Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to ...Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu’s phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 ±15.5 and 511.6±6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH˙) colorimetry with detection scheme at 515 nm. The activity was evalu- ated by the decrease in absorbance as the result of DPPH˙ color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC50 and the time needed to reach the steady state to EC50 concentration ( TEC50 ) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more ade- quate parameter for selecting antioxidants than the widely used EC50. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.展开更多
Eight compounds were isolated from the ethyl acetate- and n-butanol-soluble fractions of the ethanollc extract of the whole plant of Anoectochllus roxburghll（Wali.） Lindi. （Orchidaceee）. On the basis of spectrosco...Eight compounds were isolated from the ethyl acetate- and n-butanol-soluble fractions of the ethanollc extract of the whole plant of Anoectochllus roxburghll（Wali.） Lindi. （Orchidaceee）. On the basis of spectroscopic methods, the structures of these compounds were elucidated as quercetin-7-O-β-D-[6＂-O-（trans-feruloyi）]- giucopyranosids （compound 1）, 8-C-p-HydroxybenzyiquerceUn （compound 2）, isorhamnetin-7-O-β-D- giucopyranoside （compound 3）, isorhamnetin-3-O-β-D-giucopyranoside （compound 4）, kaempferoi-3-O-β-D- giucopyranoside （compound 5）, kaempferoi-7-O-β-D-giucopyranoside （compound 6）, 5-hydroxy-3＇,4＇,7- trimethoxyfiavonoi-3-O-β-D-rutinoside （compound 7）, and isorhamnetin-3-O-β-D-rutinoside （compound 8）. Of the compounds isoisted, compound 1 was a new flavonoid giucoside and exhibited strong scavenging activity against the 1,1-diphenyi-2-picryihydrazyi free radical, whereas the ethanolic extract showed weak activity. Compounds 2-8 were obtained from this family for the first time.展开更多
The present study was designed to establish a multi-wavelength quantitative fingerprinting method for San-Huang Tablets(SHT), a widely used and commercially available herbal preparation, where high performance liquid ...The present study was designed to establish a multi-wavelength quantitative fingerprinting method for San-Huang Tablets(SHT), a widely used and commercially available herbal preparation, where high performance liquid chromatography(HPLC) with a diode array detector(DAD) was employed to obtain the fingerprint profiles. A simple linear quantitative fingerprint method(SLQFM)coupled with multi-ingredient simultaneous determination was developed to evaluate the quality consistency of the tested samples qualitatively and quantitatively. Additionally, the component–activity relationship between chromatographic fingerprints and total radical-scavenging capacity in vitro(as assessed using the 1, 1-diphenyl-2-picrylhydrazyl(DPPH) assay) was investigated by partial least squares regression(PLSR) analysis to predict the antioxidant capacity of new samples from the chromatographic fingerprints and identify the main active constituents that can be used as the target markers for the quality control of SHT. In conclusion, the strategy developed in the present study was effective and reliable, which can be employed for holistic evaluation and accurate discrimination for the quality consistency of SHT preparations and other traditional Chinese medicine(TCM) and herbal preparations as well.展开更多
Hybrid antioxidants cinnamoyldopamine（2a）, p-coumaroyldopamine（2b）, caffeoyldopamine（2c）, feruloyldopamine（2d） and sinapoyldopamine（2e） were synthesized by conjugation of dopamine（DA） and hydroxycinnamic a...Hybrid antioxidants cinnamoyldopamine（2a）, p-coumaroyldopamine（2b）, caffeoyldopamine（2c）, feruloyldopamine（2d） and sinapoyldopamine（2e） were synthesized by conjugation of dopamine（DA） and hydroxycinnamic acids（HCAs）. The stabilities were studied in buffers at p H 1.3, p H 5.0, and p H 7.4 including the human plasma. All the compounds were found highly stable at acidic p H, but underwent hydrolysis at neutral p H. Furthermore, the hydrolysis proceeded much faster in plasma in the following order as indicated by half-life values（t1/2）, 2c（1.21 h）〈2e（1.52 h）〈2d（1.85 h）〈2b（3.38 h）〈2a（3.88 h）, correlating with the number of electron-donating groups. It has been proven by UV spectrum that 2c, 2d, and 2e displayed red shift of more than 50 nm as compared to 2a and 2b, because of the presence of OH and OCH3 groups. In addition, the compounds（2b–e） showed no cytotoxicity on normal HUVEC cells as DA, although 2a displayed a 16% inhibition of proliferation at 40 μM following 48 h incubation. Their free radical-scavenging activities were evaluated using ABTS^＊＋ and superoxide anion assays and the mechanisms were proposed. It was found that they all exhibited higher activities than trolox, a recognized antioxidant. Amazingly, in the case of the hybrids（2a–e）, their activity was higher than that of HCAs while lower or comparable to that of DA, suggesting that there may be a ＂saturation effect＂ with the hybrid molecules in the antioxidant activities.展开更多
Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3...Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.展开更多
In this study,protein from Porphyra haitanensis was used as raw material to prepare an antioxidant peptide,and its antioxidant activity was evaluated in vitro.A model of H_2O_2-induced oxidative damage in Hep G2 cells...In this study,protein from Porphyra haitanensis was used as raw material to prepare an antioxidant peptide,and its antioxidant activity was evaluated in vitro.A model of H_2O_2-induced oxidative damage in Hep G2 cells was established,and the effects of Porphyra haitanensis hydrolysates (PHHs) on superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected.Finally,the structure of PHHs was identified by ESI-MS/MS.The results showed that the 1,1-diphenyl-2-pyridylhydrazine(DPPH)-free radical-scavenging ability of PHHs was the strongest (59.28%at 1.0 mg m L~(-1)) when hydrolyzed with an acidic protease for 4 h.PHHs with different concentrations had protective effects on H_2O_2-induced damage to Hep G2 cells,and the protective effect was enhanced with increasing concentrations.When the level was 400μg m L~(-1),the cell survival rate was as high as 88.62%.Moreover,PHHs can significantly reduce oxidative damage to Hep G2 cells by H_2O_2,improve SOD activity,and reduce MDA content.The tetrapeptide Asp-Lys-Ser-Thr,with a molecular weight of 448 Da,was identified as an important fraction of PHHs by high-resolution mass spectrometry.展开更多
The antioxidant and free radical-scavenging activities of black soybean peptides(BSP)fractions(Fra-Ⅰ,Fra-Ⅱ,Fra-Ⅲ)were investigated using reducing power and DPPH·/superoxide/hydroxyl radical-scavenging assay.Th...The antioxidant and free radical-scavenging activities of black soybean peptides(BSP)fractions(Fra-Ⅰ,Fra-Ⅱ,Fra-Ⅲ)were investigated using reducing power and DPPH·/superoxide/hydroxyl radical-scavenging assay.The reducing power activity of Fra-Ⅲwas closer to that of BHT but lower than that of ascorbic acid.Fra-Ⅲshowed the strongest scavenging activity against free radicals.The radical-scavenging effect was in a dose-dependent manner and the IC50 values for DPPH·,superoxide and hydroxyl radicals were found to be 1.873,1.684 and 1.735 mg/mL,respectively.Amino acid analysis showed that Fra-Ⅲhad high hydrophobic amino acids(HAA)content and hydrophobicity.The molecular weight distribution of Fra-Ⅲwas found to vary from 100 to 1,000 Da mainly.The antioxidant activity of Fra-Ⅲis clearly related to the amino acid composition,the content of HAA and the molecular mass.The present study suggests that BSP with low molecular weight are useful nutritional antioxidant and potential functional factor for anti-aging.展开更多
文摘Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu’s phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 ±15.5 and 511.6±6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH˙) colorimetry with detection scheme at 515 nm. The activity was evalu- ated by the decrease in absorbance as the result of DPPH˙ color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC50 and the time needed to reach the steady state to EC50 concentration ( TEC50 ) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more ade- quate parameter for selecting antioxidants than the widely used EC50. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.
基金Supported by the National Natural Science Foundation of China （30270148） and the Chinese National Science Fund for 0utstanding Youths （30325047）.
文摘Eight compounds were isolated from the ethyl acetate- and n-butanol-soluble fractions of the ethanollc extract of the whole plant of Anoectochllus roxburghll（Wali.） Lindi. （Orchidaceee）. On the basis of spectroscopic methods, the structures of these compounds were elucidated as quercetin-7-O-β-D-[6＂-O-（trans-feruloyi）]- giucopyranosids （compound 1）, 8-C-p-HydroxybenzyiquerceUn （compound 2）, isorhamnetin-7-O-β-D- giucopyranoside （compound 3）, isorhamnetin-3-O-β-D-giucopyranoside （compound 4）, kaempferoi-3-O-β-D- giucopyranoside （compound 5）, kaempferoi-7-O-β-D-giucopyranoside （compound 6）, 5-hydroxy-3＇,4＇,7- trimethoxyfiavonoi-3-O-β-D-rutinoside （compound 7）, and isorhamnetin-3-O-β-D-rutinoside （compound 8）. Of the compounds isoisted, compound 1 was a new flavonoid giucoside and exhibited strong scavenging activity against the 1,1-diphenyi-2-picryihydrazyi free radical, whereas the ethanolic extract showed weak activity. Compounds 2-8 were obtained from this family for the first time.
基金This work was finically supported by the National Natural Science Foundation of China(Nos.30800767 and 31271979)the Opening Foundation of Large-scale Equipment in Tianjin University.
