Echinatin induces reactive oxygen species-mediated apoptosis via JNK/p38 MAPK signaling pathway in colorectal cancer cells.

Colorectal cancer (CRC) is a very common and deadly cancer worldwide, and oxaliplatin is used as first-line chemotherapy. However, resistance usually develops, limiting treatment. Echinatin (Ech) is the main component of licorice and exhibits various therapeutic effects on inflammation-mediated diseases and cancer, ischemia/reperfusion, and liver injuries. The present study elucidated the underlying molecular mechanism of Ech-induced apoptosis in both oxaliplatin-sensitive (HT116 and HT29) and -resistant (HCT116-OxR and HT29-OxR) CRC cells. To evaluate the antiproliferative activities of Ech, we performed MTT and soft agar assays. Ech reduced viability, colony size, and numbers of CRC cells. The underlying molecular mechanisms were explored by various flow cytometry analyses. Ech-induced annexin-V stained cells, reactive oxygen species (ROS) generation, cell cycle arrest, JNK/p38 MAPK activation, endoplasmic reticulum (ER) stress, mitochondrial membrane potential depolarization, and multi-caspase activity. In addition apoptosis-, cell cycle-, and ER stress-related protein levels were confirmed by western blotting. Moreover, we verified ROS-mediated cell death by treatment with inhibitors such as N-acetyl-L-cysteine, SP600125, and SB203580. Taken together, Ech exhibits anticancer activity in oxaliplatin-sensitive and -resistant CRCs by inducing ROS-mediated apoptosis through the JNK/p38 MAPK signaling pathway. This is the first study to show that Ech has the potential to treat drug-resistant CRC, providing new directions for therapeutic strategies targeting drug-resistant CRC.

[Preventive and therapeutic effect of bioactive component of licorice on antidepressant-induced liver injury].

Since exploding rates of modern mental diseases, application of antidepressants has increased. Worryingly, the antidepressant-induced liver injury has gradually become a serious health burden. Furthermore, since most of the knowledge about antidepressant hepatotoxicity are from pharmacovigilance and clinical case reports and lack of observational studies, the underlying mechanisms are poorly understood and there is a lack of efficient treatment strategies. In this study, antidepressant paroxetine directly triggered inflammasome activation evidenced by caspase-1 activation and downstream effector cytokines interleukin(IL)-1ß secretion. The pretreatment of echinatin, a bioactive component of licorice, completely blocked the activation. This study also found that echinatin effectively inhibited the production of inflammasome-independent tumor necrosis factor α(TNF)-α induced by paroxetine. Mechanistically, the accumulation of mitochondrial reactive oxygen species(mtROS) was a key upstream event of paroxetine-induced inflammasome activation, which was dramatically inhibited by echinatin. In the lipopolysaccharide(LPS)-mediated idiosyncratic drug-induced liver injury(IDILI) model, the combination of LPS and paroxetine triggered aberrant activation of the inflammasome to induce idiosyncratic hepatotoxicity, which was reversed by echinatin pretreatment. Notably, this study also found that various bioactive components of licorice had an inhibitory effect on paroxetine-triggered inflammasome activation. Meanwhile, multiple antidepressant-induced aberrant activation of the inflammasome could be completely blocked by echinatin pretreatment. In conclusion, this study provides a novel insight for mechanism of antidepressant-induced liver injury and a new strategy for the treatment of antidepressant-induced hepatotoxicity.

Dual inhibition of EGFR and MET by Echinatin retards cell growth and induces apoptosis of lung cancer cells sensitive or resistant to gefitinib.

Patients with non-small-cell lung cancer (NSCLC) containing epidermal growth factor receptor (EGFR) amplification or sensitive mutations initially respond to tyrosine kinase inhibitor gefitinib; however, the treatment is less effective over time. Gefitinib resistance mechanisms include MET gene amplification. A therapeutic strategy targeting MET as well as EGFR can overcome resistance to gefitinib. In the present study we identified Echinatin (Ecn), a characteristic chalcone in licorice, which inhibited both EGFR and MET and strongly altered NSCLC cell growth. The antitumor efficacy of Ecn against gefitinib-sensitive or -resistant NSCLC cells with EGFR mutations and MET amplification was confirmed by suppressing cell proliferation and anchorage-independent colony growth. During the targeting of EGFR and MET, Ecn significantly blocked the kinase activity, which was validated with competitive ATP binding. Inhibition of EGFR and MET by Ecn decreases the phosphorylation of downstream target proteins ERBB3, AKT and ERK compared with total protein expression or control. Ecn induced the G2/M cell cycle arrest, and apoptosis via the intrinsic pathway of caspase-dependent activation. Ecn induced ROS production and GRP78, CHOP, DR5 and DR4 expression as well as depolarized the mitochondria membrane potential. Therefore, our results suggest that Ecn is a promising therapeutic agent in NSCLC therapy.

