Antioxidant properties and cytotoxicity of crude polysaccharides from Lentinus polychrous Lév

Advances in the regulation of radiation-induced apoptosis by polysaccharides: A review

Polysaccharides are biomolecules composed of monosaccharides that are widely found in animals, plants and microorganisms and are of interest for their various health benefits. Cumulative studies have shown that the modulation of radiation-induced apoptosis by polysaccharides can be effective in preventing and treating a wide range of radiation injuries with safety and few side effects. Therefore, this paper summarizes the monosaccharide compositions, molecular weights, and structure-activity relationships of natural polysaccharides that regulate radiation-induced apoptosis, and also reviews the molecular mechanisms by which these polysaccharides modulate radiation-induced apoptosis, primarily focusing on promoting cancer cell apoptosis to enhance radiotherapy efficacy, reducing radiation damage to normal tissues, and inhibiting apoptosis in normal cells. Additionally, the role of gut microbiota in mediating the interaction between polysaccharides and radiation is discussed, providing innovative ideas for various radiation injuries, including hematopoiesis, immunity, and organ damage. This review will contribute to a better understanding of the value of natural polysaccharides in the field of radiation and provide guidance for the development of natural radioprotective agents and radiosensitizers.

In Addition to Damaging the Plasma Membrane, Phenolic Monoterpenoid Carvacrol Can Bind to the Minor Groove of DNA of Phytopathogenic Fungi to Potentially Control Tea Leaf Spot Caused by Lasiodiplodia theobromae

Carvacrol expresses a wide range of biological activities, but the studies of its mechanisms focused on bacteria, mainly involving the destruction of the plasma membrane. In this study, carvacrol exhibited strong activities against several phytopathogenic fungi and demonstrated a novel antifungal mechanism against Lasiodiplodia theobromae. RNA sequencing indicated that many genes of L. theobromae hyphae were predominately induced by carvacrol, particularly those involved in replication and transcription. Hyperchromic, hypsochromic, and bathochromic effects in the UV-visible absorption spectrum were observed following titration of calf thymus DNA (ctDNA) and carvacrol, which indicated the formation of a DNA-carvacrol complex. Circular dichroism (CD) spectroscopy indicated that the response of DNA to carvacrol was similar to that of 4',6-diamidino-2-phenylindole (DAPI) but different from that of ethidium bromide (EB), implying the ionic bonds between carvacrol and ctDNA. Fluorescence spectrum (FS) analysis indicated that carvacrol quenched the fluorescence of double-stranded DNA (dsDNA) more than single-stranded DNA, indicating that carvacrol mainly bound to dsDNA. A displacement assay showed that carvacrol reduced the fluorescence intensity of the DNA-DAPI complex through competition with DAPI, but this did not occur for DNA-EB. The FS assay revealed that carvacrol bound to the AAA sequence on the minor groove of ds-oligonucleotides. The hydroxyl of carvacrol was verified to bind to ctDNA through a comparative test in which structural analogs of carvacrol, including thymol and 4-ethyl-1,2-dimethyl, were analyzed. The current study indicated carvacrol can destruct plasma membranes and bind to the minor groove of DNA, inhibiting fungal proliferation by disturbing the stability of dsDNA.

Evaluation of Prebiotic Potential of Crude Polysaccharides Extracted from Wild Lentinus polychrous and Lentinus squarrosulus and Their Application for a Formulation of a Novel Lyophilized Synbiotic

