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Samul extract, containing Radix Rehmanniae, Radix Angelicae Gigantis, Radix Paeoniae, and Rhizoma Cnidii, has been traditionally used for treatment of ischemic heart and brain damages in Oriental medicine. However, little is known about the mechanism by which Samul rescues cells from cytotoxic damage. This study was designed to investigate the protective mechanisms of Samul on H₂O₂-induced death of H9c2 cells. Treatment with H₂O₂ markedly decreased the viability of H9c2 cells in a dose- and time-dependent manner, which was significantly prevented by pre-treatment with Samul. The nature of death of H9c2 cells by H₂O₂ was demonstrated by apoptotic features, including ladder-pattern fragmentation of genomic DNA and chromatin condensation, which were markedly abolished by pretreatment of Samul in H₂O₂-treated cells. We further demonstrated that MEK inhibitor, PD98059, dose-dependently attenuated the protective effects of Samul against H₂O₂, whereas inhibitors of Jnk and p38 did not. Consistently, Samul induced the early phosphorylation of Erk, p44, in H₂O₂-treated cells. In addition, treatment with Samul also resulted in an increase of expression of anti-apotogenic Bcl2 protein, which was decreased by H₂O₂. However, it inhibited the expression of apotogenic Bax protein in H₂O₂-treated cells. Taken together, these results suggest that the protective effects of Samul against oxidative damage may be achieved via activation of MAP kinase, Erk as well as Bcl2 family proteins.

We evaluated the in vivo anti-inflammatory and analgesic activities of orally administered paeonol in mice, and also investigated the anti-inflammatory activity of paeonol in a cell line. Paeonol significantly reduced the edema induced by arachidonic acid in rats. The analgesic effects were assayed using 2 different models, i.e., by acetic acid-induced writhing response and by formalin induced licking and biting time. Moreover, we examined the effects of paeonol on the release of inflammatory mediators such as NO, PGE₂ and IL-6. Our results demonstrated that paeonol inhibited LPS induced expression of NO, PGE₂ and IL-6. Paeonol prevented LPS induced iNOS, COX-2 and ERK activation. Therefore, paeonol appears to have potential as a treatment for inflammatory disease and analgesic.

Resveratrol is a polyphenol compound and prominent anti-inflammatory agent found in plants, including the fruits of Morus alba. However, the therapeutic mechanisms of resveratrol remain largely unclear. To gain insight into the biological effects of resveratrol, we examined its influence on LPS-induced IL-8 production in the human monocytic cell line, THP-1. In inflammatory diseases, IL-8 plays a central role in the initiation and maintenance of inflammatory response. In the present study, IL-8 production was measured by ELISA and RT-PCR, while MAPK activation, IκBα degradation, nuclear factor (NF)-κB activation and cyclooxygenase (COX)-2 expression were determined by Western blot analysis. Resveratrol inhibited LPS-induced IL-8 production in a dose-dependent manner. Furthermore, resveratrol inhibited extracellular signal-regulated kinase (ERK) and p38 MAPK phosphorylation, IκBα degradation, NF-κB activation and cyclooxygenase (COX)-2 expression, which suggest that resveratrol inhibits IL-8 secretion by blocking MAPK phosphorylation and NF-κB activation. Taken together, these findings may help elucidate the mechanism by which resveratrol modulates THP-1 cell activation under inflammatory conditions.

To determine the anti-inflammatory and analgesic activities of methyl gallate (MG) isolated from Galla Rhois, MG was studied in vivo for its analgesic activities using the writhing response in mice. Anti-inflammatory activity of MG was evaluated for NO and IL-6 production in RAW 264.7 cells. MG inhibited LPS-induced NO and IL-6 production. Consistent with these observations, the protein and mRNA expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were inhibited by MG. Moreover, MG suppressed the phosphorylation of ERK1/2 in LPS-induced RAW 264.7 cells in a dose-dependent manner. Taken together, the results of this study indicate that MG has anti-inflammatory effects.

A variety of flavonoids are suggested to be useful for the treatment of brain-related disorders, including dementia and depression. An investigation on the characteristics of the extracted compounds of Iris tenuifolia Pall. (IT) is of much interest, as this plant has been used as a traditional medicine. In the present study, we examined the effect of total flavonoids obtained from IT on cultured cortical neurons under oxidative-stress and found that pretreatment with IT flavonoids significantly inhibited H₂O₂-induced cell death in cortical neurons. Such a survival-promoting effect by IT flavonoids was partially blocked by inhibitors for extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase/Akt (PI3K/Akt) cascades, both of which are known as survival-promoting signaling molecules. Furthermore, the phosphorylation of Src homology-2 (SH2) domain-containing phosphatase2 (Shp2) was induced by IT flavonoids, and the protective effect of IT flavonoids was abolished by NSC87877, an inhibitor for Shp2, suggesting the involvement of Shp2-mediated intracellular signaling in flavonoid-dependent neuroprotection.

