Study of the analgesic activities, chronic toxicity and addictive potential of Jia-Yuan-Qing pill in rats.

Jia-Yuan-Qing pill (JYQP) composed of Porcellio laevis Latreille, Corydalis Rhizoma and Radix Cynanchi Paniculati at a ratio of 9:7:7 has been found to be an effective analgesic agent. The present study aimed to evaluate the safety, addictive potential and anti-cancer pain activity of JYQP in a rat model. During the 6-month chronic toxicity test, no significant changes in general behavior, defecation, postural abnormalities, dietary or water intake or blood biochemical parameters were observed in male and female rats. Although a high dose of JYQP (5 g/kg) caused swelling of the liver, spleen and kidney in male and female rats, no pathological changes were observed in all organs examined via hematoxylin and eosin staining. The analgesic effect of JYQP on bone cancer pain was successfully confirmed in a rat model of Walker 256 cell-induced bone cancer. In contrast to morphine, in a physical dependence test, JYQP produced no withdrawal symptoms following chronic administration. The data from this study provide experimental evidence supporting the clinical use of JYQP as an effective, safe and non-addictive agent for the treatment of bone cancer pain.

Involvement of the ERK pathway in the protective effects of glycyrrhizic acid against the MPP+-induced apoptosis of dopaminergic neuronal cells.

Glycyrrhizic acid (GA), a major compound separated from Radix Glycyrrhizae, has been shwon to exert various biochemical effects, including neuroprotective effects. In the present study, we investigated the protective effects of GA against 1-methyl-4-phenylpyridinium (MPP+)­induced damage to differentiated PC12 (DPC12) cells. Compared with the MPP+-treated cells, GA markedly improved cell viability, restored mitochondrial dysfunction, suppressed the overexpression of cleaved poly(ADP-ribose) polymerase (PARP), and suppressed the overproduction of lactate dehydrogenase (LDH) and intracellular Ca2+ overload. The protective effects of GA on cell survival were further confirmed in primary cortical neurons. GA markedly increased the expression of phosphorylated extracellular signal-regulated kinase (p-ERK), as well as its migration from the cytoplasm to nucleus. PD98059, an inhibitor of ERK, blocked GA-enhanced ERK activation and reduced cell viability. However, pre-treatment with GA had no effects on the expression of phosphorylated AKT (p-AKT) and total AKT (t-AKT). These results indicate that the GA-mediated neuroprotective effects are associated with its modulation of multiple anti-apoptotic and pro-apoptotic factors, particularly the ERK signaling pathway. This study provides evidence supporting the use of GA as a potential therapeutic agent for the treatment of neurodegenerative diseases and neuronal injury.

Liquiritin modulates ERK­ and AKT/GSK­3ß­dependent pathways to protect against glutamate­induced cell damage in differentiated PC12 cells.

Glutamate has a key role in the neuronal cell damage associated with Alzheimer's and Parkinson's diseases. Liquiritin (LQ), a major constituent of Glycyrrhiza Radix, possesses various pharmacological activities. The present study investigated the neuroprotective effect of LQ against glutamate­induced cell damage in the differentiated PC12 (DPC12) rat pheochromocytoma cell line. Pretreatment with 25 and 50 µM LQ for 3 h resulted in a significant increase in cell viability and inhibited excessive lactate dehydrogenase release in glutamate­exposed DPC12 cells. LQ also ameliorated glutamate­induced nuclear and mitochondrial apoptotic alterations, intracellular calcium overload and the abnormal expression of apoptosis­related proteins, including cytochrome c, B­cell lymphoma (Bcl)­2 and Bcl2­associated X protein. Treatment with LQ alone or in combination with glutamate was found to enhance the phosphoactivation of extracellular signal­regulated kinases (ERKs), AKT and its downstream element glycogen synthase kinase­3ß (GSK3ß), in a time­dependent manner. However, no effect was observed on the expression of total­ERKs, ­AKT and ­GSK3ß. Furthermore, pre­incubation with 10 µM PD98059 or LY94002, inhibitors of ERK and phosphatidylinositide 3­kinase, respectively, for 30 min significantly suppressed the LQ­induced increase in glutamate­exposed DPC12 cell viability. To the best of our knowledge, the present study provides the first experimental evidence that LQ has a neuroprotective effect against glutamate toxicity in DPC12 cells, predominantly through the ERK and AKT/GSK­3ß pathways. Therefore, LQ may have potential for the treatment of neurodegenerative diseases.

Liquiritigenin induces tumor cell death through mitogen-activated protein kinase- (MPAKs-) mediated pathway in hepatocellular carcinoma cells.

Liquiritigenin (LQ), separated from Glycyrrhiza radix, possesses anti-inflammatory, antihyperlipidemic, and antiallergic effects. Our present study aims to investigate the antihepatocellular carcinoma effects of LQ both in cell and animal models. LQ strikingly reduced cell viability, enhanced apoptotic rate, induced lactate dehydrogenase over-release, and increased intracellular reactive oxygen species (ROS) level and caspase 3 activity in both PLC/PRL/5 and HepG2 cells. The expression of cleaved PARP, the hall-marker of apoptosis, was enhanced by LQ. LQ treatment resulted in a reduction of the expressions of B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xL), and an increase of the phosphorylation of c-Jun N-terminal kinases (JNK) and P38. LQ-mediated cell viability reduction, mitochondrial dysfunction, apoptosis related protein abnormal expressions, and JNK and P38 activation were partially abolished by N-Acetyl-L-cysteine (a ROS inhibitor) pretreatment. Moreover, LQ suppressed the activation of extracellular signaling-regulated kinase (ERKs) and reduced the translocation of phosphor-ERKs from cytoplasm to nucleus. This antitumor activity was further confirmed in PLC/PRL/5-xenografted mice model. All these data indicate that the antihepatocellular carcinoma effects of LQ are related to its modulation of the activations of mitogen-activated protein kinase (MAPKs). The study provides experimental evidence supporting LQ as a potential therapeutic agent for hepatocellular carcinoma treatment.