Title : Effects of d Borneol and d Camphor inhalations on Emotional States and Brain Wave Activities in Healthy Participants
Introduction: d-Borneol and d-camphor are common volatile compounds widely used in traditional remedies because they can stimulate sense of smell and emotional center of human brain. d-Borneol (C10H18O) obtained from the tropical plants known as Dryobalanops aromatica (D. aromatica) is a highly lipid-soluble bicyclic monoterpene alcohol while d-camphor (C10H16O) obtained from the tropical plants called Cinnamomun camphora is a white, crystalline substance. d-Camphor is bicyclic monoterpene ketone. d-Borneol is used in traditional Chinese and Japanese medicine to treat analgesia, anesthesia, anxiety, depression and in traditional Thai medicine known as Phimsen as a tonic for heart and brain. In addition, d-camphor is used as antiemetic, antidiarrheal and stimulant agent in Ayurvedic medicine. In Thailand, it is an important ingredient in nasal inhaler (Ya-Dom) to treat nasal congestion. There are several previous studies on the effects and therapeutic properties of d-borneol and d-camphor. However, the studies on the effects of d-borneol and d-camphor inhalation on psychophysiological changes are limited and inconsistent.
Research Objective: This study aims to investigate the effects of d-borneol and d-camphor inhalation on psychological parameters through emotional states and central nervous system (CNS) through electroencephalography (EEG) recordings in healthy participants. The study design was a pretest-posttest design. Twenty-one participants and 24 participants were recruited into d-borneol and d-camphor groups respectively.
Methods: The EEG recordings were conducted based on 10-20 systems and a set of scales by the Geneva Emotion and the Odor Scale was used to evaluate the emotional states. For data analysis, d-borneol and d-camphor were inhaled and compared with sweet almond oil as base oil. Paired t-test was employed to measure the oil inhalation.
Results: The findings indicated that general characteristics of the participants in each intervention were similar. The d-borneol inhalation could induce positive effects on psychological parameters of emotional states by increasing the mean scores of good, active, fresh, romantic feelings significantly (p-value=0.032), (p-value<0.001), (p-value<0.001), (p-value<0.001) respectively while decreasing the mean scores of bad, stressed, frustrated, annoyed, disgusted feelings significantly (p-value<0.001),(p-value<0.001), (p-value<0.001), (p-value=0.028), (p-value=0.036) respectively and the EEG parameters by increasing the power of the beta wave in left and right posterior brain areas increased significantly (p-value=0.008), (p-value=0.003), respectively. The d-camphor inhalation caused significant changes in the emotional states and the parameters. After d-camphor inhalation, relaxed, calm feelings increased significantly (p-value<0.001) (p-value=0.008), respectively. while active, stressed feelings decreased significantly (p-value=0.019), (p-value<0.001), respectively. The power of the alpha wave over all brain areas including left anterior, right anterior, center, left posterior and right posterior brain areas increased significantly (p-value=0.004), (p-value=0.013), (p-value=0.010), (p-value=0.036), (p-value=0.042) respectively. Beta waves are related to an alert state of mind while alpha waves are associated with mental coordination, calmness and brain consciousness.
Conclusion: d-Borneol seems to possess stimulating effects while d-camphor seems to possess sedative effects on psychophysiological parameters in healthy participants.