Pulmonary arterial hypertension (PAH) is a disease of the small pulmonary arteries characterized by increased vascular resistance. Pulmonary vasoconstriction has been proven to play a pivotal role in PAH. We have previously hypothesized that Panax notoginseng saponins (PNS) might attenuate hypoxia–hypercapnia-induced pulmonary vasoconstriction. The specific objective of the present study was to investigate the role of notoginsenoside R₁, a main ingredient of PNS, in this process and the possible underlying mechanism. The third order pulmonary rings from the Sprague-Dawley rats were treated with different concentrations of notoginsenoside R₁ (8, 40, and 100 mg/L, respectively) both before and during the conditions of hypercapnia and hypoxia. Contractile force changes in the rings were detected and the optimal concentration (8 mg/L) was selected. Furthermore, an ERK inhibitor, U0126, was applied to the rings. In addition, pulmonary arterial smooth muscle cells (PASMCs) were cultured under hypoxic and hypercapnic conditions, and notoginsenoside R₁ was administered to detect the changes induced by ERK1/2. The results revealed biphasic vasoconstriction in rings under hypoxic and hypercapnic conditions. It is hypothesized that the observed attenuation of vasoconstriction and the production of vasodilation could have been induced by notoginsenoside R₁. This effect was found to be significantly reinforced by U0126 (p < 0.05 or p < 0.01). ERK expression in the PASMCs under hypoxic and hypercapnic conditions was significantly activated (p < 0.05 or p < 0.01) and the observed activation was attenuated by notoginsenoside R₁ (p < 0.05 or p < 0.01). Our findings strongly support the significant role of notoginsenoside R₁ in the inhibition of hypoxia–hypercapnia-induced vasoconstriction by the ERK pathway.

Prunella vulgaris (PV) is a traditional Chinese medicine that has been used clinically for centuries in Asian countries to treat herpetic keratitis. In previous studies, PV was shown to suppress TPA-induced activation of MMP-9 and inhibit cell invasion and migration in hepatoma cell lines. However, the detailed molecular mechanism underlying these effects is still unclear. In this study, we investigated the mechanisms underlying PV-mediated inhibition of 12-O-Tetradecanoylphorbol-13-acetate (TPA)-induced cell invasion and inhibition of secreted and cytosolic MMP-9 production in human hepatoma cells (Huh-7 and HA22T). PV suppressed VEGF and MMP-9 transcription by inhibiting activator protein (AP)-1 and nuclear factor-$\kappa$B (NF-$\kappa$B) activity. PV suppressed TPA-induced AP-1 activity by inhibiting phosphorylation of the extracellular signal-related kinase (ERK), downregulating p38 signaling pathways, and suppressing TPA-induced inhibition of NF-$\kappa$B nuclear translocation through I$\kappa$B. PV suppressed TPA-induced activation of ERK/phosphatidylinositol-3-kinase/Akt upstream of NF-$\kappa$B and AP-1. These data suggest that PV modifies the metastatic microenvironment of hepatocellular carcinoma (HCC) by inhibiting multiple signal transduction pathways. PV thus may have the therapeutic potential to inhibit the migration and invasion of HCC and act as potential agent for systemic therapies.

Baicalein (BA), one of the major compounds isolated from the root of Scutellaria baicalensis Gerogi, exhibits various pharmacological effects, such as anti-oxidant, anti-inflammatory, and anticancer effects. In this study, we found that BA reduced cell viability and increased apoptosis in ovarian cancer cells. Treatment of cells with BA enhanced microtubule-associated protein light chain 3-II (LC3-II) expression, acidic vesicular organelle and GFP-LC3 fluorescence dot accumulation. Combined treatment with chloroquine and BA apparently reduced cell viability and increased the cleavage of poly (ADPribose) polymerase (PARP) in both HEY and A2780 ovarian cancer cell lines, indicating that BA induces a protective autophagy in these cells. Knockdown of Beclin 1 by siRNA remarkably decreased BA-induced LC3-II lipidation. In addition, we found an increase in the phosphorylation of extracellular signal-regulated kinase (ERK, Thr202/Thr204) and AKT (Ser473) after BA treatment, and inhibition of ERK activation by the pharmacological inhibitor U0126 or ERK siRNA blocked BA-induced autophagy. Taken together, these results suggest that BA induces Beclin 1- and ERK-dependent autophagy in ovarian cancer cells.

