Electrochemistry detection of estrogenic effect: Regulation of de novo purine synthesis and catabolism by gibberellin and fulvestrant.

The estrogenic effect of plant growth regulators has been received little attention, which leads to the lack of relevant toxicity data. In this study, the estrogenic effect induced by gibberellin with ERα-dependent manner was found by E-screen and western blot methods, and the electrochemical signals of MCF-7 cells regulated by gibberellin and fulvestrant were investigated. The results showed that the electrochemical signals of MCF-7 cells were increased by gibberellin, while reduced by fulvestrant significantly, and displayed an extremely sensitive response to the effects of estrogenic effect induced by ERα agonist and antagonist. Western blot results showed that the expressions of phosphoribosyl pyrophosphate amidotransferase and hypoxanthine nucleotide dehydrogenase in de novo purine synthesis and adenine deaminase in catabolism were more effective regulated by gibberellin and fulvestrant, resulting in significant changes of the levels of guanine, hypoxanthine and xanthine in cells, and then electrochemical signals. The results provide a theoretical basis for the establishment of new electrochemical detection method of the estrogenic effect of plant regulators.

Electrochemical detection mechanism of estrogen effect induced by cadmium: The regulation of purine metabolism by the estrogen effect of cadmium.

Some heavy metals in the environment may have estrogen-like activity, which probably lead to major diseases such as breast cancer. It is of great importance to establish new methods to evaluate the estrogen effect of heavy metals from multiple angles due to the complex mechanism of estrogen effect. In this paper, using MCF-7 cells as model, the electrochemical detection mechanism of the estrogen effect of heavy metal cadmium (Cd) was studied. The two electrochemical signals of MCF-7 cells derived from uric acid (0.30 V) and the mixture of guanine and xanthine (0.68 V) increased in a time and dose-dependent manner when MCF-7 cells induced by Cd, reaching the maximum at 96 h and 10-9 mol L-1. Further studies found that three purine metabolism pathways about de novo synthesis, salvage synthesis and decomposition metabolism were activated by the estrogen effect of Cd. The expression of PRPP amidotransferase in purine de novo synthesis pathway and HPRT in purine salvage synthesis pathway up-regulated, especially HPRT, which promoted cell proliferation together. Nevertheless, the expression of GDA and ADA, the key enzymes in purine decomposition metabolism pathway, up-regulated in a time and dose-dependent manner, which had same tendency with that of ERα, thereby increased the content of intracellular hypoxanthine, guanine, xanthine and uric acid, and enhanced electrochemical signals.

The response of electrochemical method to estrogen effect and the tolerance to culture factors: Comparison with MTT and cell counting methods.

Estrogen substances in the environment are increasing dramatically, which interfere with the normal hormone level of human body, lead to the disorder of endocrine system and even cancer. It is difficult to screen a large number of environmental estrogen substances by existing estrogen effect detection methods, and the results are often affected by many factors, thus the development of new method has become an urgent task. Electrochemical method is promising to reflect cell proliferation by tracking intracellular purine bases directly. In this study, the estrogen level in MCF-7 cells on multiwall carbon nanotubes modified glassy carbon electrode (MWCNTs/GCE) could be tracked simply and conveniently, and the estrogen effect of estradiol could be reflected by electrochemistry in time and dose-dependent manners. Electrochemical method displayed the best tolerance to culture factors, such as different cell densities, serum types, culture medium types and serum estrogen-free methods, which responsed to estrogen effect higher than MTT (about 40%) and cell counting methods (about 50%). Further Western blotting analysis showed that the estrogen effect of estradiol promoted purine catabolism and up-regulated guanine deaminase (GDA) and adenine deaminase (ADA) expression, the key enzymes of purine catabolism pathway, in a dose-dependent manner. The up-regulation of GDA and ADA led to the increase of intracellular guanine and xanthine, which enhanced the electrochemical signal derived from guanine and xanthine.

Protective effect of Monarda didymaL. essential oil and its main component thymol on learning and memory impairment in aging mice.

The aging process of human beings is accompanied by the decline of learning and memory ability and progressive decline of brain function, which induces Alzheimer's Disease (AD) in serious cases and seriously affects the quality of patient's life. In recent years, more and more studies have found that natural plant antioxidants can help to improve the learning and memory impairment, reduce oxidative stress injury and aging lesions in tissues. This study aimed to investigate the effect of Monarda didymaL. essential oil and its main component thymol on learning and memory impairment in D-galactose-induced aging mice and its molecular mechanism. The composition of Monarda didymaL. essential oil was analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). A mouse aging model was established by the subcutaneous injection of D-galactose in mice. The behavior changes of the mice were observed by feeding the model mice with essential oil, thymol and donepezil, and the histopathological changes of the hippocampus were observed by HE staining. And the changes of acetylcholinesterase (AchE), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, and the content of malondialdehyde (MDA) in hippocampal tissues were detected by corresponding kits. The expression of mitogen activated protein kinase (MAPK) and nuclear factor E2 related factor 2 (Nrf2) pathways related proteins were detected by western blot. Animal experimental results showed that compared with model group, the above indexes in Monarda didymaL. essential oil and thymol groups improved significantly in a dose-dependent manner. Monarda didymaL. essential oil and its main active component thymol can improve the learning and memory impairment of aging mice to some extent, and Nrf2 and MAPK pathways may be involved in its action process.

The improvement of Coreopsis tinctoria essential oil on learning and memory impairment of d-galactose-induced mice through Nrf2/NF-κB pathway.

Essential oil of Coreopsis tinctoria (EOC) is a essential substance extracted from Coreopsis tinctoria with the excellent anti-oxidant effect. However, it is still unclear whether EOC can improve learning and memory impairment and its mechanism. The purpose of this study was to investigate the effect of EOC on learning and memory impairment induced by D-galactose (D-gal) in mice and reveal its mechanism. The composition of EOC was analyzed by GC-MS, and the results showed that the highest content was D-limonene. The follow-up experiments were conducted by comparing EOC with D-limonene. The aging model was established by subcutaneous injection of D-gal, and donepezil, D-limonene and EOC were given by intragastric administration. It was found that EOC and D-limonene significantly improved learning and memory impairment induced by D-gal through the Morris water maze and step-through tests. Pathological and biochemical analysis showed that the hippocampal morphologic of mice was damage and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) induced by D-gal were decreased, while the content of malondialdehyde (MDA) was increased, while EOC and D-limonene could reverse the morphological changes and reduce oxidative damage. In addition, EOC and D-limonene significantly increased body weight and organ coefficients, including liver, spleen and kidney. Moreover, EOC and D-limonene improved the expression of nuclear factor E2 related factor 2 (Nrf2) pathway and inhibited nuclear transcription factors-κB (NF-κB) pathway. In summary, the results showed that EOC and D-limonene could improve learning and memory impairment induced by D-gal through Nrf2/ NF-κB pathway. It was clear that as a mixture, EOC was better than D-limonene on improving learning and memory impairment.