Edible mushrooms, including wild mushrooms, are currently being investigated as natural sources to evaluate their prebiotic potential. This study aimed to evaluate the prebiotic potential of crude polysaccharides (CPSs) extracted from wild Lentinus squarrosulus UBU_LS1 and Lentinus polychrous UBU_LP2 and their application as cryoprotectants in the freeze-drying process to formulate a novel synbiotic product. Based on fruiting body morphology and molecular identification, two wild edible mushrooms named UBU_LS1 and UBU_LP2 were identified as Lentinus squarrosulus and Lentinus polychrous, respectively. L. squarrosulus UBU_LS1 and L. polychrous UBU_LP2 contained high amounts of CPS after hot water extraction. Monosaccharide component analysis showed that CPS_UBU_LS1 and CPS_UBU_LP2 were typical heteropolysaccharides. CPS_UBU_LS1 and CPS_UBU_LP2 showed hydrolysis tolerance to the simulated human gastric acidic pH solution, indicating that these CPSs are capable of reaching the lower gastrointestinal tract. Antioxidant activity determined using the 1,1-diphenyl-2-picrylhydrazyl assay revealed that the CPS_UBU_LS1 and CPS_UBU_LP2 displayed greater antioxidant activity comparable with that of ascorbic acid. It was found that CPS_UBU_LS1 and CPS_UBU_LP2 have a high potential for stimulating growth in all probiotic strains. Moreover, both CPS compounds could possibly be used as cryoprotectants in freeze drying, since the viability of the selected probiotic L. fermentum 47-7 exhibited cell survival of greater than 70% after 90 days of storage at 4 °C. These results highlight that wild edible mushrooms L. squarrosulus UBU_LS1 and L. polychrous UBU_LP2 are potential natural sources of prebiotics and can be applied as cryoprotectants in the freeze-drying process. The crude polysaccharide derived from this study could also be considered as a potent antioxidative compound. Therefore, our study provides evidence to support the application of CPSs from wild edible mushrooms in synbiotic product development and in various functional foods. Finally, further evaluation of these prebiotics, including the determination of the potential rehabilitation of beneficial gut microbes in diseased individuals, is currently being conducted by our research group.

Antibacterial activity of a polysaccharide isolated from Artemisia argyi leaf against Staphylococcus aureus and mechanism investigation

Abuse of antibiotics has led to excessive amounts of antibiotic residues in food and environment, thus enhancing pathogenic bacterium resistance and threatening human health. Therefore, searching and developing safe and green antibiotic alternatives are necessary. In this study, an Artemisia argyi leaf polysaccharide (AALP) fraction was extracted and analyzed. Chemical composition analysis showed that the carbohydrate, uronic acid, protein, and polyphenol content in AALP were 68.3 % ± 4.13 %, 9.4 % ± 0.86 %, 1.79 % ± 0.27 %, and 0.16 % ± 0.035 %, respectively. Chromatographic results suggested that AALP contained rhamnose, arabinose, glucosamine, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid in a molar ratio of 9.26, 1.35, 1.18, 3.04, 48.51, 2.33, 31.26, 3.93, and 9.08; the weight average molecular weight, number average molecular weight, and polydispersity of AALP were 5.41 kDa, 4.63 kDa, and 1.168, respectively. Fourier transform infrared spectroscopy indicated that AALP constituted the polysaccharide-specific groups of CH, CO, and OH. Meanwhile, AALP showed a dose-dependent inhibitory effect on Staphylococcus aureus in the inhibition zone assay, and the minimal inhibitory concentration was 1.25 mg/mL. Furthermore, AALP disrupted the cell wall, depolarized the inner membrane potential, and inhibited the activities of succinate dehydrogenase and malate dehydrogenase in S. aureus.

Proteomic characterization and biological activities of the mucus produced by the zoanthid Palythoa caribaeorum (Duchassaing & Michelotti, 1860)

Mucus, produced by Palythoa caribaeorum has been popularly reported due to healing, anti-inflammatory, and analgesic effects. However, biochemical and pharmacological properties of this mucus remains unexplored. Therefore, the present study aimed to study its proteome profile by 2DE electrophoresis and MALDI-TOF. Furthermore, it was evaluated the cytotoxic, antibacterial, and antioxidant activities of the mucus and from its protein extract (PE). Proteomics study identified14 proteins including proteins involved in the process of tissue regeneration and death of tumor cells. The PE exhibited cell viability below 50% in the MCF-7 and S-180 strains. It showed IC50 of 6.9 μg/mL for the J774 lineage, and also, favored the cellular growth of fibroblasts. Furthermore, PE revealed activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Staphylococcus epidermidis (MIC of 250 μg/mL). These findings revealed the mucus produced by Palythoa caribaeorum with biological activities, offering alternative therapies for the treatment of cancer and as a potential antibacterial agent.

