Effects of Various Temperatures and pH Values on the Extraction Yield of Phenolics from Litchi Fruit Pericarp Tissue and the Antioxidant Activity of the Extracted Anthocyanins

Litchi fruit pericarp tissue is considered an important source of dietary phenolics. This study consisted of two experiments. The first was conducted to examine the effects of various extraction temperatures (30, 40, 50, 60, 70 and 80 °C) and pH values (2, 3, 4, 5 and 6) on the extraction yield of phenolics from litchi fruit pericarp. Extraction was most efficient at pH 4.0, while an extraction temperature of 60 °C was the best in terms of the combined extraction yield of phenolics and the stability of the extracted litchi anthocyanins. The second experiment was carried out to further evaluate the effects of various temperatures (25, 35, 45, 55 and 65 °C) and pH values (1, 3, 5 and 7) on the total antioxidant ability and scavenging activities of DPPH radicals, hydroxyl radical and superoxide anion of the extracted anthocyanins. The results indicated that use of 45–60 °C or pH 3–4 exhibited a relatively high antioxidant activity. The study will help improve extraction yield of phenolics from litchi fruit pericarp and promote better utilization of the extracted litchi anthocyanins as antioxidants

Atomic insights into the thermal runaway process of hydrogen peroxide and 1,3,5-trimethybenzene mixture: Combining ReaxFF MD and DFT methods

The explosive hazard of hydrogen peroxide (H2O2) and organics mixtures had drawn much attention, but the mechanism is still unclear. In this work, the atomic insights into the thermal runaway process of H2O2 and 1,3,5-trimethylbenzene (TMB) mixture was conducted using a new approach of combining reactive molecular dynamics (ReaxFF MD) and density function theory (DFT). The detailed reaction pathways were obtained through ReaxFF MD. The kinetic and thermal properties of main reaction steps were examined by DFT. This work divided the thermal runaway process into two stages. In stage I, H2O2 molecules were decomposed first to generate center dot OOH and center dot OH free radicals. The center dot OH radicals induced the initial oxidation of TMB molecular through H-abstraction and center dot OH-combine reaction steps with the highest thermal energy of 921.76 kJ/mol released, evoking the opening and cracking of benzene ring. In stage II, once the generated small molecules were further oxidized, the reactions showed a runaway for the massive thermal energy released, which explains the mechanism of larger potential risk of H2O2-organics mixture. Notably, center dot OH is the most crucial free radical carrier for the whole reaction process, the explosion hazard will be inhibited or weakened if the concentration of center dot OH radical is controlled. It is expected that this work will help researchers and industrial practitioners to better understand the intrinsic thermal hazard of H2O2-organics, and provide valuable guidance for the further development of efficient explosion suppression methods. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.</p

Adsorption and Desorption of Phosphate on Calcite and Aragonite in Seawater

The adsorption and desorption of phosphate on calcite and aragonite were investigated as a function of temperature (5–45 °C)and salinity (0–40) in seawater pre-equilibrated with CaCO3. An increase in temperature increased the equilibrium adsorption; whereas an increase in salinity decreased the adsorption. Adsorption measurements made in NaCl were lower than the results in seawater. The higher values in seawater were due to the presence of Mg2+ and Ca2+ ions. The increase was 5 times greater for Ca2+ than Mg2+. The effects ofCa2+ and Mg2+ are diminished with the addition of SO4 2- apparently due to the formation of MgSO4 and CaSO4 complexes in solution and/or SO4 2- adsorption on the surface of CaCO3. The adsorbed Ca2+ and Mg2+ on CaCO3 (at carbonate sites) may act as bridges to PO4 3- ions. The bridging effect of Ca2+is greater than Mg2+ apparently due to the stronger interactions of Ca2+ with PO4 3-.The apparent effect of salinity on the adsorption of PO4 was largely due to changes in the concentration of HCO3 - in the solutions. An increase in the concentration of HCO3 - caused the adsorption of phosphate to decrease, especially at low salinities. The adsorption at the same level of HCO3 - (2 mM) was nearly independent of salinity. All of the adsorption measurements were modeled empirically using a Langmuir-type adsorption isotherm[ [PO4]ad = KmCm[PO4]T/(1 +Km [PO4]T) , ]where [PO4]ad and [PO4]T are the adsorbed and total dissolved phosphate concentrations, respectively. The values of Cm (the maximum monolayer adsorption capacity, (mol/g) and Km (the adsorption equilibrium constant, g/(mol) over the entire temperature (t, °C) and salinity (S) range were fitted to[ Cm = 17.067 + 0.1707t - 0.4693S + 0.0082S2 (σ = 0.7) ][ ln Km = - 2.412 + 0.0165t - 0.0004St - 0.0008S2 (σ = 0.1) ]These empirical equations reproduce all of our measurements of[PO4]ad up to 14 μmol/g and within ±0.7 μmol/g.The kinetic data showed that the phosphate uptake on carbonate minerals appears to be a multi-step process. Both the adsorption and desorption were quite fast in the first stage (less than 30 min) followed by a much slower process (lasting more than 1 week). Our results indicate that within 24 hours aragonite has a higher sorption capacity than calcite. The differences between calcite and aragonite become smaller with time. Consequently, the mineral composition of the sediments may affect the short-term phosphate adsorption and desorption on calcium carbonate. Up to 80 % of the adsorbed phosphate is released from calcium carbonate over one day. The amount of PO4 left on the CaCO3 is close to the equilibrium adsorption. The release of PO4 from calcite is faster than from aragonite. Measurements with Florida Bay sediments produced results between those for calcite and aragonite. Our results indicate that the calcium carbonate can be both a sink and source of phosphate in natural waters

