Citrus essential oils inhalation by mice: Behavioral testing, GCMS plasma analysis, corticosterone, and melatonin levels evaluation

Abstract

The use of orange essential oils (EOs) as a complementary treatment is very common in Brazilian popular culture. The levels of melatonin (MEL) and corticosterone (CORT) hormones were investigated simultaneously, by the Luminex™ immunoassay system in mice plasma, after Citrus aurantium and Citrus sinensis EOs inhalation for 30 min. The plasma was analyzed by headspace through gas chromatography coupled to mass spectrometry for investigation of the EO components. Mice were submitted to behavioral testing to research anxiolytic-like, sedative, and antidepressant-like effects. The inhalation of atmosphere obtained from vaporization of 10% solution of this Citrus EO separately did not affect MEL or CORT plasma levels; that is, the MEL and CORT levels did not present variation in function of the EO in the schedule used. On the other hand, the imipramine positive control used altered the level of MEL as expected. The EO constituents were detected in plasma at different ratios that is present in inhaled EO. Behavioral tests showed that the inhalation of 10% C. sinensis EO presents an anxiolytic-like and sedative effect. Thus, C. sinensis EO can be a valuable tool for treatment of the anxiety disturbs, apparently without interference with MEL and CORT physiological levels.

The nitrergic neurotransmission contributes to the anxiolytic‐like effect of Citrus sinensis essential oil in animal models

“…In this line, the present results suggested that NO inhibition plays an important role in this effect. Furthermore, the present results corroborated (and extended to other models) previous study indicating an anxiolytic‐like effect of C. sinensis in animal models of anxiety (Faturi et al, ; Wolffenbüttel et al, ).…”

“…This anxiolytic‐like effect of C. sinensis essential oil was already observed in the elevated plus‐maze and light/dark test (Faturi et al, ; Wolffenbüttel et al, ). In rats, C. sinensis essential oil increased the open arms exploration in the elevated plus maze and spent more time in the lit side of light/dark apparatus.…”

“…No change in locomotor activity was observed (Faturi et al, ). In a similar way, Wolffenbüttel et al () observed that inhalation of C. sinensis essential oil induced anxiolytic‐like effects in mice tested in the light/dark test, although it also decreased locomotor activity in the open‐field. This latter result can be due to different concentrations of essential oil or longer time exposition in the Wolffenbüttel et al () study.…”

“…Concerning the essential oil of C. sinensis , Faturi, Leite, Alves, Canton, and Teixeira‐Silva () observed that this essential oil exhibits anxiolytic‐like effect in rats tested in the elevated plus‐maze and in the light/dark test. This anxiolytic‐like effect of essential oil of C. sinensis on light/dark test was also seen in mice (Wolffenbüttel et al, ). Moreover, C. sinensis essential oil showed anxiolytic effect in normal volunteers submitted to experimentally induced anxiety response (Goes, Antunes, Alves, & Teixeira‐Silva, ).…”

“…All these experiments with C. sinensis essential oil (Faturi et al, ; Goes et al, ; and the present study), the main component of this essential oil is limonene (between 53% and 97%), which already showed anxiolytic‐like effect in animal models (Lima et al, ; Satou, Miyahara, Murakami, Hayashi, & Koike, ). Moreover, Wolffenbüttel et al () found that limonene is the main component detected in the plasma of mice after C. sinensis essential oil inhalation. Thus, it could be speculated that limonene may be the major constituent related to anxiolytic‐like effect of C. sinensis essential oil.…”