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1.
Bioorg Chem ; 150: 107527, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38876005

ABSTRACT

Two protoberberine alkaloids with a unique C28 skeleton, named xanthiumines A (1) and B (2), respectively, were isolated from the fruits of Xanthium sibiricum Patr. Their structures including absolute configurations were unequivocally established by the comprehensive NMR and MS spectroscopic data analysis together with gauge-independent atomic orbital (GIAO) NMR calculations, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are the first examples of natural protoberberine alkaloid with a phenolic acid group at C-13a. Their plausible biosynthetic pathway was proposed on the basis of the coexisting alkaloid monomer as the precursor. Furthermore, the effects and related molecular mechanism of compound 1 on hepatic lipid accumulation were also investigated in oleic acid (OA)-treated HepG2 cells.


Subject(s)
AMP-Activated Protein Kinases , Berberine Alkaloids , Fruit , Xanthium , Humans , Fruit/chemistry , Xanthium/chemistry , Berberine Alkaloids/chemistry , Berberine Alkaloids/pharmacology , Berberine Alkaloids/isolation & purification , Hep G2 Cells , Molecular Structure , AMP-Activated Protein Kinases/metabolism , Structure-Activity Relationship , Dose-Response Relationship, Drug , Drug Discovery , Enzyme Activators/pharmacology , Enzyme Activators/chemistry , Enzyme Activators/isolation & purification
2.
J Biol Chem ; 294(46): 17654-17668, 2019 11 15.
Article in English | MEDLINE | ID: mdl-31481464

ABSTRACT

WT P53-Induced Phosphatase 1 (WIP1) is a member of the magnesium-dependent serine/threonine protein phosphatase (PPM) family and is induced by P53 in response to DNA damage. In several human cancers, the WIP1 protein is overexpressed, which is generally associated with a worse prognosis. Although WIP1 is an attractive therapeutic target, no potent, selective, and bioactive small-molecule modulator with favorable pharmacokinetics has been reported. Phosphatase enzymes are among the most challenging targets for small molecules because of the difficulty of achieving both modulator selectivity and bioavailability. Another major obstacle has been the availability of robust and physiologically relevant phosphatase assays that are suitable for high-throughput screening. Here, we describe orthogonal biochemical WIP1 activity assays that utilize phosphopeptides from native WIP1 substrates. We optimized an MS assay to quantify the enzymatically dephosphorylated peptide reaction product in a 384-well format. Additionally, a red-shifted fluorescence assay was optimized in a 1,536-well format to enable real-time WIP1 activity measurements through the detection of the orthogonal reaction product, Pi We validated these two optimized assays by quantitative high-throughput screening against the National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection and used secondary assays to confirm and evaluate inhibitors identified in the primary screen. Five inhibitors were further tested with an orthogonal WIP1 activity assay and surface plasmon resonance binding studies. Our results validate the application of miniaturized physiologically relevant and orthogonal WIP1 activity assays to discover small-molecule modulators from high-throughput screens.


Subject(s)
Enzyme Activators/chemistry , Phosphopeptides/chemistry , Protein Phosphatase 2C/chemistry , Small Molecule Libraries/chemistry , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , High-Throughput Screening Assays , Humans , Protein Phosphatase 2C/antagonists & inhibitors , Small Molecule Libraries/isolation & purification , Small Molecule Libraries/pharmacology , Substrate Specificity , Tumor Suppressor Protein p53/chemistry
3.
Prep Biochem Biotechnol ; 50(9): 907-914, 2020.
Article in English | MEDLINE | ID: mdl-32478599

ABSTRACT

Protein C (PC) plays an important role in the balance of coagulation and anticoagulation. Thus, the detection of PC activity is diagnostically significant for patients with cardiovascular diseases. Presently, the key methods to detect PC activity are the chromogenic assay and activated partial thromboplastin time (APTT) test. PROTAC used in the chromogenic assay is isolated from Agkistrodon contortrix venom as protein C activator (PCA). However, the use of the chromogenic assay is limited because of the high price of PROTAC. In this study, PCA was successfully purified from Agkistrodon acutus venom (AAV) by ion-exchange and gel chromatography. PCA from AAV has a relative molecular mass of 24 kD, calculated from the measurement of 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The components of PCA were identified by MALDI-TOF/TOF-MS and mascot searches revealed that the coverage rate between PCA and zinc metalloproteinase AaPA from AAV was 21%. The chromogenic assay and APTT test were used to measure the enzymatic activity of PCA, and the results showed that PCA from AAV could specifically activate PC. In summary, the chromogenic assay described herein is highly sensitive and easy to perform.


