Dong-Yang Zhang

Ultrasound extraction of polysaccharides from mulberry leaves and their effect on enhancing antioxidant activity.

A Box-Behnken design (BBD) was applied to optimize the ultrasound-assisted extraction of polysaccharides from mulberry leaves. Under the optimum conditions of an extraction temperature of 57 °C, an extraction time of 80 min and a liquid/solid ratio of 53 mL/g, the mulberry leaf polysaccharide (MLP) yield was 6.92 ± 0.29%. Then, three fractions of MLPs were obtained by deproteinization, dialysis and decolorization. The carbohydrate content, FT-IR spectrum and monosaccharide composition of the MLPs were also investigated. The antioxidant activities of the three fractions were compared, and the results indicated that the antioxidant activities decreased with the increasing MLP purity. Therefore, highly concentrated MLPs were shown to have very little antioxidant activity. After quercetin (10 μg/mL) was added, the antioxidant activities were improved significantly. This result showed that MLPs and quercetin have a synergistic effect on the antioxidant activity. Although the MLPs have very little antioxidant activity alone, they greatly enhance the antioxidant activity of flavonoids. Thus, MLPs can be used as an antioxidant activity enhancer in the food industry.

Rapid determination of 1-deoxynojirimycin in Morus alba L. leaves by direct analysis in real time (DART) mass spectrometry.

A new method based on a Direct Analysis in Real Time (DART) ionization source coupled with triple quadrupole tandem mass spectrometry has been developed for rapid qualitative and quantitative analyses of 1-deoxynojirimycin (DNJ) in mulberry leaves. Two ions produced from DNJ, [M+H](+) (m/z 164) and [M-2H+H](+) (m/z 162), are observed using DART-MS in the positive ion mode. The peak areas of the two selected ions monitoring (SIM) signals of ([M+H](+) (m/z 164) and [M-2H+H](+) (m/z 162)) are integrated to determine the peak area for quantitative analyses. A reasonable linear regression equation is obtained in the range of 1.01 to 40.50 μg/mL, with a linear coefficient (R(2)) of 0.996. The limits of detection (LOD) and quantification (LOQ) of the method are 0.25 and 0.80 μg/mL, respectively. The range of recovery is shown to be 87.73-95.61%. The results derived from the developed DART-MS method are in good agreement with those from the conventional HPLC-FLD method. By contrast, DART-MS in SIM mode is a simple, rapid and high-throughput approach for the determination of the DNJ content in mulberry leaves. The present method is advantageous for the rapid screening of mulberry leaves containing high DNJ contents.

Robust composite silk fibers pulled out of silkworms directly fed with nanoparticles

This paper reports the impacts of direct feeding silkworms with different nanoparticles (Cu, Fe, and TiO2) on the morphology, structures, and mechanical properties of the resulting silk fiber (SF). The contents of the Cu nanoparticles were 38 times higher in the posterior silk glands and only 2-3 times higher in the SF and in the middle silk glands compared with the controlled groups. Significant changes of the surface morphology, structures, and diameter of the Cu nanoparticle fed SF have been observed, which are attributed to a slight SF protein reconstruction or conformational change in the mixture of silk fibroin and sericin in the silk glands. The resulting Cu-containing SF exhibits good tensile strength of 360MPa and reaches a strain of 38%, which are 89% and 36% higher than those of the natural SF. This study offers a new green strategy for the easy modification to achieve robust composite SF.

Preparation of a regenerated silk fibroin film and its adsorbability to azo dyes

In this work, a novel and sustainable biosorbent, regenerated silk fibroin film (rSFF) was successfully prepared and its adsorbability to azo dyes (acid yellow 11, naphthol orange and direct orange S) was measured. At optimal conditions, the adsorption capacity of rSFF for acid yellow 11 reached up to 59.71mg/g, which was 1.23-fold higher than that of raw silk fibroin fibers. More importantly, rSFF exhibited a high level of flexibility and functionality as well as a good shaping ability, which were crucial for its practical application. The SEM results showed that rSFF was a porous material, indicating that it had more available adsorption sites compared with raw silk fibroin fibers, which might contribute to the higher adsorption capacity of rSFF. Isotherm equilibrium studies revealed that the azo dye adsorption process followed the Langmuir model, indicating that rSFF was a structurally homogenous adsorbent. The recycle test showed that rSFF had potential to be reused in a number of treatment cycles. After five cycles, its adsorbability to acid yellow 11 remained as high as 47.20mg/g. Finally, a scale-up experiment was performed for rSFF, and the results indicated that it was feasible for rSFF to extend the practical application.

Functionalized cellulose beads with three dimensional porous structure for rapid adsorption of active constituents from Pyrola incarnata

In the present study, porous magnetic cellulose beads (CBs) were prepared and further modified using amines. The CBs appeared to have good spherical shape and three-dimensional (3D) porous structure. In the adsorption tests, the modified cellulose beads (MCBs) showed better adsorption capacities and shorter adsorption times on hyperin and 2-O-galloylhyperin than the commercial resins. The adsorption may be due to the hydrogen bonding between the target compounds and the amine groups of MCBs. After adsorption and desorption, the contents of hyperin and 2-O-galloylhyperin reached 1.32% and 3.92%, which were 4.08 and 4.23 times higher than those in the Pyrola extracts. Therefore, the prepared MCBs in this study make an excellent adsorbing material of hyperin and 2-O-galloylhyperin, and it may have potential for the separation of other natural compounds.

