RSC Advances

Yang, Qin; Yin, Zhijian; Zheng, Lifang; Yuan, Jianjun; Wei, Song; Ding, Qiuping; Peng, Yiyuan

doi: 10.1039/c8ra09864fpmid: 35517267

A novel and simple protocol for the synthesis of 4-(indole-3-yl)quinazolines via cross-dehydrogenative coupling of quinazoline-3-oxides and indoles under an air atmosphere has been developed. A series of biheteroaryl products were obtained in moderate to good yields.

Nagabhishek, Sirpu Natesh; Madankumar, Arumugam

doi: 10.1039/c8ra09886gpmid: 35517301

The marine environment has a remarkable source of natural products mainly from marine fungi, which have been a central source of novel pharmacologically bioactive secondary metabolites. In this study, the search for a new potential apoptosis-inducing metabolite is focused on marine sponge-associated symbionts. A total of sixteen different sponges were obtained from the Gulf of Mannar region, India, and twenty-three different marine fungal strains were isolated and tested for antiproliferative activity by the MTT assay. Out of these, Monascus sp. NMK7 associated with the marine sponge Clathria frondifera was found to have a promising antiproliferative property. Furthermore, to isolate the pure active metabolite, the crude material was subjected to column chromatography and HPLC. Structural characterization was conducted by a variety of spectroscopic techniques including UV, IR, MS and NMR. The obtained results from the MS and NMR spectroscopy determined 418.5 Da to be the molecular weight and C24H34O6 to be the molecular formula of the metabolite, indicating the presence of monacolin X (NMKD7). NMKD7 was found to induce dose-dependent cytotoxicity in different human breast cancer cell lines MCF-7, T47D, MDA-MB-231, MDA-MB-468 and MCF-10A normal breast cell after 24 h of exposure. For elucidating the possible mode of cell death, T47D and MDA-MB-468 cells were treated with NMKD7 for 24 h to examine the morphological change of the chromatin (PI & AO/EB). Therefore, it has been suggested as the possible mechanism of apoptosis, and apart from this, it has also exhibited antibacterial and anti-migratory properties as well as induced the ROS stress (DCFH-DA), which causes the mitochondrial membrane potential difference (Rhodamine-123), the loss of cell membrane integrity and eventually cell death. Thus, the present study features a novel promising apoptosis-inducing metabolite (NMKD7) with minimal toxicity, suggesting its potential for biotechnological applications, and substantiates that it should be further considered for the elucidation of molecular targets and signal transduction pathways.

Yuan, Huiyu; Ma, Sainan; Wang, Xinyu; Long, Hui; Zhao, Xinhua; Yang, Daoyuan; Lo, Wai Hung; Tsang, Yuen Hong

doi: 10.1039/c8ra10172hpmid: 35517299

In this work, we examined the performance of 2D titanate nanosheets for dye adsorption. Their adsorption capacity for methylene blue (MB) is up to 3937 mg g−1, which is more than 10 times higher than active carbon and occupies the highest place among all the reports.

Ye, Xi; Xu, Qingchi; Xu, Jun

doi: 10.1039/c9ra00209jpmid: 35517285

Polypyrrole (PPY) is a type of dye adsorbent with good adsorbing capability. Fabrication of PPY with a porous architecture, though technically challenging, can further enhance its dye adsorbing capability due to the tremendous increase of surface area. In this manuscript, an oxidant-templating strategy was developed to fabricate pure PPY hydrogel (PHG) beads comprising nanofibrous networks, which were utilized as highly efficient dye absorbents. For instance, PPY hydrogel beads showed a maximum adsorption capacity of 236.9 mg g−1 for methyl orange (MO), which was significantly higher than that of PPY powder. The minimal effective concentration of MO for the adsorption was as low as 0.4 ppm. Besides that, the PPY hydrogel beads displayed good regeneration performance for adsorbing organic dyes. Thus, the PPY hydrogel beads with low solid contents and large surface area could be considered as a promising organic dye absorbent for wastewater treatment in various industrial fields.

