Smelling Lavender And Rosemary Increases Free Radical Scavenging Activity And Decreases Cortisol Level In Saliva

Karimi Abdul Ghani Toshiko Atsumi and Keiichi Tonosaki: Smelling lavender and rosemary increases free radical scavenging activity and decreases cortisol level in saliva. Free reactive oxygen species are related to many biological phenomena such as inflammation,

aging

and

carcinogenesis.

The

body

have

various

antioxidative

systems(FRSA) for preventing oxidative stress, and saliva contains such activity. In this study, the total salivary FRSA induced after the smelling of lavender and rosemary essential oils had measured. The experiment has carried out on 22 healthy volunteers who understood the objective of this study, they sniffed aroma for 5min, and each subject's saliva was collected before smelling and immediately after smelling. Physiological substances in saliva: cortisol, secretory IgA, and α-amylase activity, were measured. FRSA was measured using 1,1-diphenyl-2-picrylhydrazyl. According to this study, the FRSA values were increased by stimulation with lavender and rosemary. In contrast, both lavender and rosemary stimulations decreased cortisol levels as showed in below figures, but no significant changes were found in sIgA or α-amylase.

Changes in salivary FRSA induced by the smells of lavender (a) and rosemary (b).A, control (propylene glycol), B, low con.sol. (1000 times dilution), C, high con.sol. (10 time dilution).

The effect of lavender was exhibited at a low concentration, whereas that of rosemary was exhibited at a high concentration. Lavender, which stimulates the parasympathetic nerves, and rosemary, which stimulates the sympathetic nerves, exhibited similar effects.

The

smell could have a negative effect at a high concentration, and therefore further study is necessary to find an appropriate concentration for aromatherapy. Finally we can summarize that lavender and rosemary enhance FRSA and decrease the stress hormone, cortisol, and this is the first report on the cortisol-lowering effect of smell in human saliva.