Increased glucose metabolism and alpha-glucosidase inhibition in Cordyceps militaris water extract-treated HepG2 cells.

BACKGROUND/OBJECTIVES: Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism. MATERIALS/METHODS: Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha (HNF-1α), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta (GSK-3ß) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement. RESULTS: CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through HNF-1α expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and GSK-3ß, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of α-glucosidase inhibitory activity than that from acarbose. CONCLUSION: CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment.

Lipid-lowering effects of Zanthoxylum schinifolium Siebold & Zucc. seed oil (ZSO) in hyperlipidemic rats and lipolytic effects in 3T3-L1 adipocytes.

On the basis of the antiatherosclerotic effect of Zanthoxylum schinifolium, the therapeutic potential of Zanthoxylum schinifolium seed oil (ZSO) was tested in terms of the blood lipid profile and obesity in rats. The lipolytic effects of ZSO were determined in adipocytes and the total body and liver weight were decreased in rats. Compared with the high-cholesterol high-fat (HCHF) group, the rats in the HCHF+ZSO group showed improved levels of hyperlipidemia indicators. Furthermore, western blot analysis confirmed that the improvement of hyperlipidemia indicators was induced by stimulation of lipoprotein lipase expression. Additional results indicated that the reduction in body weight was likely caused by phosphorylation of hormone-sensitive lipase (HSL) via the protein kinase A pathway, ultimately leading to lipolysis. In conclusion, the results of the in vivo experiment showed that ZSO improved the lipid profiles in the blood, lowering cardiovascular disease and arteriosclerosis and degrading cellular lipids by activating HSL.

Antiobesity effects of the water-soluble fraction of the ethanol extract of Smilax china L. leaf in 3T3-L1 adipocytes.

BACKGROUND/OBJECTIVES: Several medicinal properties of Smilax china L. have been studied including antioxidant, anti-inflammatory, and anti-cancer effects. However, the antiobesity activity and mechanism by which the water-soluble fraction of this plant mediates its effects are not clear. In the present study, we investigated the lipolytic actions of the water-soluble fraction of Smilax china L. leaf ethanol extract (wsSCLE) in 3T3-L1 adipocytes. MATERIALS/METHODS: The wsSCLE was identified by measuring the total polyphenol and flavonoid content. The wsSCLE was evaluated for its effects on cell viability, lipid accumulation, glycerol, and cyclic adenosine monophosphate (cAMP) contents. In addition, western blot analysis was used to evaluate the effects on protein kinase A (PKA), PKA substrates (PKAs), and hormone-sensitive lipase (HSL). For the lipid accumulation assay, 3T3-L1 adipocytes were treated with different doses of wsSCLE for 9 days starting 2 days post-confluence. In other cell experiments, mature 3T3-L1 adipocytes were treated for 24 h with wsSCLE. RESULTS: Results showed that treatment with wsSCLE at 0.05, 0.1, and 0.25 mg/mL had no effect on cell morphology and viability. Without evidence of toxicity, wsSCLE treatment decreased lipid accumulation compared with the untreated adipocyte controls as shown by the lower absorbance of Oil Red O stain. The wsSCLE significantly induced glycerol release and cAMP production in mature 3T3-L1 cells. Furthermore, protein levels of phosphorylated PKA, PKAs, and HSL significantly increased following wsSCLE treatment. CONCLUSION: These results demonstrate that the potential antiobesity activity of wsSCLE is at least in part due to the stimulation of cAMP-PKA-HSL signaling. In addition, the wsSCLE-stimulated lipolysis induced by the signaling is mediated via activation of the ß-adrenergic receptor.

Involvement of small GTPase RhoA in the regulation of superoxide production in BV2 cells in response to fibrillar Aß peptides.

Fibrillar amyloid-beta (fAß) peptide causes neuronal cell death, which is known as Alzheimer's disease. One of the mechanisms for neuronal cell death is the activation of microglia which releases toxic compounds like reactive oxygen species (ROS) in response to fAß. We observed that fAß rather than soluble form blocked BV2 cell proliferation of microglial cell line BV2, while N-acetyl-l-cysteine (NAC), a scavenger of superoxide, prevented the cells from death, suggesting that cell death is induced by ROS. Indeed, both fAß1-42 and fAß25-35 induced superoxide production in BV2 cells. fAß25-35 produced superoxide, although fAß25-35 is not phagocytosed into BV2 cells. Thus, superoxide production by fAß does not seem to be dependent on phagocytosis of fAß. Herein we studied how fAß produces superoxide in BV2. Transfection of dominant negative (DN) RhoA (N19) cDNA plasmid, small hairpin (sh)-RhoA forming plasmid, and Y27632, an inhibitor of Rho-kinase, abrogated the superoxide formation in BV2 cells stimulated by fAß. Furthermore, fAß elevated GTP-RhoA level as well as Rac1 and Cdc42. Tat-C3 toxin, sh-RhoA, and Y27632 inhibited the phosphorylation of p47(PHOX). Moreover, peritoneal macrophages from p47(PHOX) (-/-) knockout mouse could not produce superoxide in response to fAß. These results suggest that RhoA closely engages in the regulation of superoxide production induced by fAß through phosphorylation of p47(PHOX) in microglial BV2 cells.

