PERSON] & [PERSON]. [PERSON], which is a flowering plant that grows in China and the Republic of Korea, is a member of the _Epiolobium_ genus [2]. Unlike those of other _Epiolobium_ species, the biological effects of _E. amurense_ have not been assessed. Therefore, in the present study, to investigate the pharmacological effects of _E. amurense_ belonging to _Epiobium_ herbs, it was harvested at the flowering/fruiting stage, when it contains a high content of phenolic compounds with anti-inflammatory and antioxidant properties, and the whole plant was extracted with 95% ethanol.  
Inflammation, one of the most important host defense mechanisms, protects against foreign pathogens and infectious agents, including viruses, bacteria, damaged cells, toxic compounds, and parasites [3]. They trigger inflammatory signaling, such as nuclear factor-kappaB (NF-\(\kappa\)B) and mitogen-activated protein kinase (MAPK) pathways. The immune system relies on two major complementary systems, the innate and adaptive immune systems. However, abnormal or maladaptive interactions between these systems lead to unhealthy responses, including asthma, allergy, and other inflammatory diseases [4].  
Reactive oxygen species (ROS) are generated as byproducts of normal mitochondrial oxidative metabolism and homeostasis [5]. However, the overproduction of ROS is related to the progression of many inflammatory diseases, such as diabetic foot syndrome, cardiovascular disorders, and chronic inflammatory diseases [6]. To regulate the production of oxidants in cells, oxidants are counterbalanced by an antioxidant system [7]. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates the expression of antioxidants that protect against oxidative stress and toxic electrophiles produced during injury and inflammation [8; 9]. Before being activated by oxidants, Nrf2 is suppressed by Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-dependent ubiquitination-proteosomal degradation [10]. Nrf2 affects the production of ROS via the regulation of several stress response proteins, including heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO-1) [5]. ROS are also produced in response to the activation of NADPH oxidase (Nox). The Nox family has several isoforms, among which Nox4 is the main isoform that generates and activates H\({}_{2}\)O\({}_{2}\), an ROS [11; 12]. However, the role of Nox4 in inflammation remains controversial because it has both inflammatory and anti-inflammatory activities. Thus, the appropriate regulation of ROS-mediated No4 signaling may effectively modulate inflammatory responses; however, the underlying mechanisms during the proinflammatory phase are largely unknown.  
Therefore, in this study, we investigated the pharmacological effects of an _E. amurense_ 95% ethanol extract (EACEE) on RAW 264.7 macrophages and the molecular mechanism(s) involved in its anti-inflammatory and antioxidant activities.