Eun-Kyeong Choi

Coix seed extract attenuates the high-fat induced mouse obesity via PPARγ and C/EBPα a downregulation

The seed of the Coix lacryma-jobi L. var. ma-yuen Stapf seed (CLMS) extract has been prescribed to alleviate obesity by practitioners of traditional Korean medicine. Here, we investigated the effect of CLMS extract on PPARγ2 and c/EBPα and obesity responses in C57BL/6J obese mice fed on a high fat diet. The mouse body index, blood profile, and fat accumulation levels in the liver were measured. The protein expression levels of PPARγ2 and c/EBPα in the mice livers were also measured to determine the molecular mode-of-action of the reducing effect of CLMS extract on mouse adipogenesis. The results showed that HFD-induced mouse obesity, fat accumulation, and serum cholesterol were alleviated by the CLMS extract addition. Moreover, PPARγ2 and C/EBPα, proteins, those are related to the adipogenesis, were downregulated by the CLMS extract intake considerably. This study indicates that as a food additive, CLMS extract has a reducing effect on the high-fat diet induced fat accumulation and on body weight through the downregulation of adipogenesis.

A bitter herbal medicine Gentiana scabra root extract stimulates glucagon-like peptide-1 secretion and regulates blood glucose in db/db mouse.

ETHNOPHARMACOLOGICAL RELEVANCE Gentiana scabra root extract (GS) is frequently prescribed as an internal remedy in traditional Korean medicine for treatment of diabetes mellitus. GS contains bitter iridoid glycosides including loganic acid, gentiopicrin, trifloroside, and rindoside. We previously reported that the intestinal bitter taste sensation stimulates GLP-1 secretion, and thereupon hypothesized that the blood glucose regulatory effect of GS is due to its GLP-1 secreting effect in enteroendocrine L cells. MATERIALS AND METHOD We studied GLP-1 secreting effect of GS treatment and its cellular downstream mechanism in human enteroendocrine NCI-H716 cells using the G protein-coupled receptor (GPCR) pathway inhibitors. Intracellular calcium assay also demonstrated the signal transduction pathway stimulated by the GS treatment. Using db/db mice, we performed oral glucose tolerance test (OGTT) to examine the blood glucose lowering effect of GS administration. We also collected the mouse plasma during the OGTT to measure the GLP-1 and insulin levels. RESULT We demonstrated dose-dependent GLP-1 secreting effect of GS on the NCI-H716 cells. The GLP-1 secreting effect of GS is mediated by the G protein βγ-subunit and inositol triphosphate. Using db/db mice, we found that the effect of GS on lowering blood glucose is due to its GLP-1 secretion, and consequential insulinotropic effect. The chemical fingerprint of GS was obtained through a direct analysis in realtime mass spectrometry (DART-MS) and high-performance liquid chromatography (HPLC)/MS. Through the GLP-1 secretion study, we found that loganic acid, an iridoid glycoside, contributes to the GLP-1 secreting effect of GS. CONCLUSION The findings of this study highlight the potential of exploiting the antidiabetic effect of GS on type 2 diabetes mellitus patients.

Gentiana scabra extracts stimulate glucagon-like peptide-1 secretion via G protein-coupled receptor pathway

Glucagon-like peptide-1 (GLP-1) which secreted by enteroendocrine L cell have been issued as a therapeutic agent for type II diabetes mellitus, because of its function to stimulate insulin secretion in pancreatic β-cells. It is widely studied that sweet, bitter, and umami taste stimuli induce the secretion of GLP-1 in enteroendocrine L cell via G protein coupled receptor (GPCR) signaling pathway. Gentiana scabra (GS) is one of the bitter tasting herbal medicines which have been used in traditional oriental medicine to treat the diabetes mellitus. This study shows the GLP-1 secretion of the enteroendocrine L cell stimulated by stimulation of GS extractions through GPCR pathway. To examine the molecular mode-of-action, GLP-1 ELISA and microarray was performed. This study provides the understanding the possibility of GS used as a therapeutic herbal medicine for the type II diabetes.

