Evaluation of antioxidative and mutagenic properties of 50% ethanolic extract from red beans fermented by Aspergillus oryzae

Various bean products fermented by microorganisms are commonly consumed in Asian diets; however, the safety or functional properties of fermented beans can vary with different microbial species and with different processes being applied to different beans. The objectives of this study were to evaluate the antioxidative and mutagenic properties of 50% ethanolic extracts from red beans fermented by Aspergillus oryzae. The extracts' antioxidative activities, including alpha,alpha;-diphenyl-beta-picryl-hydrazyl (DPPH) radical-scavenging effects, Fe(2+)-chelating ability, and reducing power, were studied in vitro. The antioxidative effects provided by the extracts depended strongly on their concentrations. In general, antioxidative activity increased with extract concentration to a certain point and then leveled off as the concentration further increased. The fermented red bean extracts showed less of a scavenging effect on the DPPH radical and less reducing power than the commercial antioxidants alpha-tocopherol and butylated hydroxytoluene, but better Fe(2+)-chelating ability. No mutagenicity or toxicity effect on any of the tested strains (Salmonella Typhimurium TA97, TA98, TA100, TA102, and TA1535) was found for the 50% ethanolic extracts of fermented red beans with the Ames mutagenicity assay. These results suggest that the 50% ethanolic extracts were not mutagenic.     

Antioxidant and antiradical properties of maillard reaction products in both aqueous and ethanolic fructose-glycine oligomer solutions

The purpose of this study was to evaluate the antioxidant and antiradical properties of Maillard reaction products (MRP) in both aqueous and ethanolic fructoseglycine oligomer solutions. Antioxidant and radical scavenging activities of MRPs were investigated using different in vitro assays: the ferric ion (Fe³⁺) reducing ability, cupric ion (Cu²⁺), ferrous ion (Fe²⁺) chelating effects, DPPH and ABTS radical scavenging activities, and Fe³⁺-TPTZ reducing ability. MRPs derived from fructose-diglycine (GG) were found to be effective antioxidants in different in vitro assays. The antioxidant activity was higher in ethanolic solutions than in aqueous MRP solutions.     

Antioxidant and free radical scavenging potential of Achillea santolina extracts

The antioxidative activities of hydroalcoholic extract of Achillea santolina were investigated employing various established in vitro systems including total antioxidant activity in linoleic acid emulsion system, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and hydroxyl radicals scavenging, reducing power, and inhibitory effect on protein oxidation as well as the inhibition of Fe²⁺/ascorbate induced lipid peroxidation in rat liver homogenate. Total phenolic and flavonoid content of A. santolina extract (ASE) was also determined by a colorimetric method. The results revealed that ASE has notable inhibitory activity on peroxides formation in linoleic acid emulsion system along with concentration-dependent quenching of DPPH and superoxide radicals. Furthermore, the extract showed both nonsite-specific (Fe²⁺ + H₂O₂ + EDTA) and site-specific (Fe²⁺ + H₂O₂) hydroxyl radical scavenging suggesting potent hydroxyl radical scavenging and chelating ability for iron ions in deoxyribose degradation model. A linear correlation between ASE and the reducing power was also observed (r² = 0.9981). ASE prevents thiobarbituric acid reactive substances formation in Fe²⁺/ascorbate induced lipid peroxidation in rat liver tissue in a dose-dependent manner. Moreover, free radical induced protein oxidation was suppressed significantly by the addition of ASE over a range of concentration. These results clearly demonstrated that A. santolina extract possess a marked antioxidant activity.     

Antioxidant activities of red pepper (Capsicum annuum) pericarp and seed extracts

In this study, we examined the antioxidant activities of red pepper (Capsicum annuum, L.) pericarp and red pepper seed extracts. The extracts were evaluated by various antioxidant assays, including 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging, hydroxyl radical scavenging, [2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid)] (ABTS) radical scavenging, ferrous chelating activity, superoxide dismutase (SOD) activity and reducing power, along with the determination of total phenolic and flavonoid contents. All the extracts showed strong antioxidant activity by the testing methods. The red pepper pericarp extract exhibited strong ferrous chelating activity and high scavenging activity against free radicals, including both the hydroxyl and DPPH radicals, but it exhibited weaker scavenging activity for the superoxide anion radical and for SOD. In contrast, the red pepper seed extract exhibited strong SOD activity and high scavenging activity against the superoxide anion radical, but showed weaker ferrous chelating activity, hydroxyl radical scavenging, and DPPH radical scavenging. We observed that the reducing power level and ABTS radical scavenging activity of the red pepper seed were higher than those of the red pepper pericarp at the highest tested concentration. Most of the test results for the red pepper seed and red pepper pericarp extracts increased markedly with increasing concentration; however, the metal chelating, SOD and ABTS radical scavenging activities did not increase with the concentration. Highest total phenolic and flavonoid contents were obtained from the red pepper pericarp extracts. Overall, the red pepper seed and red pepper pericarp extracts were highly effective for the antioxidant properties assayed, with the exceptions of ferrous chelating activity, hydroxyl radical scavenging and SOD activity.     