Inhibitory effects of Capsicum annuum L. water extracts on lipoprotein lipase activity in 3T3-L1 cells.

Obesity, an intractable metabolic disease, currently has no medical treatment without side effects, so studies have been actively carried out to find natural compounds that have anti-obesity activity with minimum side effects. In this study, the anti-obesity effects of water extracts of seven Capsicum annuum L. varieties being Putgochu (Pca), Oyee gochu (Oca), Kwari putgochu (Kca), Green pepper (Gca), Yellow paprika (Yca), Red paprika (Rca) and Cheongyang gochu (Cca), were examined through the evaluation of lipoprotein lipase (LPL) mRNA expression level in 3T3-L1 cells (mouse pre-adipocytes). After capsaicin elimination by chloroform defatting, freeze-dried powder of Cca was treated to 3T3-L1 cells and anti-obesity effects were examined by determining the LPL mRNA level using the RT-PCR method. Of the primary fractions, only proven fractions underwent secondary and tertiary refractionating to determine anti-obesity effects. From seven different Capsicum annuum L., there was a significant decrease of the LPL mRNA expression level of 50.9% in Cca treatment compared to the control group. A significant decrease of the LPL mRNA expression level was shown in primary fractions (Fr) 5 (36.2% decrease) and 6 (30.5% decrease) of the Cca water extracts. Due to the impurities checked by UPLC chromatography, Fr 5 and 6 were refractionated to determine the LPL mRNA expression level. Treatment of Fr 6-6 (35.8% decrease) and Fr 5-6 (35.3% decrease) showed a significant decrease in the LPL mRNA expression level. When analyzed using UPLC, major compounds of Fr 6-6 and Fr 5-6 were very similar. Subsequently, we refractionated Fr 6-6 and Fr 5-6 to isolate the major peak for structure elucidation. Treatment of Fr 5-6-1 (26.6% decrease) and Fr 6-6-1 (29.7% decrease) showed a significant decrease in the LPL mRNA expression level. Consequently, the fractions may have a possibility to ameliorate obesity through the decrease of the LPL mRNA expression level.

Esculetin promotes type I procollagen expression in human dermal fibroblasts through MAPK and PI3K/Akt pathways.

Type I collagen is the major constituent of the skin and the reduction of dermal type I collagen content is closely associated with the intrinsic skin aging. We here found that esculetin, 6,7-dihydroxycoumarin, strongly induces type I procollagen expression in human dermal fibroblasts. Esculetin not only increased protein levels of type I procollagen but also increased mRNA levels of COL1A1 but not COL1A2. Esculetin activated the MAPKs (ERK1/2, p38, JNK) and PI3K/Akt pathways, through which it promoted the type I procollagen expression. We also demonstrated that the binding motifs for transcription factor Sp1 occur with the highest frequency in the COL1A1 promoter and that esculetin increases the Sp1 expression through the MAPK and PI3K/Akt pathways. These results suggest that esculetin promotes type I procollagen expression through the MAPK and PI3K/Akt pathways and that Sp1 might be involved in the esculetin-induced type I procollagen expression via activation of the COL1A1 transcription.

Suppressive effects of Schizandra chinensis Baillon water extract on allergy-related cytokine generation and degranulation in IgE-antigen complex-stimulated RBL-2H3 cells.

Schizandra chinensis Baillon is a traditional folk medicine plant that is used to treat and prevent several inflammatory diseases and cancer in Korea, but the underlying mechanisms involved in its anti-allergic activity are not fully understood. This study was designed to investigate mechanisms of anti-allergic activity of a Schizandra chinensis Baillon water extract (SCWE) in immunoglobulin E (IgE)-antigen complex-stimulated RBL2H3 cells and to assess whether gastric and intestinal digestion affects the anti-allergic properties of SCWE. Oxidative stress is an important consequence of the allergic inflammatory response. The antioxidant activities of SCWE increased in a concentration-dependent manner. RBL-2H3 cells were sensitized with monoclonal anti-dinitrophenol (DNP) specific IgE, treated with SCWE, and challenged with the antigen DNP-human serum albumin. SCWE inhibited ß-hexosaminidase release and expression of interleukin (IL)-4, IL-13, and tumor necrosis factor-alpha (TNF-α) mRNA and protein in IgE-antigen complex-stimulated RBL2H3 cells. We found that digested SCWE fully maintained its antioxidant activity and anti-allergic activity against the IgE-antigen complex-induced activation of RBL-2H3 cells. SCWE may be useful for preventing allergic diseases, such as asthma. Thus, SCWE could be used as a natural functional ingredient for allergic diseases in the food and/or pharmaceutical industries.

