Meng Luo

Northeast Forestry University, Charbin, Heilongjiang Sheng, China

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Publications (77)197.95 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel and effective extraction method, namely negative pressure cavitation-microwave assisted extraction technique (NMAE), was developed for the preparation of extracts of Pyrola incarnata Fisch., which are rich in the main constituents hyperin, 2′-O-galloylhyperin and chimaphilin. Single factor experiments and Box–Behnken design (BBD) were combined with a response surface methodology to examine factors affecting extraction. Maximum extraction yields of hyperin, 2′-O-galloylhyperin and chimaphilin (1.339 ± 0.029, 4.831 ± 0.117 and 0.329 ± 0.011 mg/g, respectively) were achieved under the following optimised conditions: 700 W microwave power, 50 °C extraction temperature, 30:1 mL/g liquid–solid ratio, −0.05 MPa negative pressure, 55% ethanol concentration and 12 min extraction time. First-order kinetics equation demonstrated that NMAE offered significant savings in extraction time, and enhancing extraction efficiency. Furthermore, NMAE extracts yielded excellent antioxidant activity (IC50 0.121 mg/mL for DPPH 2.896 mmol FeSO4/g DW FRAP).
    Food Chemistry 02/2015; 169:270–276. · 3.33 Impact Factor
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    ABSTRACT: In this study, sophoricoside from Fructus sophorae was highly bioconversed to genistein by co-immobilized Aspergillus niger and Yeast. Bioconversion conditions for genistein were optimized with single-factor experiments. The optimal conditions were as follows: microbial concentration 1.5 × 10(7) cells/mL, wet weight of microorganisms beads 10.0 g/g material, pH 5, ratio of liquid to solid 25:1 (mL/g), temperature 32 °C and time 24 h. Under these conditions, a 34.45-fold increase in production of genistein was observed with a bioreactor. Moreover, the antioxidant activities of the extracts from the fermented and untreated F. sophorae were 0.287 ± 0.11, 0.384 ± 0.08 mg/mL (IC50) and 1.84 ± 0.13, 1.28 ± 0.25 mmol Fe(II)/g, according to the DPPH test and FRAP assay, respectively. The results indicated that the method described in the current work were valuable procedure for the production of genistein, which is of most importance for industrial scale applications as well as food industry.
    World journal of microbiology & biotechnology. 11/2014;
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    ABSTRACT: In the present study, a homogenate-assisted negative-pressure cavitation extraction (H-NPCE) is developed for the extraction and determination of the main organic acids and flavonoids in honeysuckle by LC–MS/MS. The influential parameters of the H-NPCE procedure were optimized, and the optimal conditions were as follows: homogenate time 45 s, negative pressure −0.07 MPa, ethanol concentration 70%, liquid/solid ratio 20:1 mL/g, NPCE time 20 min and 3 extraction cycles. Furthermore, a rapid LC–MS/MS analysis method was established and validated, and it exhibited satisfactory linearity (R2 > 0.996), precision (RSD ⩽ 4.87%) and recovery (96.94–104.32%). H-NPCE followed by LC–MS/MS was successfully applied for the extraction and quantification of ten organic acids and flavonoids in honeysuckle. This work provided a fast and effective method for the sample preparation and determination of active components from plants.
    Separation and Purification Technology 10/2014; 135:80–87. · 2.89 Impact Factor
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    ABSTRACT: Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid), an active constituent of pigeonpea leaves, one of important tropical crops, is known for its clinical effects in the treatment of diabetes, hepatitis, measles and potential anti-tumor effect. In this study, the effect of the cytochrome P450 isozymes on the activity of CSA was investigated. Two hydroxylation metabolites were identified in the study. The reaction phenotype study showed that CYP3A4, CYP2C9 and CYP1A2 were the major cytochrome P450 isozymes in the metabolism of CSA. The metabolic drug-drug interaction potential was also evaluated in vitro. The effect of CSA inhibition/induction of enzymatic activities of seven drug-metabolizing CYP450 isozymes in vitro was estimated by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analytical techniques. CSA showed different inhibitory effects on different isozymes. CSA reversibly inhibited CYP3A4 and CYP2C9 activities in human liver microsomes with an IC50 of 28.3µM and 31.3µM, respectively, while exhibited no inhibition activities to CYP1A2, CYP2A6, CYP2C19, CYP2D6, and CYP2E1. CSA showed a weak effect on CYP450 enzymes in time-dependent manner. CSA did not substantially induce CYP1A2, CYP2A6, CYP2B6, CYP2E1, CYP2C9, CYP2C19, CYP2D6 or CYP3A4 at the concentration up to 30µM in primary human hepatocytes. The results of our experiments may be helpful to predict clinically significant drug-drug interactions when other drugs are combined administration with CSA.