A galacturonic acid-rich polysaccharide from Diospyros kaki peel: Isolation, characterization, rheological properties and antioxidant activities in vitro

This research elucidated the structural characteristics and antioxidant activity of a galacturonic acid-rich polysaccharide (PPP-2) isolated from Diospyros kaki peel. PPP-2 was extracted by subcritical water and subsequently purified by DEAE-Sepharose FF column. PPP-2 (12.28 kDa) mainly contained galacturonic acid, arabinose, and galactose with the molar ratios of 87.15: 5.86: 4.31. The structural characteristics of PPP-2 were revealed through FT-IR, UV, XRD, AFM, SEM, Congo red, methylation, GC/MS assay and NMR spectrum. PPP-2 owned the triple helical structure and degradation temperature of 251.09 ℃. The backbone of PPP-2 was formed by →4)-α-d-GalpA-6-OMe-(1→ and →4)-α-d-GalpA-(1→ with the side chains of →5)-α-l-Araf-(1→, →3)-α-l-Araf-(1→, →3,6)-β-d-Galp-(1→ and α-l-Araf-(1→. Moreover, the inhibitory concentration (IC₅₀) of PPP-2 to ABTS•+, DPPH•, superoxide radical and hydroxyl radical were 1.96, 0.91, 3.63, and 4.08 mg/mL, respectively. Our results suggested that PPP-2 might be a novel candidate of natural antioxidant in pharmaceuticals or functional food.

Structural Modification and Biological Activity of Polysaccharides

Natural polysaccharides are macromolecular substances with a wide range of biological activities. The structural modification of polysaccharides by chemical means can enhance their biological activity. This paper reviews the latest research reports on the chemical modification of natural polysaccharides. At present, the modification methods of polysaccharides mainly include sulfation, phosphorylation, carboxymethylation, socialization, methylation and acetylation. The chemical and physical structures of the modified polysaccharides were detected via ultraviolet spectroscopy, FT-IR, high-performance liquid chromatography, ultraviolet spectroscopy, gas chromatography-mass spectrometry, nuclear magnetic resonance and scanning electron microscopy. Modern pharmacological studies have shown that the modified polysaccharide has various biological activities, such as antioxidant, antitumor, immune regulation, antiviral, antibacterial and anticoagulant functions in vitro. This review provides fresh ideas for the research and application of polysaccharide structure modification.

Lignin Promotes Mycelial Growth and Accumulation of Polyphenols and Ergosterol in Lentinula edodes

It has been demonstrated that lignin was efficiently degraded by Lentinula edodes (L. edodes). However, the process of lignin degradation and utilization by L. edodes has not been discussed in detail. Therefore, the effects of lignin on L. edodes mycelium growth, chemical compositions, and phenolic profiles were investigated herein. It has been revealed that 0.10% lignin acted as the most effective concentration to accelerate mycelia growth, which yielded the highest biomass of 5.32 ± 0.07 g/L. Furthermore, a 0.10% concentration of lignin promoted the accumulation of phenolic compounds, especially protocatechuic acid, with peak value of 48.5 ± 1.2 μg/g. In contrast, the higher concentration of lignin (0.20%) exerted an inhibitory effect on the growth of L. edodes. Overall, the application of lignin at the optimal concentration of 0.10% could not only enhance the mycelial growth but also accumulate the phenolic acids and raise the nutritional and medical values of L. edodes.

Evaluation of Bioactive Attributes and Emulsification Potential of Exopolysaccharide Produced by a Brown-rot Fungus Fomitopsis meliae AGDP-2

Mushrooms possess wide array of biologically active secondary metabolites and have been traditionally used for their medicinal properties. Exopolysaccharide (EPS) is one of such bioactive metabolites. The bioactive attributes and emulsification capabilities of the exopolysaccharides produced by a novel brown-rot fungus Fomitopsis meliae AGDP-2 under submerged fermentation has been thoroughly investigated in the present study. Exopolysaccharide displayed anti-oxidant activities in dose dependent manner with the maximum scavenging of ABTS radicals (42.45%), DPPH radicals (75.34%), Hydroxyl radicals (63.64%), Superoxide anion radical (76.54%) and Ferric Reducing Antioxidant Power with IC₅₀ value of 231 µg/mL. Additionally, evaluation of anti-proliferative properties revealed that EPS significantly inhibited the proliferation of HepG2 and HT-29 cancer cells followed by moderate inhibition of HeLa and MCF-7 cancer cell lines and quite less inhibition of L-132 and KB cell lines. The IC₅₀ values of EPS for the abovementioned cell lines are 9.465 µg/mL, 11.25 µg/mL, 38.98 µg/mL, 87.78 µg/mL, 2061 µg/mL and 2361 µg/mL respectively. Moreover EPS also possess good anti-microbial as well as anti-biofilm properties. The studies on emulsification potential described that EPS is good emulsifier of different vegetable oils and the emulsion formed was quite stable up to 144 h.