Shayeganfar, Farzaneh; Beheshtian, Javad; Shahsavari, Rouzbeh

doi: 10.1039/c8ra09925apmid: 35517256

Water interaction and transport through nanochannels of two-dimensional (2D) nanomaterials hold great promises in several applications including separation, energy harvesting and drug delivery. However, the fundamental underpinning of the electronic phenomena at the interface of such systems is poorly understood. Inspired by recent experiments, herein, we focus on water/heavy water in boron nitride (BN) nanochannels – as a model system – and report a series of ab initio based density functional theory (DFT) calculations on correlating the stability of adsorption and interfacial properties, decoding various synergies in the complex interfacial interactions of water encapsulated in BN nanocapillaries. We provide a comparison of phonon vibrational modes of water and heavy water (D2O) captured in bilayer BN (BLBN) to compare their mobility and group speed as a key factor for separation mechanisms. This finding, combined with the fundamental insights into the nature of the interfacial properties, provides key hypotheses for the design of nanochannels.

Chaudhari, Shivshankar; Kwon, YongSung; Shon, MinYoung; Nam, SeungEun; Park, YouIn

doi: 10.1039/c8ra07136epmid: 35517247

In order to find an alternative for classical distillation in the recovery of ECH/IPA from azeotropic ECH/IPA/water (50/30/20 w/w, %) mixtures, a pervaporation process has been applied. Membranes from the crosslinking of poly(vinyl alcohol)/poly(vinyl amine) (PVA/PVAm) were prepared, and then the membrane stability and pervaporation efficiency of the crosslinked PVA/PVAm membranes were studied for highly reactive ECH systems containing a ternary feed mixture. From the Fourier-transform infrared (FT-IR) spectroscopy analysis, it was observed that all of the membranes were chemically stable for 15 days of immersion in a 50 : 30 : 20 ECH/IPA/water (w/w, %) feed mixture at 60 °C. The degree of membrane swelling increased with increasing PVAm content in the membrane composition, water content in the feed composition, and feed temperature, which was attributed to the increase in the number of hydrophilic sites in the membrane. The field-emission scanning electron microscopy (FE-SEM) study revealed that higher PVAm content membranes (PVAm1.0 and PVAm1.5) show polymer phase extraction in ECH/IPA/water (50 : 30 : 20) (w/w, %) at 60 °C in long-term stability tests. The pervaporation dehydration characteristics for all of the membranes with the feed comprising an ECH/IPA/water (50 : 30 : 20 by weight) azeotropic mixture at 30 °C were examined and excellent pervaporation dehydration efficiency was found. Quantitatively, the flux increased from 0.025 to 0.32 kg (m2 h)−1 and the separation factor decreased from 1908 to 60 with increasing PVAm content in the blended membrane.

Takise, Kent; Sato, Ayaka; Murakami, Kota; Ogo, Shuhei; Seo, Jeong Gil; Imagawa, Ken-ichi; Kado, Shigeru; Sekine, Yasushi

doi: 10.1039/c9ra00407fpmid: 35517264

Liquid organic hydrides are regarded as promising for use as hydrogen carriers via the methylcyclohexane (MCH)–toluene–hydrogen cycle. Because of the endothermic nature of MCH dehydrogenation, the reaction is usually conducted at temperatures higher than 623 K. In this work, low-temperature catalytic MCH dehydrogenation was demonstrated over 3 wt% Pt/CeO2 catalyst by application of electric field across a fixed-bed flow reactor. Results show that a high conversion of MCH beyond thermodynamic equilibrium was achieved even at 423 K. Kinetic analyses exhibited a positive correlation of hydrogen to the reaction rates and an “inverse” kinetic isotope effect (KIE), suggesting that accelerated proton hopping with the H atoms of MCH promotes the reaction. Operando analyses and DFT calculation proved that the reverse reaction (i.e. toluene hydrogenation) was suppressed by the facilitation of toluene desorption in the electric field. The electric field promoted MCH dehydrogenation by surface proton hopping, even at low temperatures with an irreversible pathway.