Subject(s)
Agkistrodon , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Protein C/agonists , Snake Venoms/chemistry , Agkistrodon/metabolism , Animals , Electrophoresis, Polyacrylamide Gel , Enzyme Activation/drug effects , Enzyme Activators/chemistry , Protein C/metabolism , Rabbits , Snake Venoms/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
4.
Bioorg Med Chem Lett ; 28(3): 240-243, 2018 02 01.
Article in English | MEDLINE | ID: mdl-29317167

ABSTRACT

Panax ginseng as a traditional Chinese medicine has been extensively used for the treatment of many diseases, especially in prolonging life and anti-tumor. Dammarane-type triterpenoids from P. ginseng have diverse beneficial effects and their chemical structures can be modified in the gastrointestinal tract after oral administration. In this paper, the dammarane-type triterpenoids were isolated from artificial gastric juice incubate of total saponins in the stems and leaves of P. ginseng through column chromatographic methods and their chemical structures were determined based on spectral data. Two new dammarane-type triterpenoids named ginsenotransmetins B (1) and C (2), along with twenty-nine known compounds (3-31), were obtained. All 31 compounds isolated were investigated for their activities of SIRT1 using SIRT1 fluorometric drug discovery assay kit. Among them, compounds 11, 17, 18, 20, 23, 24, 28, and 29, which were found to be potential as SIRT1 activators, exhibited significant stimulation of SIRT1 activity. The results showed that these compounds may be considered to be a useful medicinal resource for prolonging life and anti-tumor. In addition, the results were helpful to explain the longevity effect of ginseng from the new field of view.


Subject(s)
Enzyme Activators/chemistry , Panax/chemistry , Saponins/chemistry , Sirtuin 1/chemistry , Triterpenes/chemistry , Enzyme Activators/isolation & purification , Plant Leaves/chemistry , Plant Stems/chemistry , Saponins/isolation & purification , Stereoisomerism , Triterpenes/isolation & purification
5.
J Sci Food Agric ; 98(13): 4911-4918, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29569261

ABSTRACT

BACKGROUND: Buckwheat is an important alternative crop and a raw material for functional food formulation. Phase II detoxification proteins/enzymes provide cytoprotective roles against oxidative stress and inflammation originating from various stressors. We aimed to identify and characterize potential phase II enzyme inducers from methanolic extracts of buckwheat flour, using an activity-guided fractionation based on the induction of quinone reductase (QR) (EC 1.6.5.2) in Hepa 1c1c7 cells. RESULTS: We isolated the QR inducers N-trans-feruloyltyramine (I), syringic acid (II), quercetin (III) and myricetin (IV). The relative QR-inducing ability, as well as the concentration required to double QR specific activity (CD values, in parentheses), decreased in the order: quercetin (3.0 µmol L-1 ) > N-trans-feruloyltyramine (24 µmol L-1 ) > myricetin (58 µmol L-1 ) > syringic acid (5.4 mmol L-1 ). Quercetin and N-trans-feruloyltyramine exhibited the greatest extent of QR induction of an approximately four-fold maximum induction and these compounds also exhibited the greatest values for the ratio of IC50 (i.e. level to reduce viability by 50%): CD values of 11 and > 8.3, respectively, among the four QR inducers isolated. Isobologram analyses for binary combinations of compounds I-IV revealed primarily antagonistic interactions for QR induction. CONCLUSION: These findings add to our understanding of the nutraceutical potential of buckwheat as a chemoprophylactic dietary component. © 2018 Society of Chemical Industry.


Subject(s)
Enzyme Activators/chemistry , Fagopyrum/chemistry , Flour/analysis , NAD(P)H Dehydrogenase (Quinone)/chemistry , Plant Extracts/chemistry , Enzyme Activators/isolation & purification , Flavonoids/chemistry , Flavonoids/isolation & purification , Humans , Kinetics , Metabolic Detoxication, Phase II , Methanol , NAD(P)H Dehydrogenase (Quinone)/metabolism , Plant Extracts/isolation & purification
6.
Bioorg Med Chem Lett ; 26(2): 505-511, 2016 Jan 15.
Article in English | MEDLINE | ID: mdl-26675439

ABSTRACT

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. The major component of the plaques, amyloid-ß (Aß), is generated from amyloid-ß precursor protein (APP) by ß- and γ-secretase-mediated cleavages. Multiple lines of evidence demonstrate that overproduction/accumulation of Aß in vulnerable brain regions is a primary cause of the pathogenesis of AD. Among the twelve polyphenols isolated from the leaf extracts of Vitis thunbergii var. taiwaniana (VTT), stenophyllol C, stenophyllol B, ampelopsin C, vitisin A, and davidiol A were shown to significantly reduce both Aß40 and Aß42 levels in N2a695 cells. Further studies revealed that ampelopsin C and vitisin A reduce Aß production through inhibiting ß-secretase activity, while the effects of the other active polyphenols on reducing Aß generation are through different mechanisms. These results suggest that VTT extracts may be beneficial for AD prevention and treatment.