Storage temperature and packaging condition affect the total phenolic content and antioxidant activity of black soybeans and koji

In this study, powders of steamed black soybeans and the Aspergillus awamori‐fermented black soybeans (koji) were subjected to storage at 4 °C and 25 °C with or without deoxidant and desiccant for 120 days. It was found that total phenolic content and the antioxidant activity including the DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of the methanol extracts from black soybeans and koji decreased as the storage period was extended. Furthermore, storage temperature and packaging condition affected the antioxidant activity of the methanol extracts of black soybeans and koji. After 120‐day storage, extract from black soybeans holding at 4 °C with deoxidant and desiccant exhibited the highest residual of DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of 71.78%, 72.66% and 70.04%, respectively. Meanwhile, the highest residual of 77.78%, 81.71% and 85.05% respectively, was noted with extract from koji held at 25 °C with deoxidant and desiccant.     

ANTIOXIDATIVE ACTIVITY OF PROTEIN HYDROLYSATE FROM ROUND SCAD MUSCLE USING ALCALASE AND FLAVOURZYME

Antioxidative activity of hydrolysates from round scad (Decapterus maruadsi) muscle with degrees of hydrolysis (DH ) of 20, 40 and 60%, prepared using Alcalase (HA) or Flavourzyme (HF), was determined. At the same DH, HF exhibited a higher 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity and reducing power, but a lower Fe²⁺ chelating ability than HA. HF from isopropanol‐defatted muscle with 60% DH was extracted using different solvents, and hexane (E1), dichloromethane (E2), ethyl acetate (E3) and residual (R) fractions were obtained. Among all fractions, E2 and E3 exhibited the highest DPPH radical scavenging activity and reducing power. HF with 60% DH and E2 at 1,000 ppm exhibited antioxidant activity in linoleic oxidation and lecithin liposome systems, and the results were comparable to butylated hydroxytoluene (BHT) at 100 ppm. Therefore, type of proteinase, DH and defatting process prior to hydrolysis exerted an influence on the antioxidative activity of hydrolysates.     

Comparative study on the antioxidant activity of methanolic and aqueous extracts from the fruiting bodies of an edible mushroom <Emphasis Type="Italic">Pleurotus djamor</Emphasis>

In vitro antioxidant activities, total phenolic, and flavonoid contents of Pleurotus djamor extracts were analyzed based on radical scavenging activities of methanol and aqueous extracts using 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), total Fe³⁺ reducing power, CUPRAC, phosphomolybdenum, metal chelating activity, and lipid peroxidation inhibition assays. Both extract types showed efficient radical scavenging activities against DPPH and DMPD radicals, ferric (Fe³⁺) and cupric (Cu²⁺) ion reducing powers, metal chelating activities, and lipid peroxidation inhibition. Total phenolic contents of methanol and aqueous extracts were 2.79 and 5.95 mg of GAE/g, respectively. Flavonoid contents of methanol and aqueous extracts were 6.35 and 5.75 mg of CAE/g, respectively. Consumption of the mushroom P. djamor can be beneficial due to antioxidant properties.     

Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extracts

The antioxidant activities, reducing powers, 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radical‐scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15 µg ml^?1 extract‐containing samples in linoleic acid emulsion (0.02 M , pH 7.0) during 120 h of incubation (P > 0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical‐scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100 µg ml^?1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical‐scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01 µg ml^?1 gallic acid equivalent in 10 µg ml^?1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro‐organisms. © 2002 Society of Chemical Industry     

