Optimization of Three Extraction Methods and Their Effect on the Structure and Antioxidant Activity of Polysaccharides in Dendrobium huoshanense.

Dendrobium huoshanense is a famous edible and medicinal herb, and polysaccharides are the main bioactive component in it. In this study, response surface methodology (RSM) combined with a Box-Behnken design (BBD) was used to optimize the enzyme-assisted extraction (EAE), ultrasound-microwave-assisted extraction (UMAE), and hot water extraction (HWE) conditions and obtain the polysaccharides named DHP-E, DHP-UM, and DHP-H. The effects of different extraction methods on the physicochemical properties, structure characteristics, and bioactivity of polysaccharides were compared. The differential thermogravimetric curves indicated that DHP-E showed a broader temperature range during thermal degradation compared with DHP-UM and DHP-H. The SEM results showed that DHP-E displayed an irregular granular structure, but DHP-UM and DHP-H were sponge-like. The results of absolute molecular weight indicated that polysaccharides with higher molecular weight detected in DHP-H and DHP-UM did not appear in DHP-E due to enzymatic degradation. The monosaccharide composition showed that DHPs were all composed of Man, Glc, and Gal but with different proportions. Finally, the glycosidic bond types, which have a significant effect on bioactivity, were decoded with methylation analysis. The results showed that DHPs contained four glycosidic bond types, including Glcp-(1→, →4)-Manp-(1→, →4)-Glcp-(1→, and →4,6)-Manp-(1→ with different ratios. Furthermore, DHP-E exhibited better DPPH and ABTS radical scavenging activities. These findings could provide scientific foundations for selecting appropriate extraction methods to obtain desired bioactivities for applications in the pharmaceutical and functional food industries.

Encapsulating quercetin in cyclodextrin metal-organic frameworks improved its solubility and bioavailability.

BACKGROUND: Quercetin (Que) has many pharmacological activities, such as anticancer, antioxidant, cardiovascular protection, antihypertensive and lipid-lowering activities. However, its poor water solubility greatly limits its application in medicine and food. γ-Cyclodextrin metal-organic frameworks (γ-CD-MOFs) are novel porous carriers for loading functional products. In this study, Que was successfully loaded into γ-CD-MOFs, and the new compound (Que-CD-MOFs) was characterised by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. RESULTS: The apparent solubility of Que-CD-MOFs was enhanced by 100-fold compared with that of pure Que. The free radical scavenging ability of the encapsulated Que was significantly improved. The cytotoxicity of Que-CD-MOFs to HK-2 cells was decreased, and their inhibition on HT-29 tumour cells was maintained, as confirmed by CCK-8 assays. Flow cytometry of HT-29 cells showed that Que-CD-MOFs can inhibit G2 phase cells. Based on molecular modelling, Que molecules were preferentially located inside the cavities of γ-CD pairs in γ-CD-MOFs. CONCLUSION: γ-CD-MOFs are promising carriers for bioactive agents in food and pharmaceutical applications. © 2021 Society of Chemical Industry.

An integrated metabolic consequence of Hepatospora eriocheir infection in the Chinese mitten crab Eriocheir sinensis.

Despite the economic and evolutionary importance of aquatic host-infecting microsporidian species, at present, limited information has been provided about the microsporidia-host interactions. This study focused on Hepatospora eriocheir, an emerging microsporidian pathogen for the Chinese mitten crab Eriocheir sinensis. Hypertrophy of hepatopancreas cells was a common feature of H. eriocheir infection. More importantly, mitochondria of the hepatopancreas were drawn around the H. eriocheir, most likely to aid the uptake of ATP directly from the host. To better understand the crab anti-microsporidian response, de novo transcriptome sequencing of the hepatopancreas tissue was furtherly proceeded. A total of 47.84 M and 57.21 M clean reads were generated from the hepatopancreas of H. eriocheir infected and control groups respectively. Based on homology searches, functional annotation with 6 databases (Nr, Swiss-Prot, KEGG, KOGs, Pfam and GO) for 88,168 unigenes was performed. 2619 genes were identified as differently up-regulated and 2541 genes as differently down-regulated. Prominent functional categories enriched with differentially expressed genes (DEGs) were "ATP binding", "mitochondrion and extracellular region", "oxygen transporter activity", "oxidoreductase activity", "alanine, aspartate and glutamate metabolism", "carbohydrate metabolic process", "starch and sucrose metabolism" and "fatty acid biosynthesis". These results confirmed a parasite external energy supply and an integrated metabolic stress. In addition, simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) were also identified from the gene library. Taken together, these findings allow us to better understand the underlying mechanisms regulating interactions between H. eriocheir and the crab E. sinensis.