Subject(s)
Amyloid beta-Peptides/antagonists & inhibitors , Peptide Fragments/antagonists & inhibitors , Polyphenols/isolation & purification , Polyphenols/pharmacology , Stilbenes/isolation & purification , Stilbenes/pharmacology , Vitis/chemistry , ADAM17 Protein/metabolism , Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Animals , Aspartic Acid Endopeptidases/antagonists & inhibitors , Cell Line, Tumor , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Enzyme Activators/therapeutic use , Humans , Mice , Plant Leaves/chemistry , Polyphenols/therapeutic use , Protease Inhibitors/isolation & purification , Protease Inhibitors/pharmacology , Protease Inhibitors/therapeutic use , Stilbenes/therapeutic use
7.
Pak J Pharm Sci ; 29(6): 1985-1991, 2016 Nov.
Article in English | MEDLINE | ID: mdl-28375114

ABSTRACT

Glucose-6-phosphatase is a key enzyme of glucose metabolic pathways. Deficiency of this enzyme leads to glycogen storage disease. This enzyme also plays a negative role in diabetes mellitus disorder in which the catalytic activity of this enzyme increases. Thus there is need for activators to enhance the activity of glucose-6-phosphatase in glycogen storage disease of type 1b while in diabetes mellitus repressors are needed to reduce its activity. Crude extracts of apricot, fig, mulberry and apple fruits were investigated for their repressive/enhancive effects on glucose-6-phosphatase in vivo. Albino mice were used as experimental animal. All the selected extracts showed depressive effects on glucose-6-phosphatase, which shows that all these extracts can be used as antidiabetic supplement of food. The inhibitory pattern was competitive one, which was evident from the effect of increasing dose from 1g/Kg body weight to 3g/Kg body weight for all the selected fruit extracts. However fig and apple fruit extracts showed high repressive effects for high doses as compared to apricot and mulberry fruit extracts. None of these selected fruit extracts showed enhancive effect on glucose-6-phosphatase activity. All these fruits or their extracts can be used as antidiabetic dietary supplement for diabetes mellitus.


Subject(s)
Enzyme Inhibitors/pharmacology , Ficus/chemistry , Fruit/chemistry , Glucose-6-Phosphatase/antagonists & inhibitors , Hypoglycemic Agents/pharmacology , Malus/chemistry , Morus/chemistry , Plant Extracts/pharmacology , Prunus armeniaca/chemistry , Animals , Dose-Response Relationship, Drug , Enzyme Activation , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Enzyme Inhibitors/isolation & purification , Female , Glucose-6-Phosphatase/metabolism , Hypoglycemic Agents/isolation & purification , Male , Mice , Phytotherapy , Plant Extracts/isolation & purification , Plants, Medicinal
8.
World J Microbiol Biotechnol ; 30(1): 135-42, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23861040

ABSTRACT

The induction of laccase isoforms in Trametes versicolor HEMIM-9 by aqueous extracts (AE) from softwood and hardwood was studied. Samples of sawdust of Pinus sp., Cedrela sp., and Quercus sp. were boiled in water to obtain AE. Different volumes of each AE were added to fungal cultures to determine the amount of AE needed for the induction experiments. Laccase activity was assayed every 24 h for 15 days. The addition of each AE (50 to 150 µl) to the fungal cultures increased laccase production compared to the control (0.42 ± 0.01 U ml(-1)). The highest laccase activities detected were 1.92 ± 0.15 U ml(-1) (pine), 1.87 ± 0.26 U ml(-1) (cedar), and 1.56 ± 0.34 U ml(-1) (oak); laccase productivities were also significantly increased. Larger volumes of any AE inhibited mycelial growth. Electrophoretic analysis revealed two laccase bands (lcc1 and lcc2) for all the treatments. However, when lcc2 was analyzed by isoelectric focusing, inducer-dependent isoform patterns composed of three (pine AE), four (oak AE), and six laccase bands (cedar AE) were observed. Thus, AE from softwood and hardwood had induction effects in T. versicolor HEMIM-9, as indicated by the increase in laccase activity and different isoform patterns. All of the enzymatic extracts were able to decolorize the dye Orange II. Dye decolorization was mainly influenced by pH. The optimum pH for decolorization was pH 5 (85%), followed by pH 7 (50%) and pH 3 (15%). No significant differences in the dye decolorizing capacity were detected between the control and the differentially induced laccase extracts (oak, pine and cedar). This could be due to the catalytic activities of isoforms with pI 5.4 and 5.8, which were detected under all induction conditions.


