Optimization of extraction, characterization and antioxidant activity of polysaccharides from Brassica rapa L

The combination of Brassica rapa L. polysaccharides and cisplatin enhances the anti liver cancer effect and improves intestinal microbiota and metabolic disorders

Polysaccharides are commonly used as low-toxicity anticancer active substances to enhance the chemotherapeutic effect of cisplatin and reduce toxicity. Brassica rapa L. polysaccharides have been shown to have hepatoprotective effects; however, their anticancer effects in combination with cisplatin and their mechanisms have not been reported. An acidic polysaccharide from Brassica rapa L. (BRCPe) using hydroalcohol precipitation-assisted sonication was Characterized. The effects of BRCPe combined with cisplatin treatment on tumor growth in hepatocellular carcinoma mouse model were investigated. The impact of the combined treatment on the composition of intestinal flora, levels of short-chain fatty acids and endogenous metabolites in tumor mice were analyzed based on macrogenomic and metabolomic data Our results showed that the BRCPe combined with low-dose Cisplatin group showed better inhibitory activity against hepatocellular carcinoma cell growth in terms of tumor volume, tumor weight, and tumor suppression rate compared with the BRCPe and Cisplation alone group, and reduced the side effects of cisplatin-induced body weight loss, immune deficiency, and liver injury. Furthermore, BRCPe combined with cisplatin was found to induce apoptosis in hepatocellular carcinoma cell through the activation of the caspase cascade reaction. In addition, the intervention of BRCPe were observed to modulate the composition, structure and functional structure of intestinal flora affected by cisplatin. Notably, Lachnospiraceae bacteria, Lactobacillus murinus, Muribaculaceae, and Clostridiales bacteria were identified as significant contributors to microbial species involved in metabolic pathways. Moreover, BRCPe effectively regulate the metabolic disorders in cisplatin-induced hepatocellular carcinoma mice. In conclusion, BRCPe could potentially function as an adjuvant or dietary supplement to augment the effectiveness of cisplatin chemotherapy through the preservation of a more efficient intestinal microenvironmental homeostasis.

Polysaccharides from Brassica rapa root: Extraction, purification, structural features, and biological activities. A review

Brassica rapa (B. rapa) roots are attracting increased attention from nutritionists and health-conscious customers because of their remarkable performance in supplying necessary nutrients. Polysaccharides are major biologically active substances in B. rapa roots, which come in a variety of monosaccharides with different molar ratios and glycosidic bond types. Depending on the source, extraction, separation, and purification methods of B. rapa roots polysaccharides (BRP); different structural features, and pharmacological activities are elucidated. Polysaccharides from B. rapa roots possess a range of nutritional, biological, and health-enhancing characteristics, including anti-hypoxic, antifatigue, immunomodulatory, hypoglycemic, anti-tumor, and antioxidant activities. This paper reviewed extraction and purification methods, structural features, and biological activities as well as correlations between the structural and functional characteristics of polysaccharides from the B. rapa roots. Ultimately, this work will serve as useful reference for understanding the connections between polysaccharide structure and biological activity and developing novel BRP-based functional foods.

A Review Concerning the Polysaccharides Found in Edible and Medicinal Plants in Xinjiang

Approximately 110 types of medicinal materials are listed in the Chinese Pharmacopoeia, both for medicinal purposes and for use as food. There are several domestic scholars who have carried out research on edible plant medicine in China and the results are satisfactory. Though these related articles have appeared in domestic magazines and journals, many of them are yet to be translated into English. Most of the research stays in the extraction and quantitative testing stage, and there are a few medicinal and edible plants that are still under in-depth study. A majority of these edible and herbal plants are also highly enriched in polysaccharides, and this has an effect on immune systems for the prevention of cancer, inflammation, and infection. Comparing the polysaccharide composition of medicinal and edible plants, the monosaccharide and polysaccharide species were identified. It is found that different polysaccharides of different sizes have different pharmacological properties, with some polysaccharides containing special monosaccharides. The pharmacological properties of polysaccharides can be summarized as immunomodulatory, antitumor, anti-inflammatory, antihypertensive and anti-hyperlipemic, antioxidant, and antimicrobial properties. There have been no poisonous effects found in studies of plant polysaccharides, probably because the substances have a long history of use and are safe. In this paper, the application potential of polysaccharides in medicinal and edible plants in Xinjiang was reviewed, and the research progress in the extraction, separation, identification, and pharmacology of these plant polysaccharides was reviewed. At present, the research progress of plant polysaccharides in medicines and food in Xinjiang has not been reported. This paper will provide a data summary for the development and utilization of medical and food plant resources in Xinjiang.

