Volatile Oil of Platycladus Orientalis (L.) Franco Leaves Exerts Strong Anti-inflammatory Effects via Inhibiting the IκB/NF-κB Pathway

This study was designed to investigate the anti-inflammatory effects of volatile oil of Platycladus orientalis (L.) Franco leaves (VOPF) and the underlying molecular mechanisms by using the non-infectious inflammation rat models and infectious inflammation mouse models. Ear swelling and intraperitoneal capillary permeability in mice, and carrageenan-induced toe swelling and cotton ball-induced granuloma in rats were used to reveal anti-inflammatory effects of VOPF. Moreover, the lipopolysaccharide (LPS)-induced mouse model of acute lung injury was used to explore the anti-inflammatory mechanism of VOPF. The results showed that VOPF could significantly inhibit auricular swelling, intraperitoneal capillary permeability in mice, and reduce granuloma swelling and paw swelling in rats. Furthermore, it significantly alleviated the pathological damage of the lung tissue. In addition, VOPF could reduce the contents of IL-1β and TNF-α and increase the content of IL-10 in the serum. It had little effect on the expression of p65 but reduced the phosphorylation level of p65 and IκB in NF-κB pathway. In conclusion, VOPF has anti-inflammatory effects and the mechanisms involve the down-regulation of the phosphorylation levels of p65 and IκB and blockage of the NF-κB signaling pathway.