Subject(s)
Enzyme Activators/metabolism , Laccase/biosynthesis , Plant Extracts/metabolism , Trametes/drug effects , Trametes/enzymology , Wood/chemistry , Azo Compounds/metabolism , Benzenesulfonates/metabolism , Cedrus/chemistry , Enzyme Activators/isolation & purification , Enzyme Stability , Hydrogen-Ion Concentration , Isoenzymes/biosynthesis , Isoenzymes/chemistry , Isoenzymes/isolation & purification , Laccase/chemistry , Laccase/isolation & purification , Pinus/chemistry , Plant Extracts/isolation & purification , Quercus/chemistry , Temperature
9.
Biochemistry ; 51(33): 6609-22, 2012 Aug 21.
Article in English | MEDLINE | ID: mdl-22827463

ABSTRACT

Members of the 2-hydroxyacyl-CoA dehydratase enzyme family catalyze the ß,α-dehydration of various CoA-esters in the fermentation of amino acids by clostridia. Abstraction of the nonacidic ß-proton of the 2-hydroxyacyl-CoA compounds is achieved by the reductive generation of ketyl radicals on the substrate, which is initiated by the transfer of an electron at low redox potentials. The highly energetic electron needed on the dehydratase is donated by a [4Fe-4S] cluster containing ATPase, termed activator. We investigated the activator of the 2-hydroxyisocaproyl-CoA dehydratase from Clostridium difficile. The activator is a homodimeric protein structurally related to acetate and sugar kinases, Hsc70 and actin, and has a [4Fe-4S] cluster bound in the dimer interface. The crystal structures of the Mg-ADP, Mg-ADPNP, and nucleotide-free states of the reduced activator have been solved at 1.6-3.0 Å resolution, allowing us to define the position of Mg(2+) and water molecules in the vicinity of the nucleotides and the [4Fe-4S] cluster. The structures reveal redox- and nucleotide dependent changes agreeing with the modulation of the reduction potential of the [4Fe-4S] cluster by conformational changes. We also investigated the propensity of the activator to form a complex with its cognate dehydratase in the presence of Mg-ADP and Mg-ADPNP and together with the structural data present a refined mechanistic scheme for the ATP-dependent electron transfer between activator and dehydratase.


Subject(s)
Adenosine Triphosphate/metabolism , Bacterial Proteins/metabolism , Hydro-Lyases/metabolism , Adenosine Diphosphate/metabolism , Crystallization , Enzyme Activation , Enzyme Activators/chemistry , Enzyme Activators/isolation & purification , Iron-Sulfur Proteins/chemistry , Iron-Sulfur Proteins/isolation & purification , Iron-Sulfur Proteins/metabolism , Oxidation-Reduction , Protein Binding
10.
J Gastroenterol Hepatol ; 27 Suppl 3: 13-22, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22486866

ABSTRACT

BACKGROUND AND AIM: Cysteamine is a reducing aminothiol used for inducing duodenal ulcer through mechanisms of oxidative stress related to thiol-derived H(2)O(2) reaction. Cochinchina momordica saponins have been suggested to be protective against various gastric diseases based on their cytoprotective and anti-inflammatory mechanisms. This study was aimed to document the preventive effects of Cochinchina momordica seed extract against cysteamine-induced duodenal ulcer as well as the elucidation of its pharmacological mechanisms. METHODS: Cochinchina momordica seed extract (50, 100, 200 mg/kg) was administrated intragastrically before cysteamine administration, after which the incidence of the duodenal ulcer, ulcer size, serum gastrin level, and the ratio of reduced glutathione (GSH)/oxidized glutathione disulfide (GSSG) as well as biochemical and molecular measurements of cytoplasmic phospholipase A(2) (cPLA(2)), cyclooxygenase-2 (COX-2), 5-lipoxygenase and the expression of proinflammatory genes including IL-1ß, IL-6, COX-2 were measured in rat model. Additional experiments of electron spin resonance measurement and the changes of glutathione were performed. RESULTS: Cochinchina momordica seed extract effectively prevented cysteamine-induced duodenal ulcer in a dose-dependent manner as reflected with significant decreases in either duodenal ulcerogenesis or perforation accompanied with significantly decreased in serum gastrin in addition to inflammatory mediators including cPLA(2), COX-2, and 5-lipoxygenase. Cochinchina momordica seed extract induced the expression of γ-glutamylcysteine synthetase (γ-GCS)-related glutathione synthesis as well as significantly reduced the expression of cPLA(2). Cochinchina momordica seed extract preserved reduced glutathione through increased expressions of γ-GCS. CONCLUSION: Cochinchina momordica seed extracts exerted significantly protective effect against cysteamine-induced duodenal ulcer by either cPLA2 inhibition or glutathione preservation.