Antioxidant activity of lactic-fermented Chinese cabbage

Lactic-fermented cabbage, similar to Kimchi in Korea, is a very popular fermented vegetable product in Taiwan and China. In this study, fermented cabbage prepared by a dry-salt method was first extracted with water and methanol. Antioxidant activity such as DPPH radical scavenging effects, reducing power and Fe²⁺-chelating ability of the solvent extracts of fermented cabbage was determined and the effect of fermentation on the change of antioxidant activity, total phenolic and total flavonoid content was also investigated. Results revealed that antioxidant activity observed on the Chinese cabbage mixture may vary with extraction solvents and fermentation. Generally, the methanol extract of the cabbage mixture showed a higher DPPH radical scavenging activity and reducing activity than the water extract. Although, fermentation did not alter the Fe²⁺-chelating ability and reducing activity of the methanol extract of the cabbage mixture, it reduced these same antioxidant activities in the water extract. Amongst the various extracts examined, the methanol extract of fermented cabbage showed the highest DPPH radical scavenging effect. On the other hand, the highest Fe²⁺-ion chelating and reducing activities were exerted by the methanol extracts of both the cabbage mixture and the fermented cabbage, which showed no significant difference (p < 0.05). Additionally, the type of solvent and fermentation were also found to affect the total phenolic and flavonoid content of the extracts. Fermentation increased the total phenolic content of the methanol extract, whilst reducing the total flavonoid content of the water extract. Furthermore, changes in the antioxidant activity observed on the extracts of the cabbage mixture and fermented cabbage did not coincide exactly with the total phenolic and total flavonoid content.     

Free Radical Scavenging Activity of Aqueous and Ethanolic Extract of Brassica oleracea L. var. italica

In this study, antioxidant activities of aqueous and ethanolic extracts of Brassica oleracea L. var. italica were investigated. The antioxidant properties of both extracts of Brassica oleracea L. var. italica were evaluated using different antioxidant tests, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide radical scavenging, inhibition of microsomal lipid peroxidation, reduction of power, and metal ion chelating activities. Inhibition of superoxide scavenging by aqueous and ethanolic extracts showed an IC₅₀ of 0.93 and 0.25 mg/ml, respectively. Metal ion chelation showed an IC₅₀ of 0.35 mg/ml of both the extracts and was equipotent to positive control, ethylenediamine tetra-acetic acid. The ethanolic extract of Brassica oleracea L. var. italica exhibited higher antioxidant activity in DPPH radical and superoxide anion scavenging than that of aqueous extract. The results obtained in the in vitro models clearly suggest that, Brassica oleracea L. var. italica is a natural source for antioxidants, which could serve as a nutraceutical with potential applications in reducing the level of oxidative stress and related health benefits. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models.     

Studies on the antioxidative activity of Graptopetalum paraguayense E. Walther

This study was aimed to evaluate the antioxidative activities of water (GWE), 50% ethanolic (GE50), and 95% ethanolic (GE95) extracts of Graptopetalum paraguayense. The antioxidant activities, including the radical-scavenging effect, reducing power, and antioxidative effect on Fe/ascorbate-induced lipid peroxidation in a liposome model system, were studied in vitro. The results showed that GWE, GE50 and GE95 possessed antioxidant characteristics including radical scavenging, reducing power, and lipid peroxidation inhibition. It was found that the antioxidative activities of all the extracts increased with increasing concentrations, and the activities correlated with both the total phenol and anthocyanin contents. A comparison of the 50% inhibition concentration (IC₅₀) values of different antioxidative reactions revealed that GE50 was more effective in scavenging α,α-diphenyl-β-picrylhydrazyl (DPPH) radical and showed a higher reducing power than GWE and GE95. However, there were no significant differences (P > 0.05) in the lipid peroxidation-prevention effects among the extracts.     

Antioxidative properties and stability of ethanolic extracts of Holy basil and Galangal

The aims of this work were to assess the influence of concentration, heat treatment, and pH value on antioxidant activity of ethanolic extracts obtained from Holy basil (Ocimum sanctum Linn) and Galangal (Alpinia galanga). The antioxidative properties were evaluated. The ethanolic extracts of Holy basil and Galangal showed good heat stability (80 °C, 1 h). At neutral and acidic pH, Holy basil extracts had high antioxidative stability, whereas Galangal extracts showed higher antioxidative stability at neutral than at acidic pH ranges. Antioxidant activity of both extracts at neutral pH was higher than at acidic pH ranges. Holy basil and Galangal extracts exhibited strong superoxide anion scavenging activity, Fe²⁺ chelating activity, and reducing power in a concentration-dependent manner. Antioxidant activity of both extracts correlated well with reducing power. Furthermore, ethanolic extracts of Holy basil and Galangal acted as radical scavenger and also as lipoxygenase inhibitor.     

