Materials and test objects
Leaf samples were obtained from A. truncatum Bunge and C. deodara planted on the campus of Shandong Agricultural University (SDAU) in Taian, China. The sampled A. truncatum Bunge tree was approximately 5.60m in height and 24.5cm in diameter at breast height (DBH).The sampled C. deodara tree was approximately 11.2m in height and had a DBH of 40.5cm. The leaves facing the south were selected in the middle of the June.
A total of 120 students in SDAU (60 male and 60 female) who volunteered to participate in the trial were selected as subjects. And this work was approved by the Ethical Commission. The average age, weight and height of these students were 19.5±1.2years, 60.4±10.3kg and 160.5±7.5cm, respectively. The volunteers were all in good health, and did not take drugs, smoke, or drink alcohol and other stimulating drinks for a week before the test.
The natural environment is an important factor in human health and can influence certain aspects of human physiology and psychology. In the present study, physiological parameters were influenced by VOCs inhaled from A. truncatum Bunge and C. deodara. Blood oxygen saturation increased in both test groups, however that was only significant for the C. deodara group, whose BOS increased significantly by 0.42%. Different VOCs from different plants had positive or negative impact on the circulatory system, and people of different gender responded differently, for example Li et al. also found the BOS of female increased by 0.074% after inhaling VOCs from Juniperus chinensis, and male increased by 0.492% (P<0.05), but female and male decreased by 1.015% and 0.405% (P<0.05) respectively after inhaling VOCs from Pistacia chinensis Bunge (Li et al., 2014). Generally, the higher this value, the more beneficial to human body (Wang et al., 2010). These VOCs could improve the respiratory and GSK2606414 cost according to the data.
Previous studies have demonstrated that different VOCs affected human heart rate differently. Yamaguchi (1990) used the changes of heart rate for the measurement of effects of lemon and rose aromas. Lemon aroma caused an increase of heart rate whereas rose aroma led to a decrease of heart rate. But Kikuchi et al. (1992) found that Rosa rugosa aroma caused an increase in heart rate while Citrus limonum aroma had a calming effect and caused a reduction in heart rate. Brauchli et al. (1995) reported that a pleasant and an unpleasant odor presentation affected an autonomic variable, i.e. heart rate. It is now accepted that the pattern of changes in the heart rate reveal differences between stimulant aromas and sedative aromas (Hongratanaworakit, 2004). But Li et al. believed that 2,6-dimethyl-2,7-octdien-6-ol from J. chinensis may be the one reason for the decrease of heat rate. In the present study, heart rate reduced by 5.03% after inhalation of VOCs from C. deodara, which was consistent with subjective assessment results (Table 4, quiet 1.57, relaxing 0.96). There were no significant differences in other ECG indicators, such as the PR interval, the width of P wave and the QT interval before and after the smelling of VOCs, and the datas were all within normal ranges. Smelling the VOCs did not have other effect on atrial and ventricular depolarization and repolarization, and had no damage on cardiac function. And I believed the VOCs in the study had played an important role in calming effect. So I was more agreed with Hongratanaworakit’s conclusion.
Some aromatic plants have been found to lower SBP and DBP. Transdermal absorption of sandalwood oil and one of its main components, α-santalol led to a trend towards a larger decrease of SBP as compared to the placebo group (Hongratanaworakit et al., 2004). Gao and Yao (2011) constructed a garden space consisting of Lavandula pedunculata, Relargonium hortorum, Ocimum basilicum and other aromatic plants, and found that differences between SBP and DBP were reduced after inhalation. Yang et al. (2010) argued that lavender essential oil by olfactory pathway affected the change of the rat peripheral sympathetic nervous activity, and reduced the release of the neurotransmitter neuropeptide γ vessels, and both of them caused lower blood pressure. In the present study, SBP and DBP both decreased significantly after participants’ smelling the VOCs from C. deodara leave rather than oils. This suggests that some VOCs may have an antihypertensive effect. But the differences between genders need to be tested in further research.
Materials and test objects