The Metabolic Responses to Aerial Diffusion of Essential Oils

PLOS ONE, Dec 2019

Anxiety disorders are the most prevalent psychiatric disorders and affect a great number of people worldwide. Essential oils, take effects through inhalation or topical application, are believed to enhance physical, emotional, and spiritual well-being. Although clinical studies suggest that the use of essential oils may have therapeutic potential, evidence for the efficacy of essential oils in treating medical conditions remains poor, with a particular lack of studies employing rigorous analytical methods that capture its identifiable impact on human biology. Here, we report a comprehensive gas chromatography time-of-flight mass spectrometry (GC-TOFMS) based metabonomics study that reveals the aromas-induced metabolic changes and the anxiolytic effect of aromas in elevated plus maze (EPM) induced anxiety model rats. The significant alteration of metabolites in the EPM group was attenuated by aromas treatment, concurrent with the behavioral improvement with significantly increased open arms time and open arms entries. Brain tissue and urinary metabonomic analysis identified a number of altered metabolites in response to aromas intervention. These metabolic changes included the increased carbohydrates and lowered levels of neurotransmitters (tryptophan, serine, glycine, aspartate, tyrosine, cysteine, phenylalanine, hypotaurine, histidine, and asparagine), amino acids, and fatty acids in the brain. Elevated aspartate, carbohydrates (sucrose, maltose, fructose, and glucose), nucleosides and organic acids such as lactate and pyruvate were also observed in the urine. The EPM induced metabolic differences observed in urine or brain tissue was significantly reduced after 10 days of aroma inhalation, as noted with the loss of statistical significance on many of the metabolites in the aroma-EPM group. This study demonstrates, for the first time, that the metabonomics approach can capture the subtle metabolic changes resulting from exposure to essential oils and provide the basis for pinpointing affected pathways in anxiety-related behavior, which will lead to an improved mechanistic understanding of anxiolytic effect of essential oils.

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The Metabolic Responses to Aerial Diffusion of Essential Oils

Citation: Wu Y, Zhang Y, Xie G, Zhao A, Pan X, et al. ( The Metabolic Responses to Aerial Diffusion of Essential Oils Yani Wu 0 Yinan Zhang 0 Guoxiang Xie 0 Aihua Zhao 0 Xiaolan Pan 0 Tianlu Chen 0 Yixue Hu 0 Yumin Liu 0 Yu Cheng 0 Yi Chi 0 Lei Yao 0 Wei Jia 0 Jianping Ye, Pennington Biomedical Research Center, United States of America 0 1 School of Pharmacy, Shanghai Jiao Tong University , Shanghai , China , 2 School of Agriculture and Biology, Shanghai Jiao Tong University , Shanghai , China , 3 X-omics Research Center for Metabolic Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital , Shanghai , China , 4 Center for Translational Biomedical Research, University of North Carolina at Greensboro, Kannapolis, North Carolina, United States of America, 5 Center for Instrumental Analysis, Shanghai Jiao Tong University , Shanghai , China Anxiety disorders are the most prevalent psychiatric disorders and affect a great number of people worldwide. Essential oils, take effects through inhalation or topical application, are believed to enhance physical, emotional, and spiritual well-being. Although clinical studies suggest that the use of essential oils may have therapeutic potential, evidence for the efficacy of essential oils in treating medical conditions remains poor, with a particular lack of studies employing rigorous analytical methods that capture its identifiable impact on human biology. Here, we report a comprehensive gas chromatography time-of-flight mass spectrometry (GC-TOFMS) based metabonomics study that reveals the aromas-induced metabolic changes and the anxiolytic effect of aromas in elevated plus maze (EPM) induced anxiety model rats. The significant alteration of metabolites in the EPM group was attenuated by aromas treatment, concurrent with the behavioral improvement with significantly increased open arms time and open arms entries. Brain tissue and urinary metabonomic analysis identified a number of altered metabolites in response to aromas intervention. These metabolic changes included the increased carbohydrates and lowered levels of neurotransmitters (tryptophan, serine, glycine, aspartate, tyrosine, cysteine, phenylalanine, hypotaurine, histidine, and asparagine), amino acids, and fatty acids in the brain. Elevated aspartate, carbohydrates (sucrose, maltose, fructose, and glucose), nucleosides and organic acids such as lactate and pyruvate were also observed in the urine. The EPM induced metabolic differences observed in urine or brain tissue was significantly reduced after 10 days of aroma inhalation, as noted with the loss of statistical significance on many of the metabolites in the aroma-EPM group. This study demonstrates, for the first time, that the metabonomics approach can capture the subtle metabolic changes resulting from exposure to essential oils and provide the basis for pinpointing affected pathways in anxiety-related behavior, which will lead to an improved mechanistic understanding of anxiolytic effect of essential oils. - . These authors contributed equally to this work. Anxiety is a substantive public health problem and affects a great number of people worldwide [1]. An increasing number of studies have shown that essential oils can decrease anxiety-related behavior in humans and animals [2,3] and demonstrated that the aromatic plant-derived essential oils exhibit a variety of biological properties, such as mood enhancement, pain relief, and improved cognitive function, which is being used in complementary and traditional medicine units as well as primary care settings [4]. The inhaled aromas from the essential oils are believed to be useful for a vast array of symptoms and conditions and a large body of published literature has generally focused on the human brain and emotions [5,6]. Several studies suggest that neurotransmitters 5hydroxytryptamine and dopamine may be modulated with the anti-anxiety effect by essential oils from rose, lavender, lemon and peppermint [7,8]. Other studies investigated the effects of various plant-derived or synthetic odors on task performance, reaction time, and autonomic parameters or evaluated the direct effects of odors on the brain via electroencephalogram patterns and functional imaging studies [6]. These studies have consistently shown that odors can produce specific effects on human neuropsychological and autonomic function, suggesting that essential oils has beneficial effects in the context of stressful and adverse psychological conditions. Despite the numerous results demonstrating beneficial effects on mood and relaxation observed in behavioral and emotional studies, evidence for the efficacy and mechanistic understanding of essential oils in treating medical conditions remains poor, with a particular lack of studies employing rigorous methodology [9,10]. Some benefits that have been linked to essential oils intervention, such as relaxation and clarity of mind, may arise from the placebo effect rath (...truncated)


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Yani Wu, Yinan Zhang, Guoxiang Xie, Aihua Zhao, Xiaolan Pan, Tianlu Chen, Yixue Hu, Yumin Liu, Yu Cheng, Yi Chi, Lei Yao, Wei Jia. The Metabolic Responses to Aerial Diffusion of Essential Oils, PLOS ONE, 2012, 9, DOI: 10.1371/journal.pone.0044830