Zheng, Yajun; Li, Yan; Li, Guifeng

doi: 10.1039/c8ra10269dpmid: 35517251

Coconut cake albumin was hydrolysed by sequential digestion with alcalase, flavourzyme, pepsin and trypsin to purify bioactive peptides with ACE-inhibitory and antioxidant activities. Following fractionation with sequential ultrafiltration, Sephadex gel chromatography and RP-HPLC, three novel peptides KAQYPYV, KIIIYN and KILIYG were identified. KAQYPYV, KIIIYN and KILIYG provided an IC50 value of 37.06 μM, 58.72 μM and 53.31 μM on ACE-inhibitory activity, respectively. For hydroxyl radical scavenging activity, KAQYPYV, KIIIYN and KILIYG demonstrated an IC50 value of 70.84 μM, 77.62 μM and 95.23 μM, respectively. All the three peptides exhibited a mixed modality of noncompetitive and uncompetitive inhibition on ACE and KAQYPYV showed good stability against gastrointestinal enzymes digestion. Moreover, these peptides could effectively lower intracellular endothelin-1 content without significant cytotoxicity, and protected vascular endothelial cells from reactive oxygen species mediated damage. Furthermore, KAQYPYV, KIIIYN and KILIYG also demonstrated high ion chelating ability (62.13% ± 4.21%, 64.66% ± 5.51% and 69.82% ± 7.24% at 0.1 mg mL−1, respectively) and considerable superoxide radical scavenging activity (39.30% ± 2.72%, 46.79% ± 1.70% and 51.16% ± 3.23% at 1.0 mg mL−1, respectively). These results indicate that coconut cake albumin is a potential source of bioactive peptides possessing ACE-inhibitory and antioxidant activities.

Bautista-Renedo, Joanatan M.; Reyes-Pérez, Horacio; Cuevas-Yáñez, Erick; Barrera-Díaz, Carlos; González-Rivas, Nelly; Ireta, Joel

doi: 10.1039/c9ra00856jpmid: 35517291

This study is directed towards assessing hydrogen bond acceptor/donor capabilities of heavier group 14 homologues of HCN and HNC. A structural, energetic and topological study using ab initio (MP2, CCSD(T)), electrostatic potential (EP) and quantum theory of atoms in molecules (QTAIM) methodologies was carried out on HNX⋯HNX and HXN⋯HXN dimers and their respective monomers, where X = C, Si, Ge, Sn and Pb. The obtained results suggest the presence of weak hydrogen bonds in both kinds of complexes, and remarkably Ge and Sn act as unconventional hydrogen donors.

Han, Xiaoyan; Li, Ran; Qiu, Shengqiang; Zhang, Xiaofang; Zhang, Qing; Yang, Yingkui

doi: 10.1039/c9ra00554dpmid: 35517304

SnO2/graphene nanocomposite was successfully synthesized by a facile sonochemical method from SnCl2 and graphene oxide (GO) precursors. In the sonochemical process, the Sn2+ is firstly dispersed homogeneously on the GO surface, then in situ oxidized to SnO2 nanoparticles on both sides of the graphene nanosheets (RGO) obtained by the reduction of GO under continuous ultrasonication. Graphene not only provides a mechanical support to alleviate the volume changes of the SnO2 anode and prevent nanoparticle agglomeration, but also serves as a conductive network to facilitate charge transfer and Li+ diffusion. When used as a lithium ion battery (LIB) anode, the SnO2/graphene nanocomposite exhibits significantly improved specific capacity (1610 mA h g−1 at 100 mA g−1), good cycling stability (retaining 87% after 100 cycles), and competitive rate performance (273 mA h g−1 at 500 mA g−1) compared to those of bare SnO2. This sonochemical method can be also applied to the synthesis of other metal-oxide/graphene composites and this work provides a large-scale preparation route for the practical application of SnO2 in lithium ion batteries.