Subject(s)
Anti-Ulcer Agents/pharmacology , Arachidonate 5-Lipoxygenase/metabolism , Cysteamine , Duodenal Ulcer/prevention & control , Duodenum/drug effects , Enzyme Activators/pharmacology , Glutamate-Cysteine Ligase/metabolism , Lipoxygenase Inhibitors/pharmacology , Momordica , Phospholipases A2, Cytosolic/antagonists & inhibitors , Plant Extracts/pharmacology , Animals , Anti-Ulcer Agents/isolation & purification , Antioxidants/pharmacology , Cell Line , Cyclooxygenase 2/metabolism , Disease Models, Animal , Dose-Response Relationship, Drug , Duodenal Ulcer/chemically induced , Duodenal Ulcer/enzymology , Duodenal Ulcer/pathology , Duodenum/enzymology , Duodenum/pathology , Enzyme Activation , Enzyme Activators/isolation & purification , Gastrins/blood , Glutathione/metabolism , Inflammation Mediators/metabolism , Intestinal Mucosa/drug effects , Intestinal Mucosa/enzymology , Intestinal Mucosa/pathology , Lipoxygenase Inhibitors/isolation & purification , Male , Momordica/chemistry , Oxidation-Reduction , Oxidative Stress/drug effects , Phospholipases A2, Cytosolic/metabolism , Plant Extracts/isolation & purification , Rats , Rats, Sprague-Dawley , Seeds , Time Factors
11.
Biotechnol Lett ; 34(9): 1607-16, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22576281

ABSTRACT

Gynostemma pentaphyllum is widely used in Asian countries as a herbal medicine to treat dyslipidemia, type 2 diabetes and inflammation. An ethanol extract of G. pentaphyllum lessened obesity by activating AMP-activated protein kinase (AMPK). The levels of damulins A and B, components responsible for AMPK activation in the extract, were increased by autoclaving in a time-dependent manner. Heat-processed G. pentaphyllum extract, actiponin containing damulins A (0.93 %, w/w) and B (0.68 %, w/w), significantly stimulated fat oxidation and glucose uptake via AMPK activation in L6 myotube cells. Oral administration of actiponin to ob/ob mice for 8 weeks decreased body weight gain, liver weight, and blood cholesterol levels with AMPK activation in the soleus muscle. Our results demonstrate the beneficial effect of G. pentaphyllum on improving obesity and have elucidated the underlying molecular mechanisms.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Enzyme Activators/therapeutic use , Gynostemma/chemistry , Hot Temperature , Obesity/drug therapy , Plant Extracts/therapeutic use , Administration, Oral , Animals , Cell Line , Disease Models, Animal , Enzyme Activators/administration & dosage , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Glucose/metabolism , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Muscle Cells/drug effects , Muscle Cells/metabolism , Oxidation-Reduction , Plant Extracts/administration & dosage , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Time Factors
12.
Bioorg Med Chem ; 19(19): 5776-81, 2011 Oct 01.
Article in English | MEDLINE | ID: mdl-21893415

ABSTRACT

AMP-activated kinase (AMPK) as a key controller in the regulation of whole-body energy homeostasis, plays an important role in protecting the body from metabolic diseases. Recently, improved glucose, lipid utility and increased insulin sensitivity were observed on several diabetic rodent models treated with crude mogrosides isolated from the fruit of Siraitia grosvenorii Swingle, but the precise active compounds responsible for the anti-diabetic activity of this plant have not been clearly identified. In our current work, acid hydrolysis of crude mogrosides provided five new cucurbitane triterpenoids (1-4, 8), along with three known ones (5-7). The main aglycone mogrol (7) and compounds 4 and 8 were found to be potent AMPK activators in the HepG2 cell line. This result suggested AMPK activation by the mogroside aglycones 7 and 8 was proved to contribute at least partially to the anti-hyperglycemic and anti-lipidemic properties in vivo of S. grosvenorii.