Optimization of Extraction Process, Structure Characterization, and Antioxidant Activity of Polysaccharides from Different Parts of Camellia oleifera Abel

The flowers, leaves, seed cakes and fruit shells of Camellia oleifera are rich in bioactive polysaccharides, which can be used as additives in food and other industries. In this study, a Box-Behnken design was used to optimize the extraction conditions of polysaccharides from C. oleifera flowers (P-CF), leaves (P-CL), seed cakes (P-CC), and fruit shells (P-CS). Under the optimized extraction conditions, the polysaccharide yields of the four polysaccharides were 9.32% ± 0.11 (P-CF), 7.57% ± 0.11 (P-CL), 8.69% ± 0.16 (P-CC), and 7.25% ± 0.07 (P-CS), respectively. Polysaccharides were mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and xylose, of which the molecular weights ranged from 3.31 kDa to 128.06 kDa. P-CC had a triple helix structure. The antioxidant activities of the four polysaccharides were determined by Fe2+ chelating and free radical scavenging abilities. The results showed that all polysaccharides had antioxidant effects. Among them, P-CF had the strongest antioxidant activity, of which the highest scavenging ability of DPPH•, ABTS•+, and hydroxyl radical could reach 84.19% ± 2.65, 94.8% ± 0.22, and 79.97% ± 3.04, respectively, and the best chelating ability of Fe2+ could reach 44.67% ± 1.04. Overall, polysaccharides extracted from different parts of C. oleifera showed a certain antioxidant effect, and could be developed as a new type of pure natural antioxidant for food.

Enzyme-Assisted Extraction of Phenolics from Capparis spinosa Fruit: Modeling and Optimization of the Process by RSM and ANN

The current study intends to appraise the effect of enzyme complexes on the recovery of phenolics from Capparis spinosa fruit extract using the response surface methodology (RSM) and artificial neural networking (ANN). Enzymatic treatment of C. spinosa fruit extract was optimized under a set of conditions (enzyme concentration, pH, temperature, and time) against each enzyme formulation such as Kemzyme Plus Dry, Natuzyme, and Zympex-014. The extract yield observed for Kemzyme Plus Dry (42.00%) was noted to be higher than those for Zympex-014 (39.80%) and Natuzyme (38.50%). Based on the higher results, the values of Kemzyme Plus Dry-based extract were further employed in different parameters of RSM. The F-value (16.03) and p-values (<0.05) implied that the selected model is significant. Similarly, the higher values for the coefficient of determination (R ²) at 0.9740 and adjusted R ² (adj. R ²) at 0.9132 indicated that the model is significant in relation to given experimental parameters. ANN-predicted values were very close to the experimental values, which demonstrated the applicability of the ANN model. Antioxidant activities also exhibited profound results in terms of total phenolic content values (24.76 mg GAE/g), total flavonoid content values (24.56 mg CE/g), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (IC₅₀) (5.12 mg/mL). Scanning electron microscopy revealed that after enzymatic hydrolysis, the cell walls were broken as compared with nonhydrolyzed materials. Five phenolics, namely, quercetin, m-coumaric acid, sinapic acid, kaempferol, and p-coumaric acid, were identified from C. spinosa extract by gas chromatography-mass spectrometry (GC/MS). The results of this study reveal that the proposed optimization techniques, using Kemzyme Plus Dry among others, had a positive effect on the recovery of phenolic bioactive compounds and thus increased the antioxidant potential of C. spinosa fruit extract.

Polysaccharides of Brassica rapa L. attenuate tumor growth via shifting macrophages to M1-like phenotype

Macrophages are the major tumor-infiltrating leukocytes, and tumor-associated macrophages (TAM) play a critical role in cancer-related inflammation since they show alternative polarization to M1 (tumor-inhibited macrophages) or M2 (tumor-promoted macrophages) phenotype. Brassica rapa L. (B. rapa) has been clinically proven to have anti-tumor and immunity-enhancing activity, and the polysaccharides of B. rapa (BRP) have been reported to have an immunoregulatory effect on macrophages. In this study, we focus on macrophage polarization to investigate the mechanism of anti-tumor response of BRP in vivo and in vitro. We found that BRP improved the expression of M1 markers, including iNOS, COX-2, HLA-DR, CD11b and M1-related cytokines. The expression of M2 markers Arg-1, CD206 and CD163 induced by IL-4 were inhibited by BRP treatment, resulting in the inhibition of tumor growth both in vivo and in co-culture experiments in vitro. The activation of STAT signaling pathway were significantly regulated by BRP, which are important signals in TAM polarization. Overall, the results indicated that BRP has anti-tumor effect through mediating macrophage polarization.

Isolation, Structural Elucidation, Antioxidant and Hypoglycemic Activity of Polysaccharides of Brassica rapa L

The aim of this study was to investigate the effects of microwave ultrasonic-assisted extraction (MUAE) on the content, structure, and biological functions of Brassica rapa L. polysaccharide (BRP). Response surface methodology (RSM) was used to optimize the parameters of MUAE, and it obtained a polysaccharide with yield of 21.802%. Then, a neutral polysaccharide named BRP-1-1 with a molecular weight of 31.378 kDa was isolated and purified from BRP using DEAE-650 M and Sephadex G-100. The structures of the BRP-1-1 were elucidated through a combination of FT-IR, GC-MS, NMR, and methylation analysis. The results showed that BRP-1 consisted of mannose (Man) and glucose (Glu) in a molar ratio of 7.62:1. The backbone of BRP-1-1 mainly consisted of →6)-α-D-Glup-(1→4-β-D-Glup-(1→2)-α-D-Manp-(1→2)-α-D-Glup-(1→, the branch was [T-α-D-Manp-(1]_n→. BRP-1-1 intervention significantly inhibited α-glucosidase activity; an inhibition rate of 44.623% was achieved at a concentration of 0.5 mg/mL. The results of the in vitro biological activity showed that BRP-1-1 has good antioxidant and hypoglycemic activity, suggesting that BRP-1-1 could be developed as a functional medicine.