    Journal of agricultural and food chemistry. 10/2014;
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    ABSTRACT: A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in E. palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity and accuracy of ultra performance liquid chromatography-tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were determined to be that silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400 mg/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within less than 6 min, and exhibited satisfactory linearity, precision and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time-saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices.This article is protected by copyright. All rights reserved
    Journal of Separation Science 08/2014; · 2.59 Impact Factor
  • Industrial Crops and Products 07/2014; 58:322–328. · 3.21 Impact Factor
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    ABSTRACT: In this paper, a novel and green enzyme-assisted negative pressure cavitation extraction (E-NPCE) of five main indole alkaloids vindoline (VDL), catharanthine (CTR), vincristine (VCR), vinblastine (VLB) and anhydravinblastine (AVLB) from Catharanthus roseus leaves was investigated. The incubation conditions were studied using Box–Behnken design (BBD) with response surface methodology (RSM), which revealed these as follows: enzyme amount 0.61% (CB&P, w/w of anhydration material), pH 4.73, incubation temperature 35.87 °C and time 8.62 h. Under the optimal conditions, the extraction yields of VDL, CTR, VCR, VLB and AVLB reached 4.940 ± 0.215, 6.283 ± 0.307, 0.049 ± 0.002, 0.066 ± 0.003 and 0.038 ± 0.001 mg/g, which represented an increase of 38.8%, 51.5%, 48.4%, 37.5% and 58.3%, compared to standard NPCE, respectively. Moreover, this extraction method was also applied on pilot-scale extraction and their yields were 4.761 ± 0.227, 6.093 ± 0.294, 0.047 ± 0.002, 0.064 ± 0.003 and 0.039 ± 0.001 mg/g, respectively. Thus, it demonstrated that E-NPCE could be an alternative method for natural compounds extraction and the most important thing is that this method can be applied to industrial produce.
    Separation and Purification Technology 04/2014; 125:66–73. · 2.89 Impact Factor
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    ABSTRACT: This paper reported a new, green and effective extraction technique for polysaccharides, namely homogenization-assisted negative pressure cavitation extraction (HNPCE), which succeeded in the extraction of Astragalus polysaccharides (APs). Central composite design and kinetic model were applied to optimize the extraction conditions, and the optimal parameters were obtained as follows: homogenization time 70 s, negative pressure -0.068MPa, extraction temperature 64.8°C, ratio of water to material 13.4 and extraction time 53min. The proposed method exhibited considerable predominance in terms of higher APs yield (16.74%) with much lower temperature and shorter duration, as against the reported hot water extraction method (14.33% of APs yield with 100°C and 3h). Moreover, FT-IR results showed that HNPCE method did not alter the primary structure of polysaccharides. Furthermore, the pilot-scale application of HNPCE was successfully performed with 16.62% of APs yield. Thus, HNPCE is an excellent alternative method for the extraction of polysaccharides from Astragalus or other plant materials in industry.
    International journal of biological macromolecules 03/2014; · 2.37 Impact Factor
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    ABSTRACT: A novel and green microwave-assisted aqueous enzymatic extraction (MAAEE) of oil from Isatis indigotica seeds was investigated in the present study. Enzyme cocktail (cellulase/proteinase/pectinase = 1/1/1, w/w/w) was found to be the most effective in releasing the oil. Under the optimal conditions as enzyme concentration 1.82% (w/w), temperature 43 °C, time 83 min and irradiation power 375 W, the highest oil recovery of 59.27% was obtained using the emerging technique. As compared to conventional Soxhlet extraction-derived oil (SEO), MAAEE-derived oil (MAAEEO) revealed the similar physicochemical properties but exhibited better oxidation stability. In addition, MAAEEO had higher contents of valuable polyunsaturated fatty acids, tocopherols and phenolics as against SEO, and it exhibited considerable antioxidant activities with IC50 values 9.58 and 15.03 mg/mL, according to DPPH radical scavenging assay and β-carotene/linoleic acid bleaching test, respectively. Scanning electron micrographs illustrated the severely structural disruptions of sample cell walls and membranes by MAAEE.
