In vitro antioxidant activity of anthocyanins of black soybean seed coat in human low density lipoprotein (LDL)

Microencapsulates of Blue Maize Polyphenolics as a Promising Ingredient in the Food and Pharmaceutical Industry: Characterization, Antioxidant Properties, and In Vitro-Simulated Digestion

An anthocyanin-rich blue maize waste product was used for anthocyanin extraction. To preserve bioactive phenolic compounds, a spray-drying technique was employed using conventional wall material maltodextrin (MD), with novel one, hydroxypropyl-β-cyclodextrin (HPBCD). The obtained spray-dried maize extract (SME) and microencapsulates were analyzed based on physicochemical powder properties, chemical analysis, antioxidant activity, and digestibility. The examined microencapsulates demonstrated good powder properties, exhibited a high powder yield (up to 83%), and had a low moisture content (less than 5%). HPBCD and MD + HPBCD combinations demonstrated superior powder properties in the terms of decreasing the time necessary for rehydration (133.25 and 153.8 s, respectively). The mean average particle diameter ranged from 4.72 to 21.33 µm. DSC analyses signified high powder thermal stability, around 200 °C, related to the increasing preservation with biopolymer addition. The total phenolic and anthocyanin compounds ranged from 30,622 to 32,211 mg CE/kg (CE-catechin equivalents) and from 9642 to 12,182 mg CGE/kg (CGE-cyanidin 3-glucoside equivalents), respectively, associated with good bioactive compound protection. Microencapsulates with both carriers (15% MD and 15% HPBCD) had the highest digestibility (73.63%). Our results indicated that the microencapsulates created with the active ingredient and the wall materials (MD and HPBCD) could protect phenolic compounds/anthocyanins against ABTS radicals (63.53 and 62.47 mmol Trolox Eq/kg, respectively).

RP, R. L. R. Population structure and genetic diversity characterization of soybean for seed longevity

Seed longevity is an important trait in the context of germplasm conservation and economics of seed production. The identification of populations with high level of genetic variability for seed longevity and associated traits will become a valuable resource for superior alleles for seed longevity. In this study, Genotyping-by-sequencing (GBS)-single nucleotide polymorphism (SNP) approach, simple sequence repeats (SSR) markers and agro-morphological traits have been explored to investigate the diversity and population structure of assembled 96 genotypes. The GBS technique performed on 96 genotypes of soybean (Glycine max (L.) Merrill) resulted in 37,897 SNPs on sequences aligned to the reference genome sequence. The average genome coverage was 6.81X with a mapping rate of 99.56% covering the entire genome. Totally, 29,955 high quality SNPs were identified after stringent filtering and most of them were detected in non-coding regions. The 96 genotypes were phenotyped for eight quantitative and ten qualitative traits by growing in field by following augmented design. The STRUCTURE (Bayesian-model based algorithm), UPGMA (Un-weighed Pair Group Method with Arithmetic mean) and principal component analysis (PCA) approaches using SSR, SNP as well as quantitative and qualitative traits revealed population structure and diversity in assembled population. The Bayesian-model based STRUCTURE using SNP markers could effectively identify clusters with higher seed longevity associated with seed coat colour and size which were subsequently validated by UPGMA and PCA based on SSR and agro-morphological traits. The results of STRUCTURE, PCA and UPGMA cluster analysis showed high degree of similarity and provided complementary data that helped to identify genotypes with higher longevity. Six black colour genotypes, viz., Local black soybean, Kalitur, ACC Nos. 39, 109, 101 and 37 showed higher seed longevity during accelerated ageing. Higher coefficient of variability observed for plant height, number of pods per plant, seed yield per plant, 100 seed weight and seed longevity confirms the diversity in assembled population and its suitability for quantitative trait loci (QTL) mapping.

Black soybean (Glycine max (L.) Merr.): paving the way toward new nutraceutical

Black soybean (BS) is a nutritious legume that is high in proteins, essential amino acids, dietary fiber, vitamins, minerals, anthocyanins, phenolic acids, isoflavones, and flavones. Traditional approaches for extracting BS bioactive compounds are commonly employed because they are simple and inexpensive, but they use toxic solvents and have lower yields. As a result, new extraction techniques have been developed, such as microwave, ultrasound, and enzyme-assisted extraction. Modern approaches are less harmful to the environment, are faster, and produce higher yields. The major anthocyanin in the BS seed coat was discovered as cyanidin-3-O-glucoside, accounting for nearly 75% of the total anthocyanins. BS and its seed coat also contains phenolic acids (p-hydroxybenzoic, gallic, vanillin, syringic acid), isoflavones (daidzein, glycitein and genistein), flavones, flavonols, flavanones, and flavanols. Bioactive compounds present in BS exhibit antioxidant, anti-cancerous, anti-diabetic, anti-obesity, anti-inflammatory, cardio and neuroprotective activities. The characterization and biological activity investigation of these bioactive compounds has provided researchers and food manufacturers with valuable information for developing functional food products and nutraceutical ingredients. In this review, the nutritional makeup of BS is reviewed, and the paper seeks to provide an insight of bioactive compound extraction methods as well as bioactive compounds identified by various researchers. The biological activities of BS extracts and their potential applications in food products (noodles), biodegradable films (pH sensitive film), and therapeutic applications (wound healing and anti-inflammation) are also discussed in the study. Therefore, BS have enormous potential for use in developing functional foods and nutraceutical components. This is the first review of its sort to describe and explain various extraction methodologies and characterization of bioactives, as well as their biological activity recorded in diverse works of literature, making it possible for food manufacturers and scientists to get a quick overview.