Wheat Bread Supplemented with Agaricus bisporus Powder: Effect on Bioactive Substances Content and Technological Quality

Supplementation of food products with mushroom powder increases their health-promoting value, but at the same time affects technological quality, which often play a key role for consumers. The aim of the research was to determine the effect of adding freeze-dried white and brown button mushrooms (2.5% and 5%) to wheat bread on its health-promoting properties such as antioxidant activity (DPPH, FRAP), total polyphenols and vitamin D₂ content and as well as the technological quality as colour and texture. The breads were supplemented with mushroom lyophilisates, which were exposed to UVB radiation in order to increase their vitamin D₂ content. The content of total polyphenols and antioxidant properties were determined spectrophotometrically, and the content of vitamin D₂ by ultra-high performance liquid chromatography coupled to triple quadrupole spectrometer (UHPLC/MS/MS analysis). Colour parameters were determined in the CIE-Lab system and texture profile analysis (TPA) and sensory evaluation of the baked products were performed. The addition of dried mushrooms significantly increased the content of bioactive compounds (total polyphenols, vitamin D₂) and the antioxidant properties of bread. A small addition of mushrooms caused a significant change in the basic technological quality of breads (colour parameters, specific volume, hardness, cohesiveness, springiness). At the same time, supplementation with mushroom lyophilisates has a positive effect on most analysed attributes in the nine-point hedonic scale. Based on the conducted research, it can be concluded that mushroom lyophilisates can be a valuable raw material for the fortification of bread, which is a good matrix and carrier of substances with documented biological activities.

Antioxidant and immune-modulating activities of egg yolk protein extracts

Egg yolk is widely used to extract lecithin, which is utilized in the food and cosmetics industry. After lecithin is removed, the rest of egg yolk is generated as a by-product. Thus, it is necessary to properly utilize it. In this study, egg yolk protein extracts were produced using ethanol (EYE-E) and water (EYE-W). Their antioxidant and immunomodulatory effects were then evaluated. Antioxidant activities of EYE-E and EYE-W were determined using cellular antioxidant capacity (CAC) assay and comet assay. EYE-E and EYE-W showed significant (p<0.05) scavenging effects on intracellular reactive oxygen species (ROS) in a dose dependent manner. At a concentration of 50 μg/mL, EYE-W showed higher (p<0.05) antioxidant activity than EYE-E. EYE-E and EYE-W also exhibited protective effects against DNA damage caused by oxidative stress. After treatment with EYE-E and EYE-W, DNA damage level of 48.7% due to oxidative stress was decreased to 36.2% and 31.8% levels, respectively. In addition, EYE-E and EYE-W showed immunomodulatory effects by regulating Th1 cytokines (TNF-α and IL-2) and Th2 cytokines (IL-10 and IL-4) in Balb/c mouse splenocytes. These data suggest that EYE-E and EYE-W could be used as functional food ingredients with excellent antioxidant and immunomodulatory activities in the food industry.

Bovine lactoferrin and Lentinus edodes mycelia polysaccharide complex: The formation and the activity to protect islet β cells

The formation of complexes may be used for the development of delivery systems in foods field. The aim of this study was to explore the interaction mechanism between Lentinus edodes mycelia polysaccharide (LMP) and bovine lactoferrin (BLF), and the activity of LMP-BLF complex to inhibit oxidative stress in islet β cells. The interaction mechanisms of LMP with BLF were investigated with multi-spectroscopic techniques. The multi-spectroscopic analysis result showed that LMP bound with BLF by van der Waals force and hydrogen bond. The quenching mechanism of BLF with LMP was static quenching. Cell viability, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with thiazolyl blue tetrazolium bromide (MTT) assay, 2,7-Dichlorofluorescin diacetate (DCFH-DA) staining, Hoechst 33258 staining and Western blot methods respectively. The complex alleviated apoptosis induced by hydrogen peroxide (H₂O₂), and inhibited oxidative stress via MAPK pathways in MIN6 cells. In addition, the complex was able to promote glucose uptake in HepG2 cells. These results will broaden our understanding of LMP-BLF complexes and the applications of polysaccharide-protein complexes in the foods field.