Protective Effect of Brassica rapa Polysaccharide against Acute High-Altitude Hypoxia-Induced Brain Injury and Its Metabolomics

Brassica rapa L., a traditional Tibetan medicine, has been wildly used for treating plateau disease. Polysaccharide is an important chemical component in B. rapa. The present study aimed to evaluate the effect of B. rapa polysaccharide (BRP) against acute high-altitude hypoxia (AHH) induced brain injury and its metabolic mechanism. The rats were randomly divided into six groups: control group, AHH group, Hongjingtian oral liquid group, and three BRP groups (38, 75, and 150 mg/kg/d). Serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), and lactate dehydrogenase (LDH) were detected by commercial biochemical kits. Hippocampus and cortex histopathological changes were observed by H&E staining and Nissl staining. Neuronal apoptosis was observed by TUNEL staining. The protein and gene expression of Caspase-3, Bax, Bcl-2, p-PI3K, PI3K, p-Akt, Akt, HIF-1α, microRNA 210, ISCU1/2, and COX10 were detected by western blotting and qRT-PCR. Then, a brain metabolomics method based on UPLC-Q-Exactive-MS was performed to discover potential biomarkers and analyze metabolic pathways. It was found that BRP decreased levels of MDA, LDH, and GSSG, increased GSH and SOD, reduced the pathological changes, inhibited apoptosis, and activated the PI3K/Akt/HIF-1α signaling pathway as evidenced by increased phosphorylation of PI3K and Akt, enhanced protein expression of HIF-1α and gene levels of microRNA210, ISCU1/2, and COX10. Furthermore, 15 endogenous potential biomarkers were identified in the brain through metabolomics analysis. BRP can regulate 7 potential biomarkers and the corresponding metabolic pathways were mainly associated with pyruvate metabolism and glycolysis/gluconeogenesis. Collectively, BRP has a clear protective effect on AHH-induced brain injury and its mechanisms may be related to ameliorate oxidative stress injury, inhibit apoptosis by activating PI3K/Akt/HIF-1α signaling pathway, and reverse metabolic pathway disturbances.

Digestive Characteristics of Hericium erinaceus Polysaccharides and Their Positive Effects on Fecal Microbiota of Male and Female Volunteers During in vitro Fermentation

Hericium erinaceus polysaccharides (HEPs) have attracted widespread attention in regulating gut microbiota (GM). To investigate digestibility and fermentation of HEPs and their effects on GM composition, three polysaccharide fractions, namely, HEP-30, HEP-50, and HEP-70, were fractionally precipitated with 30%, 50%, and 70% ethanol concentrations (v/v) from hot water-soluble extracts of Hericium erinaceus, respectively. Three kinds of prepared HEPs were structurally characterized and simulated gastrointestinal digestion, and their effects on human fecal microbiota fermentations of male and female and short-chain fatty acid (SCFA) production in vitro were clarified. Under digestive conditions simulating saliva, stomach, and small intestine, HEPs were not significantly influenced and safely reached the distal intestine. After 24 h of in vitro fermentation, the content of SCFAs was significantly enhanced (p < 0.05), and the retention rates of total and reducing sugars and pH value were significantly decreased (p < 0.05). Thus, HEPs could be utilized by GM, especially HEP-50, and enhanced the relative abundance of SCFA-producing bacteria, e.g., Bifidobacterium, Faecalibacterium, Blautia, Butyricicoccus, and Lactobacillus. Furthermore, HEPs reduced the relative abundances of opportunistic pathogenic bacteria, e.g., Escherichia-Shigella, Klebsiella, and Enterobacter. This study suggests that gradual ethanol precipitation is available for the preparation of polysaccharides from Hericium erinaceus, and the extracted polysaccharide could be developed as functional foods with great development value.

Bioactive compound from the Tibetan turnip (Brassica rapa L.) elicited anti-hypoxia effects in OGD/R-injured HT22 cells by activating the PI3K/AKT pathway

Cerebral stroke, a common clinical problem, is the predominant cause of disability and death worldwide. Its prevalence increases and infarctions exacerbate with age. A Tibetan plant, Brassica rapa L., possesses multiple medicinal effects, such as anti-altitude sickness, anti-hyperlipidemia and anti-fatigue, as mentioned in the noted ancient Tibet pharmacopeia "The Four Medical Tantras". Our preliminary studies also showed the anti-hypoxia protection mechanism of B. rapa L., implying its possible relationship with anti-ischemic neuroprotection. However, the potential molecular mechanism of the active constituent of turnip against cerebral ischemia/reperfusion remains unclear. In our study, oxidative stress markers, including LDH, ROS, SOD, GPx and CAT were assayed. In controlled in vitro assays, we found that the turnip's active constituent had remarkable anti-hypoxia capability. We further showed the profound effects of the active constituent of turnip on the levels of apoptosis-related proteins, including Bax, Bcl-2 and caspase-3, which contributed to its anti-inflammatory activity. Western blot analysis results also implied that active-constituent pretreatment reversed the diminished expression of the PI3K/Akt/mTOR pathway mediated by oxygen glucose deprivation/reperfusion (OGD/R); further experimental evidence showed that the protective role was limited in the PI3K inhibitor (LY294002) treatment group. Our results demonstrated that the functional monomer of B. rapa L. exerted a neuroprotective effect against OGD/R-induced HT22 cell injury, and its potential mechanism provides a scientific basis for future clinical applications and its use as a functional food.

