A mathematical model, which represents the radio-chemical reactions in water, was developed to study the effect of the radio-chemical products on cell kiling. The five differential equations were solved using dose rate equation and cell survival as a function of dose was computed. The known chemical rate constants were taken from the literature and unknown constants were determined by curve fitting to an experimental data. Sensitivity studies were performed by varying the rate constants and showed that the yield of H-radical had little effect whereas the change in concentration of OH-radical and direct interaction resulted in significant change on cell survival. The sensitivity studies showed good agreement with the observed effects. In conclusion, we developed a mathematical model that could be used as a means for the estimation of radiation damage.
Cell Survival ; DNA/*chemistry ; Free Radicals/*chemistry ; Hydroxyl Radical/chemistry ; *Models, Molecular

OBJECTIVETo evaluate the antioxidant activities of different chemical constituents from Astragalus mongholicus Bunge and their protection against xanthine (XA)/xanthine oxidase (XO)-induced toxicity in PC12 cells.

METHODSThe compounds of Astragalus mongholicus Bunge were isolated by chromatography and the structures were elucidated on the basis of spectral data interpretation. Their antioxidant activities were detected by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities in a cell-free system. Meanwhile, the effects against XA/XO-induced toxicity were assessed using MTT assay in PC12 cells.

RESULTSTen principal constituents were isolated and identified as formononetin (I), ononin (II), calycosin (III), calycosin-7-O-beta-D-glucoside (IV), 9,10-dimethoxypterocarpan-3-O-beta-D-glucoside (V), adenosine (VI), pinitol (VII), daucosterol (VIII), beta-sitoster (IX) and saccharose (X) from Astragalus mongholicus Bunge. The compounds I, III, and IV scavenged DPPH free radicals in vitro. Formononetin and calycosin were found to inhibit XA/XO-induced cell injury significantly, with an estimated EC50 of 50 ng/mL.

CONCLUSIONCompound II, VI, and VII are first reported in this plant. Calycosin exhibits the most potent antioxidant activity both in the cell-free system and in the cell system.

Animals ; Astragalus Plant ; chemistry ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Free Radical Scavengers ; chemistry ; pharmacology ; Free Radicals ; metabolism ; Isoflavones ; chemistry ; pharmacology ; PC12 Cells ; Rats ; Xanthine ; toxicity ; Xanthine Oxidase ; toxicity

OBJECTIVETo develop a simple, reliable approach for evaluating the quality of Huangqin (Scutellaria baicalensis).

METHODTo determine the DPPH free radical scavenging activity and assay of four bioactive components: baicalin, baicalein, wogonin and wogonin-7-O-glucuronide by HPLC.

RESULTThe correlative relationship between DPPH free radical scavenging activity and baicalin content was obtained.

CONCLUSIONBioassay of DPPH free radical scavenging activity could be used as one of the methods for quality evaluation of Chinese drug Huangqin.

Biphenyl Compounds ; Flavanones ; Flavonoids ; chemistry ; isolation & purification ; pharmacology ; Free Radical Scavengers ; pharmacology ; Free Radicals ; Molecular Structure ; Picrates ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry ; Quality Control ; Scutellaria baicalensis ; chemistry

AIMTo investigate antimalarial mechanism of Qinghaosu ( QHS) and its derivatives.

METHODSThe electronic structure of QHS and its derivatives were completely optimized and calculated at B3LYP/6-31G * level, while the route was at HF/STO-3G level.

RESULTSThe peroxide bridge is the active center of QHS and induced by ferrous iron to produce cyclic product.

CONCLUSIONHeme can link with QHS derivatives.

Antimalarials ; chemistry ; isolation & purification ; Artemisia ; chemistry ; Artemisinins ; chemistry ; isolation & purification ; Electron Transport ; Free Radicals ; chemistry ; Heme ; chemistry ; Models, Chemical ; Peroxides ; chemistry ; Plants, Medicinal ; chemistry ; Quantum Theory

Animals ; Free Radicals ; metabolism ; Hepatocytes ; metabolism ; Male ; Obesity ; metabolism ; Polyphenols ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Tea ; chemistry

AIMTo determine whether repetitive exposure to high sustained +Gz acceleration induces persisting changes in the myocardial free radical metabolism and observe the protective effects of low-G training and antioxidant tea polyphenols (TP).