Subject(s)
AMP-Activated Protein Kinases/chemistry , Cucurbitaceae/chemistry , Enzyme Activators/chemistry , Glycosides/chemistry , Hypoglycemic Agents/chemistry , Triterpenes/chemistry , AMP-Activated Protein Kinases/metabolism , Enzyme Activation/drug effects , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Fruit/chemistry , Glycosides/isolation & purification , Glycosides/pharmacology , Hep G2 Cells , Humans , Hypoglycemic Agents/isolation & purification , Hypoglycemic Agents/pharmacology , Triterpenes/isolation & purification , Triterpenes/pharmacology
13.
Commun Biol ; 4(1): 209, 2021 02 19.
Article in English | MEDLINE | ID: mdl-33608631

ABSTRACT

Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, is a crucial regulator that produces multiple physiological benefits, such as the prevention of cancer and age-related diseases. SIRT1 is activated by sirtuin-activating compounds (STACs). Here, we report that quercetin 3,5,7,3',4'-pentamethyl ether (KPMF-8), a natural STAC from Thai black ginger Kaempferia parviflora, interacts with SIRT1 directly and stimulates SIRT1 activity by enhancing the binding affinity of SIRT1 with Ac-p53 peptide, a native substrate peptide without a fluorogenic moiety. The binding affinity between SIRT1 and Ac-p53 peptide was enhanced 8.2-fold by KPMF-8 but only 1.4-fold by resveratrol. The specific binding sites of KPMF-8 to SIRT1 were mainly localized to the helix2-turn-helix3 motif in the N-terminal domain of SIRT1. Intracellular deacetylase activity in MCF-7 cells was promoted 1.7-fold by KPMF-8 supplemented in the cell medium but only 1.2-fold by resveratrol. This work reveals that KPMF-8 activates SIRT1 more effectively than resveratrol does.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Breast Neoplasms/drug therapy , Enzyme Activators/pharmacology , Quercetin/pharmacology , Sirtuin 1/metabolism , Zingiberaceae , Allosteric Regulation , Antineoplastic Agents, Phytogenic/isolation & purification , Binding Sites , Breast Neoplasms/enzymology , Enzyme Activation , Enzyme Activators/isolation & purification , Female , Humans , MCF-7 Cells , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding , Protein Conformation, alpha-Helical , Quercetin/analogs & derivatives , Quercetin/isolation & purification , Resveratrol/pharmacology , Zingiberaceae/chemistry
14.
Biomed Pharmacother ; 143: 112188, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34563947

ABSTRACT

An extract from Artemisia dracunculus L. (termed PMI-5011) improves glucose homeostasis by enhancing insulin action and reducing ectopic lipid accumulation, while increasing fat oxidation in skeletal muscle tissue in obese insulin resistant male mice. A chalcone, DMC-2, in PMI-5011 is the major bioactive that enhances insulin signaling and activation of AKT. However, the mechanism by which PMI-5011 improves lipid metabolism is unknown. AMPK is the cellular energy and metabolic sensor and a key regulator of lipid metabolism in muscle. This study examined PMI-5011 activation of AMPK signaling using murine C2C12 muscle cell culture and skeletal muscle tissue. Findings show that PMI-5011 increases Thr172-phosphorylation of AMPK in muscle cells and skeletal muscle tissue, while hepatic AMPK activation by PMI-5011 was not observed. Increased AMPK activity by PMI-5011 affects downstream signaling of AMPK, resulting in inhibition of ACC and increased SIRT1 protein levels. Selective deletion of DMC-2 from PMI-5011 demonstrates that compounds other than DMC-2 in a "DMC-2 knock out extract" (KOE) are responsible for AMPK activation and its downstream effects. Compared to 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and metformin, the phytochemical mixture characterizing the KOE appears to more efficiently activate AMPK in muscle cells. KOE-mediated AMPK activation was LKB-1 independent, suggesting KOE does not activate AMPK via LKB-1 stimulation. Through AMPK activation, compounds in PMI-5011 may regulate lipid metabolism in skeletal muscle. Thus, the AMPK-activating potential of the KOE adds therapeutic value to PMI-5011 and its constituents in treating insulin resistance or type 2 diabetes.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Artemisia , Enzyme Activators/pharmacology , Hypoglycemic Agents/pharmacology , Insulin Resistance , Muscle, Skeletal/drug effects , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Aminoimidazole Carboxamide/analogs & derivatives , Aminoimidazole Carboxamide/pharmacology , Animals , Artemisia/chemistry , Cell Line , Diet, High-Fat , Disease Models, Animal , Enzyme Activation , Enzyme Activators/isolation & purification , Hypoglycemic Agents/isolation & purification , Male , Metformin/pharmacology , Mice, Inbred C57BL , Muscle, Skeletal/enzymology , Myoblasts, Skeletal/drug effects , Myoblasts, Skeletal/enzymology , Phosphorylation , Phytochemicals/isolation & purification , Plant Extracts/isolation & purification , Ribonucleotides/pharmacology , Signal Transduction/drug effects
15.
Bioorg Med Chem Lett ; 20(14): 4128-31, 2010 Jul 15.
Article in English | MEDLINE | ID: mdl-20541406