Different techniques for concentration of extracellular biopolymers with herbicidal activity produced by Phoma sp

The natural ability of microorganisms to secrete high levels of bioactive compounds make them attractive hosts for producing novel compounds. Microbial biopolymers have potential applications in most of the sectors of the world economy. According to the physicochemical properties, they present some advantages, such as biodegradability, reproducibility, and stability. Based on this context, the objective of this work was to evaluate different methods for concentration and characterisation of extracellular biopolymers produced by Phoma sp. Extracellular biopolymers were produced by submerged fermentation and were concentrated by hollow fibre membranes and by adsorption. The structural characterisation of purified biopolymers was determined by Fourier Transform Infrared spectroscopy. Phytotoxic effects were assessed through absorption assays in detached leaves of Cucumis sativus and evaluated on the seventh day after application. The surface tension was evaluated for each sample. Hollow-fibre microfiltration membrane presented a higher purification factor than hollow-fibre ultrafiltration membrane. Extracellular biopolymers were identified in the permeate and retentate fractions, but in higher concentration in the retentate fractions. The adsorption process was efficient for recovering more than 88% of extracellular biopolymers from cell-free fermented broth. The best performance was obtained by using silica and activated carbon as adsorbent, with a recovery higher than 93%. The herbicidal activity was proportional to the concentration of biopolymers and the results are very promising for future applications because a concentrated solution of biopolymers can increase weed control. Membrane processes can be used to develop a liquid formulation of bioherbicide, whereas adsorption can be used to develop a solid formula.

Phytochemical characterization of turnip greens (Brassica rapa ssp. rapa): A systematic review

Objective

The Turnip (Brassica rapa L. ssp. rapa) is a leaf and root vegetable grown and consumed worldwide. The consumption of Turnip has been associated with beneficial effects on human health due to their phytochemicals that may control a variety of physiological functions, including antioxidant activity, enzyme regulation, and apoptotic control and the cell cycle. The current systematic review of the literature aims to evaluate both the profile and quantity of phytochemicals commonly found in Turnip greens and to provide perspectives for further investigation.

Methods

This review was conducted following the PRISMA guidelines. Four bibliographic databases (PubMed, Embase, Web-of-Science and Cochrane Central Register of Controlled Trials) were searched to identify published studies until April 8th, 2020 (date last searched) without data and language restriction. Studies were included if they used samples of Turnip greens (the leaves), and evaluated its phytochemical content. Two reviewers independently evaluated the titles and abstracts according to the selection criteria. For each potentially eligible study, two reviewers assessed the full-texts and independently extracted the data using a predesigned data extraction form.

Results

Based on the search strategy 5,077 potentially relevant citations were identified and full texts of 37 studies were evaluated, among which 18 studies were eligible to be included in the current review. The majority of included studies were focused on identification of glucosinolates and isothiocyanates (n = 14, 82%), four studies focused on organic acids, and five studies reported phenolic component profile in Turnip greens. Among included studies nine studies (50%) provided information on phytochemical’s content. We found 129 phytochemicals (19 glucosinolates, 33 glucosinolate-breakdown products, 10 organic acids and 59 polyphenolic compounds) reported in Turnip greens. Flavonoids were mainly present as quercetin, kaempferol and isorhamnetin derivatives; while aliphatic forms were the predominant glucosinolate (gluconapin was the most common across five studies, followed by glucobrassicanapin). In general, the phytochemical content varied among the leaves, tops and Turnip roots.

Conclusions

Emerging evidence suggests the Turnip as a substantial source of diverse bioactive compounds. However, detailed investigation on the pure compounds derived from Turnip green, their bioavailability, transport and metabolism after consumption is further needed. Additional studies on their biological activity are crucial to develop dietary recommendations on the effective dosage and dietary recommendation of Turnip greens for nutrition and health.

Neuroprotection against cerebral ischemia/reperfusion by dietary phytochemical extracts from Tibetan turnip (Brassica rapa L.)

ETHNOPHARMACOLOGICAL RELEVANCE

The Tibetan turnip (Brassica rapa L.) has a wide array of medicine properties including heat-clearing, detoxifying and anti-hypoxia as listed in the famous centuries-old Tibetan medicine classic "The Four Medical Tantras". Evidence-based medicine also indicated the anti-hypoxic effect of turnips, suggesting a potential link to neuroprotective effect on ischemic stroke. This thereby enables turnips to serve as a novel nontoxic agent in related treatment.