    Industrial Crops and Products 03/2014; 45:303–311. · 3.21 Impact Factor
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    ABSTRACT: In this study, ionic liquid based microwave-assisted extraction (IL-MAE) followed by high-performance liquid chromatography (HPLC) was developed for determination of major organic acids in honeysuckle tea. The results suggest that varying the anion and cation had significant effects on the preparative extraction efficiency; aqueous solution of [C6mim]Br was selected as solvent. The optimized extraction parameters were obtained as follows: IL concentration 0.5 M, temperature 50 °C, solvent to material ratio 20:1 mL/g and duration 9 min. Moreover, principal component analysis (PCA) was used to analyze the significances of these factors for IL-MAE and their interactions, and IL concentration was proved to be the most significant parameter. Compared with conventional sample preparation method, the content of organic acids in analytical sample was enhanced about 1.5-fold using IL-MAE in a shorter duration. In addition, a kinetic model of the preparative extraction process was established to fit the experimental data (R2 > 0.99). The proposed HPLC method was successfully applied for determination of 5 organic acids in honeysuckle tea. The present research supported necessary data for sample preparation and quality analysis of honeysuckle tea
    Journal of Food Composition and Analysis 03/2014; · 2.09 Impact Factor
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    ABSTRACT: This study evaluated the antioxidant activity of the main active compound of an endophytic fungus MD-R-1 from pigeon pea. This fungus was identified as Aspergillus fumigates by ITS sequence. The antioxidant capacity was evaluated by DPPH, hydroxyl radical scavenging, reducing power, lipid peroxidation and XOD inhibitory effect assays. Among the four fractions, the EtOAc fraction showed the best antioxidant activity (IC50 values were 16.38, 35.20, 19.69, 22.64 and 193.24 μg/mL, respectively) and the highest phenolic and flavonoid content. Furthermore, it possessed good protective activity from oxidative DNA damage. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) in HepG2 cells treated with MD-R-1 EtOAc extracts were also determined. The results showed that EtOAc extracts significantly increased the activities of SOD, CAT and GR in HepG2 cells in a dose-dependent manner. The LC–MS/MS was used to analyze EtOAc fraction and the result pointed to a notable antioxidant compound, luteolin. The present investigation suggests that MD-R-1 represents a valuable natural antioxidant source and may be applicable in health food industry potentially.
    Food Research International 02/2014; 56:243–251. · 3.05 Impact Factor
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    ABSTRACT: Aspidin BB, a phloroglucinol derivative extracted from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In the present study, antibacterial activities and mechanisms of aspidin BB against Staphylococcus aureus were investigated. Aspidin BB exhibited strong antibacterial activity against standard and three clinical S. aureus, with minimal inhibition concentration (MIC) values ranging from 15.63 μg/mL to 62.5 μg/mL. After treatment with aspidin BB for 72 h using the MTT assay, the IC50 value was 48.14 μM (22.11 μg/mL). The time-kill assay indicated that aspidin BB could kill S. aureus completely at 2 MIC (MBC) within 4 h. Aspidin BB was capable to induce an increase in NADPH oxidase activity from 4.03 U/mg to 7.48 U/mg when the concentrations were increased from 1/2 MIC to 4 MIC. Simultaneously, aspidin BB attenuated antioxidant defense by decreasing superoxide dismutase (SOD) activity and glutathione (GSH) levels. The level of reactive oxygen species (ROS) was apparently elevated when measuring OD575. This phenomenon was blocked by pretreatment of S. aureus with the antioxidant compound catalase (200 U/mL) and the survival rate of S. aureus increased from 3.95% to 73.04%. These results showed that ROS was indeed an important mediator in the antibacterial action of aspidin BB. In addition, aspidin-BB-induced peroxidation of membranes, DNA damage and protein degradation of S. aureus were all verified in a dose-dependent manner. In conclusion, aspidin BB induced generation of ROS by activating NADPH oxidase activity and inhibiting SOD activity and GSH levels, damaging the membrane, DNA and proteins and finally led to cell death.
