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21.
22.
Kezhen Yang Taotao Lv Jiaojuan Wu Xudong Zhang Yanjun Xue Pengcheng Yu Qingguo Liu 《Biomedical chromatography : BMC》2022,36(5):e5338
Hypertension affects multiple organs in the body during the development of the disease. The antihypertensive effect of acupuncture has been confirmed. How the protective effect of electroacupuncture on the renal cortex of the spontaneously hypertensive rat (SHR) is achieved has not yet been determined. The purpose of this study was to understand the impact of electroacupuncture on the blood pressure of SHRs and the impact on metabolites in the renal cortex, looking for potential differential metabolites and then proceeding to the next step of exploratory research. The experimental animals were divided into four groups: control group, model group, electroacupuncture group and losartan potassium group. Electroacupuncture on bilateral Taichong (LR3) and Zusanli (ST36) lasted for 3 weeks, and the renal cortex was collected for metabonomics research. UHPLC–MS was used to analyze the changes in the metabolic spectrum of renal cortex tissue. The results showed that electroacupuncture can significantly reduce the blood pressure of SHRs. A total of 12 metabolites changed significantly in the comparison between each group and the model group.The possible mechanism is that the primary bile acid biosynthesis, bile secretion, tryptophan metabolism and other metabolic pathways affect the renal cortex. 相似文献
23.
《Journal of Macromolecular Science: Physics》2013,52(4-6):657-669
The possibility of phase transformation toughening is demonstrated by the example of the β-modification isotactic polypropylene (β-iPP), which undergoes the β–α transformation (i.e., from hexagonal to monoclinic) during mechanical loading. The β–α recrystallization was examined on essential work of fracture (EWF) specimens with two processing conditions. Differential scanning calorimetry and wide-angle x-ray diffraction demonstrate the occurrence of this β–α transformation. Some structural changes can be identified in EWF specimens by using nano-indentation machine. Toughness of the α- and β-iPP is studied and compared with the EWF concept by using static-loaded deeply double-edge-notched tensile specimens. The main effect of the β–α transformation is a large increase in the specific plastic work consumed in the necked zone. 相似文献
24.
Fayçal Boukhari Nacéra Tigrine‐Kordjani Brahim Youcef Meklati 《Helvetica chimica acta》2013,96(6):1168-1175
Walnut (Juglans regia L.) leaves are used traditionally as an herbal tea indicated for non‐insulin‐dependent diabetics. In recent years, the type‐II diabetes is occurring worldwide with increasing frequency. Thus, there is an urgent need to explore the new beneficial biomolecules on the human health. Our objective was to investigate, for the first time, the volatiles profile of Juglans regia L. leaves from Algiers region. The extraction of essential oil of fresh plant material was performed by microwave‐assisted hydrodistillation (MAHD), for the first time, a relatively recent method, then by the conventional hydrodistillation technique (HD) for comparison. The collected extracts were analyzed by GC‐FID and GC/MS using two capillary columns with different polarity. Extraction time of 1 h by MAHD provided higher yields (0.050±0.001% (w/w)) than by HD (0.030±0.006% (w/w)) after 3 h. A total of 38 compounds were identified using both techniques. Essential oils had similar qualitative but different quantitative composition in terms of chemical compounds. The MAHD method improved yield while reducing the extraction time. The sesquiterpenes were the dominant family in both MAHD and HD essential oils with β‐caryophyllene being the major constituent. Monoterpenes, including hydrocarbon and oxygenated, prevail in HD volatile fraction with β‐pinene and eucalyptol, respectively, as major components. 相似文献
25.
《Comptes Rendus Chimie》2014,17(3):181-186
The development of alternative techniques to classic hydrodistillation (HD) has been prompted because of the drawbacks of the more traditional technique. These drawbacks include: partial thermal degradation, high energy consumption and the fact that it is a time-consuming process. In situ microwave-generated hydrodistillation (MGH) and microwave hydrodiffusion and gravity (MHG) are suitable methods which may improve the preparation of essential oils. In this work, we report a comparison study of HD, MGH and MHG used in the extraction of four plant species cultivated in Piedmont (Italy): lavender, oregano, basil and sage. Both microwave-assisted procedures gave excellent results; in particular the essential oils obtained under MHG were very similar to those obtained with HD. In MGH, the polarity and the physico-chemical properties of the extracted compounds caused bigger differences in essential oil composition. 相似文献
26.
《Arabian Journal of Chemistry》2014,7(4):480-485
A laboratory study was conducted to determine the effect of three extraction parameters (soaking time, extraction time and the ratio of solid to liquid) on the yield and chemical composition of Foeniculum vulgare seeds essential oils. The bioactivity of the essential oil extracted for the optimum extraction parameters was assessed against Culex pipiens mosquito. F. vulgare essential oil composition included large amounts of phenylpropanoids. Through an extraction time of 6 h and a ratio solid to liquid of 300 g/L we can get over than 72% of trans-anethol without soaking the seeds. With bioassays, essential oils showed different activities on C. pipiens larvae and pupae. Results show that a concentration at 40 mg/L was sufficient to register 50% mortality for the second instars larvae and this, after 2 h exposition time. Moreover, concentration at 60 mg/L ensured after 4 h exposition time 90% mortality for the fourth instars larvae. However, pupae needed 24 h exposition time to show promising mortalities when using concentration at 200 mg/L. Even if laboratory bioassays are only the first step towards the use of essential oils in practical applications, these substances represent a potential alternative to chemical insecticides in some markets. 相似文献
27.