Isolation and Characterization of Aphidicolin Derivatives from Tolypocladium inflatum.

Inflatin G (1), a new aphidicolin analogue, together with seven known compounds inflatin A (2), inflatin B (3), aphidicolin (4), aphidicolin-17-monoacetate (5), gulypyrone A (6), pyridoxatin rotamers A (7) and B (8), were isolated from the ascomycete fungus Tolypocladium inflatum. Their structures were determined through NMR analyses and the circular dichroism data of the in situ formed [Rh2(OCOCF3)4] complexes. Compounds 1, 4, 5, 7, and 8 showed modest cytotoxicity against four human cancer cell lines A549, CNE1-MP1, A375, and MCF-7.

Exogenous ascorbic acid and glutathione alleviate oxidative stress induced by salt stress in the chloroplasts of Oryza sativa L.

The effects of exogenous ascorbic acid (AsA) and reduced glutathione (GSH) on antioxidant enzyme activities [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)] and the contents of malondialdehyde (MDA) and H2O2, as well as of endogenous AsA and GSH, in the chloroplasts of two rice cultivars, the salt-tolerant cultivar Pokkali and the salt-sensitive cultivar Peta, were investigated. Exogenous AsA and GSH enhanced SOD, APX, and GR activities, increased endogenous AsA and GSH contents, and reduced those of H2O2 and MDA in the chloroplasts of both cultivars under salt stress (200 mM NaCl), but the effects were significantly more pronounced in cv. Pokkali. GSH acted more strongly than AsA on the plastidial reactive oxygen scavenging systems. These results indicated that exogenous AsA and GSH differentially enhanced salinity tolerance and alleviated salinity-induced damage in the two rice cultivars.

Transcriptomics provides insights into toxicological effects and molecular mechanisms associated with the exposure of Chinese mitten crab, Eriocheir sinensis, to dioxin.

Dioxins are stable, ubiquitous, persistent, and halogenated environmental pollutants that have recently garnered increasing attention. This study constructed a microcosmic system to simulate the real breeding conditions of the Chinese mitten crab (Eriocheir sinensis) to evaluate the impact of environmental dioxins on these aquaculture animals. Histological observation and detection of antioxidant enzyme activities revealed that dioxin exposure for different durations substantially damaged the hepatopancreas of Chinese mitten crabs, increasing the enzymatic activities of total superoxide dismutase (T-SOD) and catalase (CAT) but decreasing that of malondialdehyde (MDA). We also obtained the gene expression profiles of the hepatopancreas corresponding to different periods of dioxin exposure using RNA-seq technology. Compared with the control group, 2999 and 941 differentially expressed genes (DEGs) corresponding to different periods of dioxin exposure were identified in the hepatopancreas. Enrichment analysis indicated that some pathways, such as those governing carbohydrate metabolism, fatty acid metabolism, and immune disease, also responded to dioxin exposure. Subsequently, we selectively analyzed DEGs involved in oxidoreductase activity, carbohydrate metabolic processes, and other processes, identifying that increased expression of Hsp70, Ldh, and Trx1 and decreased expression of Lgbp, Bgal1, and Acsbg2 were potentially caused by sensitivity to environmental dioxin exposure. Therefore, we contend that, although crabs exposed to unfavorable environmental pollutants, such as dioxin, may adapt via antioxidant and immune response modulation. However, continued dioxin exposure would disrupt such homeostatic restorative capabilities. Thus, this study may provide new insights into the toxicological effects exerted by dioxin on aquatic organisms, such as E. sinensis, as well as the mechanisms underlying such toxicity.

Relationship between Molecular Structure and Heat-Induced Gel Properties of Duck Myofibrillar Proteins Affected by the Addition of Pea Protein Isolate.