ABSTRACT

AMP-activated protein kinase (AMPK) is a potential therapeutic target for the treatment of metabolic syndrome including obesity and type-2 diabetes. As part of an ongoing search for new AMPK activators from plants, this study found that the total extract of Myristica fragrans (nutmeg) activated the AMPK enzyme in differentiated C2C12 cells. As active constituents, seven 2,5-bis-aryl-3,4-dimethyltetrahydrofuran lignans, tetrahydrofuroguaiacin B (1), saucernetindiol (2), verrucosin (3), nectandrin B (4), nectandrin A (5), fragransin C(1) (6), and galbacin (7) were isolated from this extract. Among the isolates, compounds 1, 4, and 5 at 5 microM produced strong AMPK stimulation in differentiated C2C12 cells. In addition, the preventive effect of a tetrahydrofuran mixture (THF) on weight gain in a diet-induced animal model was further examined. These results suggest that nutmeg and its active constituents can be used not only for the development of agents to treat obesity and possibly type-2 diabetes but may also be beneficial for other metabolic disorders.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Anti-Obesity Agents/pharmacology , Enzyme Activators/pharmacology , Myristica/chemistry , Anti-Obesity Agents/chemistry , Anti-Obesity Agents/isolation & purification , Enzyme Activators/chemistry , Enzyme Activators/isolation & purification , Magnetic Resonance Spectroscopy , Mass Spectrometry
16.
Fitoterapia ; 147: 104758, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33069833

ABSTRACT

Three new isopimarane-type diterpenoids, botrysphins G-I (1-3), a new muurolane-type sesquiterpenoid, 11,12-dihydroxylentideusether (4), and two new triketides, 4-dechlorobotrysphone C (5) and 4,5-dihydroxy-3-methoxy-6-undecanoyloxy-2-cyclohexen-1-one (6), together with one known diterpenoid, sphaeropsidin A (7), one sesquiterpenoid, lentideusether (8), and one triketide sphaeropsidone (9), were isolated from culture of the fungus Botrysphaeria laricina associated with the moss Rhodobryum umgiganteum. The structures of the new compounds were established on the basis of extensive spectroscopic techniques including HRMS and 1D and 2D NMR data. Compounds 1 and 2 exhibited NO inhibitory activity with IC50 values of 13.9 µM and 41.9 µM, respectively. At the same time, these two compounds showed quinone reductase inducing activity with 2.7-fold of induction for 1 at 12.5 µM and 1.6-fold for 2 at 25.0 µM.


Subject(s)
Ascomycota/chemistry , Diterpenes/pharmacology , Polyketides/pharmacology , Sesquiterpenes/pharmacology , Animals , Bryophyta/microbiology , Cell Line, Tumor , China , Diterpenes/isolation & purification , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Mice , Molecular Structure , NAD(P)H Dehydrogenase (Quinone) , Nitric Oxide/metabolism , Polyketides/isolation & purification , RAW 264.7 Cells , Sesquiterpenes/isolation & purification
17.
Endocr Res ; 34(4): 101-8, 2009.
Article in English | MEDLINE | ID: mdl-19878070

ABSTRACT

INTRODUCTION: Charcoal- or resin-stripping of fetal bovine serum (FBS) or bovine calf serum (BCS) intended for supplementation of cell culture media is widely practiced to remove a variety of endogenous compounds, including steroid, peptide, and thyroid hormones. The possibility that stripping removes other biologically relevant factors from serum may not be appreciated. METHODS: In this report, standardized clinical laboratory testing methods were used to assess the effects of resin- and charcoal-stripping on content in FBS and BCS of more than 25 analytes in the sera. RESULTS AND CONCLUSION: In addition to hormones, the serum constituents affected by stripping are certain vitamins, electrolytes, enzyme activities, and metabolites.


Subject(s)
Charcoal/pharmacology , Culture Media , Resins, Synthetic/pharmacology , Serum/drug effects , Animals , Cattle , Cell Culture Techniques/methods , Cell Culture Techniques/standards , Culture Media/chemistry , Culture Media/standards , Electrolytes/analysis , Electrolytes/isolation & purification , Enzyme Activators/analysis , Enzyme Activators/isolation & purification , Enzymes/analysis , Enzymes/metabolism , Hormones/analysis , Hormones/isolation & purification , Serum/chemistry , Vitamins/analysis , Vitamins/isolation & purification
18.
Phytother Res ; 23(2): 289-92, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18698667

ABSTRACT

Extraction and purification conditions of lignans from the fruits and seeds of Schisandra chinensis (Turcz.) were investigated through an orthogonal design of L(9)(3(4)) assay and macroporous resin technology. The extraction was optimized using 95% ethanol. For purification, the extract was dissolved in 30% ethanol, then adsorbed on a AB-8 macroporous resin and eluted with 30% ethanol and 70% ethanol successively, the latter resulting in a residue containing 65.2% of lignans. By HPLC analysis schisandrin, deoxyschisandrin and gamma-schisandrin were quantitatively determined. UMR 106 cells were used to examine the stimulatory activity of the lignans on osteoblasts in vitro. The lignans stimulated the proliferation of and the activity of alkaline phosphatase in the osteoblasts indicating their potential activity against osteoporosis.


