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ABSTRACT: Oat contains different components that possess antioxidant properties; no study to date has addressed the antioxidant effect of the extract of oat bran on the cellular level. Therefore, the present study focuses on the investigation of the protective effect of oat bran extract by enzymatic hydrolysates on human dermal fibroblast injury induced by hydrogen peroxide (H(2)O(2)). Kjeldahl determination, phenol-sulfuric acid method, and high-performance liquid chromatography (HPLC) analysis indicated that the enzymatic products of oat bran contain a protein amount of 71.93%, of which 97.43% are peptides with a molecular range from 438.56 to 1301.01 Da. Assays for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity indicate that oat peptide-rich extract has a direct and concentration-dependent antioxidant activity. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and the TdT-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay for apoptosis showed that administration of H(2)O(2) in human dermal fibroblasts caused cell damage and apoptosis. Pre-incubation of human dermal fibroblasts with the Oatp for 24 h markedly inhibited human dermal fibroblast injury induced by H(2)O(2), but application oat peptides with H(2)O(2) at same time did not. Pre-treatment of human dermal fibroblasts with Oatp significantly reversed the H(2)O(2)-induced decrease of superoxide dismutase (SOD) and the inhibition of malondialdehyde (MDA). The results demonstrate that oat peptides possess antioxidant activity and are effective against H(2)O(2)-induced human dermal fibroblast injury by the enhanced activity of SOD and decrease in MDA level. Our results suggest that oat bran will have the potential to be further explored as an antioxidant functional food in the prevention of aging-related skin injury.
Journal of Zhejiang University SCIENCE B 02/2013; 14(2):97-105. · 1.10 Impact Factor
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ABSTRACT: Two new steroidal saponins, dioscins E (1) and F (2), along with nine known steroidal saponins, were isolated from the biotransformation product of the rhizomes of Dioscorea nipponica using Aspergillus oryzae. The structures of new compounds were established as 25(R)-spirost-5-en-21β-methyl-3β-ol-3-O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (1) and (25R)-spirost-5-en-3β-ol-7-one 3-O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (2) by detailed spectroscopic analyses including 1D and 2D NMR spectral data ((1)H-(1)H COSY, HSQC, and HMBC) and MS spectrometry.
Journal of Asian natural products research 05/2012; 14(7):640-6. · 0.61 Impact Factor
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ABSTRACT: Recent studies have shown that dermal fibroblasts possess multiple types of voltage-dependent K(+) channels, and the activation of these channels induces apoptosis. In the present study, we aimed to investigate whether hydrogen peroxide (H(2)O(2)), an oxidative stress inducer, could modulate these channels or induce human dermal fibroblasts injury.
The effects of H(2)O(2) on K(+) currents were studied using a whole-cell recording. Intracellular PKC levels were measured with a direct human PKC enzyme immunoassay kit. Cell viability was assessed using PI staining and apoptotic nuclei were detected with TdT-mediated digoxigenin-dUTP nick-end labelling assay (TUNEL) assay.
Treatment of cells with 100μM H(2)O(2) resulted in a partially reversible increase in non-inactivating outward K(+) currents and an alteration in the steady-state activation property of the channels. The H(2)O(2)-induced increase in K(+) currents was mimicked by a PKC activator, and was blocked by the PKC inhibitor or the large conductance Ca(2+)-activited K(+) (BK) channel blockers. The intracellular PKC levels were significantly enhanced by H(2)O(2) treatment in a concentration-dependent manner. After exposure to H(2)O(2), evaluation of fibroblasts survival rate and damaged cell number with TUNEL-positive nuclei revealed an increased cell injury. Blocking the K(+) channels with blockers significantly decreased the H(2)O(2)-induced human dermal fibroblasts injury.
Our results revealed that H(2)O(2) could enhance BK currents by PKC pathway. Increased K(+) currents might be related to H(2)O(2)-induced human dermal fibroblasts injury. The results reported here contribute to our understanding of the mechanism underlying H(2)O(2)-induced human dermal fibroblasts injury.
Life sciences 03/2012; 90(11-12):424-31. · 2.56 Impact Factor
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ABSTRACT: Five new glucosylated steroidal glycosides, cantalasaponin I-B(1) (1), I-B(2) (2), I-B(3) (3), I-B(4) (4) and I-B(5) (5), were isolated and purified from the transformed product of the cantalasaponin I by using Toruzyme 3.0 l as biocatalyst. Their structures were elucidated on the basis of high-resolution electrospray ionization mass spectrometry, one-dimensional ((1) H and (13) C NMR) and two-dimensional [COSY, heteronuclear single-quantum correlation (HSQC), HMBC and HSQC-TOCSY] NMR spectral analyses and chemical evidence.
