Green and highly effective extraction of bioactive flavonoids from Fructus aurantii employing deep eutectic solvents-based ultrasonic-assisted extraction protocol.

In China, Jiang Fructus aurantii (JFA) has attracted increasing interest as a famous traditional herbal medicine and valuable economic food for its valuable medicinal and industrial properties. In the current work, contrasted with conventional extraction techniques, natural flavonoids from JFA (naringin and neohesperidin) were extracted with remarkable effectiveness utilizing a sustainable deep eutectic solvents combined ultrasonic-assisted extraction (DESs-UAE) protocol. The optimal extraction capacity can be achieved by mixing 30 % water with a molar ratio of 1:3 for choline chloride and ethylene glycol, as opposed to the classical extraction solvents of 95 % ethanol, methanol, and water. Moreover, the DESs-UAE extraction programs were also systematically optimized employing Box-Behnken design (BBD) trials, and the eventual findings suggested that the best parameters were a 27 % water content in DES, a 16 mL/g liquid-solid ratio, a 72 min extraction time, and a 62 °C extraction temperature, along with the corresponding greatest contents of NAR (48.18 mg/g) and NEO (34.50 mg/g), respectively. Notably, by comparison with the pre-optimization data, the optimized DES extraction efficiency of flavonoids is markedly higher. Thereafter, the characterization of the solvents before and after extraction, as well as the differences between the four extraction solvent extracts, were compared using the FT-IR analyses. Furthermore, SEM results suggested that the penetration and erosion abilities of the plant cell wall of DES-1 were stronger than those of the other three traditional solvents, thus allowing more release of flavonoid compounds. In conclusion, the present research develops a straightforward, sustainable, and exceedingly efficient approach for the extraction of bioactive flavonoids from JFA, which has the potential to facilitate the efficient acquisition of active ingredients from TCM.

Partially oxidized MoS2 nanosheets with high water-solubility to enhance the peroxidase-mimic activity for sensitive detection of glutathione.

Surface oxidation engineering is an effective strategy to construct nanomaterials with enhanced biocatalytic activity. In this study, a facile one-pot oxidation strategy was proposed to synthesize partially oxidized molybdenum disulfide nanosheets (ox-MoS2 NSs), which exhibit good water solubility and can be used as an excellent peroxidase substitute. Under the oxidation process, Mo-S bonds are partially broke and S atoms are replaced by excess oxygen atoms, and the released abundant heat and gases efficiently expended the interlayer distance and weaken the van der Waals forces between adjacent layers. Porous ox-MoS2 NSs can be easily exfoliated by further sonication, and the nanosheets exhibits excellent water dispersibility and no obvious sediment appear even after store for months. Benefiting from the desirable affinity property with enzyme substrates, optimized electronic structure and prominent electron transfer efficiency, the ox-MoS2 NSs exhibit enhanced peroxidase-mimic activity. Furthermore, the ox-MoS2 NSs catalyzed 3,3',5,5'-tetramethylbenzidine (TMB) oxidation reaction could be inhibited by the redox reaction that take place between glutathione (GSH) as well as the direct interaction between GSH and ox-MoS2 NSs. Thus, a colorimetric sensing platform was constructed for GSH detection with good sensitivity and stability. This work provides a facile strategy for engineering structure of nanomaterials and improving enzyme-mimic performance.

Effective extraction of bioactive alkaloids from the roots of Stephania tetrandra by deep eutectic solvents-based ultrasound-assisted extraction.

