Effect of light on structural properties and antioxidant activities of polysaccharides from soybean sprouts

Structural characterization, physicochemical properties and hypoglycemic activity of soluble dietary fibers from salt stressed mung bean sprouts

Low-salt stress germination is an effective way to improve the nutritional composition of food crops. A novel soluble dietary fiber (MS-SDF) was isolated from low-salt stress mung bean sprouts that were exposed to low-salt stress using anion exchange and gel permeation techniques. Structural analysis revealed that MS-SDF was a homogeneous heteropolysaccharide with an average molecular weight of 164.997 KDa. It featured a loose structure and contained the characteristic functional groups typical of polysaccharides. MS-SDF was composed of arabinose, galactose, glucose, and mannose with a molar ratio of 3.95:3.86:82.69:9.02. The structure was mainly composed of →6)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, and →3,6)-α-D-Glcp-(1→ as the main chain. Branched at O-3 position with single β-D-Manp-(1→ as major the side chain. Furthermore, in vitro hypoglycemic assays indicate that MS-SDF exhibits α-glucosidase inhibitory activity, significantly enhancing glucose uptake, glycogen synthesis, and pyruvate kinase activity in insulin-resistant HepG2 cells. Overall, MS-SDF could be used as a promising source of functional hypoglycemic foods.

Effects of different enzyme extraction methods on the properties and prebiotic activity of soybean hull polysaccharides

In this study, five different processes, including hot water (HW-ASP), single enzyme (cellulase, pectinase and papain; C-ASP, PE-ASP, and P-ASP), and compound-enzyme (cellulose: pectinase: papain = 3:3:1; CE-ASP) for the extraction of soybean hull polysaccharides (ASPs) were employed, and the characterization and prebiotics activity of five polysaccharides were analyzed. These polysaccharides possessed different primary structural characteristics, including molecular weight distribution, monosaccharide composition, chemical composition, surface morphology, potential particle size, etc., while similar functional groups. In vitro digestibility assay indicated that C-ASP had strong resistance to gastric juice hydrolysis and α-amylase as compared with HW-ASP. Furthermore, C-ASP elevated the acidifying activity and promoted the growth of probiotics (Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus acidophilus) during the fermentation (p < 0.05). C-ASP improved the levels of total short-chain fatty acids (SCFAs) and had better prebiotic activity than HW-ASP (p < 0.05). These findings denote that enzyme-assisted polysaccharides extracted from soybean hulls have the potential to be served as novel probiotics.

Chemically Sulfated Polysaccharides from Agaricus blazei Murill: Synthesis, Characterization and Anti-HIV Activity

AIDS, caused by HIV-1, is one of the most dangerous infectious diseases in the world. Therefore, it is necessary to develop new drugs with more potent bioactivities, less toxicity and higher tolerability for controlling the viral load, particularly by using the raw materials that are widely available. Agaricus blazei Murill (AbM), known in China as jisongrong, is of great importance as a food source and as a health-promoting supplement for immunomodulation. The polysaccharides of AbM exhibit various biological activities, such as regulating cellular immunity and providing anti-oxidative, anti-infective, and anti-inflammatory effects. At present, to our knowledge, no report has explored the chemically sulfated and anti-HIV-1 activity of AbM polysaccharides. Herein, the sulfated AbM polysaccharides with different sulfur contents were prepared by the chlorosulfonic acid-pyridine method. The characteristics of sulfated derivatives were established by the determination of the sulfur content, the relative molecular weight, and the Fourier-transform infrared spectroscopy. The anti-HIV activities of the sulfated AbM polysaccharides were evaluated by CCK-8 and the single-cycle pseudovirus infection (TZM-bl) assay. The sulfated AbM polysaccharides had strong antiviral properties, and the half-maximal inhibitory concentrations approached that of the positive control, azidothymidine. Sulfated modification of AbM polysaccharides can increase their anti-HIV pharmacological activity, which makes them promising alternative candidates as bioactive macromolecules for biomedical applications in HIV/AIDS.

