OBJECTIVETo evaluate the inhibitory effect of Nandeshi, an acrosin inhibitor, on human acrosin activity.

METHODSWe collected sperm samples from 10 healthy fertile men and cultured them with Nandeshi at 30 degrees C for 5 minutes at the concentrations of 0. 100, 0.120, 0.144, 0.173, 0.207, 0.249, 0.299, 0.358 and 0.430 mmol/L, with the controls treated with a well-known acrosin inhibitor N-alpha-p-tosyl-L-lysine chloromethylketone (TLCK) at 150.0, 189.8, 213.6, 240.3, 270.3, 304.1 and 342.1 mmol/L. Then we determined the residual activity of human acrosin by improved Kennedy assay.

RESULTSThe residual activity of acrosin was negatively correlated with the Nandeshi concentration, and Nandeshi exhibited an inhibition rate about 800 times that of TLCK.

CONCLUSIONNandeshi has a powerful inhibitory effect on human acrosin, and improved Kennedy assay is a simple, practical and highly sensitive technique for the detection of human acrosin activity.

Acrosin ; antagonists & inhibitors ; metabolism ; Contraceptive Agents, Female ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Humans ; Male ; Spermatozoa ; drug effects ; Tosyllysine Chloromethyl Ketone ; pharmacology

AIMTo establish a method for determinate of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis.

METHODSThe characteristic absorptive wavelength of hippuric acid determined by ultraviolet spectrophotometer is 228 nm. The method employed a melted capillary column, 50 mmol.L-1 phosphoric acid (pH 8.3) buffer solution, inject pressure 4.8 kPa, inject time 3 s, separation voltage 20 kV and detection wavelength 228 nm.

RESULTSThe reactant and resultant was separated completed within 7 min. IC50 of captopril was 0.019 mumol.L-1. Captopril is a competitive inhibitor, which was proved by enzyme reaction dynamics.

CONCLUSIONThe method was shown to be accurate, simple and rapid and can be used for determination of the inhibitory activity of captopril.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Captopril ; pharmacology ; Electrophoresis, Capillary ; methods ; Hippurates ; analysis ; Peptidyl-Dipeptidase A ; metabolism

AIMTo study the direct effect and kinetics of sodium quercetin-7,4'-disulphate (SQDS) on recombinant human protein kinase CK2 holoenzyme.

METHODSThe recombinant human CK2 holoenzyme activity was assayed by detecting incorporation of 32P of [gamma-32P] ATP into the substrate in various conditions.

RESULTSThe recombinant human CK2 was a second messenger (Ca2+, cAMP and cGMP) independent protein kinase. The characterization and function of the reconstituted holoenzyme were consistent with those of native CK2. SQDS was shown to strongly inhibit the holoenzyme activity of recombinant human protein kinase CK2 with an IC50 of 4.4 mumol.L-1, which was more effective than DRB and A3, known CK2 special inhibitors. Kinetic studies of SQDS on recombinant human CK2 showed: the inhibition was competitive with ATP and noncompetitive with casein.

CONCLUSIONSQDS is a potent inhibitor of protein kinase CK2. This study provide experimental basis for the development of more effective inhibitors of CK2 and for clinical application of SQDS in the future.

Casein Kinase II ; Dichlororibofuranosylbenzimidazole ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Humans ; Kinetics ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Quercetin ; analogs & derivatives ; pharmacology ; Recombinant Proteins ; antagonists & inhibitors ; metabolism

Animals ; Enzyme Inhibitors ; pharmacology ; Hepatitis ; immunology ; Immune Sera ; pharmacology ; Mice ; Sodium-Potassium-Exchanging ATPase ; antagonists & inhibitors ; metabolism

Flavanoids are important phytochemistry compositions in foods and traditional Chinese medicines (TCM) and are mainly oxidized by CYP1A family in vivo. Some methoxyflavones could also be metabolized through demethylation. Usually, flavanoids own one or more phenolic hydroxyl group in their molecular structures, which facilitate conjugation with glucuronic acid and sulphuric acid, forming metabolites with good water-solubility to excrete. Natural flavanoids mainly exist in glycoside, and after oral ,they would be easily metabolized to aglycone by hydratase in gut microflora and then absorbed into blood. Besides, many flavanoids have strong inhibitory actions on Cytochrome P450 enzymes, which are significant mechanisms in cancer precaution and tumor inhibition. In this paper, we reviewed lots of articles and summarized metabolism characteristics of flavanoids and metabolism interaction with Cytochrome P450 enzymes.
Animals ; Cytochrome P-450 Enzyme Inhibitors ; Cytochrome P-450 Enzyme System ; metabolism ; Drug Therapy ; Flavonoids ; metabolism ; pharmacology ; therapeutic use ; Humans

OBJECTIVETo search alpha-glucosidase inhibitors from Rubia cordifolia.

METHODThe alpha-glucosidase inhibitors were isolated by the column chromatographic techniques and the bioassay-guided method in vitro. A combination of MS and NMR spectroscopy was used to identify the chemical structures. The inhibitory kinetics of the inhibitors were also investigated.