Magnetic Resonance in Chemistry 01/2012; 50(1):79-83. · 1.44 Impact Factor
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Xu Pang,
Yue Cong,
He-Shui Yu,
Li-Ping Kang, Bing Feng,
Bing-Xing Han,
Yang Zhao,
Cheng-Qi Xiong,
Da-Wei Tan,
Wei Song,
Bin Liu,
Yu-Wen Cong,
Bai-Ping Ma
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ABSTRACT: Nine spirostanol saponins (1-9) and seven mixtures of 25 R and 25 S spirostanol saponin isomers (10-16) were obtained from the seeds of Trigonella foenum-graecum after enzymatic hydrolysis of the furostanol saponin fraction by β-glucosidase. Their structures were determined by NMR and MS spectroscopy. Among them, 1- 4, 6, 8, and 9 were new compounds and five, 11B, 12A, 13B, 14A, and 14B, were new structures observed from seven mixtures. In addition, the inhibitory effects of all saponins on rat platelet aggregation were evaluated.
Planta Medica 11/2011; 78(3):276-85. · 2.15 Impact Factor
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ABSTRACT: Abstract Five commercial enzyme preparations were screened for hydrolysis of the glucuronic acid units of glycyrrhizin (GL) and baicalin. Two preparations hydrolyzing GL to glycyrrhetic acid (GA) and four enzyme preparations hydrolyzing baicalin to baicalein were obtained. One enzyme preparation with the ability to hydrolyze both GL and baicalin, namely Rapidase Pineapple, was purified by anion exchange, cation exchange and molecular sieve chromatography. The results of purification indicated that the enzymes containing the glycyrrhizin-β-d-glucuronidase (GBDG) and baicalin-β-d-glucuronidase (BBDG) activities were distinct, with different substrate specificities, molecular weights and enzymatic characteristics. GBDB hydrolyzed GL to GA, but had no detectable activity on baicalin, and BBDG hydrolyzed baicalin to baicalein, but could not hydrolyze GL. However, both GBDG and BBDG could hydrolyze the artificial substrate p-nitrophenyl- β-d-glucuronide (pNPGA).
09/2011; 29(5):179-185.
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ABSTRACT: Timosaponin BII (1), a steroidal saponin showing potential anti-dementia activity, was regioselectively hydrolyzed into its deglycosyl derivatives by the crude enzyme from Aspergillus niger AS 3.0739. Three biotransformation products, timosaponin BII-a (2), timosaponin BII-b (3), and timosaponin BII-c (4), were purified and their structures were elucidated on the basis of 1D NMR, 2D NMR, FAB-MS, and HR-ESI-MS spectral data. Compounds 2 and 3 are new compounds.
Journal of Asian natural products research 11/2010; 12(11):955-61. · 0.61 Impact Factor
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ABSTRACT: It is known that the sugar chains of steroidal saponins play an important role in the biological and pharmacological activities. In order to synthesize steroidal saponins with novel sugar chains in one step for further studies on pharmacological activity, we here describe the glucosylation of steroidal saponins, and 5 compounds, timosaponin AIII (1), saponin Ta (2), saponin Tb (3), trillin (4) and cantalasaponin I (5), were converted into their glucosylated products by Toruzyme 3.0 L, a cyclodextrin glucanotransferase (CGTase). 12 glucosylated products were isolated and their structures elucidated on the basis of spectral data; they were all characterized as new compounds. The results showed that Toruzyme 3.0 L had the specific ability to add the α-D-glucopyranosyl group to the glucosyl group linked at the sugar chains of steroidal saponins, and the glucosyl group was the only acceptor. This is the first report of steroidal saponins with different degrees of glucosylation. The substrates and their glucosylated derivatives were evaluated for their cytotoxicity against HL-60 human promyelocytic leukemia cell by MTT assay. The substrates all exhibited high cytotoxicity (IC(50) < 10 µmol/L), excluding compound 5 (IC(50) > 150 µmol/L), and the cytotoxicity of most of the products showed no obvious changes compared with those of their substrates.
Planta Medica 10/2010; 76(15):1724-31. · 2.15 Impact Factor
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Wen-bin Zhou, Bing Feng,
Hong-zhi Huang,
Yu-juan Qin,
Yong-ze Wang,
Li-ping Kang,
Yang Zhao,
Xiao-nan Wang,
Yun Cai,
Da-wei Tan,
Bai-ping Ma
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ABSTRACT: Timosaponin BII (BII), a steroidal saponin showing potential anti-dementia activity, was converted into its glucosylation derivatives by Toruzyme 3.0L. Nine products with different degrees of glucosylation were purified and their structures were elucidated on the basis of (13)C NMR, HR-ESI-MS, and FAB-MS spectra data. The active enzyme in Toruzyme 3.0L was purified to electrophoretic homogeneity by tracking BII-glycosylase activity and was identified as Cyclodextrin-glycosyltransferase (CGTase, EC 2.4.1.19) by ESI-Q-TOF MS/MS. In this work, we found that the active enzyme catalyzed the synthesis of alpha-(1-->4)-linked glucosyl-BII when dextrin instead of an expensive activated sugar was used as the donor and showed a high thermal tolerance with the most favorable enzymatic activity at 100 degrees C. In addition, we also found that the alpha-amylases and CGTase, that is, GH13 family enzymes, all exhibited similar activities, which were able to catalyze glucosylation in steroidal saponins. But other kinds of amylases, such as gamma-amylase (GH15 family), had no such activity under the same reaction conditions.