AIM OF THE STUDY

This study aimed to investigate the neuroprotective effect and elucidate the mechanism of aqueous extract of turnip (AET) on cerebral ischemia/reperfusion.

MATERIALS AND METHODS

The experimental models of cerebral ischemia included transient middle cerebral artery occlusion/reperfusion (MCAO) in C57BL/6J mice and oxygen-glucose deprivation/reoxygenation (OGD/R) in HT-22 cells. Long-term effect of AET on infarct volume was evaluated by microtubule-associated protein 2 (MAP2) immunofluorescence 28 days after MCAO, and on neurofunctional outcomes determined by rotarod, grid walking, and cylinder tests in the meantime. Efficacy of AET was determined by the cell viability, the release of lactate dehydrogenase (LDH) and reactive oxygen species (ROS) in neurons. The underlying mechanism of AET rescued OGD/R cells were characterized by PI3K, Akt and mTOR expressions, which were further used to validate AET's role in the pathway.

RESULTS

AET can reduce cerebral infarct volume and ameliorate behavioral deficits of MCAO/R mice dose-dependently. In vitro experiment further demonstrated that suitable concentrations of AET inhibited ROS, LDH production and restored mitochondrial expression induced by OGD/R. AET pretreatment can reverse the OGD/R-induced decreased level of phosphorylation of PI3K, Akt, mTOR, whereas this effect was blocked in the LY294002 (PI3K inhibitor) treatment group.

CONCLUSIONS

AET improved the survival of OGD/R-injured HT-22 cells by activating the PI3K/Akt/mTOR pathway. Based on the results above, aqueous extract of turnip has a protective effect on focal cerebral ischemic injury.

Extraction of sulfated agar from Gracilaria lemaneiformis using hydrogen peroxide-assisted enzymatic method

In this study, an eco-friendly extraction method was explored to obtain high sulfate content agar and repair the deficiency of enzymatic extraction by taking full advantage of H₂O₂. The sulfate content of EHA (H₂O₂-assisted enzymatic extracted agar) reached 3.56 %, which is significantly higher than that of traditional alkali-extracted agar (AA, 1.8 %). Moreover, EHA exhibited lower viscosity (9.4 cP), which improved 26.6 % and 14 % of filtration and gel dehydration rates than EA (enzymatic extracted agar), respectively. Additionally, the physicochemical properties of the agars were evaluated and compared. Among these agars, EHA showed some favorable properties, such as high yield (16.08 %) and low dissolution temperature (88.9 °C). The surface of algae became smoother after treatment with H₂O₂ due to effective degradation of cellulose. Besides, mass spectrometry analysis revealed that EHA preserved a great amount of sulfate, while thermogravimetric analysis suggested that the thermal stability of EA and EHA both decreased.

Brassica rapa Polysaccharides Ameliorate CCl4 -Induced Acute Liver Injury in Mice through Inhibiting Inflammatory Apoptotic Response and Oxidative Stress

Brassica rapa L., also called NIUMA, is used empirically in Tibetan medicine for its antioxidant, anti-inflammatory and antiradiation activities. This study explored the hepatoprotective effects of B. rapa polysaccharides (BRPs) on acute liver injury induced by carbon tetrachloride (CCl₄ ) in mice and the underlying mechanisms. Mice were treated with CCl₄ after the oral administration of BRPs (55, 110 and 220 mg/kg) or bifendate (100 mg/kg) for 7 days. Blood and liver samples of mice were collected for analysis after 24 h. The ALP, ALT and AST levels and the biological activities of SOD, MDA and GSH-Px were measured. Histopathological changes in the liver were determined through hematoxylin and eosin staining. Moreover, TNF-α, IL-1β and IL-6 expression levels were detected by commercial reagent kits. Finally, Western blot analysis was used to check the relative expression levels of caspase-3, p-JAK2 and p-STAT3. The BRP pre-treatment significantly decreased the enzymatic activities of ALT, ALP and AST in the serum, markedly increased the activities of SOD and GSH-Px in the liver and reduced the MDA concentration in the liver. BRPs alleviated hepatocyte injury and markedly inhibited the expression of TNF-α, IL-1β and IL-6, also downregulating the CCl₄ -induced hepatic tissue expression of caspase-3. Furthermore, BRPs inhibited the JAK2/STAT3 signaling pathway in a dose-dependent manner in the liver. This study demonstrated that BRPs exert hepatoprotective effect against the CCl₄ -induced liver injury via modulating the apoptotic and inflammatory responses and downregulating the JAK2/STAT3 signaling pathway. Therefore, B. rapa could be considered a hepatoprotective medicine.