RESULTThe chloroform extract showed high inhibitory activity, and three active compounds were isolated and identified as 1,3-dihydroxy-2-methylanthraquinone (1), 1-hydroxy-2-methylanthraquinone (2) and 1,2-dihydroxyanthraquinone (3). The IC5o values of compound 1-3 were all lower than that of acarbose. Compound 1 and 2 shown competitive type manner on alpha-glucosidase, whereas compound 3 shown noncompetitive type model.

CONCLUSIONCompounds 1-3 as strong inhibitors of alpha-glucosidase were reported for the first time.

Binding, Competitive ; Enzyme Inhibitors ; analysis ; metabolism ; pharmacology ; Glycoside Hydrolase Inhibitors ; Inhibitory Concentration 50 ; Kinetics ; Rubia ; chemistry ; alpha-Glucosidases ; metabolism

Animals ; Brain ; metabolism ; Brain Injuries ; metabolism ; Enzyme Inhibitors ; pharmacology ; Guanidines ; pharmacology ; Neuroprotective Agents ; pharmacology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; antagonists & inhibitors ; Rats

The work aims to study the drug metabolizing enzymes involved in the metabolism of butylphthalide and evaluate the induction and inhibition activities of butylphthalide on CYP450 isoenzymes by using in vitro (liver microsome incubation system of rats and human) and in vivo (CYP induced model of rats) method. Butylphthalide was incubated with selective inhibitors of CYP450, and its metabolic rate was determined to identify the metabolizing isoenzymes of NBP in rat (normal and induced rats) and human liver microsomes. The in vitro inhibition effect of butylphthalide on 6 main liver microsomal CYP450 isoenzymes was evaluated by using probe drugs; the induction and inhibition activities in vivo of butylphthalide on CYP450 isoenzymes were evaluated by NBP ig dosing (160 mg x kg(-1)) and iv dosing (20 mg x kg(-1)) in rats. After adding the specific inhibitors of CYP2C11, 2E1 and 3A 1/2 for rat, CYP2C19, 2E1 and 3A4/5 for human, the metabolism of NBP in rat and human liver microsomes were reduced 38.8%, 86.2%, 78.4% and 51.0%, 92.0%, 58.9% of control, respectively. The metabolic rates of NBP in CYP2E1 and 3A 1/2 induced rat liver microsomes were increased 25.5% and 68.9%. High concentration of NBP (≥ 200 μmol x L(-1), in vitro) could inhibit the activities of CYP1A2, 2C6, 2C11 and 2D2 in rats, and high concentration of NBP ( ≥ 15 μmol x L(-1), in vitro) could inhibit the activity of CYP2C19 in human. All the results indicated that NBP should be mainly metabolized by CYP2E1, 2C11 and 3A 1/2 in rats and CYP2E1, 2C19 and 3A4/5 in human. High concentration of NBP could inhibit human CYP2C19 in vitro. No significant induction/inhibition effects of NBP were observed on rat liver CYP450 isoforms after ig 160 mg x kg(-1) NBP or iv 20 mg x kg(-1) NBP.
Animals ; Benzofurans ; pharmacology ; Cytochrome P-450 Enzyme Inhibitors ; pharmacology ; Cytochrome P-450 Enzyme System ; metabolism ; Humans ; Isoenzymes ; metabolism ; Liver ; metabolism ; Microsomes, Liver ; metabolism ; Rats

Actins ; metabolism ; Animals ; Calcium ; metabolism ; Cells, Cultured ; Cytoskeleton ; metabolism ; Enzyme Inhibitors ; pharmacology ; Genistein ; pharmacology ; Hepatocytes ; drug effects ; metabolism ; Male ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Rats ; Rats, Wistar

Drugs are exogenous compounds for human bodies, and will be metabolized by many enzymes after administration. CYP450 enzyme, as a major metabolic enzyme, is an important phase I drug metabolizing enzyme. In human bodies, about 75% of drug metabolism is conducted by CYP450 enzymes, and CYP450 enzymes is the key factor for drug interactions between traditional Chinese medicine( TCM) -TCM, TCM-medicine and other drug combination. In order to make clear the interaction between metabolic enzymes and TCM metabolism, we generally chose the enzymatic activity as an evaluation index. That is to say, the enhancement or reduction of CYP450 enzyme activity was used to infer the inducing or inhibitory effect of active ingredients and extracts of traditional Chinese medicine on enzymes. At present, the common method for measuring metabolic enzyme activity is Cocktail probe drugs, and it is the key to select the suitable probe substrates. This is of great significance for study drug's absorption, distribution, metabolism and excretion (ADME) process in organisms. The study focuses on the interaction between TCMs, active ingredients, herbal extracts, cocktail probe substrates as well as CYP450 enzymes, in order to guide future studies.
Animals ; Cytochrome P-450 Enzyme Inhibitors ; metabolism ; pharmacology ; Cytochrome P-450 Enzyme System ; chemistry ; metabolism ; Drugs, Chinese Herbal ; metabolism ; pharmacology ; Enzyme Activation ; drug effects ; Enzyme Activators ; metabolism ; pharmacology ; Humans