In vitro antioxidative and antimutagenic activities of oak mushroom (Lentinus edodes) and king oyster mushroom (Pleurotus eryngii) byproducts

The in vitro antioxidative and antimutagenic activities of ethanolic extracts from oak mushroom (Lentinus edodes) and king oyster mushroom (Pleurotus eryngii) byproducts were investigated. The antioxidant capacity of the extracts was assessed by determining the ferricyanide reducing power, scavenging activity on nitrite, DPPH radical, superoxide anions and hydroxyl radicals, ferrous ion chelating ability, and inhibitory effect on linoleic acid peroxidation and xanthine oxidase. The antimutagenic activity, on the other hand, was based on the suppression of mitomycin C-induced mutagenesis in Escherichia coli cells. Both the mushroom extracts showed strong antioxidative and antimutagenic effects at higher concentrations. In general, extracts from the oak mushroom byproduct had greater antioxidative and antimutagenic abilities than that of the king oyster extract. Results of this study demonstrate that the mushroom byproducts possess strong antioxidant capacity in vitro and may be useful as a functional biomaterial in the preparation of health-promoting food products and animal feeds.     

Antioxidant Capacity and Phenolic Content of the Aqueous Extract of Commonly Consumed Cucurbits

The antioxidant capacity of commonly consumed cucurbits vegetable was determined by the DPPH, FRAP, Fe³⁺ reducing power, and hydrogen peroxide scavenging assay. The aqueous extract of Luffa cylindrica showed the highest value of phenolic content and antioxidant capacity based on FRAP, Fe³⁺ reducing power, and hydrogen peroxide scavenging assay. However, Laginaria siceraria extract showed the highest flavonoid and DPPH scavenging activities among all three cucurbits used in this study. Phenolic content in aqueous extracts of Luffa cylindrica and Laginaria siceraria was almost equal. Cucurbita maxima exhibited the lowest phenolic, flavonoid content, and exhibited the lowest power of antioxidant scavenging. The antioxidant capacity of cucurbits was significantly correlated (P < 0.05) with the phenolic content of their extracts. The antioxidant capacity of Luffa cylindrica and Laginaria siceraria have also shown a significant correlation (P < 0.05).     

Effect of irradiation on the antioxidative and antigenotoxic activities of a green tea leaf and stem extract

Green tea (Camellia sinensis) leaf and stem extract, a major byproduct of the green tea industry, was investigated for its antioxidative and antigenotoxic activities after 20 kGy of irradiation. In vitro antioxidative activities, including 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, hydrogen peroxide inhibition, tyrosinase inhibition activities, and the reducing power were tested. Green tea leaf extract (GTLE) had higher antioxidative activities than the green tea stem extract (GTSE). Irradiation of 20 kGy to GTLE showed a decreasing tendency in DPPH radical, hydrogen peroxide‐scavenging activities, and reducing power, while that to GTSE showed an increasing tendency of the antioxidative activities. Tyrosinase inhibition activity showed no difference on irradiation, in GTLE and GTSE. Overall, irradiation had positive influences on the antioxidative activity in the GTSE more than in the GTLE. Antigenotoxic effect of the green tea extracts on an oxidative DNA damage in human leucocytes by a DNA comet assay also indicated a protective effect of GTLE. The irradiated GTLE began to decrease the DNA damage significantly at 10 μg mL^?1, which showed a higher inhibition activity than the non‐irradiated GTLE. The non‐irradiated and irradiated GTSE showed similar inhibition trends and they were comparable with that of the GTLE. Results suggest that the extract of GTSE, a major byproduct of the green tea industry, can be considered as a cost‐effective functional ingredient for industrial applications. Furthermore, irradiation of the GTSE may have beneficial effects on its functional activity.     

Effect of in vitro gastrointestinal digestion on the antioxidant activity of protein hydrolysates prepared from Cape hake by‐products

The antioxidant activity of fish protein hydrolysates may change in the digestive tract during the human gastrointestinal digestion depending on their preparation conditions. Thus, the objective of this study was to assess the antioxidant properties of Cape hake hydrolysates prepared by three different methods (HPH‐A, HPH‐B and HPH‐C) and the effect of their in vitro gastrointestinal digestion on their antioxidant properties. HPH‐A showed the highest reducing power, while HPH‐B and HPH‐C exhibited the highest OH antiradical activity. Fe²⁺‐chelating activity was similar for all hydrolysates, but HPH‐C had a higher Cu²⁺‐chelating activity comparable to that of EDTA. The in vitro gastrointestinal digestion of hydrolysates caused a decrease in the DPPH inhibition, but an increase in scavenging ABTS in all hydrolysates. Copper‐ and iron‐chelating activities increased after digestion of hydrolysates. The results showed that the gastrointestinal digestion of HPHs generally increased their antioxidant properties.     