Physicochemical characteristics and in vitro and in vivo antioxidant activity of a cell-bound exopolysaccharide produced by Lactobacillus fermentum S1

A cell-bound exopolysaccharide (c-EPS) from Lactobacillus fermentum S1 was isolated and purified to near homogeneity by anion exchange and gel filtration chromatography. The c-EPS is a homogeneous heteropolysaccharide with an average molecular weight of 7.19 × 10⁵ Da and comprises mainly mannose, rhamnose, glucose, and galactose. Fourier transform infrared spectroscopy spectrum of the c-EPS exhibited typical characteristic absorption peaks of polysaccharides. Methylation and NMR analyses showed that the c-EPS had a backbone of α-D-Galp-(1 → 3), α-L-Rhap-(1 → 2), α-D-Glcp-(1 → 3), β-D-Galp-(1 → 3), β-D-Glclp-(1 → 2), and β-L-Rhap-(1 → 3,4) residues, terminated with α-D-Manp-(1 → residue. The advanced structure study indicated the c-EPS not to have a triple-helical conformation, while the microstructural study revealed a hollow porous structure for c-EPS. Further, the thermal analysis showed that the degradation temperature for the c-EPS was 288.0 °C; its peak temperature was 89.4 °C with an enthalpy value of 273.1 J/g. Moreover, the c-EPS exhibited potent DPPH, hydroxyl, and ABTS⁺ radicals scavenging activities, as well as FRAP in a dose-dependent manner, which could significantly enhance the T-AOC and SOD activity and reduce MDA level in Caenorhabditis elegans. Therefore, this c-EPS could be utilized as a promising natural antioxidant for application in functional foods.

The Effect of Hemicellulose and Lignin on Properties of Polysaccharides in Lentinus edodes and Their Antioxidant Evaluation

Lentinus edodes, whose polysaccharides possess diverse bioactivities, commonly grows on hardwood sawdust composed of hemicellulose, lignin and cellulose. In this study the effect of hemicellulose and lignin on the growth of mycelia, as well as the physicochemical properties of polysaccharides from L. edodes mycelia (LEPs) were investigated. The antioxidant properties of LEPs were evaluated through radical scavenging assays in vitro and through the Caenorhabditis elegans model in vivo. The results showed that hemicellulose at a concentration of 4% increased the yield of the mycelia biomass to twice that of the control group. Meanwhile, when cultured with 4.0% hemicellulose, the polysaccharide content of the mycelia was raised by 112.2%. In addition, the appropriate concentration of lignin could stimulate mycelia growth and polysaccharide biosynthesis in L. edodes. Monosaccharide composition analysis showed that a higher content of xylose was found when mycelia were cultured with higher concentrations of hemicellulose. The molecular structure, including the molecular weight distribution and configuration type, was affected by hemicellulose and lignin. Antioxidant assays indicated that LEPs supplemented with hemicellulose and/or lignin possessed higher radical scavenging abilities in vitro and exhibited a thermal resistance effect on C. elegans, implying that the antioxidant effect is potent in vivo. In summary, the addition of hemicellulose and lignin improved the biosynthesis and bioactivity of LEPs.

Comparative study on the physicochemical properties and bioactivities of polysaccharide fractions extracted from Fructus Mori at different temperatures

This study examined the effects of different extraction temperatures (30 °C and 90 °C) on the physicochemical properties and bioactivities of polysaccharides (MFPs-30-60, MFPs-30-80, MFPs-90-40, MFPs-90-60 and MFPs-90-80) extracted at same ethanol gradation (40, 60 and 80%).

p-Coumaric acid as a prophylactic measure against normobaric hypoxia induced pulmonary edema in mice

AIMS

Previous studies indicate that the anti-hypoxia effects of Tibetan Turnip (Brassica rapa ssp. rapa) were closely related to its characteristic components being p-coumaric acid (CA) and p-coumaric acid‑β‑d‑glucopyranoside (CAG). Since CAG would be converted to CA in vivo, this study aims to further examine the efficacy and mechanism of CA against pulmonary edema induced by normobaric hypoxia.

MAIN METHODS

Male ICR mice were assigned to the normoxia group and several hypoxia groups, given sterile water, CA or dexamethasone orally, once daily for four consecutive days. One hour after the final gavage, mice in the above hypoxia groups were put into the normobaric hypoxia chamber (9.5% O₂) for 24 h while mice in normoxia group remained outside the chamber. After hypoxia exposure, lung water content (LWC), pulmonary vascular permeability, the protein content of bronchoalveolar lavage fluid (BALF), plasma total nitrate/nitrite (NO_x) and endothelin-1 (ET-1) content, histological and ultra-microstructure analyses were performed. Expression of occludin was assayed by immunohistochemistry.

KEY FINDINGS

In a hypoxic environment of 9.5% O₂, mice treated with 100 mg/kg body wt CA had significantly lower LWC and BALF protein content than mice in the hypoxia vehicle group. Meanwhile, mice in CA group showed intact lung blood-gas-barrier, increased levels of plasma total NO, decreased levels of plasma ET-1 and upregulation of occludin expression.

SIGNIFICANCE

CA exerts preventive effects against normobaric hypoxic pulmonary edema in mice, its mechanisms involved improving the integrity of the lung barrier, inhibiting oxidative stress and inflammation.

