Lemongrass essential oil attenuates nasal hyperresponsiveness induced by Japanese cedar pollen in mice.

Lemongrass essential oil (LG) has known to exhibit anti-allergic and anti-inflammatory activities. However, the potential effects of LG on allergic rhinitis (AR) have not been investigated. The present study investigated the effects of LG on AR induced by Japanese cedar pollen (JCP). The present study investigated the effects of LG on AR induced by JCP. Mice were actively sensitized by i.p. injections of JCP adsorbed to alum, and then repeatedly challenged by intranasal administrations of JCP. A subset of animals was treated intranasally with LG prior to each JCP challenge. Repeated intranasal administration of JCP induced nasal allergic responses, as evidenced by increased frequencies of sneezing and nasal rubbing, accompanied by elevated levels of total and Cry J1-specific IgE in serum. Furthermore, the nasal response to intranasally administered histamine was significantly augmented after the last JCP challenge, indicating the development of nasal hyperresponsiveness (NHR). LG pretreatment significantly attenuated both JCP-induced nasal allergic responses and NHR without affecting serum IgE levels. These findings suggest that LG, which is widely used in aromatherapy, may represent a novel complementary approach for the treatment of AR induced by JCP.