Effects of different softening methods on quality of Glycyrrhizae Radix et Rhizoma / 中草药

Objective: A method was established to obtain fingerprint and determination of six components in Glycyrrhizae Radix et Rhizoma Pieces (GRRP) based on HPLC-PDA, and samples with four kinds of softening methods (showering moistening, steaming, 70 ℃ decompression steaming, 85 ℃ decompression steaming) were analyzed. Methods: The content of total flavonoids and total saponins was determined by ultraviolet spectrophotometry with liquiritin and glycyrrhizic acid as reference materials. Simultaneous determination of six components of liquiritin, ononin, isoliquiritin, glycyrrhizin, echinatin, glycyrrhizic acid was performed based on HPLC. Changes of the components content in the samples which treated by different softening methods were compared. The similarity evaluation of samples with different softening methods was carried out by the chromatographic fingerprint similarity evaluation system of traditional Chinese medicine, and cluster analysis was also carried out. Results: The results showed that the content of total flavonoids and total saponins in untreated samples was the highest, and the content of total flavonoids and total saponins in samples treated by showering moistening was the lowest. The three treatment methods of atmospheric pressure steaming, steaming decompression at 70 ℃ and steaming decompression at 85 ℃ had little effect on the samples. The content determination showed that the content of isoliquiritin was decreased significantly after softening treatment. The difference among the different softening treatment groups was not significant. The samples with different softening methods of the three batches of samples were grouped together with their raw products. Different softening methods had no significant difference in the composition of the medicinal herbs. Conclusion: The established method can quickly and accurately determine the six components, and in particular, the content of isoglycyrrhizin should be monitored. Combining production efficiency, production cost and quality evaluation, steaming is the most feasible in the production process. This study provided theoretical guidance for the large-scale production of softening, which was conducive to further standardizing the production process of GRRP.

Retrochalcone Echinatin Triggers Apoptosis of Esophageal Squamous Cell Carcinoma via ROS- and ER Stress-Mediated Signaling Pathways.

Esophageal squamous cell carcinoma (ESCC) is a poor prognostic cancer with a low five-year survival rate. Echinatin (Ech) is a retrochalone from licorice. It has been used as a herbal medicine due to its anti-inflammatory and anti-oxidative effects. However, its anticancer activity or underlying mechanism has not been elucidated yet. Thus, the objective of this study was to investigate the anti-tumor activity of Ech on ESCC by inducing ROS and ER stress dependent apoptosis. Ech inhibited ESCC cell growth in anchorage-dependent and independent analysis. Treatment with Ech induced G2/M phase of cell cycle and apoptosis of ESCC cells. It also regulated their related protein markers including p21, p27, cyclin B1, and cdc2. Ech also led to phosphorylation of JNK and p38. Regarding ROS and ER stress formation associated with apoptosis, we found that Ech increased ROS production, whereas its increase was diminished by NAC treatment. In addition, ER stress proteins were induced by treatment with Ech. Moreover, Ech enhanced MMP dysfunction and caspases activity. Furthermore, it regulated related biomarkers. Taken together, our results suggest that Ech can induce apoptosis in human ESCC cells via ROS/ER stress generation and p38 MAPK/JNK activation.

Antioxidant Mechanisms of Echinatin and Licochalcone A.

Echinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine Gancao. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous solution, namely Cu2+-reduction, Fe3+-reduction, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging measurements, while 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging colorimetric measurements were conducted in methanol solution. The four sets of measurements showed that the radical-scavenging (or metal-reduction) percentages for both echinatin and licochalcone A increased dose-dependently. However, echinatin always gave higher IC50 values than licochalcone A. Further, each product of the reactions of the chalcones with DPPH• was determined using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The UPLC-ESI-Q-TOF-MS/MS determination for echinatin yielded several echinatin⁻DPPH adduct peaks (m/z 662, 226, and 196) and dimeric echinatin peaks (m/z 538, 417, and 297). Similarly, that for licochalcone A yielded licochalcone A-DPPH adduct peaks (m/z 730, 226, and 196) and dimeric licochalcone A peaks (m/z 674 and 553). Finally, the above experimental data were analyzed using mass spectrometry data analysis techniques, resonance theory, and ionization constant calculations. It was concluded that, (i) in aqueous solution, both echinatin and licochalcone A may undergo an electron transfer (ET) and a proton transfer (PT) to cause the antioxidant action. In addition, (ii) in alcoholic solution, hydrogen atom transfer (HAT) antioxidant mechanisms may also occur for both. HAT may preferably occur at the 4-OH, rather than the 4'-OH. Accordingly, the oxygen at the 4-position participates in radical adduct formation (RAF). Lastly, (iii) the 1,1-dimethyl-2-propenyl substituent improves the antioxidant action in both aqueous and alcoholic solutions.