Effect of Processing on Bioactive Compounds, Antioxidant Activity, Physicochemical, and Sensory Properties of Orange Sweet Potato, Red Rice, and Their Application for Flake Products

Orange sweet potato (OSP) and red rice (RR) are rich sources of health benefit-associated substances and can be conventionally cooked or developed into food products. This research approach was to closely monitor the changes of bioactive compounds and their ability as antioxidants from the native form to the food products which are ready to be consumed. Moreover, this research explored the individual carotenoids and tocopherols of raw and cooked OSP and RR and their developed flake products, and also investigated their antioxidant activity, physicochemical properties, and sensory properties. Simultaneous identification using the liquid chromatographic method showed that OSP, RR, and their flake products have significant amounts (µg/g) of β-carotene (278.58–48.83), α-carotene (19.57–15.66), β-cryptoxanthin (4.83–2.97), α-tocopherol (57.65–18.31), and also γ-tocopherol (40.11–12.15). Different responses were observed on the bioactive compound and antioxidant activity affected by heating process. Meanwhile, OSP and RR can be combined to form promising flake products, as shown from the physicochemical analysis such as moisture (5.71–4.25%) and dietary fiber (13.86–9.47%) contents, water absorption index (1.69–1.06), fracturability (8.48–2.27), crispness (3.9–1.5), and color. Those quality parameters were affected by the proportions of OSP and RR in the flake products. Moreover, the preference scores (n = 120 panelists) for the flakes ranged from slightly liked to indifferent. It can be concluded that OSP and RR are potential sources of bioactive compounds which could act as antioxidants and could be developed into flake products that meet the dietary and sensory needs of consumers.

MYB-6 and LDOX-1 regulated accretion of anthocyanin response to cold stress in purple black carrot (Daucus carota L.)

AIM

Anthocyanin, an essential ingredient of functional foods, is present in a wide range of plants, including black carrots. The current investigation was carried out to analyse the effect of cold stress on the expression of major anthocyanins and anthocyanin biosynthetic pathway genes, MYB6 and LDOX-1.

METHODS AND RESULTS

Five cultivated carrot genotypes belonging to the eastern group, having anthocyanin pigment, were used in the current study. The qRT-PCR analysis revealed that relative gene expression of transcription factor MYB-6 and LDOX1gene was highly expressed upon cold stress compared to non-stress samples. High-performance liquid chromatography-based quantification of Cyanidin 3-O-glucoside (Kuromanin chloride), Ferulic acid, 3,5-Dimethoxy-4-hydroxycinnamic acid (Sinapic acid), and Rutin revealed a significant increase in these major anthocyanins in response to cold stress when compared to control plants.

CONCLUSION

We conclude that MYB6 and LDOX1 gene expression increases upon cold stress, which induces accumulation of major anthocyanins in purple black carrot and suggests a possible cross-link between cold stress and anthocyanin biosynthesis in purple black carrot.

Comparative metabolic profiling of cultivated and wild black soybeans reveals distinct metabolic alterations associated with their domestication

Generally, cultivated black soybean (CBS) has been used as a major source of various nutrients for humans and animals. To assess the metabolic alterations induced by domestication in soybean, we performed a comprehensive metabolite profiling of 56 soybean varieties, including 28 CBS and 28 wild black soybean (WBS) varieties. A total of 48 metabolites were characterized, including 45 primary and 3 secondary metabolites, from CBS and WBS. The results of principal component analysis and hierarchical cluster analysis (HCA) revealed significant metabolic differences between CBS and WBS that were closely related to metabolic pathways. The results indicate that flavonoids correlated positively with phenylalanine, a precursor for phenylpropanoid biosynthesis; the contents of flavonoids and phenylpropanoids were higher in WBS. Pathway analysis revealed that CBS contained large amounts of TCA cycle intermediates, amino acids, and fatty acids as a result of increased energy metabolism, amino acid metabolism, and seed filling. The projection to latent structure method, using the partial least squares method, was applied to predict the flavonoid content in soybean seed, which indicated that sucrose, threonic acid, citric acid, and fatty acids are important in predicting the antioxidant content of samples. This work will provide important information for designing new soybean cultivars with enhanced nutritional and agricultural traits.

Protection of natural antioxidants against low-density lipoprotein oxidation

This chapter reports essential information about the protective action of antioxidants against LDL oxidation. The activity of individual compounds (tocopherols, vitamin C, phenolic compounds) as well as extracts obtained from plant material (cereals, fruits, legumes, nuts, mushrooms, by-products of food industry) is reported. The structure-antioxidant activity relationship of phenolic compounds is discussed. This article summarizes the findings to date of both in vitro and in vivo studies using foods or phenolic extracts isolated from foodstuffs at inhibiting the incidence of LDL oxidation. This chapter summarizes also the reportings to date of in vivo studies using foods or beverages at inhibiting the incidence of LDL oxidation.

