-
[show abstract]
[hide abstract]
ABSTRACT: Ultrasound-assisted extraction was employed to extract polysaccharides from longan seed (LSP), with aids of a Box-Behnken statistical design to investigate the effects of ultrasonic power, time and liquid/solid ratio on the extraction recovery of the LSP. The structural analysis indicated that arabinose, galactose, glucose and mannose were major components of LSP, with →6)-Gal-(→1, Glc-(→1 and →6)-Glc-(1→ glycosidic linkages. In an in vitro antioxidant activity of the 1,1-diphenyl-2-picryldydrazyl radical-scavenging assay, LSP exhibited a dose-dependent property within the concentration range tested.
Carbohydrate polymers. 01/2013; 92(1):758-64.
-
[show abstract]
[hide abstract]
ABSTRACT: Litchi (Litchi chinensis Sonn.) is a delicious fruit widely accepted by consumers all over the world. In this work, phytochemical investigation of litchi pericarp methanol extracts led to the isolation of a novel phenolic, 2-(2-hydroxyl-5-(methoxycarbonyl) phenoxy) benzoic acid, together with kaempferol, isolariciresinol, stigmasterol, butylated hydroxytoluene, 3,4-dihydroxyl benzoate, methyl shikimate and ethyl shikimate. Most were found in litchi pericarp for the first time. Their structures were mainly elucidated by NMR and MS evidences. Antioxidant activities of the eight compounds were determined by a DPPH radical scavenging assay and the results showed that 2-(2-hydroxy-5-(methoxycarbonyl) phenoxy)benzoic acid, kaempferol, isolariciresinol, butylated hydroxytoluene and 3,4-dihydroxy benzoate exhibited good antioxidant activities. An interesting finding was that butylated hydroxytoluene was detected as a natural antioxidant in this work, which was usually taken as a synthesized antioxidant. Furthermore, the novel compound exhibited no inhibitory effects against tyrosinase and α-glucosidase activities.
Food Chemistry 01/2013; 136(2):563-8. · 3.65 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study was conducted to increase the bioactivity of litchi pericarp polysaccharides (LPPs) biotransformed by Aspergillus awamori. Compared to the non-A. awamori-fermented LPP, the growth effects of A. awamori-fermented LPP on Lactobacillus bulgaricus and Streptococcus thermophilus were four and two times higher after 3 days of fermentation, respectively. Increased 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and DNA protection activity of litchi pericarp polysaccharides were also achieved after A. awamori fermentation. Moreover, the relative content of glucose and arabinose in LPP after fermentation decreased from 58.82% to 22.60% and from 18.82% to 10.09%, respectively, with a concomitant increase in the relative contents of galactose, rhamnose, xylose, and mannose. Furthermore, lower molecular weight polysaccharides were obtained after A. awamori fermentation. It can be concluded that A. awamori was effective in biotransforming LPP into a bioactive mixture with lower molecular weight polysaccharides and higher antioxidant activity and relative galactose content.
BioMed research international. 01/2013; 2013:413793.
-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Litchi (Litchi chinensis Sonn.) pericarp is a major byproduct which contains a significant amount of polyphenol. This study was designed to biotransformation litchi pericarp extract (LPE) by Aspergillus awamori to produce more bioactive compounds with stronger antioxidant activities. RESULTS: The study exhibited that the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities significantly (p < 0.05) increased from 15.53% to 18.23% in the water-extracted fraction and from 25.41% to 36.82% in the ethyl acetate-extracted fraction. Application of DNA cleavage assay further demonstrated the enhanced protection effect of the fermented phenolics on DNA damage. It is also noted that the water-extracted fraction of the fermented LPE possessed a much stronger capacity than the ethyl acetate-extracted fraction to prevent from damage of supercoiled DNA. Interestingly, it was found that some new compounds such as catechin and quercetin appeared after of A. awamori fermentation of LPE, which could account for the enhanced antioxidant activity. CONCLUSION: The DPPH radical scavenging activity and DNA protection effect of LPE were increased by Aspergillus awamori bioconversion while some compounds responsible for the enhanced antioxidant activity were identified. This study provided an effective way of utilizing fruit pericarp as a readily accessible source of the natural antioxidants in food industry and, thus, extended the application area such as fruit by-products.
