ABSTRACT
It has been reported that the effect of shoseiryuto, a traditional Japanese “Kampo” medicine, on allergic rhinitis depends on several mechanisms. Previously, we reported that shoseiryuto administered in an allergic rhinitis rat model, inhibited increases of substance P (SP) and calcitonin gene-related peptide (CGRP) in the nasal mucus, which in turn are involved in the exacerbation of rhinitis symptoms and allergic symptoms. In the present research, we looked into whether the secretion of SP and CGRP are directly inhibited by the administration of shoseiryuto.<br>Histamine solution 5µl (10 mg/ml) was instilled in both nostrils of healthy, male SD rats, thereby inducing allergic symptoms, and for the group to which shoseiryuto had been pre-administered, increase in the concentration of SP and CGRP in the nasal mucus was significantly inhibited. Moreover, upon investigating SP and CGRP production in the trigeminal ganglia by means of immunostaining, it was found to be similarly significantly inhibited. The above results indicate that shoseiryuto directly inhibits the secretion of SP and CGRP in the C-fibers of nasal mucosa.
ABSTRACT
<b>Objective:</b> In general, antiallergic drugs, steroids, and autonomic drugs are administered for patients with allergic diseases, but the chronic administration of these medicines may occasionally induce side effects. As such, several complementary and alternative medicine (CAM) are used, even though their effectiveness has not been established by a significant amount of evidence. Health food, herbal medicines, herbal tea, and aromatherapy, etc., are used for the treatment of allergic rhinitis (AR) as CAM. Rosmarinic acid is a type of polyphenol, and is reported to have antiallergic, antioxydative and anti-inflammatory properties. Rosmarinic acid is included in Perilla Herbs, which are used in health foods and herbal medicines (Kampo medicines), Rosemary and Lemon balm, which are used as herbal teas and essential oils of aromatherapy. This study was performed to evaluate the effect of rosmarinic acid on AR using AR model rats.<br> <b>Methods:</b> Six-week-old male Sprague-Dawley rats were sensitized with toluene 2,4-diisocyanate (TDI) to induce AR. Rosmarinic acid (1 mg/kg i.p. or 3 mg/kg i.p.) is administrated for 21 days. On day 22, the symptom of nasal allergy was evaluated by counting the number of sneezes within 10 minutes. Substance P (SP), calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in the nasal lavage fluids were also measured.<br> <b>Result:</b> SP and CGRP take part in the exacerbation of rhinitis symptoms, and are secreted from the nerve ending following nerve stimulation by chemical mediators such as histamine. The administration of Rosmarinic acid had no effect on NGF, but significantly suppressed increases of sneezes, SP and CGRP dose-relatedly. Conclusion: Rosmarinic acid could control the symptom of nasal allergy, and one of the mechanisms was suppressing of the secretion of SP and CGRP.<br>