Meng Luo

Northeast Forestry University, Charbin, Heilongjiang Sheng, China

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Publications (69)159.49 Total impact

  • [show abstract] [hide abstract]
    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. · 2.47 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 01/2014; 125:66–73. · 2.89 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 01/2014; · 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. 01/2014; 56:243–251.
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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; · 2.91 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.
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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
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    ABSTRACT: In the present work, Forsythia suspense seed oil (FSSO) was investigated for the first time as an alternative non-conventional feedstock for the preparation of biodiesel. The FSSO yield is 30.08±2.35% (dry weight of F. suspense seed basis), and the oil has low acid value (1.07mg KOH/g). The fatty acid composition of FSSO exhibits the predominance of linoleic acid (72.89%) along with oleic acid (18.68%) and palmitic acid (5.65%), which is quite similar to that of sunflower oil. Moreover, microwave-assisted transesterification process of FSSO with methanol in the presence of potassium hydroxide catalyst was optimized and an optimal biodiesel yield (90.74±2.02%) was obtained. Furthermore, the fuel properties of the biodiesel product were evaluated as against ASTM D-6751 biodiesel standards and an acceptable agreement was observed except the cetane number. Overall, this study revealed the possibility of FSSO as a potential resource of biodiesel feedstock.
    Bioresource Technology 06/2013; · 4.75 Impact Factor
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    ABSTRACT: A novel negative pressure and microwave assisted extraction technique (NMAE) was first proposed and applied for extraction of phenolic compounds from pyrola. [C4MIM]BF4 aqueous solution was selected as extraction solvent. Optimal extraction conditions were microwave power 700 W, negative pressure -0.07 MPa, temperature 40 °C, liquid-solid ratio 20 : 1, ionic liquid (IL) concentration 0.5 M, extraction time 15 min. The predominance of NMAE was investigated by comparing with microwave-assisted extraction (MAE) and negative pressure cavitation extraction (NPCE) using a first-order kinetics equation. The C∞ values of the target compounds by NMAE were from 0.406 to 5.977 mg g(-1) higher than these by MAE and NPCE, which indicated that NMAE had higher extraction yields. The K values of NMAE were also the highest; it was testified that the target compounds could be transferred from matrix into solvent much more effectively by NMAE than by MAE and NPCE. In addition, the NMAE method was validated in terms of repeatability and reproducibility, the relative standard deviation for relative recovery was lower than 5.43 and 8.78%, respectively. Therefore, NMAE was a developed extraction technique for analytical sample preparation. The RP-HPLC-UV method was also successfully applied for the quantification of six target compounds in pyrola.
    The Analyst 06/2013; · 4.23 Impact Factor
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    ABSTRACT: Aspidin BB, an effective phloroglucinol derivative from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In this study, we analyzed the underlying mechanisms of aspidin BB on human ovarian cancer cell line, HO-8910. Aspidin BB significantly inhibited HO-8910 cell proliferation in a dose- and time-dependent manner. The IC50 values were 15.02 μM, 25.79 μM and 68.81 μM after 72 h, 48 h and 24 h treatment, respectively. Meanwhile, aspidin BB markedly induced apoptosis evidenced by characteristic apoptotic morphological changes, nuclear DNA fragmentation, annexin V-FITC/propidium iodide (PI) double staining and S peak. Western blot analysis showed that aspidin BB suppressed Bcl-2 expression and enhanced Bax expression to desintegrate the outer mitochondrial membrane, then caused cytochrome c release which led to the activation of effector caspase-3, and further cleaved the poly ADP-ribose polymerase (PARP) in the nucleus, finally induced cell apoptosis. Furthermore, aspidin BB provoked S phase arrest in HO-8910 cells with up-regulation of pRb, E2F1, CDK2, cyclin E and cyclin A proteins. Taken together, these findings support the conclusion that aspidin BB exhibits cytotoxicity towards human ovarian cancer HO-8910 cells through induction of apoptosis via mitochondrial pathway and arresting cell cycle progression in S phase.
    Chemico-biological interactions 04/2013; · 2.46 Impact Factor
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    ABSTRACT: Cajaninstilbene acid (CSA), an active compound separated from pigeon pea leaves, possesses the highly efficient antioxidant activities. Transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular oxidative stress. This study examined the role of Nrf2 in CSA-mediated antioxidant effects on human hepatocarcinoma (HepG2) cell line. The generation of reactive oxygen species (ROS) upon H2O2 and CSA treatment was lower than that of H2O2 alone. CSA activated Nrf2 as evaluated by Western blotting. A luciferase reporter assay also demonstrated that CSA-activated signaling resulted in the increased transcriptional activity of Nrf2 through binding to the antioxidant response element (ARE) enhancer sequence. Our study indicated that treatment of HepG2 cells with CSA induces Nrf2-dependent ARE activity and gene expression of heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase modifier subunits by activation of PI3K/AKT, ERK and JNK signaling pathways. Inhibition of Nrf2 by siRNA reduced CSA-induced upregulation of these Nrf2-related enzymes. These results suggest that the Nrf2/ARE pathway plays an important role in the regulation of CSA-mediated antioxidant effects in HepG2 cells.