    Research in Microbiology 01/2014; · 2.89 Impact Factor
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    ABSTRACT: A rapid, green and effective miniaturized sample preparation and analytical technique, i.e. ionic liquids-assisted microwave distillation coupled with headspace single-drop microextraction (ILAMD-HS-SDME) followed by gas chromatography-mass spectrometry (GC-MS) was developed for the analysis of essential oil (EO) in Fructus forsythiae. In this work, ionic liquids (ILs) were not only used as the absorption medium of microwave irradiation but also as the destruction agent of plant cell walls. 1-Ethyl-3-methylimidazolium acetate ([C2mim]OAc) was chosen as the optimal ILs. Moreover, n-heptadecane (2.0μL) was selected as the appropriate suspended solvent for the extraction and concentration of EO. Extraction conditions of the proposed method were optimized using the relative peak area of EO constituents as the index, and the optimal operational parameters were obtained as follows: irradiation power (300W), sample mass (0.7g), mass ratio of ILs to sample (2.4), temperature (78°C) and time (3.4min). In comparison to previous reports, the proposed method was faster and required smaller sample amount but could equally monitor all EO constituents with no significant differences.
    Analytica chimica acta 12/2013; 804C:143-150. · 4.31 Impact Factor
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    ABSTRACT: The variation of antioxidant activity and active components in pyrola [Passiflora incarnata Fisch.] from eight sites in Northeast China were investigated. Total phenolic and flavonoid contents were determined and varied within the range of 39.66-181.48mg/g and 2.47-22.11mg/g, respectively. Antioxidant activities were determined by scavenging activity against DPPH and ABTS, by a reducing power test and by a β-carotene-linoleic acid bleaching test. The IC50 of Tahe samples determined by the DPPH test was 0.106±0.006mg/mL which was very close to that of Vc (0.076±0.004mg/mL). The Tahe samples had good antioxidant activity. Principal component activity analysis indicated that the Tahe samples of P. incarnata had the highest potential antioxidant properties, and may be a valuable antioxidant natural resource in the northeast of China.
    Food Chemistry 12/2013; 141(3):2213-9. · 3.33 Impact Factor
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    ABSTRACT: A rapid, green and effective miniaturized sample preparation technique, ionic-liquid-assisted microwave distillation coupled with headspace single-drop microextraction was developed for the extraction of essential oil from dried Dryopteris fragrans. 1-Ethyl-3-methylimidazolium acetate was the optimal ionic liquid as the destruction agent of plant cell walls and microwave absorption was medium. n-Heptadecane (2.0 μL) was adopted as the suspended microdrop solvent in the headspace for the extraction and concentration of essential oil. The optimal parameters of the proposed method were an irradiation power of 300 W, sample mass of 0.9 g, mass ratio of ionic liquids to sample of 2.8, extraction temperature of 79°C, and extraction time of 3.6 min. In comparison to the previous reports, the proposed technique could equally monitor all the essential oil components with no significant differences in a simple way, which was more rapid and required a much lower amount of sample.
    Journal of Separation Science 10/2013; · 2.59 Impact Factor
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    ABSTRACT: Pigeon pea is an important and multiuse grain legume crop, and its leaves are very valuable natural resource. To obtain high-quality biological resource, it is necessary to choose the excellent cultivar and determine appropriate harvest time. In this study, the variation in contents of main active components and antioxidant activity in leaves of six pigeon pea cultivars during growth was investigated. The level of each individual active component significantly varied during growth, but with a different pattern, and this variation was different among cultivars. Flavonoid glycosides orientin, vitexin and apigenin-6,8-di-C-α-L-arabinopyranoside showed two peak values at mid-late and final stage of growth in most cases. Pinostrobin chalcone, longistyline C and cajaninstilbene acid showed a remarkablely higher value at mid-late stage of growth than other stages. Pinostrobin had an extremely different variation pattern compared with other active components. Its content was the highest at earlier stage of growth. Principal component analysis (PCA) revealed that vitexin and apigenin-6,8-di-C-α-L-arabinopyranoside were mainly responsible for the distinguish of cultivars analyzed. In a comprehensive consideration, the leaves should preferentially be harvested at the 135th day after sowing when the level of active components and antioxidant activity reached higher values. Cultivars ICP 13092, ICPL 87091 and ICPL 96053 were considered to be excellent ones with high antioxidant activity. Our findings can provide valuable information for producing high-quality pigeon pea resource.