N-Butanol Subfraction of Brassica Rapa L. Promotes Reactive Oxygen Species Production and Induces Apoptosis of A549 Lung Adenocarcinoma Cells via Mitochondria-Dependent Pathway

Brassica rapa L., an edible and medical vegetable, has been traditionally used in Uyghur folk medicine to treat coughs and asthma in the Xinjiang Uygur Autonomous Region, China. In this study, we prepared an n-butanol subfraction of B. rapa L. (BRBS) and investigated the anti-tumor effect on A549 lung adenocarcinoma cells. The proliferation of A549 cells was significantly inhibited by BRBS treatment in a dose- and time-dependent manner. BRBS significantly induced cell cycle arrest and apoptosis in A549 cells through increased reactive oxygen species (ROS) production and mitochondrial dysfunction characterized by a reduction in mitochondrial membrane potential and the release of cytochrome c, which promoted caspase-3 and poly(ADP-ribose) polymerase processing. Moreover, BRBS significantly suppressed the migration of A549 cells in vitro. These results suggest that BRBS inhibited A549 cell proliferation through increased ROS production and the mitochondria-dependent apoptosis pathway. Consequently, BRBS might be a potential candidate for the treatment of lung cancer.

Efficient Approach for the Extraction and Identification of Red Pigment from Zanthoxylum bungeanum Maxim and Its Antioxidant Activity

Red pigment (RP) was extracted from the peels of Zanthoxylum bungeanum Maxim (PZB) by ultrasonic-assisted extraction (UAE) in this work. Box⁻Behnken design⁻response surface methodology (BBD-RSM) was employed to research the efficiency of the RP extraction. Based on the optimization of RSM, results showed that the optimal extraction conditions were as follows: liquid⁻solid ratio of 31 mL/g, extraction time of 41 min, and extraction temperature of 27 °C, and under these conditions, the actual absorbance value was 0.615 ± 0.13%, highly agreeing with the predicted value by the model. Furthermore, ultra-performance liquid chromatography⁻mass spectrometry (UPLC-MS) was used to separate and analyze RP. The compounds of RP were mainly flavonoids, and there were five compounds detected for the first time in PZB. In addition, RP showed significant antioxidant activities in vitro, which could be developed for anti-aging candidate drugs and functional foods. In conclusion, ultrasound-assisted extraction with BBD-RSM and chromatographic separation technology with UPLC-MS are efficient strategies for the isolation and identification of RP from PZB.

Evaluation of chemical property, cytotoxicity and antioxidant activity in vitro and in vivo of polysaccharides from Fuzhuan brick teas

Fuzhuan brick tea (FBT) possesses various health-promoting functions. However, the available information regarding biological activity of polysaccharides from FBT (FBTPS) is still limited. In this work, the chemical property, cytotoxicity and antioxidant activity in vitro and in vivo of FBTPS were evaluated. It was found that FBTPSs were typical acidic heteropolysaccharides mainly composed of Man, Rha, GalA, Glc, Gal and Ara with little molar content of Rib and GlcA. FBTPS showed little toxicity to human hepatic epithelial (L-02) cell. FBTPS exhibited antioxidant activities, including limited scavenging activity on DPPH free radicals (ranged from 54.3 ± 1.9 to 67.8 ± 2.5%), noticeable scavenging activity on superoxide radicals (over 85%), superior scavenging activity on ABTS radicals (near 100%), and protective effect on H₂O₂-induced oxidative injury in rat pheochromocytoma line 12 (PC12) cell. Moreover, FBTPS showed significant amelioration of high-fat diet-induced oxidative injury in mice. The results suggest that FBTPS, as natural safe antioxidants, may have potential application in functional foods.

Physicochemical properties and activities of comfrey polysaccharides extracted by different techniques

The effects of extraction techniques on the physicochemical properties, antioxidant activity and antihyperglycemic activity of comfrey polysaccharides (CPs) were evaluated. Four techniques were used to extract CPs: hot water extraction (HW), ultrasonic-assisted extraction (UA), enzyme-assisted extraction (EA) and enzyme-ultrasonic-assisted extraction (EUA). Experimental results indicated that CPs extracted by the UA (UA-CPs) and EUA methods (EUA-CPs) had higher extraction yields. The four CPs showed the same monosaccharide composition but a significant difference in monosaccharide content. CPs showed antioxidant activities and antihyperglycemic activities in a concentration-dependent manner. UA-CPs exhibited better antioxidant capacity, which might have been related to its smaller molecular weight and higher uronic acid content. In addition, UA-CPs showed notable α-glucosidase inhibition activity. These results suggested that ultrasonic-assisted extraction technology was more beneficial to enhance the extraction yields of the polysaccharides, and obtain higher bioactive polysaccharides from comfrey.

Extraction condition optimization and effects of drying methods on physicochemical properties and antioxidant activities of polysaccharides from Astragalus cicer L

Response surface methodology (RSM) including three variables was performed to optimize the extraction parameters of Astragalus cicer L. polysaccharides (ACPs). The influence of different drying techniques on the physicochemical properties and antioxidant abilities of ACPs were evaluated. The ACPs were dried with hot air (HD), vacuum (VD) and freeze drying (FD) methods. The optimal conditions for ACPs extraction were as follows: water to raw material ratio of 25 mL/g, extraction time of 61 min and temperature of 75 °C. Under these parameters, an ACPs yield of 10.97% was obtained. HPLC analysis showed that the monosaccharide compositions of the three ACPs dried with HD, VD or FD techniques were identical. The three ACPs exhibited antioxidant abilities in a concentration-dependent manner. ACPs dried with the FD method (FD-ACPs) had the best antioxidant activities, which might be related to their smaller molecular weight and higher uronic acid content. At the determined concentration of 1 mg/mL, the ferric reducing power, and DPPH and ABTS free radical scavenging capacities of FD-ACPs were 0.762, 75.30% and 99.21%, respectively. Therefore, FD was a good choice for the drying of Astragalus cicer L. polysaccharides.