Antimutagenic effects of subfractions of Chaga mushroom (Inonotus obliquus) extract.

Inonotus obliquus is a mushroom commonly known as Chaga that is widely used in folk medicine in Siberia, North America, and North Europe. Here, we evaluated the antimutagenic and antioxidant capacities of subfractions of Inonotus obliquus extract. The ethyl acetate extract was separated by vacuum chromatography into three fractions, and the fraction bearing the highest antimutagenic activity was subsequently separated into four fractions by reversed phase (ODS-C18) column chromatography. The most antimutagenic fraction was then separated into two subfractions (subfractions 1 and 2) by normal phase silica gel column chromatography. Ames test analysis revealed that the subfractions were not mutagenic. At 50 µg/plate, subfractions 1 and 2 strongly inhibited the mutagenesis induced in Salmonella typhimurium strain TA100 by the directly acting mutagen MNNG (0.4 µg/plate) by 80.0% and 77.3%, respectively. They also inhibited 0.15 µg/plate 4NQO-induced mutagenesis in TA98 and TA100 by 52.6-62.0%. The mutagenesis in TA98 induced by the indirectly acting mutagens Trp-P-1 (0.15 µg/plate) and B(α)P (10 µg/plate) was reduced by 47.0-68.2% by the subfractions, while the mutagenesis in TA100 by Trp-P-1 and B(α)P was reduced by 70.5-87.2%. Subfraction 1 was more inhibitory than subfraction 2 with regard to the mutagenic effects of 4NQO, Trp-P-1, and B(α)P. Subfractions 1 and 2 also had a strong antioxidant activity against DPPH radicals and were identified by MS, 1H NMR and 13C NMR analyses as 3ß-hydroxy-lanosta-8, 24-dien-21-al and inotodiol, respectively. Thus, we show that the 3beta-hydroxy-lanosta-8, 24-dien-21-al and inotodiol components of Inonotus obliquus bear antimutagenic and antioxidative activities.

Cyclooxygenase-2 promotes cell proliferation, migration and invasion in U2OS human osteosarcoma cells.

Osteosarcoma is the most common primary bone tumor, but the pathogenesis is not well understood. While cyclooxygeanse-2 (COX-2) is known to be closely associated with tumor growth and metastasis in several kinds of human tumors, the function of COX-2 in osteosarcoma is unclear. Therefore, to investigate the function of COX-2 in osteosarcoma, we established stable cell lines overexpressing COX-2 in U2OS human osteosarcoma cells. COX-2 overexpression as well as prostaglandin E2 treatment promoted proliferation of U2OS cells. In addition, COX-2 overexpression enhanced mobility and invasiveness of U2OS cells, which was accompanied by increases of matrix metalloproteinase-2 and -9 (MMP-2 and -9) activities. Selective COX-2 inhibitors, NS-398 and celecoxib, inhibited cell proliferation and abrogated the enhanced mobility, invasiveness and MMP activities induced by COX-2 overexpression. These results suggest that COX-2 is directly associated with cell proliferation, migration and invasion in human osteosarcoma cells, and the therapeutic value of COX-2 inhibitors should be evaluated continuously.

Inhibitory effects of fermented nutraceuticals on NO production and T cell proliferation in juvenile atopic dermatitis.

As the most common inflammatory skin disease in children, atopic dermatitis begins in infancy or early childhood, with about 90% of cases appearing under age of 5. The prevalence of atopic dermatitis has rapidly increased among children in recent years. Physiological and psychological abnormalities and social impact are also well known in children with atopic dermatitis and in their families. Atopic dermatitis not only seriously affects the quality of life of the children and their families but also is leading chronic disease in children with hard-to-cure.Recently, we found that the fermented extract of several plants had considerable potential to treat juvenile atopic dermatitis. This extract therefore is now under investigation to find the underlying immunopathological mechanism by determining its inhibitory effects on nitric oxide (NO) release and T cell proliferation. The fermented extract dose dependently blocked NO production. In particular, the inhibitory effect of the extract was maximized up until 80-fold dilution of the original extract. This extract did not induce cytotoxic effects up to 80-fold dilution. Interestingly, doses between 320- and 80-fold dilution significantly protected cell death mediated by LPS-induced NO production. The fermented extract also significantly suppressed CD3 induced T cell proliferation in a dose dependent manner.