Topological Indices of Certain Transformed Chemical Structures

Topological indices like generalized Randić index, augmented Zagreb index, geometric arithmetic index, harmonic index, product connectivity index, general sum-connectivity index, and atom-bond connectivity index are employed to calculate the bioactivity of chemicals. In this paper, we define these indices for the line graph of k-subdivided linear [n] Tetracene, fullerene networks, tetracenic nanotori, and carbon nanotube networks

14–3-3ζ inhibits heme oxygenase-1 (HO-1) degradation and promotes hepatocellular carcinoma proliferation: involvement of STAT3 signaling

Abstract Background Heme oxygenase 1 (HO-1) has been reported to be very important in the pathogenesis or progression of multiple types of cancer. Identification of novel hmox1 binding proteins may reveal undefined oncogenes, tumor suppressors, signaling pathways, and possible treatment targets. Methods Immunoprecipitation and mass spectrometry analyses were used to identify novel regulators of HO-1. The association of the 14–3-3ζ protein with HO-1 and modulation of the stability of HO-1 were investigated by co-immunoprecipitation, immunofluorescence, western blotting, and quantitative RT-PCR. Degradation and in vivo ubiquitination assays were utilized to examine whether 14–3-3ζ stabilizes the HO-1 protein by inhibiting its ubiquitination. The effect of 14–3-3ζ on proliferation was investigated by function assays conducted in vitro using the CCK-8 and colony formation assays and in vivo in a xenograft mouse model. The biological functions of the 14–3-3ζ/HO-1 axis were demonstrated by western blotting and rescue experiments. Using gain-of-function and loss-of-function strategies, we further clarified the impact of 14–3-3ζ/HO-1 complex on the signal transducers and activators of transcription 3 (STAT3) signaling pathway in cancer cells. Results We identified 14–3-3ζ as a novel HO-1 binding protein. The binding inhibited the ubiquitination and proteasome-mediated degradation of HO-1, thus facilitating its stabilization. Enforced expression of 14–3-3ζ significantly promoted cell proliferation in vitro, as well as tumorigenesis in vivo, while 14–3-3ζ knockdown had opposite effects. The data indicated that 14–3-3ζ can stabilize HO-1 expression and thus influence cancer cell proliferation. We further demonstrated the involvement of the STAT3 pathway in 14–3-3ζ/HO-1 regulation of hepatocellular carcinoma cell proliferation. Conclusions Collectively, these data show that 14–3-3ζ regulates the stability of HO-1 to promote cancer cell proliferation and STAT3 signaling activation. The data establish the 14–3-3ζ-HO-1-STAT3 axis as an important regulatory mechanism of cancer cell growth and implicate HO-1 and 14–3-3ζ as potential therapeutic targets in hepatocellular carcinoma

Discovery of Novel Pazopanib-Based HDAC and VEGFR Dual Inhibitors Targeting Cancer Epigenetics and Angiogenesis Simultaneously

Herein a novel series of pazopanib hybrids as polypharmacological antitumor agents were developed based on the crosstalk between histone deacetylases (HDACs) and vascular endothelial growth factor (VEGF) pathway. Among them, one <i>ortho</i>-aminoanilide <b>6d</b> and one hydroxamic acid <b>13f</b> exhibited considerable total HDACs and VEGFR-2 inhibitory activities. The HDAC inhibitory activities endowed <b>6d</b> and <b>13f</b> with potent antiproliferative activities, which was not observed in the approved VEGFR inhibitor pazopanib. Compounds <b>6d</b> and <b>13f</b> possessed comparable HDAC isoform selectivity profiles to the clinical class I HDAC inhibitor MS-275 and the approved pan-HDAC inhibitor SAHA, respectively. <b>6d</b> and <b>13f</b> also exhibited uncompromised multiple tyrosine kinases inhibitory activities relative to pazopanib. The intracellular dual inhibition to HDAC and VEGFR of <b>6d</b> and <b>13f</b> was validated by Western blot analysis. In both HUVECs tube formation assay and rat thoracic aorta rings assay, <b>6d</b> and <b>13f</b> showed comparable antiangiogenic potencies to pazopanib. What’s more, <b>6d</b> possessed desirable pharmacokinetic profiles with the oral bioavailability of 72% in SD rats and considerable in vivo antitumor efficacy in a human colorectal adenocarcinoma (HT-29) xenograft model

Optimization of N-Substituted Oseltamivir Derivatives as Potent Inhibitors of Group-1 and -2 Influenza A Neuraminidases, Including a Drug-Resistant Variant

none25simixedZhang, Jian; Poongavanam, Vasanthanathan; Kang, Dongwei; Bertagnin, Chiara; Lu, Huamei; Kong, Xiujie; Ju, Han; Lu, Xueyi; Gao, Ping; Tian, Ye; Jia, Haiyong; Desta, Samuel; Ding, Xiao; Sun, Lin; Fang, Zengjun; Huang, Boshi*; Liang, Xuewu; Jia, Ruifang; Ma, Xiuli; Xu, Wenfang; Murugan, Natarajan Arul; Loregian, Arianna; Huang, Bing; Zhan, Peng; Liu, XinyongZhang, Jian; Poongavanam, Vasanthanathan; Kang, Dongwei; Bertagnin, Chiara; Lu, Huamei; Kong, Xiujie; Ju, Han; Lu, Xueyi; Gao, Ping; Tian, Ye; Jia, Haiyong; Desta, Samuel; Ding, Xiao; Sun, Lin; Fang, Zengjun; Huang, Boshi; Liang, Xuewu; Jia, Ruifang; Ma, Xiuli; Xu, Wenfang; Murugan, Natarajan Arul; Loregian, Arianna; Huang, Bing; Zhan, Peng; Liu, Xinyon