Melia azedarach Flowers and Their Volatile Components Improved Human Physiological and Psychological Functions

Abstract

In the present study, we examined the modulatory effects of Melia azedarach Linn flowers on human physiological and psychological behaviors. Inhalation of fresh flowers for 20 min decreased salivary amylase activity. Electroencephalogram analysis exhibit that inhalation of fresh flowers reduced alpha brainwave, while gamma, delta, and theta-brainwaves were increased. Moreover, systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were decreased after inhalation of flowers. Furthermore, inhalation of flowers reduced sympathetic nervous system (SNS) activity and increased parasympathetic nervous system (PSNS) activity. In addition, we extracted volatiles from the flowers by the solid-phase micro-extraction (SPME) method and the chemical composition was determined by mass spectrometry. Fifteen compounds were identified, among them benzaldehyde (68.50 %) and phenylacetaldehyde (22.26 %) were the major compounds. Similarly, inhalation of 0.25 % benzaldehyde or phenylacetaldehyde reduced SBP, DBP, HR, and SNS activity, whereas PSNS was increased. Furthermore, the profile of mood states (POMS) scores support that inhalation of fresh flowers significantly reduced depression, confusion, and tension. Anger, fatigue, and vigor were also decreased. These results suggest that M. azedarach flowers or their major compounds can be novel modulators of SNS dysfunction as well as aromatherapy.