Antibacterial and probiotic promotion potential of a new soluble soybean polysaccharide‑iron(III) complex

In this study soluble soybean polysaccharide‑iron(III) (SSPS-Fe(III)) was synthesized to investigate the effects on the growth of Escherichia coli, Staphylococcus aureus and Bacillus licheniformis. Two new detection methods of real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) and microcalorimetry were used to evaluate the effects of different concentrations of SSPS-Fe(III) on the growth of three bacteria. The copy numbers of three bacteria showed that SSPS-Fe(III) had different impacts on the growth of E. coli, S. aureus and B. licheniformis. E. coli growth was inhibited by SSPS-Fe(III) in the higher concentration range and S. aureus growth was inhibited at any concentration, however B. licheniformis growth was promoted. The thermogenic curves for growth metabolism of E. coli and S. aureus presented peak shapes while those of B. licheniformis did platform shapes. As SSPS-Fe(III) concentration increased, the peak heights lowered for E. coli and S. aureus, and the time reaching stationary phase advanced for B. licheniformis. These findings demonstrate that SSPS-Fe(III) has an inhibitory effect on the foodborne pathogens of E. coli and S. aureus, and an enhancement on the probiotics of B. licheniformis.

Analysis of the polysaccharide fractions isolated from pea (Pisum sativum L.) at different levels of purification

Crude pea (Pisum sativum L.) polysaccharides (CPPs) were extracted under ultrasound assistance, and CPP yield was highest to 6.27381%, which optimized using response surface methodology. Enzymatic method was more effective in deproteinization than Trichloroacetic acid and Sevag method, when considering the polysaccharide retention value as well as the protein clearance. Three-phase partitioning deproteinization indicated that the combination of the enzyme and Sevag method was more effective than their single use. Pea polysaccharide fractions were obtained by diethylaminoethyl-52 cellulose (W-DE-PP, N-DE-PP1, and N-DE-PP2) and Sephadex G-100 size-exclusion chromatography (W-DE-GPP, N1-DE-GPPa, and N1-DE-GPPb) in that order. Polysaccharide fractions W-DE-GPP and N1-DE-GPPa were showed a smooth surface with many cavities by Scanning electron microscopy (SEM) in 1,000 folds. All polysaccharides, characterized by high-performance liquid chromatography (HPLC), were composed of rhamnose, arabinose, galactose, glucose, and mannose, with the highest concentrations of galactose and glucose. Compared with different purification levels, N-DE-GPP showed the strongest activity against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and the highest ferric reducing antioxidant power, which were similar to the results of W-DE-GPP. Therefore, W-DE-GPP and N-DE-GPP may be promising natural sources of antioxidants. PRACTICAL APPLICATIONS: Recently, numerous studies on the extraction, purification, characteristics, and bioactivities of polysaccharides have been conducted. We mainly focused on the functional compounds of legumes. Comprehensive studies on pea polysaccharides are limited. Therefore, in the present study, extraction of CPPs was performed to optimize conditions using response surface methodology. Polysaccharide fractions were obtained from different purification levels and were chemically characterized using HPLC and SEM. Antioxidant activities of polysaccharides with different purification levels were determined. All the conventional methods, described in previous studies, were applied in the study. Furthermore, we analyzed and compared the characteristics of polysaccharides at different purification levels. We believe that our results would likely supplement the fundamental studies on pea polysaccharides.

Sulfation, structural analysis, and anticoagulant bioactivity of ginger polysaccharides

In this study, ginger polysaccharide (GP), ginger polysaccharide 1 (GP1), and ginger polysaccharide 2 (GP2) from ginger were firstly modified by sulfation. Fourier transform infrared, and nuclear magnetic resonance spectra investigation of sulfated ginger polysaccharide (SGP), sulfated ginger polysaccharide 1 (SGP1), and sulfated ginger polysaccharide 2 (SGP2) revealed that the sulfation successfully occurred with the characteristic absorption peak of polysaccharide. Congo red experiment showed that triple helical structure existed in SGP and SGP1, but random coils existed in SGP2. SGP, SGP1, and SGP2 all showed a rough and rugged surface with plenty of small pores. The blood clotting time of SGP2 or SGP at 2 mg/mL in activated partial thromboplastin time (APTT) assay was 41.42 or 38.01 s, respectively, which were approximately 1.33- and 1.22-fold longer than that of the physiological saline. Compared to the saline control group, prothrombin time (PT) was increased by 1.22-fold with the addition of GP at 2 mg/mL. However, no clotting inhibition phenomenon was observed in thrombin time test even at the concentrations that APTT and PT were obviously prolonged. It indicated that GP2, SGP2, and SGP inhibited the intrinsic pathway of coagulation, but GP inhibited both the intrinsic and extrinsic pathways of coagulation. Hence, ginger polysaccharides might be used as anticoagulants and therapeutic reagents for thrombosis.

