Papers by Keyword: Reducing Power

Abstract: The antioxidant activities of extracts and residuum of Perillafrutescens fruits from supercritical CO₂ extraction were determined in vitro. The residuum was extracted in turn with water, propyl alcohol and ethyl acetate. The antioxidant activities of the extracts were assayed with antioxidant capacity in linoleic acid model system, reducing powers, radical scavenging activity using 1,1-diphenyl-2-picrylhy-drazyl (DPPH) method. The results show that the ethyl acetate extract of Perillafrutescens possesses strongest DPPH radical scavenging activity and reducing power in a concentration-dependent manner.

Abstract: In this article,Cordyceps militaris,that from Hubei and Yunnan,were used as the research objects, to extract seleno-polysaccharide ,then the antioxidant activity of seleno-polysaccharide were determined by reducing power,the scavenging capacity on superoxide anion radical and hydroxyl radical.The results indicated that,the content of selenium in Hubei and Yunnan Cordyceps militaris samples were 210.0μg/g and 57.5μg/g,respectively;the share of Se-polysaccharide in total selenium were 11.086% and 26.713%,respectively,lower degree to turn the selenium organic in Hubei Cordyceps militaris.The reducing power of seleno-polysaccharide from Hubei and Yunnan Cordyceps militaris were 0.0253,0.0297,respectively;two kinds of Cordyceps militaris have certain ability to remove superoxide anion radical and different between them,the seleno-polysaccharide of Yunnan Cordyceps militaris has a better effect to remove superoxide anion radical under different sample amount.About hydroxyl radical,there were no ability to remove it.

Abstract: Pulverized rhizome of Curcuma peliolata on hydrodistillation, afforded light yellow essential oil in the yield of 0.13% v/w. The chemical constituent of the essential oil was determined by GC-MS. Nine compounds representing 95.34 % of the total oil were identified. The major compounds of the oil were 2-methyl-5-pentanol, 1H-pyrrol-1-amine,2-(4-methoxyphenyl)-n,n,5-trimethyl, and curcumol. The distillated aqueous was extracted with dicloromethane (DCM), ethyl acetate (EtOAc), and n-butanol. The DPPH radical scavenging and reducing power of the extracts were investigated. Curcumin and ascorbic acid were used as standard references. The DPPH radical scavenging activity was decrease in order: curcumin ascorbic acid EtOAc extract > DCM extract > n-butanol extract > aqueous extract. The EtOAc extract showed significantly highest inhibition of the radical scavenging activity with IC₅₀ 0.092 ± 0.001 mg/mL (curcumin and ascorbic acid (IC₅₀ 0.012 and 0.013 mg/mL, respectively (P<0.05)). While, the DCM extract showed highest reducing power with IC₅₀ = 0.271 mg/mL which lower than that of standard curcumin (IC₅₀ = 0.013 mg/mL) and ascorbic acid (IC₅₀ = 0.002 mg/mL).Introduction

Abstract: The Ablmoschus manihot (L.) Medic, an edible hibiscus of the Malvaceae family, is abundant with total flavonoid. The content of total flavonoid from A. manihot flowers (TFA) was extracted by 70% ethanol (ethanol:water, 70:30). The scavenging effects of TFA on superoxide anions and hydrogen radicals were related to the total flavonoid concentrations with the IC50 values of 63.90 ±2.21 μg/mL and 266.88±28.32 μg/mL, respectively. However, the IC50 values of standard ascorbic acid were 436.52 ±14.36 μg/mL and 439.58±21.41 μg/mL, respectively. The DPPH radical scavenging activity increased with increasing of TFA concentrations and the highest inhibition was 94.63 ±3.01% at 50 μg/mL, as compared to ascorbic acid 34.94 ±1.50%. The extract also showed good reducing power. The data from this study suggest A. manihot flower extract has significant potential to use as health supplements and nutraceuticals.

Abstract: Collagen was extracted from jellyfish (Stomolophus meleagris) and hydrolyzed to prepare collagen peptides. Three fractions (JCP-1<1kDa, 1kDa3kDa) were collected by ultrafiltration from jellyfish collagen peptides and inhibitory abilities of melanogenesis were evaluated using cultured B16 melanoma cells. The results showed three fractions could inhibit intracellular tyrosinase activity, decrease melanin content and enhance glutathione synthesis. Furthermore, they decreased intracellular cAMP levels and suppressed tyrosinase mRNA expression. JCP-2 showed much higher anti-melanogeneic activities than JCP-1 and JCP-3 because of its amino acids composition and molecular weight distribution. Our results indicated JCP-2 could be used as a natural skin-lightening agent in the medicine and food industries.