METHODSThirty-two male Wistar rats were randomly divided into four groups (n=8 each): group A, restrained, was only submitted to +1 Gz for 5 min. Group B, centrifuged, was exposed to five plateaus of 30 s at +10 Gz for intermittent times, three times a week, for three weeks. Group C, low-G trained, was exposed to +2 Gz for 5 min about 1 h prior to +10 Gz stress, and group D was orally given TP at dose of 200 mg/kg about 1 h prior to +10 Gz stress. On the next day morning after last centrifuge run, the rats were decapitated and the hearts were quickly removed. Malondialdehyde (MDA) concentration and superoxide dismutase (SOD) activity were measured. Additionally, CuZn-SOD and inducible NO synthase (iNOS) enzymatic contents were examined by immunohistochemical staining and their mRNA were analyzed by semi-quantitative reverse transcription polymerase chain reaction(RT-PCR).

RESULTSCompared with group A, MDA concentration and iNOS enzymatic content in myocardial mitochondria were increased significantly (P < 0.05) in group B. Compared with group B, mitochondrial SOD activity was significantly increased in group C (P < 0.05). iNOS enzymatic content was significantly decreased in group C and D. There were no significant differences of CuZn-SOD content, CuZn-SOD and iNOS mRNA levels among the four groups.

CONCLUSIONRepeated high +Gz exposure can induce myocardial free radical metabolic disorder and mainly result in mitochondrial peroxidative injury. But low-G training and natural antioxidant TP have protective effects, and the former is better.

Acceleration ; Adaptation, Physiological ; physiology ; Animals ; Free Radicals ; metabolism ; Male ; Myocardium ; metabolism ; Polyphenols ; pharmacology ; Rats ; Rats, Wistar ; Tea ; chemistry

OBJECTIVE: To observe the changes of free radicals in the cochlea of guinea pigs after noise exposure directly using electron spin resonance (ESR) technology. METHOD: Forty-two guinea pigs as experimental group were given (125 +/- 1) dB SPL noise exposure for 2 hours, and then investigated auditory function immediately, at 2, 6, 12, 24, 48 and 72 hour. After ABR examinations, 21 animals decollated and extracted cochlea immediately and then placed the cochleas to liquid nitrogen for deep freezing and measuring free radicals using ESR technology. Another 21 animals observed hair cells morphology by AgNO3 staining. Meantime, 6 animals without noise exposure were served as negative control group. RESULT: A few free radicals were detected in the cochlea at control group and the relative value of free radicals were (21.68 +/- 1.27) dB SPL. After noise exposure, the relative value of free radicals increased obviously and achieved to the max of (147.01 +/- 4.95) dB SPL at 2 h and gradually decreased near the normal level. CONCLUSION Free radicals in the cochlea increase evidently and have a concentration-time rule after acute acoustic trauma. The ESR method can be used to examine the content of free radicals in cochlea for its direct, objective and sensitive characters.
Animals ; Cochlea ; chemistry ; Electron Spin Resonance Spectroscopy ; Free Radicals ; analysis ; Guinea Pigs ; Hearing Loss, Noise-Induced ; physiopathology