In vitro immunomodulatory activity of water-soluble glucans from fresh and dried Longan (Dimocarpus longan Lour.)

Longan (Dimocarpus longan Lour.) is a seasonal tropical fruit used by Chinese medicine in both fresh and dried pulp forms. Their polysaccharides have been reported to have biological activity. However, their composition and immune activity have not yet been disclosed. To fulfil this aim, hot water-soluble polysaccharides of fresh and dried longan pulp were fractionated according to their molecular weight by ultrafiltration (10, 50, 100 kDa cut off). The main polysaccharides recovered were 1,6-linked glucans branched at O-3 (4-8%), O-2 (1%), O-2,4 (0.1%), and O-3,4 (0.1%). The drying process promotes the solubility of the polysaccharides. These glucans from fresh and dried longan pulp have immunomodulatory activity, shown by in vitro phagocytosis, NO, TNF-α, and IL-6 macrophages production assays. They showed also to inhibit the inflammatory response induced by LPS. The immunological activity of these glucans seems to have different responses dependent on their molecular weight, related to the immune regulatory pathways.

β-Glucan: A dual regulator of apoptosis and cell proliferation

β-Glucans are polysaccharides generally obtained from the cell wall of bacteria, fungi, yeasts, and aleurone layer of cereals. β-Glucans are polymers, with β-1,3 glucose as core linear structure, but they differ in their main branch length, linkages and branching patterns, giving rise to high and low-molecular-weight β-glucans. They are well-known cell response modifiers with immune-modulating, nutraceutical and health beneficial effects, including anticancer and pro-apoptotic properties. β-Glucan extracts have shown positive responses in controlling tumor cell proliferation and activation of the immune system. The immunomodulatory action of β-glucans enhances the host's antitumor defense against cancer. In consonance with the above, many studies have shown that β-glucan treatment leads to the induction of apoptotic death of cancer cells. The ability of β-glucans to stimulate apoptotic pathways or the proteins involved in apoptosis prompting a new domain in cancer therapy. β-glucan can be a potential therapeutic agent for the treatment of cancer. However, there is a need to legitimize the β-glucan type, as most of the studies include β-glucan from different sources having different physicochemical properties. The body of literature presented here focuses on the effects of β-glucan on immunomodulation, proliferation, cell death and the possible mechanisms and pathways involved in these processes.

Carboxymethylation of polysaccharide isolated from Alkaline Peroxide Mechanical Pulping (APMP) waste liquor and its bioactivity

In recent years, the biological activity of polysaccharides and their derivatives has been widely studied. However, in addition to the natural polysaccharides directly extracted from plants and animals, there are rich polysaccharides in the pulping waste liquor that have not been fully utilized. The extracted polysaccharide from eucalyptus Alkaline Peroxide Mechanical Pulping (APMP) waste liquor was used as a raw material. For the production of carboxymethyl polysaccharide, the effects of temperature (T), the amount of alkali (NaOH) and the amount of etherifying agent (ClCH₂COOH) on the degree of substitution (DS) were investigated, the optimal preparation conditions are: reaction time 2 h, temperature 75 °C, and the molar ratio of polysaccharide, NaOH and ClCH2COOH is 1:1:2, the highest DS is 1.47; FT-IR, NMR and GPC were used to characterize the structure and Molecular weight, the results show that the polysaccharide of APMP waste liquor is rich in xylan, and it was proved that the carboxymethyl substitution was successful and the positions of the substituent group were determined. The characterization and biological activity research of xylan polysaccharide (XP) and carboxymethyl xylan polysaccharide (CMXP), such as antioxidation, moisture absorption/retention, bacteriostatic action and cytotoxicity were discussed. CMXP shows better effects compared with XP.