Black soybean seed coat polyphenols promote nitric oxide production in the aorta through glucagon-like peptide-1 secretion from the intestinal cells

Black soybean seed coat polyphenols were reported to possess various bioregulatory functions. However, the effects of black soybean seed coat polyphenols on vascular functions are unknown. Vascular dysfunction caused by aging and vascular stiffness is associated with a risk of cardiovascular disease (CVD), and a reduction in nitric oxide (NO) levels can trigger the onset of CVD. In the present study, we investigated the effect of polyphenol-rich black soybean seed coat extract (BE) on vascular functions and the underlying mechanisms involved. The oral administration of BE at 50 mg per kg body weight to Wistar rats increased NO levels as determined by eNOS phosphorylation. The administration of BE also increased GLP-1 and cAMP levels. Furthermore, the effects of BE were inhibited in the presence of a GLP-1 receptor antagonist. This suggests that GLP-1 is strongly involved in the underlying mechanism of NO production in vivo. In conclusion, BE contributes to the improvement of vascular functions by promoting NO production. Regarding the putative underlying mechanism, GLP-1 secreted from intestinal cells by the polyphenols in BE activates eNOS in vascular endothelial cells.

Absorption of Anthocyanin Rutinosides after Consumption of a Blackcurrant ( Ribes nigrum L.) Extract

The dominant anthocyanins in blackcurrant are delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside. Data on their absorption and distribution in the human body are limited. Therefore, we performed a human pilot study on five healthy male volunteers consuming a blackcurrant ( Ribes nigrum L.) extract. The rutinosides and their degradation products gallic acid and protocatechuic acid were determined in plasma and urine. The rutinosides' concentrations peaked in both plasma and urine samples within 2 h of extract ingestion. The recoveries of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside from urine samples were 0.040 ± 0.011% and 0.048 ± 0.016%, respectively, over a 48 h period. Protocatechuic acid concentration increased significantly after ingestion of the blackcurrant extract. Our results show that after ingestion of a blackcurrant extract containing delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, significant quantities of biologically active compounds circulated in the plasma and were excreted via urine. Furthermore, these results contribute to the understanding of anthocyanin metabolism in humans.

Changes on the Structural and Physicochemical Properties of Conjugates Prepared by the Maillard Reaction of Black Bean Protein Isolates and Glucose with Ultrasound Pretreatment

The conjugates of black bean protein isolate (BBPI) and glucose (G) were prepared via the wet heating Maillard reaction with ultrasound pretreatment. The physicochemical properties of UBBPI-G conjugates prepared by ultrasound pretreatment Maillard reaction had been compared with classical Maillard reaction (BBPI-G). The reaction rate between BBPI and glucose was speeded up by ultrasound pretreatment. A degree of glycation (DG) of 20.49 was achieved by 2 h treatment for UBBPI-G, whereas 5 h was required using the classical heating. SDS-PAGE patterns revealed that the BBPI-G conjugates with higher molecular weight were formed after glycosylation. The results of secondary structure analysis suggested that the α-helix and β-sheet content of UBBPI-G were lower than that of BBPI-G. In addition, UBBPI-G conjugates had exhibited bathochromic shift compared with BBPI by fluorescence spectroscopy analysis. Finally, UBBPI-G achieved higher level of surface hydrophobicity, solubility, emulsification property and antioxidant activity than BBPI and BBPI-G (classical Maillard reaction).

Comparisons of nutritional constituents in soybeans during solid state fermentation times and screening for their glucosidase enzymes and antioxidant properties

This research was the first to demonstrate the variations of nutritional constituents, glucosidase properties and antioxidant activities in soybeans during different solid state fermentation times (germination → 5 periods for 12 days) with Tricholoma matsutake. Total isoflavones were significantly reduced (2661.54 → 1559.04 μg/g) with the increase of aglycone contents (107.61 → 1285.66 μg/g, 12 times) for fermentation, whereas amino acid and fatty acid slightly increased. Among them, daidzein (43.2 → 43.6 → 421.9 → 721.4 → 634.0 μg/g), genistein (52.7 → 24.4 → 339.5 → 546.6 → 512.8 μg/g) and glutamic acid (0.3 → 1.7 → 3.9 → 6.6 → 16.1 mg/g) markedly increased between germinated and fermented soybeans. Total phenolic contents and antioxidant abilities also considerably increased, especially, ABTS displayed the predominant scavenging capacities (33.1 → 94.8%) at 200 μg/ml, followed by DPPH (11.9 → 87.0%) and hydroxyl (11.2 → 49.2%) radicals. Interestingly, α-glucosidase inhibition (11.8 → 84.9%) and β-glucosidase (3.1 → 40.3 unit/g) exhibited the highest activities after 9 days. Our results implied that fermented soybeans may be contributed to enhance the soybean value in nutrition and biological effect aspects to development of new functional foods.

Effect of germination on composition profiling and antioxidant activity of the polysaccharide-protein conjugate in black soybean [Glycinemax (L.) Merr.]

