Alleviation effects of natural volatile organic compounds from Pinus densiflora and Chamaecyparis obtusa on systemic and pulmonary inflammation

Abstract

<i>Chamaecyparis obtusa</i> (<i>C. obtusa</i>) and <i>Pinus densiflora</i> (<i>P. densiflora</i>) have been traditionally used as antibiotic, antinociceptive and anti-inflammatory agents in Asian folk medicine. Recent studies have demonstrated antioxidant, antiproliferative and anti-inflammatory effects of <i>C. obtusa</i> and <i>P. densiflora</i> extracts. In the present study, volatile organic compounds (VOCs) of <i>C. obtusa</i> and <i>P. densiflora</i> were examined to determine whether they have anti-inflammatory capabilities. To evaluate the anti-inflammatory effects of VOCs of <i>C. obtusa</i> and <i>P. densiflora</i>, lipopolysaccharide (LPS) was administered to the lung by nasal injection and to the whole body by intraperitoneal injection. Alterations in serum immunoglobulin E (IgE) levels and prostaglandin E2 (PgE2) were examined using ELISA. LPS-increased serum IgE and PgE2 levels were recovered by administration of dexamethasone and VOCs of <i>C. obtusa</i> and <i>P. densiflora</i>. Levels of mRNA expression of inflammatory cytokines were determined in an LPS-induced inflammation mouse model. Reverse transcription-quantitative polymerase chain reaction was used to determine the mRNA expression levels of cyclooxygenase 2, interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-13 in peripheral blood mononuclear cells. The expression of all examined cytokine mRNAs increased by LPS was suppressed by dexamethasone and VOCs of <i>C. obtusa</i> and <i>P. densiflora</i>. Similar tendencies were observed in lung tissues and cells obtained via bronchoalveolar lavage. The results of the present study suggested that VOCs of <i>C. obtusa</i> and <i>P. densiflora</i>, through their immunosuppressive activities, may have therapeutic potential in the treatment or prevention of inflammation.