Carbohydrate research 08/2010; 345(12):1752-9. · 2.03 Impact Factor
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ABSTRACT: It has been previously reported that a glucoamylase from Curvularia lunata is able to hydrolyze the terminal 1,2-linked rhamnosyl residues of sugar chains at C-3 position of steroidal saponins. In this work, the enzyme was isolated and identified after isolation and purification by column chromatography including gel filtration and ion-exchange chromatography. Analysis of protein fragments by MALDI-TOF/TOF proteomics Analyzer indicated the enzyme to be 1,4-alpha-D-glucan glucohydrolase EC 3.2.1.3, GA and had considerable homology with the glucoamylase from Aspergillus oryzae. We first found that the glucoamylase was produced from C. lunata and was able to hydrolyze the terminal rhamnosyl of steroidal saponins. The enzyme had the general character of glucoamylase, which hydrolyze starch. It had a molecular mass of 66 kDa and was optimally active at 50 degrees C, pH 4, and specific activity of 12.34 U mg of total protein(-1) under the conditions, using diosgenin-3-O-alpha-L-rhamnopyranosyl(1-->4)-[alpha-L-rhamnopyranosyl (1-->2)]-beta-D-glucopyranoside (compound II) as the substrate. Furthermore, four kinds of commercial glucoamylases from Aspergillus niger were investigated in this work, and they had the similar activity in hydrolyzing terminal rhamnosyl residues of steroidal saponin.
Applied Microbiology and Biotechnology 10/2007; 76(6):1329-38. · 3.42 Impact Factor
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Bing Feng,
Hong-zhi Huang,
Wen-bin Zhou,
Li-ping Kang,
Peng Zou,
Yi-xun Liu,
He-shui Yu,
Bin-qing Han,
Ya-yong Li,
Ling-ling Zhang,
Tao Zhang,
Bai-ping Ma
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ABSTRACT: It is known that the sugar chain linked to steroidal frame plays an important role in physiological and pharmacological activities. In the previous research, we found and confirmed that the terminal C3-O-α-1,2-rhamnosyl moiety linked to the C-3 of steroidal saponin is the key group of platelet aggregation and cytotoxicity. In order to make a complete approach for the structure–activity relationship, we have tried to find the specific enzymes modifying the structure of C3-sugar chain. In the present paper, we describe a novel enzyme from, Klerzyme-150 (K-150), which is specifically capable of hydrolyzing the α-1,4-glycosyl residues at C-3 postion of steroidal saponins. 15 steroidal saponins with different monosaccharides at C3-sugar chains were chosen as substrates to investigate the substrate specificity of K-150. The results showed, based on TLC, HPLC and spectra data analyses, that all products were determined as secondary saponins with the α-1, 4-glycosyl residues removed, which indicated that the enzyme exhibited strict regioselectivity and stereoselectivity. The novel enzyme was purified from K-150 to apparent homogeneity and its structure was identified as rhamnogalacturonan lyase A (Rgl A). The molecular mass of the purified enzyme was 52.08 kDa.
Process Biochemistry.
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ABSTRACT: This study was conducted to investigate the protective effects of epigallocatechin-3-gallate (EGCG) on hydrogen peroxide (H2O2)-induced oxidative stress injury in human dermal fibroblasts. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay and the use of Hoechst staining and terminal deoxynucleotidyl transferase dUTP nick end labeling for apoptosis detection indicated that the administration of H2O2 to human dermal fibroblasts caused cell damage and apoptosis. The incubation of human dermal fibroblasts with EGCG markedly inhibited the human dermal fibroblast injury induced by H2O2. The assay for 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity indicated that EGCG had a direct, concentration-dependent antioxidant activity. Treatment of human dermal fibroblasts with EGCG significantly reversed the H2O2-induced decrease of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px), and the inhibition of malondialdehyde (MDA) levels. These results showed that EGCG possessed antioxidant activity and was effective against H2O2-induced human dermal fibroblast injury by enhancing the activity of SOD and GSH-px, and by decreasing the MDA level. Our results suggested that EGCG should have the potential to be used further in cosmetics and in the prevention of aging-related skin injuries.
Journal of cosmetic science 64(1):35-44. · 0.28 Impact Factor