Black soybeans are commonly consumed as health foods and used in traditional Chinese medicine, but they are rarely cultivated as edible sprouts. During germination, the composition of seeds undergoes distinct changes that cause variations in bioactivities. In this study, the water-soluble black soybean polysaccharide (BSPS) was isolated from sprouts harvested at two-day intervals during the first week of seedling growth. The chromatographic profiles of the BSPS in ungerminated seeds showed fraction 1 (F1, about 64kDa) and fraction 2 (F2, <1kDa) that degraded during germination. The polysaccharide in F1 fraction of ungerminated seeds was covalently associated with the protein and mainly contained arabinose, galactose, glucose, and galacturonic acid at various levels during germination. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) scavenging activities and the reducing power of F1 were highest on the seventh day of germination. The phenolic and flavonoid content significantly increased after the fifth day of germination, suggesting that these ingredients also contributed to the antioxidant activities. During long-term germination, the polysaccharide-protein conjugate in the F1 fraction with enhanced antioxidant activities is regarded as a potential natural antioxidant for the development of functional foods.

The Potential Protective Effects of Phenolic Compounds against Low-density Lipoprotein Oxidation

BACKGROUND

The exact mechanism(s) of atherosclerosis in humans remains elusive, but one theory hypothesizes that this deleterious process results from the oxidative modification of low-density lipoprotein (LDL). Research suggests that foods rich in dietary phenolic compounds with antioxidant activity can mitigate the extent of LDL oxidation in vivo. With regard to the different classes of flavonoids, there appears to be a structurefunction relationship between the various moieties/constituents attached to the flavonoids' three ring system and their impact at retarding LDL oxidation.

METHODS

This article summarizes the findings to date of both in vitro and in vivo studies using foods or phenolic extracts isolated from foodstuffs at inhibiting the incidence of LDL oxidation. Three bases: SCOPUS, Web Science, and PubMed were used for search.

RESULTS

An often used method for the determination of antioxidant properties of natural phenolic compounds is the LDL oxidation assay. LDLs are isolated from human plasma and their oxidation is induced by Cu2+ ions or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The sample is incubated with a phenolic extract or individual/isolated phenolic compounds. LDL oxidation is then monitored by various chemical methods (e.g., measurement of the generation of conjugated dienes and trienes). This technique confirmed the antioxidant properties of several extracts as obtained from plant material (e.g., grapes, berries, orange, grapefruit, coffee, tea, chocolate, olives, nuts) as well as the individual phenolic compounds (e.g., luteolinidin, apigenidin, caffeic acid, chlorogenic acid, catechin, quercetin, rutin). Several studies in vivo confirmed protective effects of phenolic compounds against LDL oxidation. They covered the healthy subjects with hyperlipidaemia, overweight, obesity, metabolic syndrome, heavy smokers, patients receiving haemodialysis, patients with peripheral vascular disease, and subjects at high cardiovascular risk. The studies comprise individuals of all ages, and the number of participants in the different experiments varied widely.

CONCLUSION

Properly designed double-blind, placebo-controlled randomised clinical trials offer stronger evidence as to the impact of dietary phenolics consumption at retarding LDL oxidation. More such clinical trials are needed to strengthen the hypothesis that foods rich in dietary phenolic compounds with antioxidant activity can mitigate the extent of LDL oxidation in vivo.

Protective effects of dietary polyphenols from black soybean seed coats on islet and renal function in streptozotocin-induced diabetic rats

BACKGROUND

The aim of this study was to investigate the antidiabetic effects of the crude polyphenol extract (BSCP) from black soybean seed coats (BSC) and the whole flour of BSC and illustrate the mechanism in terms of islet and renal protection.

RESULTS

BSCP and BSC effectively controlled the increased blood glucose level and impaired glucose tolerance in streptozotocin (STZ)-induced diabetic rats after 8 weeks of treatment. They increased the concentrations of serum insulin, C-peptide and Glp-1 (P < 0.05) by improving the STZ-induced damage of islet β-cells and increasing their insulin expression (P < 0.05). Lipid profiles and antioxidant activities were also improved. Moreover, BSCP and BSC tended to decrease serum creatinine (0.05 < P < 0.1), and blood urea nitrogen was decreased by BSC significantly (P < 0.05). They also led to significantly lower glomerular volume (P < 0.05).

CONCLUSION

Long-term intervention with BSC at a low dose of polyphenols plays a role in controlling blood glucose and lipids levels by promoting insulin secretion and restoring islet β-cell function, the same as BSCP. These benefits are accompanied by their potential protection of diabetic renal dysfunction. BSCP is mainly responsible for the antidiabetic effect of BSC. © 2017 Society of Chemical Industry.

Differences in the metabolic profiles and antioxidant activities of wild and cultivated black soybeans evaluated by correlation analysis

Wild soybeans are considered a potential resource for soybean domestication and an important source of genetic diversity for soybean crop improvement. Understanding metabolite-caused bioactivity differences between cultivated and wild soybeans is essential for designing a soybean with enhanced nutritional traits. In this study, the non-targeted metabolic profiling of 26 soybean varieties, 15 wild black soybeans (WBS) and 11 cultivated black soybeans (CBS), using liquid chromatography-mass spectrometry (LC-MS) in combination with multivariate analysis revealed significant differences in 25 differential metabolites. Among these, the soyasaponins Ab and Bb were found to be characteristic metabolites expressed more substantially in CBS than in WBS. Three different antioxidant assays and correlation analysis identified major and minor antioxidants that contributed to WBS having an antioxidant activity 4- to 8-fold stronger than that of CBS. Epicatechin, procyanidin B2, and cyanidin-3-O-glucoside were identified by both association analysis and the online LC-ABTS radical scavenging assay as being major antioxidants.