Generic DART-MS platform for monitoring the on-demand continuous-flow production of pharmaceuticals: Advancing the quantitative protocol for caffeates in microfluidic biocatalysis

&NA; Today, continuous processing is regarded as an effective on‐demand production technique of pharmaceuticals. Homemade microreactors packed with immobilized lipase under continuous‐flow conditions were first applied to tailor the production of high‐value caffeic acid phenethyl ester (CAPE) from methyl caffeate (MC) and 2‐phenylethanol (PE) in cyclohexane via transesterification; however, this method is challenging due to the lack of a rapid platform for monitoring caffeates in microfluidic biocatalysis. The reactants were directly analyzed using Direct Analysis in Real Time Mass Spectrometry (DART‐MS), and the corresponding ionization parameters were investigated. Special ions produced from MC (parent ion m/z 192.87 and product ion m/z 133.44) and CAPE (parent ion m/z 282.93 and product ion m/z 178.87) were determined using DART‐MS2 in the negative ion mode. The peak areas of the select reaction monitoring (SRM) signals were calculated to develop the standard curves for quantitative analyses of the concentration. Reasonable linear regression equations of MC and CAPE were obtained in the range of 3.125–50.000 mg/L, with linear coefficients (R2) of 0.9515 and 0.9973, limits of detection (LOD) of 0.005 and 0.003 mg/L, limits of quantification (LOQ) of 0.02 and 0.01 mg/L, and recovery ranges of 92.50–97.11% and 90.11–97.60%, respectively. The results using DART–MS2 were in good agreement with those using conventional High‐Performance Liquid Chromatography with a UV detector (HPLC‐UV) and were successfully applied to monitor the kinetics constants and mass transfer coefficients in a continuous‐flow packed bed microreactor. Thus, the DART‐MS2 method is an efficient tool for analyzing caffeates in microfluidic biocatalysis with limited sample preparation and short operating time. Graphical abstract Figure. No caption available. HighlightsDART‐MS monitors continuous‐flow production of active pharmaceutical ingredients.Continuous‐flow microreactor packed with immobilized enzyme used to produce APIs.Simultaneous determination of MC and CAPE by DART‐MS2 at a speed of 40 s/sample.Results of DART‐MS2 were in good agreement with those using conventional HPLC‐UV.DART‐MS2 firstly used to measure kinetics and mass transfer coefficients in microreactors.

Effect of different planting areas on the chemical compositions and hypoglycemic and antioxidant activities of mulberry leaf extracts in Southern China

Guangdong, Guangxi and Chongqing are emerging sericulture areas in China where the production of mulberry leaves is huge. In order to identity high quality mulberry leaves that are suitable for healthy products to expand planting, 24 samples from three regions (Guangdong, Guangxi, Chongqing) in the south of China were quantified for two alkaloids (1-deoxynojirimycin and fagomine) and five phenols (chlorogenic acid, rutin, isoquercitrin, etc.) using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Additionally, the total phenolic and total flavonoid contents, antioxidant and glycosidase inhibitory activities (hypoglycemic activity) were tested using different assays (DPPH, ABTS, FRAP) to comprehensively evaluate the quality of the mulberry leaves. The contents of DNJ and fagomine ranged from 0.401±0.003 to 5.309±0.036 mg/g and from 0.279±0.031 to 2.300±0.060 mg/g, respectively. The main phenolic constituents were chlorogenic acid, rutin and isoquercitrin, with chlorogenic acid present in the highest concentrations, ranging from 3.104±0.191 to 10.050±0.143 mg/g. The antioxidant activity exhibited a tendency as follows: Guangxi > Guangdong > Chongqing, except for two samples from Chongqing, which showed the highest antioxidant activity. Based on our study, mulberry leaves from Guangdong and Guangxi could be future sources of natural hypoglycemic and antioxidant products.

Microwave assisted extraction for the determination of chlorogenic acid in Flos Lonicerae by direct analysis in real time mass spectrometry (DART-MS)

Flos Lonicerae was an important Chinese medicine. In this research, a microwave assisted extraction method was applied for the extraction of chlorogenic acid from Flos Lonicerae. The operating conditions were optimized using a Box-Behnken design test. Under the optimal conditions, the extraction yield of chlorogenic acid reached 32.52u202f±u202f1.31u202fmg/g. Next, a direct analysis in real time mass spectrometry (DART-MS) method was utilized to quantify of chlorogenic acid in Flos Lonicerae extracts. The primary parameters were optimized to obtain maximum signal intensity. In the detection process of the actual samples, the results obtained by DART-MS are consistent with those obtained by HPLC method with short detection time and acceptable repeatability and precision (<15%). In addition, the DART-MS/MS method has several advantages, such as speed, low cost and simplicity. Therefore, the DART-MS method is an efficient method that can be applied in the quantification of chlorogenic acid in Flos Lonicerae.