The paper is aimed to search more natural plant antioxidants and further research and develop new medicinal plant resources in Guizhou. The Guizhou special miao medicine "bod zangd dak" was extracted with 60% ethanol. The antioxidant activity of the different polarity components separated from the extract was tested by DPPH method with ascorbic acid as positive control. The results showed that the IC50 of the different polarity components was as following: ascorbic acid (0.033 4 g x L(-1)) < ethyl acetate components (0.052 3 g x L(-1)) < total tannins components (0.054 9 g x L(-1)) < 60% ethanol extraction components (0.076 7 g x L(-1)) < butanol extraction components (0.110 g x L(-1)) < water-soluble polysaccharides components (0.168 g x L(-1)) < water extraction components (0.174 g x L(-1)) < water components after extraction (0.226 g x L(-1)) < total polysaccharides components (0.645 g x L(-1)). It is concluded that the different polarity components have different free radical scavenging activity and that provides a scientific basis for further search of the active ingredients and the activive mechanism.
Antioxidants ; chemistry ; isolation & purification ; Biphenyl Compounds ; chemistry ; China ; ethnology ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Free Radicals ; chemistry ; Medicine, Chinese Traditional ; Picrates ; chemistry ; Plant Roots ; chemistry ; Plant Stems ; chemistry ; Smilax ; chemistry

The present study was designed to establish a multi-wavelength quantitative fingerprinting method for San-Huang Tablets (SHT), a widely used and commercially available herbal preparation, where high performance liquid chromatography (HPLC) with a diode array detector (DAD) was employed to obtain the fingerprint profiles. A simple linear quantitative fingerprint method (SLQFM) coupled with multi-ingredient simultaneous determination was developed to evaluate the quality consistency of the tested samples qualitatively and quantitatively. Additionally, the component-activity relationship between chromatographic fingerprints and total radical-scavenging capacity in vitro (as assessed using the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay) was investigated by partial least squares regression (PLSR) analysis to predict the antioxidant capacity of new samples from the chromatographic fingerprints and identify the main active constituents that can be used as the target markers for the quality control of SHT. In conclusion, the strategy developed in the present study was effective and reliable, which can be employed for holistic evaluation and accurate discrimination for the quality consistency of SHT preparations and other traditional Chinese medicine (TCM) and herbal preparations as well.
Antioxidants ; chemistry ; Biphenyl Compounds ; chemistry ; Chemistry Techniques, Analytical ; methods ; Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; chemistry ; Free Radicals ; chemistry ; Molecular Structure ; Picrates ; chemistry ; Quality Control ; Tablets ; chemistry

OBJECTIVETo observe the protective effects of catechin morphon (GCG and EGCG) on hypoxia-reoxygenation induced injury in myocardial cells and to explore the mechanisms.

METHODIn cultured neonatal rat cardiomyocytes, we investigated the preconditioning protection by GCG and EGCG on the spontaneous beating, the survival rate, the release of LDH, MDA, SOD, GSH-Px and the ATP enzyme activity of cardiomyocyte cellular membrane in cultured rat cardiomyocytes treated during the reoxygenation 1h following hypoxia 3 h. The blocking agent of protien kinase C staurosporine (10 nmol x L(-1)) or the deactivator of Gi/o protein pertussis toxin (PTX, 200 microg x mL(-1)) were added before the catechin treatment.

RESULTSPreconditioning by GCG and EGCG increased the spontaneous beating and the survival rate, and decreased the release of LDH and MDA with the rise of SOD and ATP enzyme activity. Inhibition of PKC by staurosporine and Gi/o protein by PTX abolished the protection by catechin with the reduction of the beating, survival rate and activity of SOD, and the increase of the release of LDH and MDA. The results indicated that the activation of signal transduction pathway from PKC and Gi/o protein seemed to be involved in the cardioprotection of preconditioning by GCG and EGCG.

CONCLUSIONThe protection by GCG and EGCG on hypoxia-reoxygenation injury in cultured neonatal rat cardiomyocytes is found, which is related with scavenging of free radicals, and PKC Gi/o signal transduction pathway.

Animals ; Cardiotonic Agents ; chemistry ; pharmacology ; Catechin ; analogs & derivatives ; chemistry ; pharmacology ; Female ; Free Radicals ; metabolism ; Hypoxia ; complications ; Myocytes, Cardiac ; drug effects ; metabolism ; pathology ; Oxygen ; metabolism ; Protein Kinase C ; metabolism ; Proteins ; metabolism ; Rats ; Signal Transduction ; drug effects ; Survival Rate