Antimicrobial Activities of Phenolic Extracts Derived from Seed Coats of Selected Soybean Varieties

Soybean hulls or seed coats consist of complex carbohydrates, proteins, lipids, and polyphenols such as anthocyanidins, proanthocyanidins, and isoflavones. The polyphenolics in the seed coats give them various colors such as black, brown, green, yellow, or even a mottled appearance. In this study, the antimicrobial effects of phenolic extracts from the seed coats of different colored soybeans (yellow, dark brown, brown, and black) were evaluated against foodborne pathogens such as Salmonella Typhimurium, Escherichia coli O157:H7, and Campylobacter jejuni in broth-cultures as well as on chicken skin. The highest total phenolic content was observed for the phenolic extract from soybean variety (R07-1927) with black colored seed coat (74.1 ± 2.1 mg chlorogenic acid equivalent [CAE]/g extract) and was significantly different (P <0.0001) from the extract of the conventional soybean variety (R08-4004) with yellow colored seed coat (7.4 ± 1.2 mg CAE/g extract). The extract from black colored soybean produced reductions of 2.10 ± 0.08 to 2.20 ± 0.08-log CFU/mL for both E. coli O157:H7 and C. jejuni after 3 d when incubated in broth-culture having 4-log CFU/mL of bacteria, whereas a 6 d incubation was found to reduce S. Typhimurium and E. coli O157:H7 at 2.03 ± 0.05 and 3.3 ± 0.08-log CFU/mL, respectively. The extract also reduced S. Typhimurium and E. coli O157:H7 attached to chicken skin by 1.39 ± 0.03 and 1.24 ± 0.06-log CFU/g, respectively, upon incubation for 6 d. Soybean seed coat extracts may have a potency as antimicrobial agents to reduce foodborne bacteria contaminating poultry products.

Agmatine modulates melanogenesis via MITF signaling pathway

Agmatine contained in soybean is also found in Manaca, an anti-aging plant, inhabited in Amazon and induces vasodilation by the promotion of NO synthesis in blood vessel. However, the research of agmatine on melanin synthesis related to hair greying is lacking. The aim of this study was to investigate the melanogenic effect of agmatine via regulation of MITF signaling pathway in B16F1 cells. It was determined whether agmatine regulates melanin synthesis at cellular level in addition to the effect of agmatine on mushroom tyrosinase in vitro in the presence of different concentrations of agmatine. Furthermore, the effect of agmatine on the protein expressions of tyrosinase, TRP-1, TRP-2, BMP-4, BMP-6, C-KIT, p-p38, MITF and C-FOS were examined by western blot analysis. In addition, immunofluorescence staining was carried out to visualize the location of MITF expression in cell. Agmatine at 256μM or more increased melanin synthesis as well as tyrosinase activity. Moreover, whereas agmatine increased the expression levels of TRP-1, BMP-6, p-p38 and MITF, it reduced the expression level of BMP-4. It was also found that agmatine enhanced the expression level of MITF in nucleus. These results suggest that agmatine could induce melanin synthesis though the regulation of MITF transcription factor via BMP-6/p38 signaling pathway.

Black soybean seed coat polyphenols prevent AAPH-induced oxidative DNA-damage in HepG2 cells

Black soybean seed coat extract (BE), which contains abundant polyphenols such as procyanidins, cyanidin 3-glucoside, (+)-catechin, and (−)­epicatechin, has been reported on health beneficial functions such as antioxidant activity, anti-inflammatory, anti-obesity, and anti-diabetic activities. In this study, we investigated that prevention of BE and its polyphenols on 2,2'-azobis(2-methylpropionamide) dihydrochloride (AAPH)-induced oxidative DNA damage, and found that these polyphenols inhibited AAPH-induced formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker for oxidative DNA damage in HepG2 cells. Under the same conditions, these polyphenols also inhibited AAPH-induced accumulation of reactive oxygen species (ROS) in the cells. Inhibition of ROS accumulation was observed in both cytosol and nucleus. It was confirmed that these polyphenols inhibited formation of AAPH radical using oxygen radical absorbance capacity assay under the cell-free conditions. These results indicate that polyphenols in BE inhibit free radical-induced oxidative DNA damages by their potent antioxidant activity. Thus, BE is an effective food material for prevention of oxidative stress and oxidative DNA damages.

Characterization and hepatoprotective activity of anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8)

The hepatoprotective activity of anthocyanin-rich purple sweet potato extract (APSPE) was demonstrated. Sixty mice were randomly divided into six groups: control group [without carbon tetrachloride (CCl₄) or APSPE]; model group (with CCl₄ only); positive control group (50 mg/kg body weight silymarin); low-dose group (100 mg/kg body weight APSPE); medium-dose group (200 mg/kg body weight APSPE); and high-dose group (400 mg/kg body weight APSPE). After 10 days intragastric administration of the respective supplements, the mice in all groups except control were injected intraperitoneally with CCl₄ (0.15% in arachis oil, 10 mL/kg body weight, intravenous). Twelve hours after CCl₄ injection, the mice were measured in terms of liver index, levels of aspartate aminotransferase and alanine aminotransferase in serum, as well as glutathione, superoxide dismutase, and malondialdehyde in liver homogenate. Additionally, the livers of mice were stained with hematoxylin and eosin and sectioned for observation. Nineteen purple sweet potato anthocyanins were identified from the purple sweet potato cultivar Eshu No. 8 and analyzed by liquid chromatography–electrospray ionization–tandem mass spectrometry. Peonidin 3-coumaryl-p-hydroxybenzoyl sophoroside-5-glucoside was first identified in purple sweet potato. The results showed that anthocyanins in Eshu No. 8 had good hepatoprotective activity.