《Arabian Journal of Chemistry》2022,15(1):103482
The red flour beetle, Tribolium castaneum, and the mold Aspergillus flavus are well known threats of stored grain commodities, causing nutritional loss and poisoning of stored products, respectively. T. castaneum has developed resistance against most insecticides, leading to the use of extensive amounts of synthetic insecticides to protect stored grains. Synthetic pesticides not only toxify the environment but also cause serious health issues in humans using pesticide treated grains. This study aimed to identify plant-based natural pesticides to control T. castaneum and A. flavus. Essential oils were extracted from fresh aerial parts of Chenopodium ambrosioides, Conyza sumatrensis, Erigeron canadensis, and Tagetes minuta through steam distillation and investigated for insecticidal and anti-fungal activities against adult T. castaneum and A. flavus, respectively. GC–MS analysis of C. sumatrensis revealed the presence of 37.7% cis-lachnophyllum ester, 13.4% germacrene D, and 21.6% limonene, whereas in E. canadensis the major compounds were limonene, germacrene D, and cis-lachnophyllum ester (43.4%, 12.9% and 5.9%, respectively). In bioassays with treated grain, C. sumatrensis and E. canadensis essential oils exhibited excellent toxicity against adult T. castaneum with LD50 of 3.7 and 5.6 mg per 10 g grains whereas in a fumigation bioassay they showed LD50 of 6.6 and 10.6 mg/L, respectively. The essential oils extracted from C. ambrosioides and E. canadensis exhibited good anti-fungal activity against A. flavus. Our findings suggest that essential oils of C. sumatrensis and E. canadensis can play an important role in protecting stored grains from T. castaneum and A. flavus contamination. 相似文献
28.
《Arabian Journal of Chemistry》2022,15(9):104076
The chemical composition and potential bioactivities of essential oil from Quercus mongolica bark (EOQMB) were researched for value-added utilization processing by-product. The results of gas chromatography-mass spectrometry (GC–MS) analysis showed that 30 components accounting for 98.42% were identified in EOQMB, with pentadecanoic acid the most abundant compound accounting for 34.90%, which was further confirmed by the Fourier transform infrared observation. EOQMB exerts antioxidant activities, and the IC50 values for scavenging DPPH radical, ABTS radical, and hydroxyl radical were 8.48, 0.77, and 3.54 mg/mL, respectively. The effects of EOQMB on prolonging activated partial thromboplastin time and thrombin time and on decreasing fibrinogen are similar to those of heparin, and the promising anticoagulant activities of EOQMB could be largely contributed by pentadecanoic acid. Herein, the present study uncovered that the waste Q. mongolica bark can serve as a new potential material in pharmaceutical products. 相似文献
29.
《Arabian Journal of Chemistry》2022,15(11):104225
Cinnamomum camphora leaf essential oil (CEO) was extracted using enzymatic-ultrasound pretreatment followed by microwave assisted extraction (EUP-MAE) method and simultaneously studied as a mycelial growth inhibitor against five important pathogens which cause potato dry rot. The optimum EUP-MAE conditions with a real CEO yield of 19.23 ± 0.12 mg/g were obtained through Plackett–Burman design and Box–Behnken design as follows: 3 % of enzyme dosage, 2 h of pretreatment time, 5 of pH, 210 W of ultrasound power, 50 °C pretreatment temperature, 16 mL/g of water to solid ratio, 30 min of microwave time and 500 W of microwave power. Compared to the reference methods, EUP-MAE possessed a highest CEO yield than these of ultrasound-microwave assisted extraction (U-MAE) and traditional hydrodistillation (HD). Gas chromatography-mass spectrometry (GC–MS) analysis demonstrated that eucalyptol, camphor, and α-terpineol were the three main constituents of CEO. Results from in vitro antifungal activity assay revealed that the mycelial growths of all the five tested Fusarium solani, Fusarium culmorum, Fusarium trichothecioides, Fusarium sporotrioides, and Fusarium avenaceum were apparently affected by CEO. These findings not only provide a potential paradigm for the separation of plant essential oil, but also guarantee a promising utilization of the CEO for potato protection to control the Fusarium spp. 相似文献
30.
Bernardita Cayupe Carlos Morgan Gustavo Puentes Luis Valladares Hctor Burgos Amparo Castillo Alejandro Hernndez Luis Constandil Miguel Ríos Patricio Sez-Briones Rafael Barra 《Molecules (Basel, Switzerland)》2021,26(12)
Prenatally malnourished rats develop hypertension in adulthood, in part through increased α1-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α1-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α1-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α1-adrenoceptor density in whole hypothalamus and the expression levels of α1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α1-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular–coerulear excitatory interactions in prenatally undernourished young-adult rats. 相似文献