Optimization of water-soluble polysaccharides from stem lettuce by response surface methodology and study on its characterization and bioactivities

Stem lettuce is widely consumed as a vegetable in China. It is also used as a traditional Chinese medicine for a long time. Up to now, no information is available for stem lettuce polysaccharide (SLP). In this study, extraction optimization, characterization, and antioxidant activity of SLP was investigated.The maximum SLP yield of 20.89% was obtained under the optimal extraction conditions as follows: extraction temperature 95°C, extraction time 3.3h and ratio of water to material 25mL/g. The sulfate content of SLP was 5.82% and the main monosaccharides were GalA, Gal, and Ara with a mole ratio of 49.2: 23.3: 22.9. FT-IR spectrum and HPGPC result further indicated that SLP is a sulfated polydisperse heterpolysaccharide. Congo-red test and AFM scan indicated that SLP might be branching and intertwining structure with triple helix conformation. Moreover, SLP exhibited potent antioxidant activity and α-amylase inhibitory activity, hence it could be used as a potential natural antioxidant and hypoglycemic agent in medicine or functional food fields.

Structural Characterization and Immunostimulatory Activity of Polysaccharides from Brassica rapa L.

Two neutral polysaccharides (BRNP-1, 6.9 kDa; BRNP-2, 4.8 kDa) were purified from the common edible plant Brassica rapa L. via the combined techniques of ion-exchange chromatography and high-performance gel permeation chromatography. Monosaccharide composition analysis showed that BRNP-1 and BRNP-2 were composed of glucosyl residues. Methylation and 1D- and 2D-NMR analyses revealed that both BRNP-1 and BRNP-2 contained a backbone chain that was composed of α-D-(1 → 4)-linked Glcp residues and side chains that were composed of terminally linked Glcp residues attached at the O-6 position of backbone-glycosyl residues. BRNP-1 and BRNP-2, however, differed in branch degree and molecular weight. Bioassay results showed that treatment with the higher dosage (400 μg/mL) of BRNP-1 and BRNP-2 stimulated the proliferation, NO release, and cytokine secretion (IL-6 and TNF-α) of RAW264.7 macrophages. These results suggested that BRNP-1 and BRNP-2 may enhance macrophage-mediated immune responses.

Extraction optimization and influences of drying methods on antioxidant activities of polysaccharide from cup plant (Silphium perfoliatum L.)

Response surface methodology (RSM) was used to investigate the extraction condition of polysaccharide from cup plant (Silphium perfoliatum L.) (named CPP). Water to raw material ratio (10-30 mL/g), extraction time (40-80 min) and extraction temperature (60-100°C) were set as the 3 independent variables, and their effects on the extraction yield of CPP were measured. In addition, the effects of drying methods including hot air drying (HD), vacuum drying (VD) and freeze drying (FD) on the antioxidant activities of CPP were evaluated. The results showed that the optimal condition to extract CPP was: water to raw material ratio (15 mL/g), extraction time (61 min), and extraction temperature (97°C), a maximum CPP yield of 6.49% was obtained under this condition. CPP drying with FD method showed stronger reducing power (0.943 at 6 mg/mL) and radical scavenging capacities against DPPH radical (75.71% at 1.2 mg/mL) and ABTS radical (98.06 at 1.6 mg/mL) than CPP drying with HD and VD methods. Therefore, freeze drying served as a good method for keeping the antioxidant activities of polysaccharide from cup plant. The polysaccharide from cup plant has potential to use as a natural antioxidant.

Extraction optimization, preliminary characterization and antioxidant activities of polysaccharides from Glycine soja

Single-factor experiment and Central Composite Design (CCD) was applied to optimize the ultrasound-assisted extraction (UAE) conditions of polysaccharides from Glycine soja (CGPS), and a preliminary characterization of three polysaccharide fractions (CGPS, GPS-1, and GPS-2) and their antioxidant activities were investigated. Under the optimal conditions: ratio of liquid to solid 42.7mL/g, extraction power 293.7W, extraction temperature 68.9°C, and extraction time 34.7min, the experimental CGPS yield was 6.04mg/g. CGPS was further purified by DEAE-cellulose and Sephadex-100 chromatography to obtain two fractions (GPS-1 and GPS-2), and their monosaccharides compositions were characterized by HPLC. Fourier-transform infrared spectra (FT-IR) indicated the chemical structures of them. Moreover, they exhibited high antioxidant activities in a concentration-dependent manner in vitro. In summary, the present study suggested that UAE was a very effective method to extract polysaccharides from Glycine soja and the polysaccharides could be explored as potential antioxidant agents for medicine and function food.