Anthocyanin contents in the seed coat of black soya bean and their anti-human tyrosinase activity and antioxidative activity

OBJECTIVE

The seed coat of black soya bean (SCBS) contains high amount of anthocyanins and shows antioxidant and anti-mushroom tyrosinase activities. The objectives of this study were to analyse the anthocyanins in SCBS with different solvents and to find the relationship between anthocyanin profile with anti-human and anti-mushroom tyrosinase activities.

METHODS

SCBS was extracted with hot water, 50 and 80% ethanol, 50 and 80% acetone and 50 and 80% acidified acetone. Total phenol and total flavonoid contents in the extracts were determined. Anthocyanins in the extracts were analysed using HPLC and LC/MS/MS. A genetically engineered human tyrosinase was used to evaluate the anti-tyrosinase potential of the extracts from SCBS.

RESULTS

80% acetone extract from SCBS obtained the highest total phenol, total flavonoid and cyanidin-3-O-glucoside (C3G) contents among all the extracts, whereas the hot water extract showed the lowest antioxidant contents. Three anthocyanin compounds were found in all the extracts from SCBS, and the analysis of HPLC and LC/MS/MS indicated that they were C3G, delphinidin-3-O-glucoside (D3G) and peonidin-3-O-glucoside (P3G). The ratios of C3G (2.84 mg g(-1) ), D3G (0.34 mg g(-1) ) and P3G (0.35 mg g(-1) ) in 80% acidified acetone extract were 76.6, 9.1 and 9.3%, respectively. All the extracts from SCBS possessed anti-human tyrosinase activity. Moreover, a good correlation was found between the anti-human tyrosinase activities and C3G contents in the extracts.

CONCLUSION

Antioxidants in SCBS also possess anti-human and anti-mushroom tyrosinase activities.

Effect of Blueberry Anthocyanins Malvidin and Glycosides on the Antioxidant Properties in Endothelial Cells

The objective of this research was to survey the antioxidant functional role of the main anthocyanins of blueberries in endothelial cells. Changes on the reactive oxygen species (ROS), xanthine oxidase-1 (XO-1), superoxide dismutase (SOD), and heme oxygenase-1 (HO-1) in cells of malvidin and the two glycosides were investigated. The results showed that these anthocyanins decreased the levels of ROS and XO-1 but increased the levels of SOD and HO-1. Glycosides improved the antioxidant capacity of malvidin to a great extent. The changes in the antioxidant properties of malvidin-3-glucoside were more pronounced than malvidin-3-galactoside. Variation in levels of malvidin-3-glucoside and malvidin-3-galactoside had a significant impact on antioxidant properties to different extents. It indicates that blueberries are a good resource of anthocyanins, which can protect cells from oxidative deterioration and use blueberry as a potential functional food to prevent diseases related to oxidative stress.

Changes occurring in compositions and antioxidant properties of healthy soybean seeds [Glycine max (L.) Merr.] and soybean seeds diseased by Phomopsis longicolla and Cercospora kikuchii fungal pathogens

Changes in the compositions (isoflavone, protein, oil, and fatty acid) and antioxidant properties were evaluated in healthy soybeans and soybeans diseased by Phomopsis longicolla and Cercospora kikuchii. The total isoflavone content (1491.3 μg/g) of healthy seeds was observed to be considerably different than that of diseased seeds (P. longicolla: 292.6, C. kikuchii: 727.2 μg/g), with malonlygenistin exhibiting the greatest decrease (726.1 → 57.1, 351.9 μg/g). Significantly, three isoflavones exhibited a slight increase, and their structures were confirmed as daidzein, glycitein, and genistein, based on their molecular ions at m/z 253.1, 283.0, and 269.1 using the negative mode of HPLC-DAD-ESI/MS. The remaining compositions showed slight variations. The effects against 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radicals in healthy seeds were stronger than the diseased soybeans, depending upon the isoflavone level. Our results may be useful in evaluating the relationship between composition and antioxidant activity as a result of changes caused by soybean fungal pathogens.

Study and characterization of an ancient European flint white maize rich in anthocyanins: Millo Corvo from Galicia

In the second half of the last century, the American dent hybrids began to be widely grown, leading to the disappearance or marginalization of the less productive traditional varieties. Nowadays the characterization of traditional landraces can help breeders to discover precious alleles that could be useful for modern genetic improvement and allow a correct conservation of these open pollinated varieties (opvs). In this work we characterized the ancient coloured cultivar "Millo Corvo" typical of the Spanish region of Galicia. We showed that this cultivar accumulates high amounts of anthocyanins (83.4 mg/100g flour), and by TLC (Thin Layer Chromatography) and HPLC (High Pressure Liquid Chromatography) analysis, we demonstrated that they mainly consisted of cyanidin. Mapping and sequencing data demonstrate that anthocyanin pigmentation is due to the presence of the red color1 gene(r1), a transcription factor driving the accumulation of this pigment in the aleurone layer. Further chemical analysis showed that the kernels are lacking in carotenoids, as confirmed by genetic study. Finally a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging ability test showed that Millo Corvo, even though lacking carotenoids, has a high antioxidant ability, and could be considered as a functional food due to the presence of anthocyanins.