The efficient and green extraction of bioactive ingredients from natural plants play a vital role in their corresponding drug effects and subsequent studies. Recently, deep eutectic solvents (DESs) have been considered promising new green solvents for efficiently and selectively extracting substances from varied plants. In this work, an environment-friendly DESs-based ultrasonic-assisted extraction (DESs-UAE) procedure was developed for highly efficient and non-polluting extraction of alkaloids from the roots of Stephania tetrandra (ST). A total of fifteen different combinations of DESs, compared with traditional organic solvents (methanol and 95% ethanol) and water, were evaluated for extraction of bioactive alkaloids (FAN and TET) from ST, and the results revealed that DESs system made up of choline chloride and ethylene glycol with mole ratio of 1:2 exhibited the optimal extraction efficiency for alkaloids. Additionally, a four-factor and three-level Box-Behnken design (BBD), a particular pattern of response surface methodology (RSM), was used to optimize extraction conditions. RSM results indicated that the maximum extraction yields of FAN, TET, and TA were attained 7.23, 13.36, 20.59 mg/g, respectively, within extraction temperature of 52 °C, extraction time of 82 min, DES water content of 23% (v/v), and liquid-solid ratio of 23 mL/g. The measured results were consistent with the predicted values. Notably, the optimized DES extraction efficiency of TA, according to the experimental data analysis, is 2.2, 3.3 and 4.1 times higher than methanol, 95% ethanol and water, respectively. Meanwhile, based on 3D response surface plots, interactive effects plots and contour maps, the effects of the aforementioned four essential factors on the extraction yield and their interactions on the response were visualized. The results revealed that the mutual interactions between extraction temperature and liquid-solid ratio exhibited positive effects on all responses, while extraction time and water content in DES posed a negative effect. Therefore, these results suggest that DESs, as a class of novel green solvents, with the potential to substitute organic solvent and water, can be widely and effectively applied to extract bioactive compounds from natural plants.

Hydrophilic Porous Poly(l-Lactic Acid) Nanomembranes: Self-Assembly, and Anti-Biofouling and Anti-Thrombosis Effects.

Hydrophilic PEGylated porous self-assembled nanomembranes (PSANMs) with average thickness and pore diameter of ca. 10 and 20-24 nm were successfully prepared by an emulsification-induced programmable self-assembly strategy. The hydrophilicity, anti-biofouling, and anti-thrombosis properties of PEGylated PSANMs were largely improved in comparison with the nonfunctionalized PSANMs, which could transform into hydrophilic (PEGylated PSANMs, minimum water contact angle: 38.8°) from hydrophobic units (PSANMs, maximum water contact angle: 137.5°) with increasing PEG density and length. The total protein adsorption of PEGylated PSANMs was about six times lower than that of the PSANMs, while the thrombosis of the PEGylated PSANMs (maximum R-time: 5.37 min) was also greatly relieved in comparison with the PSANMs (minimum R-time: 2.93 min). Such PEG-modified PSANMs may have applications in drug delivery and tissue and organ repair in vivo.

Coordinatively Self-Assembled Luminescent Gold Nanoparticles: Fluorescence Turn-On System for High-Efficiency Passive Tumor Imaging.

A fluorescence turn-on system for highly efficient and prolonged tumor imaging has been established by a Co2+-induced coordination self-assembly strategy, in which luminescent glutathione (GSH)-modified gold nanoparticles (LGAuNPs) are assembled into LGAuNPs assemblies (LGAuNPs-Co) through a coordination bond between an unoccupied orbit of Co2+ and lone pair electrons of GSH on the surface of LGAuNPs. The LGAuNPs-Co is sensitive to microenvironment pH, and its quenched luminescence will be turned on in tumor tissues (acidic microenvironment), which behaves as a fluorescence turn-on system for passive tumor imaging. The fluorescence turn-on system combines advantages of the enhanced permeability and retention (EPR) effect of NPs and pH-induced fluorescence turn-on property at the tumor site, which results in a larger fluorescence intensity (FI) difference between normal and tumor tissues as compared with that of luminescent Au NPs (LAuNPs, only with the EPR effect) (∼12-fold). Such a large FI difference results in that LGAuNPs-Co has rapid (∼1.6 h), persistent (∼24 h p.i.), and highly efficient tumor targeting capability in comparison with LGAuNPs. Moreover, the LGAuNPs-Co also has much longer tumor retention, faster renal clearance, and lower reticuloendothelial system (RES) uptake than LGAuNPs. Therefore, the fluorescence turn-on system is very promising for cancer diagnosis and therapy.