    Journal of Agricultural and Food Chemistry 09/2013; · 3.11 Impact Factor
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    ABSTRACT: An efficient microwave-assisted aqueous two-phase extraction (MA-ATPE) technique was developed to simultaneously extract and enrich genistein and biochanin A from Dalbergia odorifera T. Chen leaves. Three salts were investigated, and dipotassium hydrogen phosphate was selected to form aqueous two-phase system (ATPS). Box–Behnken Design combined with response surface methodology was applied to optimize the operating parameters of MA-ATPE. The optimal conditions were as follows: salt concentration 20%, absolute alcohol concentration 25%, extraction temperature 45.5 °C, extraction time 10 min and irradiation power 300 W. Under the optimized condition, the extraction yields of genistein and biochanin A reached 1.034 mg/g DM and 2.023 mg/g DM, respectively. Compared with microwave assisted extraction (MAE) and heat reflux extraction (HRE), the contents of genistein and biochanin A in the extracts reached 12.966 mg/g extract and 25.526 mg/g extract, which were 2.48- and 2.30-fold to that of MAE, 2.64- and 2.80-fold to that of HRE. Furthermore, the antioxidant activities of extracts from MA-ATPE, MAE and HRE were 0.342, 0.389, 0.411 mg/mL (IC50), according to the DPPH radical-scavenging assay. Moreover, the phase-forming salt can be recyclable. In conclusion, MA-ATPE was an efficient, eco-friendly and economical technique, which represented an excellent alternative for the extraction of bioactive compounds from plant.
    Separation and Purification Technology 08/2013; 115:136–144. · 2.89 Impact Factor
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    ABSTRACT: With strong dissolution abilities of ionic liquids to plant cell walls, an integrated microwave-assisted ionic liquids pretreatment followed by hydro-distillation method (MILP–MHD) was performed for the efficient extraction of essential oil from the rare Dryopteris fragrans. Under optimal conditions, this innovative MILP–MHD provided the remarkable superiority of much higher yield (0.91%) of D. fragrans essential oil (DEO) within much shorter extraction duration (14.2 min) than those of the reported solvent-free microwave extraction technique (0.33% and 94 min). Furthermore, the antioxidant efficacy of DEO in the stabilization of sunflower oil was determined and found to be comparable to the commonly-employed α-tocopherol (VE) but a little lower than the synthetic antioxidant butylated hydroxytoluene (BHT). Therefore, MILP–MHD is a potential and highly efficient technique for the extraction of valuable essential oils in flavor food industries and DEO can be explored as a potent natural antioxidant additive for edible oils or lipid foods storage.
    Journal of Food Engineering 08/2013; 117(4):477–485. · 2.28 Impact Factor
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    ABSTRACT: Eight different strains of yeasts, Aspergillus niger, Aspergillus oryzae and White-rot fungus were tested for biotransformation of saponins to astragaloside IV in potato medium with Radix Astragali. Among these strains, immobilized cells of A. niger M85 exhibited the best performance on the biotransformation of saponins to astragaloside IV from Radix Astragali. After the biotransformation with immobilized A. niger M85, the contents of astragaloside IV and total astragalosides in Radix Astragali increased 10.7-fold (2.326 mg/g) and 8.6-fold (2.56 mg/g) to the solvent extraction sample, respectively. Optimization was done at incubation period 5 days, the amount of Radix Astragali powder 2 g, medium volume 50 mL/g, incubation temperature 30 °C and initial pH 6.0. The immobilized A. niger M85 can be reused seven times and retained 71% of its residual activity. The A. niger M85 was found to be a highly efficient producer of astragaloside IV.
    Biocatalysis and Agricultural Biotechnology. 07/2013; 2(3):196–203.
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    ABSTRACT: In this study, aqueous enzymatic process (AEP) assisted by microwave extraction (ME) of oil from yellow horn (Xanthoceras sorbifolia Bunge.) seed kernel was investigated. Central composite design (CCD) and response surface methodology (RSM) were used to optimise an enzyme cocktail (cellulase, hemicellulase, pectinase) for AEP. The main factors of ME were also studied. A maximal oil extraction yield of 55.8% was achieved under optimal conditions. Moreover, scanning electron microscope (SEM) was applied to characterise the extraction process. Analysing chemical composition of the extracted oil by GC-MS showed that the content of unsaturated fatty acids by this emerging method (91.18%) was similar to that by conventional organic solvent extraction (88.76%). In addition, the main physicochemical properties and antioxidant activities of yellow horn oil were measured to evaluate its quality. The present research supported necessary data for the green extraction method of edible oil in food industry.
    Food Chemistry 06/2013; 138(4):2152-8. · 3.33 Impact Factor