This paper investigates the relationship between the molecular structure and thermally induced gel properties of duck myofibrillar protein isolate (DMPI) as influenced by the addition of pea protein isolate (PPI). The results showed that b* value of the gels increased; however, a* value decreased with the increase of PPI content (p < 0.05). The whiteness of the gels decreased significantly with the addition of pea protein compared with 0% vs. 0.5% addition. Nuclear magnetic resonance tests showed the area of immobilized water also increased with increasing PPI addition (0−2%), thus consistent with the increased water-holding capacity (p < 0.05). The penetration force of the gels increased with increasing PPI addition (p < 0.05), while the storage modulus and loss modulus of the gels were also found to increase, accompanied by the transformation of the α-helix structure into ß-sheet, resulting in better dynamics of gel formation. These results indicated the gel-forming ability of DMPI, including water retention and textural properties, improves with increasing PPI addition. Principal component analysis verified these interrelationships. Thus, pea protein could improve the properties of duck myofibrillar protein gels to some extent and improve their microstructure, potentially facilitating the transition from a weak to a non-aggregated, rigid structure.

Physicochemical properties and gel-forming ability changes of duck myofibrillar protein induced by hydroxyl radical oxidizing systems.

This paper focuses on the changes of physicochemical properties and gel-forming ability of duck myofibrillar proteins (DMPs) induced using hydroxyl radical oxidizing systems. DMPs were firstly extracted and then oxidized at various H2O2 concentrations (0, 4, 8, and 12 mmol/L) using Fenton reagent (Fe3+-Vc-H2O2) to generate hydroxyl radicals, and the effects of hydroxyl radical oxidation on the physicochemical changes and heat-induced gel-forming capacity of DMPs were analyzed. We observed obvious increases in the carbonyl content (p < 0.05) and surface hydrophobicity of DMPs with increasing of H2O2 concentrations (0-12 mmol/L). In contrast, the free thiol content (p < 0.05) and water retention ability of DMPs decreased with increasing H2O2 concentrations (0-12 mmol/L). These physicochemical changes suggested that high concentrations of hydroxyl radicals significantly altered the biochemical structure of DMPs, which was not conducive to the formation of a gel mesh structure. Furthermore, the gel properties were reduced based on the significant decrease in the water holding capacity (p < 0.05) and increased transformation of immobilized water of the heat-induced gel to free water (p < 0.05). With the increase of H2O2 concentrations, secondary structure of proteins analysis results indicated α-helix content decreased significantly (p < 0.05), however, random coil content increased (p < 0.05). And more cross-linked myosin heavy chains were detected at higher H2O2 concentrations groups through immunoblot analysis (p < 0.05). Therefore, as H2O2 concentrations increased, the gel mesh structure became loose and porous, and the storage modulus and loss modulus values also decreased during heating. These results demonstrated that excessive oxidation led to explicit cross-linking of DMPs, which negatively affected the gel-forming ability of DMPs. Hence, when processing duck meat products, the oxidation level of meat gel products should be controlled, or suitable antioxidants should be added.

The Impacts of Different Pea Protein Isolate Levels on Functional, Instrumental and Textural Quality Parameters of Duck Meat Batters.

This study aimed to investigate the effect of pea protein isolate (PPI) on the functional, instrumental and textural quality parameters of duck meat batters (DMB). Ground duck breast meat was mixed with different concentrations of PPI (0%, 3%, 6% or 9%, w/w) to prepare DMB. The color, cooking yield, water-holding capacity, water distribution and migration, rheological properties and texture profile of the DMB were evaluated. The results showed that the L* value of the gel decreased and the b* value increased with the increasing pea protein addition. The cooking yield and water-holding capacity showed a gradual increase, but the difference was not significant (p > 0.05). Compared with the control, the storage modulus (G') and loss modulus (G″) were higher at the beginning and at the end and increased with the addition of pea protein, which was in accordance with the Fourier series relationship. The hardness, chewiness and gumminess of the gels gradually increased; on the contrary, the springiness and cohesiveness first increased and then decreased, respectively, reaching a maximum value of 0.96 and 0.81 when the addition amount reached 6%. Adding pea protein to the gels not only increased the area of immobilized water but also decreased the area of free water, thus improving the water-holding capacity of the batters. Therefore, pea protein can promote the formation of a stable and elastic network structure of duck meat batters.