Hexane fraction of Citrus aurantium L. stimulates glucagon-like peptide-1 (GLP-1) secretion via membrane depolarization in NCI-H716 cells

Citrus species have been used traditionally as a medicinal herb in oriental pharmacology. Here, we reported on the anti-diabetic function of Citrus aurantium L. (CA). The hexane fraction of CA (HFCA) stimulates NCI-H716 cells and results in the secretion of glucagon-like peptide-1 (GLP-1). Because it regulates insulin secretion in pancreatic β-cells, GLP-1 has been used for the treatment of type II diabetes mellitus. Hence, we carried out a series of experiments to demonstrate the functions of HFCA against diabetes mellitus at the molecular level. Four fractions of CA were used in a GLP-1 assay. The GLP-1 ELISA assay was performed to measure the concentrations of GLP-1 after treatment with the four fractions of CA. The hexane fraction showed the best results and was chosen for the microarray analysis in the genome wide analysis. Through the analysis, it was found that voltage-gated potassium (Kv) channels drove membrane depolarization and then influenced Ca2+ currents in NCIH716 cells. These results suggest this is a new oriental herbal drug that has proven effects for the remedy of type II diabetes mellitus.

The Multi-Targeted Effects of Chrysanthemum Herb Extract Against Escherichia coli O157:H7

The Chrysanthemum lavandulifolium extract, which includes chrysoeriol, sudachitin, and acacetin, has excellent antibiotic effects on Escherichia coli O157:H7 (E. coli O157). A notable point is that the antibiotic targets of the herb extract are similar to the targets of commonly used antibiotic drugs, including bacterial cell wall biosynthesis, bacterial protein synthesis, and bacterial DNA replication and repair. In addition, the herbal antibiotic inhibits the etiological factors that contribute to the pathogenic property. The herbal sample was extracted and fractionated and then inoculated through a disk diffusion method to confirm its antibiotic effect against E. coli O157. Total RNA was isolated from the affected bacterial cells, and its expression level was analyzed through a microarray analysis. To confirm the accuracy of the microarray data, a real‐time PCR was performed. Three active compounds, chrysoeriol, sudachitin, and acacetin, were identified with a high‐performance liquid chromatography‐electrospray ionization/mass spectrometry chromatogram, and the disk diffusion study confirmed that chrysoeriol and sudachitin contribute to the antibiotic properties of the herb extract. The results demonstrate that the multi‐target efficacy of the herbal sample may indicate the potential for the development of more effective and safer drugs that will act as substitutes for existing antibiotics. Copyright

Hexane Fractions of Bupleurum falcatum L. Stimulates Glucagon-Like Peptide-1 Secretion through Gβγ-Mediated Pathway

Bupleurum falcatum L. has been used traditionally as a medicinal herb in Korean medicine. The hexane fraction of BF (HFBF), which was profiled with Direct Analysis in Real Time-Mass Spectrometry (DART-MS), activates the secretion of glucagon-like peptide-1 (GLP-1) in NCI-H716 cells significantly. We performed a microarray analysis and GLP-1 ELISA assay, as well as calcium imaging experiments with inhibitors, to investigate the mechanism of action of the HFBF. Through the microarray analysis, it was found that the ITPR2 gene that encodes the inositol 1,4,5-trisphosphate (IP3) receptor is up-regulated and the HFBF induces cell depolarization by inhibiting the voltage-gated channel expression in NCI-H716 cells. In addition, we found that the intracellular calcium in NCI-H716 cells, with Gallein, U73122, and 2APB as inhibitors, was decreased. These results suggest that the HFBF activates the GLP-1 secretion through the Gβγ pathways in the enteroendocrine L cells after treatment with the HFBF.