    Toxicology Letters 03/2013; · 3.15 Impact Factor
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    ABSTRACT: AIMS: Isolation, identification and characterization of endophytes from pigeon pea [Cajanus cajan (L.) Millsp.], as novel producer of cajanol and its in vitro cytotoxicity assay. METHODS AND RESULTS: Isolation, identification and characterization of novel endophytes producing cajanol from the roots of pigeon pea were investigated. The endophytes were identified as Hypocrea lixii by morphological and molecular methods. Cajanol produced by endophytes were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). R-18 produced the highest levels of cajanol (322.4 ± 10.6 μg L(-1) or 102.8 ± 6.9 μg g(-1) dry weight of mycelium) after incubation for seven days. The cytotoxicity towards human lung carcinoma cells (A549) of fungal cajanol was investigated in vitro. CONCLUSIONS: A novel endophyte Hypocrea lixii, producing anticancer agent cajanol, was isolated from the host pigeon pea [Cajanus cajan (L.) Millsp.] firstly. Fungal cajanol possessed stronger cytotoxicity activity towards A549 cells in time- and dose-dependent manners. SIGNIFICANCE AND IMPACT OF THE STUDY: This endophyte is a potential handle for scientific and commercial exploitation, and it could provide a promising alterative approach for large-scale production of cajanol to satisfy new anticancer drug development. © 2013 The Authors Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.
    Journal of Applied Microbiology 03/2013; · 2.20 Impact Factor
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    ABSTRACT: A new biotransformation method of producing resveratrol with co-immobilized edible Aspergillus niger and Yeast (AY) was investigated. The biotransformation conditions were optimized for the resveratrol production under 30°C, pH 6.5, 2days, liquid-solid ratio 12:1 (mL/g), the yield of resveratrol reached 33.45mg/g, which increased 11-fold to that of untreated one. The conversion rate of polydatin reached 96.7%. The residual activity of immobilized microorganism was 83.2% after used for 15 runs. The developed method could be an effectively alternative biotransformation method for producing resveratrol from the plants.
    Bioresource Technology 03/2013; · 4.75 Impact Factor
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    ABSTRACT: Dihydroquercetin (DHQ) is a well-known antioxidant agent. In the present investigation, we reported for the first time that DHQ stimulates the expression of phase II detoxifying enzymes through the Nrf2-dependent signaling pathway. The IC50 values of DHQ for reduction of 2,2-diphenyl-1-picrylhydrazol (DPPH), reducing power assay, lipid peroxidation assay, and xanthine oxidase inhibition were 5.96, 4.31, 2.03, and 13.24 μM, respectively. DHQ possessed considerable protective activity from oxidative DNA damage. A luciferase reporter assay also demonstrated that DHQ-activated signaling resulted in the increased transcriptional activity of Nrf2 through binding to the ARE (antioxidant response element) enhancer sequence. Furthermore, Western blotting and luciferase assay revealed DHQ activated ERK1/2, Akt, and JNK signaling pathways, subsequently leading to Nrf2 nuclear translocation. DHQ upregulated the Nrf2-related antioxidant genes heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase-1 (NQO1), and glutamate-cysteine ligase modifier subunits. Inhibition of Nrf2 by siRNA reduced DHQ-induced upregulation of these antioxidant genes.
    Journal of Agricultural and Food Chemistry 03/2013; · 2.91 Impact Factor
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    ABSTRACT: In the present study, the main natural estrogen-agonist/antagonist from Pigeonpea roots was studied by the estrogen receptor α-dependent signaling pathway in human prostate cancer cell. First, the natural products with estrogenic activity in Pigeonpea roots were screened by pER8-GFP transgenic Arabidopsis, and cajanol (5-hydroxy-3-(4-hydroxy-2-methoxyphenyl)-7-methoxychroman-4-one) was confirmed as the active compound. Further study showed that cajanol significantly arrested the cell cycle in the G1 and G2/M phase and induced nuclei condensation, fragmentation and the formation of apoptotic bodies. Western blotting showed that cajanol modulated the ERα-dependent PI3K pathway and induced the activation of GSK3 and CyclinD1 closely following the profile of PI3K activity. Based on above results, we proposed a mechanism through which cajanol could inhibit survival and proliferation of estrogen-responsive cells (PC-3 cells) by interfering with an ERα-associated PI3K pathway, following a process that could be dependent of the nuclear functions of the ERα. Above all, we conclude that cajanol represents a valuable natural phytoestrogen source and may potentially be applicable in health food industry. Copyright © 2013 John Wiley & Sons, Ltd.
    Phytotherapy Research 02/2013; · 2.07 Impact Factor

Publication Stats

138 Citations
14 Downloads
3k Views
159.49 Total Impact Points

Institutions

  • 2012–2014
    • Northeast Forestry University
      • • State Key Laboratory of Tree Breeding
      • • Key Laboratory of Plant Ecology, Ministry of Education
      Charbin, Heilongjiang Sheng, China