Structural characterization of two water-soluble polysaccharides from black soybean (Glycine max (L.) Merr.)

Black soybeans (Glycine max (L.) Merr.) have been widely used as a health food and medicinal herb in oriental medicine. In the present study, the chemical structures of two water-soluble polysaccharides (black soybean polysaccharide 1 (BSPS-1) and black soybean polysaccharide 3 (BSPS-3)) isolated from black soybeans were characterized by high performance size-exclusion chromatography (HPSEC), methylation analysis, and 1D (1H, 13C) and 2D (COSY, TOCSY, HSQC, NOESY, and HMBC) NMR spectra. The molecular weights of BSPS-1 and BSPS-3 were 1.95 × 105 and 1.88 × 105 Da, respectively. Methylation analysis and NMR spectra indicate that BSPS-1 is composed of 1,6-α-d-glucopyranosyl residues. By contrast, BSPS-3 is mainly composed of a 1,3-β-d-galactopyranosyl residue backbone with side chains substituted at the O-6 position consisting of large content of T-α-l-Araf-(1→ residues, and small contents of →5)-α-l-Araf-(1→, →2)-α-l-Rhap-(1→, and 4-O-Me-β-d-GlcAp-(1→ residues. Our results suggest that BSPS-1 is a linear (1→6)-α-d-glucan, whereas BSPS-3 is a type II arabinogalactan. The unique structures of BSPS-1 and BSPS-3 indicate that they might have wide applications in food and pharmaceutical industries.

Extraction, characterization and in vitro antioxidant activity of polysaccharides from black soybean

Optimization of extraction conditions, preliminary characterization and in vitro antioxidant activity of polysaccharides from black soybean (BSPS) were investigated. The results of Box-Behnken design showed that the optimal extraction conditions for BSPS were as follows: ratio of water to material of 20 ml/g, extraction time of 6.4h and extraction temperature of 92 °C, with a corresponding yield of 2.56%. The crude BSPS were further fractionated on DEAE-52 and Sepharose CL-4B chromatography to afford three purified fractions (BSPS-1, BSPS-2 and BSPS-3). Chemical analysis showed that the three purified fractions were mainly composed of carbohydrate and uronic acid. In addition, BSPS-1 was composed of arabinose, rhamnose, galactose, glucose and mannose in the molar ratio of 1.79:1.00:2.59:26.54:1.01. BSPS-2 was composed of arabinose, rhamnose, xylose, galactose and mannose in the molar ratio of 8.10:4.80:9.15:13.38:1.00. BSPS-3 was composed of arabinose, rhamnose, galactose and mannose in the molar ratio of 16.80:3.60:33.66:1.00. The results of Fourier transform-infrared spectroscopy further confirmed the characteristic polysaccharide structures of the three purified fractions. Moreover, antioxidant assays showed crude BSPS and its purified fractions had potential superoxide anion and DPPH radical scavenging activities, and their antioxidant activity decreased in the order of crude BSPS > BSPS-3 > BSPS-2 > BSPS-1.

In Vivo Antioxidant Activity of Black Soybean Peptide in Aging Mice Caused by D-Galactose

Black soybean peptides (BSPs) with potent antioxidant activity were purified from black soybean protein hydrolysates (BSH) by using the ultrafiltration (UF) and macroporous adsorption resin (MAR), andin vivoantioxidant activity of the fraction BSP-DA-c was evaluated in aging mice induced byD-galactose. The results showed that orally administration of BSP-DA-c fraction at the dose of 500 and 1000 mg/kg per day could remarkably increase (P<0.05) the activity of SOD and GSH-Px in liver and the activity of GSH-Px in serum, the contents of MDA in serum and liver were reduced significantly (P<0.05), inferred that BSP-DA-c had strong antioxidant activity in mice.

Seed maturity differentially mediates metabolic responses in black soybean

The soybean seed is placed in the middle of the morphological and developmental alterations, such as changes in seed size, weight, and colour, and alteration of the composition and contents of metabolites during maturation. In this study, we used black soybean seeds to investigate the effect of maturity on metabolite levels at different maturity stages. Seeds were sorted into five maturity categories, from M1 to M5, based on seed size and external pigmentation. Maturity stages M1, M3, and M5 are equivalent to R6, R7, and R8 on the soybean reproductive growth stage scale, indicating full seed, beginning maturity, and full maturity, respectively. As seed maturation progressed, the seed size decreased and the water soluble extract changed, indicating that a change of seed pigmentation occurred. At the same time, numerous metabolites responded differentially to seed maturation. The partial least squares (PLS) scores plot indicated that the metabolic alteration during maturation was clearly visible. Furthermore, isoflavones were highly associated with seed maturity on the PLS loading plot while fatty acids, glucose, fructose, and sucrose were less linked with seed maturity, indicating that those metabolites responded less to seed maturation. Overall, the results indicate that each category of metabolites is mediated differentially during maturation in black soybean seeds.

