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

Chamaecyparis obtusa (C. obtusa) and Pinus densiflora (P. densiflora) 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 C. obtusa and P. densiflora extracts. In the present study, volatile organic compounds (VOCs) of C. obtusa and P. densiflora were examined to determine whether they have anti-inflammatory capabilities. To evaluate the anti-inflammatory effects of VOCs of C. obtusa and P. densiflora, 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 C. obtusa and P. densiflora. 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 C. obtusa and P. densiflora. Similar tendencies were observed in lung tissues and cells obtained via bronchoalveolar lavage. The results of the present study suggested that VOCs of C. obtusa and P. densiflora, through their immunosuppressive activities, may have therapeutic potential in the treatment or prevention of inflammation.