Inhibitory effects of geranium essential oil and its major component, citronellol, on degranulation and cytokine production by mast cells

Abstract

We investigated the effects of geranium essential oil (GEO) on anaphylaxis. GEO can exert antioxidant and anti-inflammatory effects, but its roles in allergic reactions are incompletely understood. Here, we used mouse cells to show that GEO inhibited the degranulation of cultured mast cells (CMCs). Citronellol is the major component of GEO and inhibited CMC degranulation. The l-enantiomer of citronellol more effectively suppressed CMC degranulation than did d-citronellol. We also examined whether citronellol could inhibit the immunoglobulin (Ig) E-induced production of tumor necrosis factor (TNF)-α. Treatment with various concentrations of citronellol before CMC activation with IgE significantly inhibited the induction of TNF-α in a dose-dependent manner. Mechanistically, citronellol suppressed the phosphorylation of mitogen-activated protein kinase (ERK), which is critical for ERK activation and the production of inflammatory cytokines in mast cells. These findings suggest that citronellol may represent a candidate compound for the effective treatment of allergic diseases.

Citronellol, a monoterpene alcohol with promising pharmacological activities - A systematic review

“…Substances with lipolytic action can trigger chronic elevation of circulating fatty acids that may present toxic action at tissue level (Engin, 2017). However, with respect to the anti-allergic and anti-inflammatory effects, CT was effective, acting through the TNF-α, COX-2, PGE 2 , NF-κB and IκBα pathways, important mechanisms already described in the literature in relation to anti-inflammatory drugs (Abe et al, 2003;Kobayashi et al, 2016). These results can explain the data reported by Brito et al (Brito et al, 2012), where CT presented an antinociceptive effect in the second phase of the formalin test (inflammatory phase).…”

“…The studies described several pharmacological activities for CT, and some mechanisms of action have already been defined, especially those involving antiinflammatory (Abe et al, 2003;Renan G Brito et al, 2015;Kobayashi et al, 2016), antioxidant (Jagdale et al, 2016) and analgesic (Brito et al, 2012;Renan G Brito et al, 2015;Renan G. Brito et al, 2013b) pathways (Figure 3), indicating this compound as an alternative treatment for such disorders.…”

“…This review article presents papers that described pharmacological activities of CT relevant to use in humans. In vitro studies investigated possible antibacterial (Echeverrigaray et al, 2008;Kotan et al, 2007;Mulyaningsih et al, 2011;Ngan et al, 2012;Nostro et al, 2013), antifungal (Kim and Park, 2012;Mahmoud, 1994;Pereira et al, 2015;Shin and Lim, 2004;Viollon and Chaumont, 1994;Zore et al, 2011), anti-lice (Gonzalez-Audino et al, 2011), repellent (Michaelakis et al, 2014;Semmler et al, 2014), lipolytic (Choi, 2006), anti-allergic (Kobayashi et al, 2016), anti-inflammatory (Abe et al, 2003;Su et al, 2010) and antispasmodic (Sadraei et al, 2013;Vasconcelos et al, 2016) properties. In vivo studies investigated possible cardiovascular (Bastos et al, 2009;Igor A C Menezes et al, 2010;Ribeiro-Filho et al, 2016), antidiabetic (Jagdale et al, 2016;Srinivasan and Muruganathan, 2016), anti-cholesterol (Batubara et al, 2015), antinociceptive (Brito et al, 2012;Renan G Brito et al, 2013), antihyperalgesic (Renan G , anti-anxiety (Umezu et al, 2002) and anticonvulsant (Sousa et al, 2006) activities.…”

“…Most of the in vitro studies did not describe the isomeric form of CT used in the study. Among those which did describe the isomeric form, 3 reported using only the isomeric form (±) (Mulyaningsih et al, 2011;Su et al, 2010;Vasconcelos et al, 2016), 1 used (+) and (-) (Ngan et al, 2012), and 1 used the (+), (-) and (±) forms (Kobayashi et al, 2016). In vivo studies mainly used the form (-) in studies that aimed to investigate antinociceptive and antihyperalgesic activities (Brito et al, 2012;Renan G Brito et al, 2015), (±) in studies investigating cardiovascular activities (Bastos et al, 2009;Igor A C Menezes et al, 2010) and (+) for anticonvulsant activity (Sousa et al, 2006).…”

“…The anti-allergic activity of CT was evaluated recently by Kobayashi et al (Kobayashi et al, 2016). The authors tested different enantiomers forms of CT (0.5-1 mM) in relation to degranulation and cytokine production by mast cells induced by immunoglobulin E (IgE).…”