## 3 Results
### Ability of Caryophyllane sesquiterpenes to Modulate Macrophage Function  
Macrophages are mononuclear phagocytes that compose a heterogeneous population of immune cells, whose major functions are antigen presentation, cytokine production, phagocytosis, and the processing of foreign materials, including pathogens [26]. Due to their highly effective phagocytic capacity, they are deemed to be \"professional\" phagocytic cells, along with monocytes, dendritic cells, neutrophils, and mast cells [27]. Specialized macrophages can be identified in tissues and can be subdivided into two main classes, including tissue resident and infiltrated macrophages [27]. The first ones, such as the microglia in the central nervous system (CNS), Langerhans cells in the skin, Kupffer cells in the liver, osteoclasts in the bone, and alveolar macrophages in the lung, are present in tissues under homeostatic conditions and regulate homeostasis, tissue development, remodelling, and repair [27]. Infiltrated macrophages are pro-inflammatory cells, recruited from the blood into inflamed tissues and arise from circulating monocyte differentiation [27; 28]. Both resident and recruited macrophages can be polarized into different phenotypes in response to the local tissue microenvironment and several stimuli and participate in the homeostasis modulation and inflammation response. Indeed, they can switch from a pro-inflammatory M1 phenotype to a M2 anti-inflammatory one: the first phenotype is activated in response to lipopolysaccharidesaccharide (LPS), \(\gamma\)-interferon (IFN-\(\gamma\)), tumor necrosis factor alpha (TNF-\(\alpha\)), and granulocyte/macrophage colony-stimulating factor (GM-CSF), while the M2 phenotype is induced by interleukin-4 (IL-4), IL-10, IL-13, transforming growth factor-\(\beta\) (TGF-\(\beta\)), and macrophage colony-stimulating factor (M-CSF). The polarization of macrophages depends on a complex regulation in which different pathways are involved, including signal transducer and activator of transcription (STAT) and the peroxisome proliferatorator-activated receptor-\(\gamma\) (PPARy), and cytokines, released by both the  
Figure 2: Chemical structures of plant-based caryophyllane sesquiterpenes with immunomodulatory properties. M1 and the M2 macrophages with both pro-inflammatory and anti-inflammatory functions [29]. The M1 macrophages have potent antimicrobial and anti-tumor activities and the ability to release pro-inflammatory cytokines and chemokines, leading to the exacerbation of inflammation and tissue damage [28]. Conversely, the M2 macrophages possess a potent phagocytic capacity and anti-inflammatory and immunosuppressive properties, which contribute to the resolution of inflammation and tissue repair [26,28]. Macrophages can also modulate painful conditions, acting as nocicopter activators or favouring pain resolution, through the release of pro-inflammatory mediators (e.g., ROS, cytokines, and chemokines such as prostaglandin E2 (PGE2), IL-1\(\beta\), and TNF-\(\alpha\)) and analgesic factors (e.g., \(\beta\)-endorphin), respectively [26]. Modulation of macrophage function by caryophyllane sesquiterpenes has been evaluated in both in vitro models, such as murine RAW 264.7 macrophages, primary splenocytes from BALB/c mice, and M2-M\(\phi\)s BALB/c mice bone-marrow-derived M2 macrophage, and in vivo (Table 1). [PERSON] et al. [30] found that \(\beta\)-caryophyllene was nontoxic in RAW 264.7 macrophages at the concentrations of 10 and 50 \(\upmu\)M after a 3-day exposure, although the expression of the key proteins involved in cell proliferation was affected by the treatment with 50 \(\upmu\)M of the test substance (Table 1); indeed, a lowering in the mitogen-activated protein kinases (MAPK) levels and an increase in Ras, protein kinase B(Akt), p21, \(\upbeta\)-catenin, and caspase-3, involved in apoptotic cell death, was found.