Goo Yoon

Licochalcone E reduces chronic allergic contact dermatitis and inhibits IL-12p40 production through down-regulation of NF-κB.

Licochalcone, a constituent of licorice, has antitumor, antimicrobial, and anti-inflammatory effects. Recently, licochalcone E was isolated from the roots of Glycyrrhiza inflata and its biological functions are not fully examined. In this study, we investigated its ability to modulate production of IL-12p40, a common subunit of IL-12 and IL-23. Licochalcone E dose-dependently inhibited IL-12p40 production from lipopolysaccharide-stimulated RAW264.7 macrophage cells. The repressive effect was mapped to a region in the IL-12 gene promoter containing a binding site for NF-kappaB. Furthermore, licochalcone E decreased binding to the NF-kappaB site in RAW264.7 macrophage cells. Using a chronic allergic contact dermatitis model induced by repeated application of oxazolone, we showed that licochalcone E inhibited the increased IL-12p40 expression and ear thickness induced by oxazolone. Taken together, licochalcone E inhibits IL-12p40 production and has therapeutic potential to reduce skin inflammation.

Licochalcone Suppresses LXRα-Induced Hepatic Lipogenic Gene Expression through AMPK/Sirt1 Pathway Activation

Licochalcone (LC), a major phenolic retrochalcone from licorice, has anti-inflammatory activity. This study investigated the effects of licochalcone A (LCA) and licochalcone E (LCE) on Liver X receptor-α (LXRα)-mediated lipogenic gene expression and the molecular mechanisms underlying those effects. LCA and LCE antagonized the ability of LXRα agonists (T0901317 or GW3965) to increase sterol regulatory element binding protein-1c (SREBP-1c) expression and thereby inhibited target gene expression (e.g., FAS and ACC) in HepG2 cells. Moreover, treatment with LCA and LCE impaired LXRα/RXRα-induced CYP7A1-LXRE-luciferase (CYP7A1) transactivation. The AMPK-Sirt1 signaling pathway is an important regulator of energy metabolism and, therefore, a potential therapeutic target for metabolic diseases, including hepatic steatosis. We found here that LCE increased AMPK phosphorylation and Sirt1 expression. We conclude that LC inhibits SREBP-1c-mediated hepatic lipogenesis via activation of the AMPK/Sirt1 signaling pathway.

HPLC Analysis, Optimization of Extraction Conditions and Biological Evaluation of Corylopsis coreana Uyeki Flos

A method for the separation and quantification of three flavonoids and one isocoumarin by reverse-phase high performance liquid chromatography (HPLC) has been developed and validated. Four constituents present in a crude ethanolic extract of the flowers of Coryloposis coreana Uyeki, were analyzed. Bergenin, quercetin, quercitrin and isosalipurposide were used as calibration standards. In the present study, an excellent linearity was obtained with an r2 higher than 0.999. The chromatographic peaks showed good resolution. In combination with other validation data, including precision, specificity, and accuracy, this method demonstrated good reliability and sensitivity, and can be conveniently used for the quantification of bergenin, quercetin, quercitrin and isosalipurposide in the crude ethanolic extract of C. coreana Uyeki flos. Furthermore, the plant extracts were analyzed with HPLC to determine the four constituents and compositional differences in the extracts obtained under different extraction conditions. Several extracts of them which was dependent on the ethanol percentage of solvent were also analyzed for their antimicrobial and antioxidant activities. One hundred % ethanolic extract from C. coreana Uyeki flos showed the best antimicrobial activity against the methicillin-resistant Staphylococcus aureus (MRSA) strain. Eighty % ethanolic extract showed the best antioxidant activity and phenolic content. Taken of all, these results suggest that the flower of C. coreana Uyeki flos may be a useful source for the cure and/or prevention of septic arthritis, and the validated method was useful for the quality control of C. coreana Uyeki.

JAK2 regulation by Licochalcone H inhibits the cell growth and induces apoptosis in oral squamous cell carcinoma

BACKGROUND Licochalconce (LC) H is an artificial compound in the course of synthesizing LCC in 2013. So far, few studies on the effects of LCH have been found in the literature. Despite progress in treatment modalities for oral cancer, the cure from cancer has still limitations. PURPOSE The effects of LCH were investigated on human oral squamous cell carcinoma (OSCC) cells to elucidate its mechanisms. STUDY DESIGN We explored the mechanism of action of LCH by which it could have effects on JAK2/STAT3 signaling pathway. METHODS To confirm LCH anti-cancer effect, analyzed were MTT assay, DAPI staining, soft agar, kinase assay, molecular docking simulation, flow cytometry and Western blotting analysis. RESULTS According to docking and molecular dynamics simulations, the predicted pose of the complex LCH and JAK2 seems reasonable and LCH is strongly bound to active JAK2 with opened activation loop. The LCH inhibitor is surrounded by specific ATP-binding pocket in which it is stabilized by forming hydrogen bonds and hydrophobic interactions. It is shown that LCH plays as a competitive inhibitor in an active state of JAK2. LCH caused a dose-dependent decrease in phosphorylation of JAK2 and STAT3. More interestingly, LCH suppressed JAK2 kinase activity in vitro by its direct binding to the JAK2. LCH significantly inhibited the JAK2/STAT3 signaling pathway, causing the down-regulation of target genes such as Bcl-2, survivin, cyclin D1, p21 and p27. In addition, LCH inhibited cell proliferation and colony formation of OSCC cells in a dose- and time-dependent manner, as well as induction of cell apoptosis through extrinsic and intrinsic pathway. The induction of apoptosis in OSCC cells by LCH was evident in the increased production of ROS, loss of mitochondrial membrane potential, release of cyto c, variation of apoptotic proteins and activation of caspase cascade. CONCLUSION LCH not only induces apoptosis in OSCC cells through the JAK/STAT3 signaling pathway but also inhibits cell growth. It is proposed that LCH has a promising use for the chemotherapeutic agent of oral cancer.