Table 2.

Transient Receptor Potential (TRP) thermoreceptors-mediated activities of eucalyptol (1,8-cineole) and menthol.

	TRPM8	TRPV3	TRPA1	Other	References
1,8-Cineole	Activation, less than menthol (reduced nociceptive effect).	Desensitization Decreases allyl isothiocyanate-induced-TRPV3 currents.	Blocking, less than menthol (anti-inflammatory and antinociceptive effects).	Suppresses smoke respiratory irritation.	Santos, Rao 2000; Takaishi et al., 2012; Liedtke and Heller, 2007
Menthol	Bimodal action. Low-to-moderate concentrations reduce cinnamaldehyde- and capsaicin-induced irritation, heat hypersensitivity or hyperalgesia mediated by TRPV1, and headaches. High concentrations cause cold allodynia and hyperalgesia.	Desensitization.	Bimodal action: activating at submicromolar doses, inhibiting at higher concentrations.	In inhalation, it reduces cough sensitivity to inhaled capsaicin, influences respiratory flow, suppressing smoke respiratory irritation.	Haeseler et al., 2002; Bautista et al., 2007; Sherkheli et al., 2009; Millqvist et al., 2013