Aloe-emodin (AE) is derived from Aloe vera and rhubarb (Rheum palmatum) and exhibits anticancer activities via multiple regulatory mechanisms in various cancers. AE can also enhance the anticancer efficacy of cisplatin, doxorubicin, docetaxel, and 5-fluorouracil; however, its effects remain poorly characterized. MCF-7, MDA-MB-231, MDA-MB-468, BT-474, and HCC-1954 breast cancer cell lines were treated with the indicated conditions of AE, and cell viability assays were performed. The expression levels of signaling proteins were determined by western blot analysis, intracellular reactive oxygen species (ROS), cell cycle distributions, and rates of apoptosis as estimated by flow cytometry. In comparison with other cells, MCF-7 cells were more sensitive to AE treatment; AE enhanced the cytotoxicity of 9$\mu$g/ml tamoxifen by reducing EGFR, ER$\alpha$, Ras, ERK, c-Myc, and mTOR protein expression and blocking PI3K and mTOR activation. Finally, although co-treatment of AE with tamoxifen increased intracellular ROS, there were no effects on cell cycle progression. Besides facilitating tamoxifen-induced cell death, AE also enhanced the antiproliferative activity of tamoxifen by blocking Ras/ERK and PI3K/mTOR pathways in breast cancer cells, thus demonstrating the chemosensitizing potential of AE.

Glioblastoma is the most common primary malignant tumor of the central nervous system, with an annual incidence of 5.26 per 100000 people. The clinical outcome of standard therapy and the survival rate remain poor; therefore, there is an unmet need for a new strategy to treat this lethal disease. Although amentoflavone was known to have anticancer potential in various types of cancers, its antiglioblastoma ability and mechanism remain unrecognized. We demonstrated that amentoflavone may suppress glioblastoma invasion and migration by transwell assay. Moreover, we established NF-$\kappa$B reporter gene system and used that for verifying NF-$\kappa$B inhibition efficacy of amentoflavone on in vitro and in vivo studies. Here, we indicated that amentoflavone not only diminished NF-$\kappa$B activation, but also reduced NF-$\kappa$B-mediated downstream oncogenes expression, such as MMP-2, MMP-9, XIAP, cyclinD1 and VEGF, which was elucidated by Western blot and immunohistochemistry (IHC). Tumor growth inhibition and NF-$\kappa$B reduction was found in the amentoflavone treatment group, which was revealed by the glioblastoma-bearing animal model. In this study, we also used ERK inhibitor and NF-$\kappa$B inhibitor (QNZ) to confirm whether the beneficial result of amentoflavone on glioblastoma was mainly regulated by blockage of ERK/NF-$\kappa$B signaling. In summary, ERK/NF-$\kappa$B signaling pathway has a role in the inhibition of tumor growth by amentoflavone in glioblastoma.

A previous study presented that glycyrrhizic acid as the hepatoprotective agent inhibits total parenteral nutrition-associated acute liver injury in rats. However, the anticancer effect and mechanism of glycyrrhizic acid in human hepatocellular carcinoma (HCC) is ambiguous. The purpose of the present study was to investigate the effect of glycyrrhizic acid on apoptosis dysregulation and metastatic potential in HCC in vitro and in vivo. Both SK-Hep1 and Hep3B cells were treated with different concentrations of glycyrrhizic acid for 24 or 48h. SK-Hep1/luc2 tumor-bearing mice were treated with vehicle or glycyrrhizic acid (50mg/kg/day by intraperitoneal injection) for 7 days. Tumor cells growth, apoptotic, and metastatic signaling transduction were evaluated by using MTT assay, digital caliper, bioluminescence imaging (BLI), flow cytometry, western blotting assay, and immunohistochemistry (IHC) staining. The results demonstrated glycyrrhizic acid significantly inhibits tumor cell growth, cell invasion, and expression of AKT (Ser473), extracellular-signal-regulated kinase (ERK), epidermal growth factor receptor (EGFR) phosphorylation, anti-apoptotic and metastatic proteins in HCC in vitro and in vivo. Glycyrrhizic acid also significantly triggered apoptosis and extrinsic/intrinsic apoptotic signaling transduction. In addition, PD98059 (ERK inhibitor) and LY294002 (AKT inhibitor) obviously reduced cell invasion and expression of metastasis-associated proteins. Taken together, these results indicated that glycyrrhizic acid induces apoptosis through extrinsic/intrinsic apoptotic signaling pathways and diminishes EGFR/AKT/ERK-modulated metastatic potential in HCC in vitro and in vivo.