Subject(s)
Cyclooctanes/isolation & purification , Lignans/isolation & purification , Osteoblasts/drug effects , Polycyclic Compounds/isolation & purification , Schisandra/chemistry , Alkaline Phosphatase/metabolism , Animals , Cell Line , Cell Proliferation/drug effects , Chromatography, High Pressure Liquid , Cyclooctanes/pharmacology , Enzyme Activators/isolation & purification , Enzyme Activators/pharmacology , Lignans/pharmacology , Osteoblasts/enzymology , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Polycyclic Compounds/pharmacology , Rats
19.
Food Chem Toxicol ; 133: 110754, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31401185

ABSTRACT

The active components of Malus pumila flowers on antioxidant and tyrosinase activity were investigated with the method of spectrum-effect relationship and knock-out. Some compounds were identified by UPLC-MS/MS method. The chemical fingerprints were established by HPLC and the activity of antioxidant and tyrosinase were assayed in vitro. Chromatographic peaks P34, P35, P39, P44, P45 and P49 were identified as phloridzin, hyperoside, astragalin, afzelin, quercetin and kaempferol by UPLC-MS/MS method. Hyperoside and kaempferol were identified in M. pumila flowers for the first time. When the concentration was 1 g/mL of sample (equivalent to raw material), the scavenging capacity of P35 (hyperoside) on DPPH free radicals were consistent with the spectrum-effect relationship. The scavenging capacity of P34 (phloridzin) and P45 (quercetin) on ABTS free radicals were consistent with the spectrum-effect relationship. The activation effect of P45 (quercetin) on tyrosinase was consistent with the spectrum-effect relationship. The inhibitory effect of P34 (phloridzin), P35 (hyperoside) on tyrosinase were consistent with the spectrum-effect relationship.


Subject(s)
Enzyme Activators/chemistry , Enzyme Inhibitors/chemistry , Flavonoids/chemistry , Free Radical Scavengers/chemistry , Malus/chemistry , Monophenol Monooxygenase/antagonists & inhibitors , Chromatography, High Pressure Liquid/methods , Enzyme Activators/isolation & purification , Enzyme Inhibitors/isolation & purification , Flavonoids/isolation & purification , Flowers/chemistry , Free Radical Scavengers/isolation & purification , Tandem Mass Spectrometry/methods
20.
Theranostics ; 9(12): 3501-3514, 2019.
Article in English | MEDLINE | ID: mdl-31281493

ABSTRACT

Identification of proper agents to increase or activate UCP1+ cells in adipose tissues remains a potent therapeutic strategy to combat obesity. Screening systems for UCP1 activators have been previously established and allow for unbiased discovery of effective compound(s). Methods: A previously established Ucp1-2A-GFP reporter system was applied to a chemical library containing 33 phosphatase inhibitors. Compounds that can significantly activate UCP1 expression were further tested in vivo in mouse adipose tissues. Possible underlying mechanism was explored via RNA profiling, CMAP analysis, CRISPR targeting as well as inhibitor treatments. Results: We identified BML-260, a known potent inhibitor of the dual-specific phosphatase JSP-1, that significantly increased UCP1 expression in both brown and white adipocytes. BML-260 treatment also activated oxidative phosphorylation genes, increased mitochondrial activity as well as heat generation in vitro and in vivo. Mechanistic studies revealed that effect of BML-260 on adipocytes was partly through activated CREB, STAT3 and PPAR signaling pathways, and was unexpectedly JSP-1 independent. Conclusion: The rhodanine derivate BML-260 was previously identified to be a JSP-1 inhibitor, and thus was proposed to treat inflammatory and proliferative disorders associated with dysfunctional JNK signaling. This work provides evidences that BML-260 can also exert a JSP-1-independent effect in activating UCP1 and thermogenesis in adipocytes, and be potentially applied to treat obesity.


Subject(s)
Adipocytes/drug effects , Enzyme Activators/metabolism , Gene Expression Regulation/drug effects , Rhodanine/analogs & derivatives , Rhodanine/metabolism , Transcriptional Activation , Uncoupling Protein 1/metabolism , Adipocytes/enzymology , Animals , Cells, Cultured , Enzyme Activators/isolation & purification , Humans , Mice, Inbred C57BL , Mitochondria/drug effects , Rhodanine/isolation & purification , Signal Transduction/drug effects , Thermogenesis/drug effects
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