Abstract: Holiota nameko is an edible mushroom widely cultivated in the northeast of China. The cold water, hot water and ethanol extracts were prepared and their antioxidant properties were studied. At 2 mg/mL, the cold water extract showed a high reducing power of 1.502, whereas those of hot water and ethanol extracts were 0.868 and 0.159. With regard to the scavenging ability on DPPH free radicals, extracts were effective in the order: cold water > hot water > ethanol extracts. EC50 values for chelating ability on ferrous ions for cold water, hot water, and ethanol extracts were 1.461, 0.663, and 11.791 mg/mL, respectively. Based on EC50 values, the water extracts of P. nameko were effective antioxidants.

Abstract: The petroleum ether, acetic ester, methanol and water extracts of laoying tea were prepared and their antioxidant properties were studied. At 160 µg/mL, the methanol extract showed a high reducing power of 1.206. With regard to the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, extracts were effective in the order: methanol > acetic ester > water > petroleum ether extracts. EC₅₀ values for chelating ability on ferrous ions for petroleum ether, acetic ester, methanol and water extracts were 11.76, 14.32, 6.05 and 1.02 mg/mL, respectively. Based on EC₅₀ values, the various extracts from laoying tea were effective antioxidants.

Abstract: The total anthocyanin content (TAC) of pigment extracted from fruits of Padus racemosa and Padus virginiana was determined by pH-differential method. TAC in pigment from fruits of Padus racemosa was higher than that in Padus virginiana. The vitro antioxidant activity of the two kinds of pigment was evaluated by different assays, including DPPH• assay, ABTS•⁺ assay, OH• assay and reducing power assay. The results showed that except for reducing power, pigment from fruit of Padus racemosa showed stronger ABTS•⁺, DPPH• and OH• radical scavenging activity than pigment from fruit of Padus virginiana. The study concluded that pigment extracted from fruit of Padus racemosa and Padus virginiana can be used as a source of natural antioxidants instead of synthetic antioxidants.

Abstract: Chroogomphis rutillus is an ectomycorrhizal edible mushroom available in China. The ethanolic, cold water and hot water extracts were prepared and their antioxidant properties studied. At 4 mg/mL, the ethanolic extract showed a high reducing power of 1.561, whereas those of cold water and hot water extracts were 1.161 and 0.808. With regard to the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, extracts were effective in the order: ethanolic > cold water > hot water extracts. EC₅₀ values for chelating ability on ferrous ions for ethanolic, cold water and hot water extracts were 15.755, 0.059, and 0.067 mg/mL, respectively. Based on EC₅₀ values, the various extracts from C. rutillus were effective antioxidants.

Abstract: The polyphenol and flavonoid contents and antioxidation capabilities, including total reducing power, DPPH radical scavenging capability and lipid peroxidation inhibition, of ethanol extracts of water hyacinth (Eichhomia crassipes) were investigated and compared with those extracted from red tide seaweed (Enteromorpha prolifera) and from the most common seaweed (Porphyra haitanensis). Results showed that E. crassipes contained higher amounts of polyphenols [6.68 mg gallic acid equivalents (GAE)/g] in the leaf than in the stem (4.37 mg GAE/g) or in P. haitanensis (4.27 mg GAE/g). The E. crassipes also contained higher contents of flavonoids [1524 and 453 mg rutin equivalents (RE)/g in leaf and stem, respectively] than did E. prolifera (233 mg RE/g). Accordingly, both the leaf and stem of E. crassipes had relatively higher reducing power [118.35 and 47.21 100μg ascorbic acid equivalents (AscAE)/g, respectively] and DPPH radical scavenging capability (74.6% for leaf and 62.7% for stem) when compared with E. prolifera (reducing power of 16.5 and DPPH radical scavenging capability of 42.96%). Statistical analysis showed that the antioxidation capabilities, especially reducing power, of extracts of the three aquatic plants were positively correlated with their total polyphenol contents, but not with the contents of flavonoids. The correlation coefficient (r) of the content of polyphenols and reducing power of those extracts was r=0.9028, that for DPPH scavenging and lipid peroxidation inhibition was r=0.9311 and 0.9099, respectively. These results indicated that phenolic compounds are the main compounds contributing to the antioxidation activities of seaweed extracts. E. crassipes can be a source for extracting natural antioxidants.