Preparation, physicochemical characterization, and cytotoxicity of selenium nanoparticles stabilized by Oudemansiella raphanipies polysaccharide.

Selenium nanoparticles (SeNPs) have attracted substantial attention recently owing to their excellent bioavailability and low toxicity. In the present study, Oudemansiella raphanipies polysaccharide (ORPS)-decorated selenium nanoparticles (ORPS-SeNPs) were synthesized, and their physicochemical, storage stability, and antiproliferative activities were assessed by cell cytotoxicity and apoptosis experiments. The results revealed that orange-red, zero-valent, amorphous and spherical SeNPs with a mean diameter of approximately 60 nm were successfully prepared by using ORPS as a capping agent. Furthermore, the ORPS-SeNPs solution stored at 4 °C in the dark was stable for at least 90 days. Moreover, ORPS-SeNPs treatment inhibited the proliferation of four cancer cell lines in a dose-dependent manner, while no significant cytotoxicity towards human mesangial cell (HMC) cell lines was observed. Compared with their sensitivities to the other cancer cell lines (SGC-7901 and HT-29), the sensitivity of ORPS-SeNPs towards 786-O cells was higher, with an IC50 value of 18.88 ± 1.52 mg/L. Furthermore, the apoptotic pathway triggered by ORPS-SeNPs in 786-O cells was determined to be induced by reactive oxygen species (ROS) imbalance and mitochondria-mediated pathways and to eventually result in cellular oxidative stress damage. The results of this study suggest that ORPS-SeNPs can be developed as a potential treatment for cancer, especially human renal carcinoma.

Pholiotone A, a new polyketide derivative from Pholiota sp.

Pholiotone A (1), a new polyketide derivative, with tetrahydrobenzofuran-4(2H)-one skeleton, together with four known compounds, trichodermatides A (2) and B (3) and koninginins B (4) and E (5), were isolated from the crude extract of Pholiota sp. The structures of all the isolated compounds were determined mainly by NMR experiments, the modified Mosher method and electronic circular dichroism (ECD) calculations. The antifungal and cytotoxicity of all isolates were evaluated.

Untargeted metabonomics reveals intervention effects of chicory polysaccharide in a rat model of non-alcoholic fatty liver disease.

In the current study, serum metabolomics techniques were used to evaluate the potential mechanism of the effect of chicory polysaccharides in non-alcoholic fatty liver disease (NAFLD) rats. A rat model of NAFLD was constructed according to the histopathological data and biochemical parameters, while the underlying mechanisms of high-fat diet (HFD) induced NAFLD and the therapeutic effects of chicory polysaccharides (CP) were studied by the adoption of serum metabolomics. The serum metabolites were analyzed by GC/MS. Multivariate statistical approaches such as principal component analysis, revealed significant differences with HFD model and CP groups against the control. Results indicated that CP plays a regulatory role in the occurrence of NAFLD. Meantime, a total of 65 candidate biomarkers were screened and identified. Cluster analysis, enrichment analysis and metabolic pathway analysis of differential metabolites also indicated that amino acid metabolism and fatty acid biosynthesis in NAFLD rats, the ß-oxidation and urea cycle of very long-chain fatty acids were mainly disturbed when compared against the control group. The corresponding metabolic pathways in the CP group were relieved compared against the NAFLD rats. These results showed that untargeted metabonomics helps to explain intervention effects of chicory polysaccharide with the rat model of NAFLD.

Two new polyketides from the ascomycete fungus Leptosphaeria sp.

Leptosphaerins H and I (1 and 2), two new xanthone derivatives, and six known compounds, leptosphaerin F (3), monodictysin B (4), norlichexanthone (5), leptosphaerin D (6), moniliphenone (7) and emodinbianthrone (8) have been isolated from a scale-up fermentation of the ascomycete fungus Leptosphaeria sp. Their structures were primarily elucidated by interpretation of NMR spectroscopic data. The absolute configuration of 1 was assigned using the modified Mosher method, whereas that of C-8a in 2 was determined via the CD data. Compound 6 showed modest cytotoxicity against a panel of three human tumor cell lines.