Global transcriptome analysis of the E. coli O157 response to Agrimonia pilosa extract

Antibiotics are certainly beneficial to treat the bacterial infection. However, inappropriate use puts patients at danger for avoidable adverse drug reactions. This inappropriate use accelerates the emergence of resistance and potentially increases overall health-care costs. In oriental pharmacology, herbal medicines had been used as an antibiotic drug, but its antibiotic mechanism has not yet been proved completely. Here, we studied the antibiotic effects of Agrimonia pilosa on E. coli O157:H7. Especially, it is noteworthy that the antibiotic efficacy of the herb extract on three proven targets for a main antibiotic drug: bacterial cell wall biosynthesis, protein synthesis and DNA replication and repair. The results show the antibiotic effects through the inhibition of bacterial cell wall synthesis, folic acid synthesis, and multidrug efflux.

Effects of the inhaled treatment of liriope radix on an asthmatic mouse model.

As a treatment for allergic asthma, inhaled treatments such as bronchodilators that contain β2-agonists have an immediate effect, which attenuates airway obstructions and decreases airway hypersensitivity. However, bronchodilators only perform on a one off basis, but not consistently. Asthma is defined as a chronic inflammatory disease of the airways accompanying the overproduction of mucus, airway wall remodeling, bronchial hyperreactivity and airway obstruction. Liriope platyphylla radix extract (LPP), a traditional Korean medicine, has been thoroughly studied and found to be an effective anti-inflammatory medicine. Here, we demonstrate that an inhaled treatment of LPP can attenuate airway hyperresponsiveness (AHR) in an ovalbumin-induced asthmatic mouse model, compared to the saline-treated group (p < 0.01). Moreover, LPP decreases inflammatory cytokine levels, such as eotaxin (p < 0.05), IL-5 (p < 0.05), IL-13 (p < 0.001), RANTES (p < 0.01), and TNF-α (p < 0.05) in the bronchoalveolar lavage (BAL) fluid of asthmatic mice. A histopathological study was carried out to determine the effects of LPP inhalation on mice lung tissue. We performed UPLC/ESI-QTOF-MS, LC/MS, and GC/MS analyses to analyze the chemical constituents of LPP, finding that these are ophiopogonin D, spicatoside A, spicatoside B, benzyl alcohol, and 5-hydroxymethylfurfural. This study demonstrates the effect of an inhaled LPP treatment both on airway AHR and on the inflammatory response in an asthmatic mouse model. Hence, LPP holds significant promise as a nasal inhalant for the treatment of asthmatic airway disease.

Comparative transcriptomic analysis of the multi-targeted effects of the herbal extracts against Escherichia coli O157:H7

Antibiotics can be classified based upon drug-target interaction and lethality. Bactericidal drugs, which target cell wall/membrane synthesis, DNA replication and repair or protein synthesis, induce hydroxyl radical leading to the bacterial cell death with extreme efficacy. The antibiotic mechanism of the bactericidal drugs is followed by stimulating oxidation of nicotinamide adenine dinucleotide hydrate (NADH) via the electron transport chain that is dependent upon the tricarboxylic acid (TCA) cycle. The five herbal samples, Houttuynia cordata Thunb (HCT), Chrysanthemum lavandulifolum (CL), Patrinia scabiosaefolia (PS), Angelica dahurica Bentham et Hooker (ADBH) and Agrimonia pilosa (AP) were extracted to acquire the fractions, and then inoculated to investigate their antibiotic effect against the bacteria Escherichia coli O157:H7 through the disk diffusion method. Total RNA of the treated cells was isolated to compare and analyze their gene expression profiling. Results from this study indicate that the molecular mechanisms of simultaneous multi-target antibiotic efficacy of the five herbal samples include bacterial cell wall/membrane synthesis, DNA replication and repair, and protein synthesis. The antibiotic mechanisms were associated with the hydroxyl radical damage followed by overproduction of superoxide. Moreover, inhibition of multidrug resistance system and etiological factors are encouraging development of novel antibiotics. Our study suggests that the five herbal samples have a molecular mechanism similar to that of bactericidal drugs that is induction of hydroxyl radical damage which leads to bacterial cell death.