Influence of preheating on antioxidant activity of the water extract from black soybean and color and sensory properties of black soybean decoction

BACKGROUND

Our previous study indicated that black soybean (BS) tea (BST) made from preheated BS showed a significant protective effect against CCl4 -induced liver damage in Sprague Dawley rats due to BS's antioxidant activity. In this study, we investigated three different preheating methods on the antioxidant activity of water extract from BS (WBS) (Glycine max (L.) Merrill), as well as on the color and sensory properties of BST.

RESULTS

WBS baked at 130 °C for 5 min showed high total phenol, flavonoid and anthocyanin contents among three preheating methods, as well as high DPPH radical-scavenging activity, ferrous ion chelating ability and reducing power. BST baked at 130 °C for 5 min had higher polyphenol oxidase activity and L*, a* and b* values but lower peroxidase activity then BST made from unheated BS. Sensory evaluation indicated that BST made from baked BS produced better aroma and flavor than the tea made from unheated BS or a commercial preheated BS.

CONCLUSION

An appropriate preheating process improved the amount of extractable antioxidant and the antioxidant activity in WBS. BST baked at 130 °C for 5 min had good flavor properties, as well as high amount of antioxidant.

Black soybean seed coat polyphenols prevent B(a)P-induced DNA damage through modulating drug-metabolizing enzymes in HepG2 cells and ICR mice

Black soybean seed coat is a rich source of polyphenols that have been reported to have various physiological functions. The present study investigated the potential protective effects of polyphenolic extracts from black soybean seed coat on DNA damage in human hepatoma HepG2 cells and ICR mice. The results from micronucleus (MN) assay revealed that black soybean seed coat extract (BE) at concentrations up to 25μg/mL was non-genotoxic. It is noteworthy that BE (at 4.85μg/mL) and its main components, procyanidins (PCs) and cyanidin 3-glucoside (C3G), at 10μM significantly reduced the genotoxic effect induced by benzo[a]pyrene [B(a)P]. To obtain insights into the underlying mechanism, we investigated BE and its main components on drug-metabolizing enzyme expression. The results of this study demonstrate that BE and its main components, PCs and C3G, down-regulated B(a)P-induced cytochrome P4501A1 (CYP1A1) expression by inhibiting the transformation of aryl hydrocarbon receptor. Moreover, they increased expression of detoxifying defense enzymes, glutathione S-transferases (GSTs) via increasing the binding of nuclear factor-erythroid-2-related factor 2 to antioxidant response elements. Collectively, we found that PCs and C3G, which are the main active compounds of BE, down-regulated CYP1A1 and up-regulated GST expression to protect B(a)P-induced DNA damage in HepG2 cells and ICR mice effectively.

Anthocyanin-rich purple wheat prolongs the life span of Caenorhabditis elegans probably by activating the DAF-16/FOXO transcription factor

Colored cereals attract public attention due to their potential antioxidant properties and corresponding health benefits. Purple wheat, rich in anthocyanins, is one of the newly developed cereals on the market. Cyanidin-3-O-glucoside (42.6%) is the predominant anthocyanin in purple wheat, followed by peonidin-3-O-glucoside (39.9%) and malvidin-3-O-galactoside (17.4%). To investigate the potential antiaging and antioxidant properties of purple wheat, the nematode Caenorhabditis elegans was chosen as an experimental model organism. It was found that an anthocyanin-rich methanolic extract of purple wheat extended the mean life span of wild type worms and of mev-1(hn1) mutants, which are sensitive to oxidative stress, by 10.5 and 9.2%, respectively. Life span extension depends on the transcription factor DAF-16; no significant increase of longevity was seen in daf-16 (mgDf50) mutant worms. Translocation of DAF-16/FOXO to the nucleus implies that the transcription factor DAF-16/FOXO was activated under purple wheat treatment by inhibition of the insulin/IGF-1-like signaling pathway which includes the insulin receptor DAF-2. Moreover, purple wheat increased stress response in C. elegans as well as reduced oxidative stress. Anthocyanins of purple wheat apparently exhibit beneficial effects in C. elegans. They may exert similar properties in humans, which is an issue to be explored in future studies.

Antihyperglycemic and Antihyperlipidemic Effects of Fermented Rhynchosia nulubilis in Alloxan-induced Diabetic Rats

Alloxan administration in rats is used as a model for non-insulin dependent diabetes mellitus (NIDDM). NIDDM is a multifactorial disease, characterized by hyperglycemia and lipoprotein abnormalities. In this study, we evaluated the antihyperglycemic and antihyperlipidemic effects of fermented Rhynchosia nulubilis (FRN) through the regulation of glucose uptake in alloxan-induced rats. Fermented R. nulubilis was administered orally for 28 d at 500 mg/kg of body weight. Body weight and food intake were monitored every day. Biochemical parameters were quantified after 4 week. In the diabetic + FRN group, body weight increased significantly and blood glucose concentrations decreased when compared to those of the diabetic group. After 2 hr of administration, the oral glucose tolerance test (OGTT) indicated a significant reduction in the diabetic + FRN group compared to diabetic group. The diabetic + FRN group experienced a significant reduction in total cholesterol, triglycerides, low density lipoprotein, coronary risk factors, and malondialdehyde concentrations, with significantly increased high density lipoprotein compared to those of diabetic group. These results demonstrate that fermented R. nulubilis possesses potent antihyperglycemic and antihyperlipidemic activity in alloxan-induced diabetic rats.