Chemistry Central Journal 09/2012; 6(1):108. · 3.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Fusarium proliferatum was isolated as a major pathogen causing the Fusarium disease in harvested banana fruit. One of its major compounds, fusaric acid, was identified by high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). Because the light intensity of the luminescent bacterium Vibrio qinghaiensis sp. Nov. Q67 can be inhibited by fusaric acid, the fusaric acid content of F. proliferatum was assessed and compared by both the HPLC and luminescent bacterium methods. Although both methods afforded almost similar values of fusaric acid, the latter indicated slightly lower content than the former. Czapek medium was more suitable for the growth of F. proliferatum and fusaric acid production than modified Richard medium, with an optimum pH of approximately 7.0. However, no significant (P < 0.05) correlation was obtained between the fusaric acid production and growth of mycelia of F. proliferatum. The study suggests that the bioevaluation by use of the luminescent bacterium was effective in monitoring fusaric acid production by F. proliferatum without expensive equipment.
Analytical and Bioanalytical Chemistry 11/2011; 402(3):1347-54. · 3.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Rapid and efficient methods to assess nanoparticle toxicity are desired in current research. Here we showed that Escherichia coli labeled by green fluorescent protein can be a good model bacterium for assessing acute toxicity of TiO(2) (about 50% inhibition ratios after 135 min exposure). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that TiO(2) nanoparticles (NPs) can influence certain protein expression in the recombinant bacterium, and the obvious effects in repressed expression and elevated expression were observed in 30/40, 10/20 μg mL(-1) treated cells, respectively. However, the GFP expression (27 kD) was not influenced by introduced TiO(2) NPs. The change of the fluorescence intensity may be caused by the damage in folding and chromophore formation of the GFP post-translational modification due to generated reactive oxygen species. Furthermore, TiO(2) NPs at higher concentrations decreased their toxicity because of aggregation. 20 μg mL(-1) humic acid (HA) introduced to the medium can decrease the fluorescent inhibition owing to the barrier of steric hindrance it provides between NPs and cells.
Journal of Environmental Monitoring 01/2011; 13(1):42-8. · 1.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Ultrasonic assisted extraction was employed to extract oligosaccharides from longan fruit pericarp (OLFP). A Box-Behnken design was applied to investigate the effects of ultrasonic temperature (30-70 degrees C), power (120-300 W), and time (10-50 min) on OLFP recovery. The model showed a good agreement with the experimental results on the basis of R(2) of 0.9655 and P-value <0.05. From response surface plots, ultrasonic power, time, and temperature exhibited independent and interactive effects on OLFP recovery. The optimal conditions to obtain the highest OLFP recovery were determined to be 13 min, 121 W, and 65 degrees C. Gas chromatography analysis indicated that purified OLFP comprised Gal (71.5%), Glc (24.6%), and GalA (3.9%). The analysis of glycosidic linkages showed that the backbone consisted of -->3)-Gal-(1-->, -->6)-Gal-(1-->, Glc-(1--> and -->3)-GalA-(1--> with a molar proportion of 13:5:6:1. Furthermore, the 1,1-diphenyl-2-picryldydrazyl (DPPH) and superoxide anion radical scavenging assays showed that OLFP exhibited strong antioxidant activities in a dose-dependent manner.
Journal of Agricultural and Food Chemistry 09/2009; 57(19):9293-8. · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cinnamomum has long been regarded as a food or medicinal plant. Leaves of five species of Cinnamomum, namely C. burmanni, C. cassia, C. pauciflorum, C. tamala and C. zeylanica, were chosen to investigate their antioxidant activities in this study. C. zeylanica exhibited the highest total phenolic content while C. burmanni had the highest flavonoid content among the five species. These five species were then screened for their antioxidant potentials using various in-vitro models such as total antioxidant capability, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing power and superoxide anion scavenging activity at various concentrations. C. zeylanica showed the highest DPPH radical scavenging activity, total antioxidant activity and reducing power, while C. tamala exhibited the highest superoxide anion scavenging activity. By the analysis of the high performance liquid chromatography coupled to diode array detector (HPLC-DAD), three flavonoid compounds namely quercetin, kaempferol and quercetrin were identified and quantified. This study suggested that Cinnamomum leaf can be used potentially as a readily accessible source of natural antioxidants.Industrial relevanceThis study was focused to evaluate the antioxidant activities of five species of Cinnamomum leaf which is normally used in medicine and also used in food preparation. This study provided an alternative of utilizing Cinnamomum leaf as a readily accessible source of natural antioxidants in food and pharmaceutical industry.
Innovative Food Science & Emerging Technologies.
