The Composition of (-)-Linalool, (-)-Borneol and Trans-Caryophyllene Inhibits Inflammation and Apoptosis Through Suppression of NF-κB and Activation of Nrf2/HO-1 Signaling Pathways in RAW264.7 Macrophages

OBJECTIVE: Blumea balsamifera (L.) DC volatile oil (BBO) has a long history in China, which was used to relieve swelling and pain, burn healing and the treatment of fevers. Researches showed that BBO had valuable effects on anti-inflammatory activity, among which (-)-Linalool, (-)-Borneol and Trans-Caryophyllene are the main constituents of BBO and all have certain anti-inflammatory effect. Therefore, according to the content of these three compounds in BBO, we made a formula of (-)-Linalol, (-)-Borneol and trans-Caryophyllene, and studied the anti-inflammatory effect and mechanism of this formula. METHODS: MTS Assay was performed to measure cytotoxicity; ELISA analyzed the standards of PGE2, LTB4 and IL-1β; Griess assay method was used to analyze the production of NO and iNOS; Western blot measured the expression of HO-1, Nrf-2, IκB-α, COX-2and5-LOX; The phosphorylation expression of IKKα, IκB-α and P65 were measured by Western blot. The mRNA levels of IL-1β and TNF-α were detected by qPCR. RESULTS: The results revealed that Formula significantly inhibited cellular inflammation induced by LPS, and leukotriene B4(LTB4) and prolandin E2 (PGE2) were down-regulated by inhibiting the expression of cyclooxygenase-2 (COX-2) and lipoxygenase-5 (5-LOx) in RAW 264.7 cells. Meanwhile, Formula could inhibit the activation of NF-κB, thus reducing the LPS-induced secretion of nitric oxide (NO), inducible NO synthase (iNOS), interleukin(IL-1β) and tumor necrosis factor (TNF-α) and reducing apoptosis. In addition, Formula can effectively increase the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant enzyme heme oxygenase-1 (HO-1), activate the Nrf2/HO-1 pathway to achieve anti-inflammatory effect. The formulation could inhibit the activation of NF-κB, thereby reducing the secretion of nitric oxide (NO), nitric oxide synthase (iNOS), interleukin (IL-1β) and tumor necrosis factor (TNF-α) induced by lips-induced apoptosis. In addition, this formula could effectively increase the expression of nuclear factor erythrocyte 2 related factor 2(Nrf2) and antioxidant enzyme heme oxygenase 1(HO-1), activate Nrf2/HO-1 pathway, and achieve anti-inflammatory effect. CONCLUSION: The results suggest that Formula may have great potential effects for the treatment of acute and chronic inflammation.