基金supported by the National Science&Technology Pillar Program of China(2007BAI27B04)National Nonprofit Institute Research Grant of CATAS-ITBB(No.ITBBZD1041)
基金the Guangdong Provincial Natural Science Foundation of China(003062) Guangdong Provincial Science and Technology Planning Projects of China(2003C20406)
基金financially supported by the National Natural Science Foundation of China(No.81560695)the Doctoral Research Fund of Dali University(No.KYBS201512)
文摘The present study was designed to establish a multi-wavelength quantitative fingerprinting method for San-Huang Tablets(SHT), a widely used and commercially available herbal preparation, where high performance liquid chromatography(HPLC) with a diode array detector(DAD) was employed to obtain the fingerprint profiles. A simple linear quantitative fingerprint method(SLQFM)coupled with multi-ingredient simultaneous determination was developed to evaluate the quality consistency of the tested samples qualitatively and quantitatively. Additionally, the component–activity relationship between chromatographic fingerprints and total radical-scavenging capacity in vitro(as assessed using the 1, 1-diphenyl-2-picrylhydrazyl(DPPH) assay) was investigated by partial least squares regression(PLSR) analysis to predict the antioxidant capacity of new samples from the chromatographic fingerprints and identify the main active constituents that can be used as the target markers for the quality control of SHT. In conclusion, the strategy developed in the present study was effective and reliable, which can be employed for holistic evaluation and accurate discrimination for the quality consistency of SHT preparations and other traditional Chinese medicine(TCM) and herbal preparations as well.
基金The National Natural Science Foundation of China(Grant No.21302079)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2014-151)
文摘Hybrid antioxidants cinnamoyldopamine（2a）, p-coumaroyldopamine（2b）, caffeoyldopamine（2c）, feruloyldopamine（2d） and sinapoyldopamine（2e） were synthesized by conjugation of dopamine（DA） and hydroxycinnamic acids（HCAs）. The stabilities were studied in buffers at p H 1.3, p H 5.0, and p H 7.4 including the human plasma. All the compounds were found highly stable at acidic p H, but underwent hydrolysis at neutral p H. Furthermore, the hydrolysis proceeded much faster in plasma in the following order as indicated by half-life values（t1/2）, 2c（1.21 h）〈2e（1.52 h）〈2d（1.85 h）〈2b（3.38 h）〈2a（3.88 h）, correlating with the number of electron-donating groups. It has been proven by UV spectrum that 2c, 2d, and 2e displayed red shift of more than 50 nm as compared to 2a and 2b, because of the presence of OH and OCH3 groups. In addition, the compounds（2b–e） showed no cytotoxicity on normal HUVEC cells as DA, although 2a displayed a 16% inhibition of proliferation at 40 μM following 48 h incubation. Their free radical-scavenging activities were evaluated using ABTS^＊＋ and superoxide anion assays and the mechanisms were proposed. It was found that they all exhibited higher activities than trolox, a recognized antioxidant. Amazingly, in the case of the hybrids（2a–e）, their activity was higher than that of HCAs while lower or comparable to that of DA, suggesting that there may be a ＂saturation effect＂ with the hybrid molecules in the antioxidant activities.
基金supported by the High Technology Research and Development Program of China (No. 2006AA09Z438)the National Natural Science Foundation of China (No. 30871943).
文摘Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.
基金supported by the National Key R&D Pro-gram of China (No. 2018YFD0901102)the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2020KJ151)+1 种基金the Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences (No. 2020 TD69)the China Agriculture Research System (No. CARS-50)。
文摘In this study,protein from Porphyra haitanensis was used as raw material to prepare an antioxidant peptide,and its antioxidant activity was evaluated in vitro.A model of H_2O_2-induced oxidative damage in Hep G2 cells was established,and the effects of Porphyra haitanensis hydrolysates (PHHs) on superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected.Finally,the structure of PHHs was identified by ESI-MS/MS.The results showed that the 1,1-diphenyl-2-pyridylhydrazine(DPPH)-free radical-scavenging ability of PHHs was the strongest (59.28%at 1.0 mg m L~(-1)) when hydrolyzed with an acidic protease for 4 h.PHHs with different concentrations had protective effects on H_2O_2-induced damage to Hep G2 cells,and the protective effect was enhanced with increasing concentrations.When the level was 400μg m L~(-1),the cell survival rate was as high as 88.62%.Moreover,PHHs can significantly reduce oxidative damage to Hep G2 cells by H_2O_2,improve SOD activity,and reduce MDA content.The tetrapeptide Asp-Lys-Ser-Thr,with a molecular weight of 448 Da,was identified as an important fraction of PHHs by high-resolution mass spectrometry.
文摘The antioxidant and free radical-scavenging activities of black soybean peptides(BSP)fractions(Fra-Ⅰ,Fra-Ⅱ,Fra-Ⅲ)were investigated using reducing power and DPPH·/superoxide/hydroxyl radical-scavenging assay.The reducing power activity of Fra-Ⅲwas closer to that of BHT but lower than that of ascorbic acid.Fra-Ⅲshowed the strongest scavenging activity against free radicals.The radical-scavenging effect was in a dose-dependent manner and the IC50 values for DPPH·,superoxide and hydroxyl radicals were found to be 1.873,1.684 and 1.735 mg/mL,respectively.Amino acid analysis showed that Fra-Ⅲhad high hydrophobic amino acids(HAA)content and hydrophobicity.The molecular weight distribution of Fra-Ⅲwas found to vary from 100 to 1,000 Da mainly.The antioxidant activity of Fra-Ⅲis clearly related to the amino acid composition,the content of HAA and the molecular mass.The present study suggests that BSP with low molecular weight are useful nutritional antioxidant and potential functional factor for anti-aging.