-
[show abstract]
[hide abstract]
ABSTRACT: Ultrasound-assisted extraction was employed to prepare polysaccharides from Isodon lophanthoides var. gerardianus (Bentham) H. Hara (Xihuangcao). Response surface methodology was used to optimize the ultrasound-assisted extraction parameters. Central-composite design was applied to estimate the effects of ultrasonic time, liquid/solid ratio and pH on the yield of the polysaccharides from I. lophanthoides var. gerardianus (Bentham) H. Hara (ILHP). A mathematical model with high fitness was obtained. Ultrasonic time, liquid/solid ratio and pH exhibited independent and interactive effects on ILHP yield. Gas chromatography analysis suggested that ILHP-3 comprised Rha, Man, Glc with relative molar percentages of 3.9%, 8.0% and 88.1%, respectively. The assay of glycosidic linkage showed that ILHP-3 was consisted of →2)-Man-(1→, →6)-Glc-(1→, →3)-Rha-(1→ with a molar proportion of 1.9:26.5:1. The average molecular weight of ILHP-3 was measured to be 247 kDa by high-performance gel permeation chromatography. Furthermore, a good antioxidant activity was observed for ILHP-3.
Carbohydrate Polymers 85(3):541-547. · 3.63 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Polysaccharides of longan fruit pericarp (PLFP) were purified by gel filtration chromatography and methylated by methyl iodide. The structure of methylated PLFP was identified by gas chromatography/mass spectrometry. The results indicated that the percentages of methylated Ara, Glc and Gal increased gradually to a maximal value with increasing volume of methyl iodide. Methylation resulted in a decrease in the DPPH radical scavenging activity of PLFP, while the superoxide anion radical scavenging activity of PLFP decreased with increasing the degree of methylation. When the degree of methylation reached up to 47.4% or a higher value, a promoted effect on the generation of superoxide anion was observed. Furthermore, a high correlation coefficient between degree of methylation and superoxide anion radical scavenging activity of PLFP was determined, which indicated the important role of hydroxyl groups of monosaccharide units in the radical scavenging activity of PLFP.
Food Chemistry.
-
[show abstract]
[hide abstract]
ABSTRACT: Hardening is an important physiological disorder of chestnut fruit during storage. In this study, polysaccharides of chestnut (PCs) at 0%, 50% and 100% degrees of hardening (DH) were extracted and then sequentially fractionated using 40% and 80% ethanol in order to obtain PCs I and II. For fresh chestnut, arabinose, fructose, glucose and galactose were the main monosaccharides of PCs I and II. Significantly positive correlations (P < 0.01) existed between xylose, galactose, arabinose contents and DH, while significantly negative correlations (P < 0.01) were present between glucose, fructose contents and DH for both PCs I and II. The appearance in hardening of chestnut fruit was accompanied with decreases in the contents of 1,3-fructose, 1,3- and 1,6-glucose, and increases of 1,4-arabinose, 1,6-galactose and 1,3-xylose. The results confirmed that cell wall degradation of chestnut induced the structural changes in PCs I and II, which further led to the occurrence of hardening.
Food Chemistry.
-
[show abstract]
[hide abstract]
ABSTRACT: Two alkali-soluble polysaccharide fractions (ASPs I and II) were extracted from longan fruit pericarp in this work. The results of chemical composition indicated that ASP I and II fractions comprised mainly of polysaccharides, proteins and lignins. Four monosaccharides, namely Xyl, Ara, Glc and Gal, were identified for both ASPs I and II. Xyl was the dominant monosaccharide in the two alkali-soluble polysaccharides with relative molar percentages of >60%. It constructed the backbone in combination with Ara for both ASPs I and II. The analysis of glycosidic linkage indicated that Xyl had two linkages,→3)-Xyl-(1→ and →3, 4)-Xyl-(1→. The substitution at C-4 position indicated that Xyl was of pyranose structure. The infrared spectra of ASPs I and II showed the characteristic bands at approximate 897 cm− 1 which indicated the β-linkage configuration of Xyl.Industrial relevanceHemicellulose has been suggested as an important polysaccharide with good pharmaceutical properties, including immune modulation and anti-cardiovascular diseases. In this work, alkali-soluble polysaccharides were extracted from longan fruit pericarp and fractionated. The structural characteristics were identified by gas chromatography/mass spectrometry and infrared spectrophotometry. The results will be helpful for application of hemicellulose in functional food industry.
Innovative Food Science & Emerging Technologies.
