Establishment and evaluation of biotechnological platform for screening health food with antiinflammation ability

Identification of Scoparone from Chinese Olive Fruit as a Modulator of Macrophage Polarization

Chinese olive (Canarium album L.) has been highlighted for its remarkable health benefits. We previously showed that the ethyl acetate fraction of Chinese olive (COE) is an effective anti-inflammatory agent. In this study, we used a luciferase-based RAW 264.7 cell platform to detect the transcriptional activity of NF-κB, a key mediator of inflammation, and the promoter activity of its downstream target, COX-2. Through functional-oriented screening using these platforms, we further divided COE into several subfractions. Subsequently, we used silica gel column chromatography for purification, and the active compounds were separated and isolated by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The structure of the resulting compound with high anti-inflammatory activity was then identified as scoparone. Our results showed that scoparone not only inhibited lipopolysaccharide (LPS)-induced secretion of nitric oxide and suppressed M1 macrophage markers (iNOS, Il-6, Ccl2, and Tnf-α) but also markedly decreased the production of pro-inflammatory cytokines (IL-6, CCL2, and TNF-α). Treatment with scoparone significantly reduced the protein level of TNF-α in LPS-treated bone-marrow-derived macrophages (BMDMs). In addition, scoparone promoted macrophages toward an M2 anti-inflammatory phenotype, as determined by the significantly increased gene expression of M2 macrophage markers (Arg1, Ym1, Mrc1, Il-10, and Cd206) and the protein level of Arg1. This study indicates that COE fruit has high therapeutic potential for various inflammatory diseases as a result of switching the macrophage phenotype from pro-inflammatory M1 to anti-inflammatory M2.

The methanol-ethyl acetate partitioned fraction from Chinese olive fruits inhibits cancer cell proliferation and tumor growth by promoting apoptosis through the suppression of the NF-κB signaling pathway

Chinese olives (Canarium album L.) have historically been used for medicinal purposes rather than commercially for oil. In this report, we reveal that the methanol-ethyl acetate partitioned fraction from Chinese olive fruits (MEO), of which ellagic acid accounted for 12%, exhibited profound anti-proliferative activities in the human colon cancer cell line, HCT116. Additionally, oral administration of MEO remarkably inhibited the tumor growth of subcutaneously implanted CT26 cells, a mouse colon carcinoma cell line, in BALB/c mice. Treatment with MEO induced a significant increase in the percentage of apoptotic cells and resulted in poly(ADP-ribose) polymerase (PARP) cleavage, suggesting that MEO inhibits cancer cell proliferation by promoting apoptosis. Our study also showed that MEO exerted the most potent effect on the inhibition of NF-κB-mediated signaling among the partitioned fractions from Chinese olives. This process employed the use of reporter-based bio-platforms that are capable of detecting the activation of NF-κB. In addition, phosphorylation of NF-κB signaling-associated proteins, IKKα/β, IκBα, and p65, was reduced in MEO-incubated cancer cells, indicating that MEO suppresses NF-κB activation. Moreover, MEO treatment significantly suppressed lipopolysaccharide (LPS)-induced cancer cell proliferation, demonstrating that MEO promotes cancer cell apoptosis through the inhibition of the NF-κB signaling pathway. In summary, our findings demonstrate that the methanol-ethyl acetate partitioned fraction from Chinese olive fruits inhibits cancer cell proliferation and tumor growth by promoting apoptosis through the suppression of NF-κB signaling. Therefore, the Chinese olive fruit has promising potential in cancer treatment.

Establishment of reporter platforms capable of detecting NF-κB mediated immuno-modulatory activity

Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are transcriptional targets of nuclear factor kappa B (NF-κB) that are involved in inflammatory responses. The aim of this study is to develop a method for efficiently detecting inflammation modulatory activities. Here we established RAW264.7 macrophage cells stably expressing a luciferase reporter gene directed by iNOS or COX-2 promoter. Lipopolysaccharide (LPS) treatment stimulated the luciferase activity which paralleled with increased iNOS and COX-2 mRNA levels determined by RT-q-PCR. The LPS-stimulated luciferase activity was blocked by NF-κB inhibitor CAPE and by nobiletin, an anti-inflammatory natural product from citrus peels. We have applied the platforms to screen various mushroom species; analysis by scatter plot revealed a strong correlation to the results obtained by ELISA-based detection of TNF-α. Together we have established luciferase reporter systems sensitive to NF-κB-dependent iNOS and COX-2 activation, which provides an alternative screening method for identifying food components with immune-modulatory activities.