In vitro study on antioxidant activities of peanut protein hydrolysate

Peanut protein was hydrolysed with a commercial protease, Alcalase 2.4L, and the resulting hydrolysate was investigated for its antioxidant activities, including the ability to inhibit the autoxidation of linoleic acid, the scavenging effect on the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical, the reducing power and the inhibition of liver lipid oxidation. As compared with the peanut protein, peanut protein hydrolysate showed strong inhibition of the autoxidation of linoleic acid, to scavenge DPPH free radical and showed strong reducing power. Moreover, peanut protein hydrolysate also displayed noticeable inhibition of liver lipid autoxidation and lipid oxidation induced by H₂O₂ or Fe²⁺ in vitro. All these effects of the sample were concentration‐dependent. These results suggest that peanut protein hydrolysate could be a suitable natural antioxidant and may be a health food for humans. Copyright © 2006 Society of Chemical Industry     

PHENOLIC COMPOUND CONTENT, PROFILES AND ANTIOXIDANT ACTIVITIES OF AMARANTHUS HYBRIDUS (PIGWEED), BRACHIARIA BRIZANTHA (UPRIGHT BRACHIARIA) AND PANICUM MAXIMUM (GUINEA GRASS)

Amaranthus hybridus, Brachiaria brizantha and Panicum maximum are wild cereal grains that have been consumed mainly in times of drought especially in the Manicaland Province, which is the worst‐hit province in Zimbabwe whenever there are droughts. Methanolic extract solutions were prepared from sun‐dried A. hybridus, B. brizantha and P. maximum grains. We studied the phenolic compound content and antioxidant properties including high‐performance liquid chromatography, 1‐diphenyl‐2‐pierylhydrazyl radical scavenging and reducing power. B. brizantha was found to contain the highest phenolic compound concentration of 3.180 ± 0.072 mgGA/100 mg, while A. hybridus was found to have the least phenolic compound concentration of 1.127 ± 0.133 mgGA/100 mg. The grains were found to contain caffeic acid, ferulic acid, p‐coumaric acid, p‐hydroxybenzoic acid and protocatechuic acid. P. maximum had the highest DPPH scavenging capacity and the highest reducing power as well. A. hybridus had the least reducing power and required 20.33 mg of sample equivalent per milliliter to reduce Fe³⁺ to Fe²⁺.     

Antioxidant,free radical scavenging and type II diabetes‐related enzyme inhibition properties of traditionally processed Jequirity bean (Abrus precatorius L.)

The methanolic extract of raw Abrus precatorius (Jequirity bean, red‐ and black‐coloured seed coat) seeds contains a total phenolic content of 14.2 ± 0.39 g catechin equivalent/100 g extract. An analysis of phenolic profile revealed the presence of syringic acid, caffeic acid and (?)‐epicatechin in the methanolic extract of A. precatorius seeds. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1247 mmol Fe[II]/mg extract), inhibition of β‐carotene bleaching (53.37%), 2,2‐Diphenyl‐1‐picryl‐hydrazyl (DPPH, 62.13%) and superoxide (64.47%) radical scavenging activities were exhibited by the extract of raw samples. Inhibition characteristics of 68.69%α‐amylase and 51.74%α‐glucosidase enzyme were also recorded under in vitro starch digestion bioassay. Sprouting + oil‐frying caused a significant increase in the total phenolic content and also substantially improved the antioxidant and free radical scavenging capacities, while soaking + cooking as well as open‐pan roasting treatments showed diminishing effects.     

Antioxidant activity of predigested protein obtained from a range of farmed edible insects

This study investigated the antioxidant activities of peptides obtained by in vitro gastrointestinal digestion of edible insects. The antioxidant potential of edible insects' hydrolysates was determined as the free radical‐scavenging activity, ion chelating activity and reducing power. The highest antiradical activity against DPPH^˙, whose IC₅₀ value is the lowest, was noted for Amphiacusta annulipes (19.1 μg/mL) and that against ABTS^˙+ was the highest for Zophobas morio (4.6 μg/mL). The peptides obtained from A. annulipes also showed the highest Fe²⁺ chelation ability (58.82%) and reducing power (0.652). The highest ability to chelate Cu²⁺ was noted for Locusta migratoria (86.05%). The locust was characterised by the highest concentration of peptides before digestion and after digestion (3.13 and 5.88 mg/mL, respectively), and the DH was 36.29%.