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.
BACKGROUND/OBJECTIVESRecent 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/METHODSColorimetric 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-3β) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement.RESULTSCMW 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-3β, 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.CONCLUSIONCMW 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.
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.
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