Variation in Morphological and Quality Parameters in Garlic (Allium sativum L.) Bulb Influenced by Different Photoperiod, Temperature, Sowing and Harvesting Time

Photoperiod (light) and temperature as abiotic factors having significant impact on the garlic bulb morphology and quality. In various bulb plants including garlic, bulbing is affected by photoperiod, temperature, sowing date and the plant age. In this backdrop experiments were performed to understand the effect of different photoperiods (10 h/14 h, 12 h/12 h and 14 h/10 h (light/dark)), temperatures (25 °C/18 °C and 30 °C/20 °C (light/dark)), sowing dates (D₀₈₀₁: 1^st August, D₀₉₀₁: 1^st September and D₁₀₀₁: 1^st October) and plant ages (A₈₀, A₆₀ and A₄₀: 80, 60 and 40 days after planting) on garlic cultivars viz; G103, G024 and G2011-5. Parameters including morphological (plant height, fresh weight and pseudostem diameter), bulb attributes (diameter, weight, height and bulbing index), growth period and bulb quality related traits (total soluble solid (TSS), contents of soluble protein, soluble sugar, total sugar, glucose, sucrose, fructose, starch, total phenol and total flavonoid) were assayed. Longer photoperiod (14 h), higher temperature (30 °C), early sowing (D₀₈₀₁) and maximum plant age (A₈₀) had maximum morphological and bulb quality related traits for cv. G103. These results showed that early sowing, maximum plant age, longer photoperiod and higher temperature are important for garlic bulb formation and quality. Moreover, the regulation of garlic bulb morphology and quality is achievable over the switch of sowing date, plant age, light and growth temperature.

Hydrogen gas mediates ascorbic acid accumulation and antioxidant system enhancement in soybean sprouts under UV-A irradiation

The soybean sprout is a nutritious and delicious vegetable that is rich in ascorbic acid (AsA). Hydrogen gas (H2) may have potential applications in the vegetable processing industry. To investigate whether H2 is involved in the regulation of soybean sprouts AsA biosynthesis under UV irradiation, we set 4 different treatments: white light(W), W+HRW, UV-A and UV-A+HRW. The results showed that H2 significantly blocked the UV-A-induced accumulation of ROS, decreased TBARS content and enhanced SOD and APX activity in soybean sprouts. We also observed that the UV-A induced accumulation of AsA was enhanced more intensely when co-treated with HRW. Molecular analyses showed that UV-A+HRW significantly up-regulated AsA biosynthesis and recycling genes compared to UV-A in soybean sprouts. These data demonstrate that the H2 positively regulates soybean sprouts AsA accumulation under UV-A and that this effect is mediated via the up-regulation of AsA biosynthesis and recycling genes.

The antioxidant activities effect of neutral and acidic polysaccharides from Epimedium acuminatum Franch. on Caenorhabditis elegans

A neutral polysaccharide (EAP-1N) and an acidic polysaccharide (EAP-2A) were purified from Epimedium acuminatum by DEAE-52 cellulose anion-exchange chromatography and gel-filtration chromatography. Their structures were characterized by chemical composition analysis, high-performance size exclusion chromatography (HPSEC), Fourier transform infrared spectrometry (FT-IR), and gas chromatography-mass spectrometry (GC-MS). Further, their antioxidant activities were investigated both in vitro and in vivo. Results showed that EAP-2A had higher uronic acid content and larger average molecular weight than EAP-1N. Compared with EAP-1N, EAP-2A exhibited significantly scavenging activities against free radical in vitro, as well as strongly stimulating effect on antioxidant enzyme activities (including superoxide dismutases (SOD), catalases (CAT), and glutathione peroxidases (GSH-PX)) and preferably inhibitory effect on lipid peroxidation and protein carboxyl in the mode of Caenorhabditis elegans.

Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95% ± 0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.