Yasuhiro Yamazaki

Lavender essential oil (LEO) is commonly used in aromatherapy for stress reduction, relaxation and recovery from (muscle) fatigue. However, molecular mechanisms underlying its potential physiological effects on the skeletal muscle remain unclear. This study investigates whether LEO affects the intracellular signaling pathways in skeletal muscle cells that respond to physical activity. Prior to the experiment, GC-MS analysis confirmed linalyl acetate and linalool as the main components of LEO used in this study. Transdermal permeability was assessed using a reconstructed human epidermis model, which showed that linalool permeated the epidermal layer, while linalyl acetate showed minimal permeation. Following this confirmation, the differentiated C2C12 myotubes were treated with LEO in an in vitro muscle contraction model using electrical pulse stimulation (EPS). LEO significantly increased Interleukin 6 (IL-6) mRNA expression under EPS, and DNA whole-genome microarray analysis showed that LEO induced different gene expression profiles depending on the contraction state of the muscle cells. These results provide the first molecular evidence that LEO modulates skeletal muscle gene networks in a stimulation-dependent manner and may indicate its potential use as an aid to recovery (from fatigue) after exercise. Notably, the skin permeation of LEO components showed a saturation trend at concentrations above 5%, suggesting the presence of an optimal concentration range for topical application in sports aromatherapy.