Angiotensin-I converting enzyme inhibitory peptide derived from the shiitake mushroom (Lentinula edodes)

Abstract

Angiotensin-I converting enzyme (ACE) inhibitors are widely used to control hypertension. In this study, protein hydrolysates from shiitake mushroom were hydrolyzed to prepare ACE-inhibitory peptides. Optimum process conditions for the hydrolysis of shiitake mushrooms using Alcalase were optimized using response surface methodology. Monitoring was conducted to check the degree of hydrolysis (DH) and ACE inhibitory activity. In the results, the optimum condition with the highest DH value of 28.88% was 50.2 °C, 3-h hydrolysis time, and 1.16 enzyme/substrate ratios. The highest ACE inhibitory activity (IC₅₀ of 0.33 μg/mL) was under 47 °C, 3 h 28 min hydrolysis time, and 0.59 enzyme/substrate ratios. The highest activity was fractionated into 5 ranges of molecular weight, and the fraction below 0.65 kDa showed the highest activity with IC₅₀ of 0.23 μg/mL. This fraction underwent purification using RP-HPLC, meanwhile the peak which offered a retention time of about 37 min showed high ACE inhibitory activity. Mass spectrometry identified the amino acid sequence of this peak as Lys-Ile-Gly-Ser-Arg-Ser-Arg-Phe-Asp-Val-Thr (KIGSRSRFDVT), with a molecular weight of 1265.43 Da. The synthesized variant of this peptide produced an ACE inhibitory activity (IC₅₀) of 37.14 μM. The peptide KIGSRSRFDVT was shown to serve as a non-competitive inhibitor according to the Lineweaver-Burk plot findings. A molecular docking study was performed, which showed that the peptide binding occurred at an ACE non-active site. The findings suggest that peptides derived from shiitake mushrooms could serve either as useful components in pharmaceutical products, or in functional foods for the purpose of treating hypertension.

Graphic abstract

Glucose-rich polysaccharide from dried 'Shixia' longan activates macrophages through Ca2+ and CR3- mediated MAPKs and PI3K-AKT pathways

A water-soluble glucose-rich polysaccharide from dried 'Shixia' longan pulp (LPsx) has been isolated for the first time, and its structure and immuno-regulatory mechanism were studied. LPsx is a hetero-polysaccharide with the average molecular weight 4102 g/mol. It was mainly consisted of glucose (95.9%), and small proportions of arabinose (2.1%), galactose (1.0%), mannose (0.6%), and xylose (0.4%). As analyzed by NMR, LPsx was mainly composed of (1 → 6)-α-d-glucose and (1 → 6)-β-d-glucose, branched with α-d-glucose-(1→. The immunomodulatory activity study showed that LPsx significantly increased the phagocytosis of macrophages, and strongly promoted the production of NO, IL-1β, IL-6 and TNF-α. Moreover, LPsx could inhibit the inflammatory response induced by lipopolysaccharide. The immuno-regulatory mechanism of LPsx was studied using RNA- sequencing and receptors activity analyses. It was found that LPsx induced macrophage activation via Ca²⁺ and CR3-mediated MAPKs and PI3K-AKT signaling pathways. The results would be helpful for revealing the health promoting mechanism of dried 'Shixia' longan in traditional Chinese medicine.

Physicochemical properties and bioactivities of original and Se-enriched polysaccharides with different molecular weights extracted from Pleurotus ostreatus

Three polysaccharides (WZP1, WZP2, WZP3) and their Se-enriched products (SeWZP1, SeWZP2 and SeWZP3) were obtained from Pleurotus ostreatus using a simple, rapid method and HNO3-Na2SeO3 method, respectively. The molecular weight distribution profiles of all samples except SeWZP2 showed double peaks. The average molecular weights (Mw) of WZP1-3 were 48.6 kDa, 20.2 kDa and 11.8 kDa, respectively, and of SeWZP1-3 were 19.6 kDa, 37.7 kDa, 14.5 kDa, respectively. The complexity of monosaccharide composition of WZP1-3 was inversely proportional to the ethanol concentration used in the ethanol precipitation process. Additionally, the results of biological activity tests indicated that α-glucosidase inhibitory activity of WZP1-3 was related to the molecular weight and the monosaccharide composition complexity. The selenized modification can improve the α-glucosidase-inhibiting, hydroxyl radical-scavenging activity of P. ostreatus polysaccharides. Therefore, by improving their bioactivities by selenization, the polysaccharides of P. ostreatus could be utilized as a natural health food supplement.

Chemical characterization, antioxidant properties and anticancer activity of exopolysaccharides from Floccularia luteovirens

Two polysaccharides, ALF1 and ALF2 were obtained from the fermentation liquid of Floccularia luteovirens. These fractions had good performance in scavenging radicals and ALF1 exhibited obvious antioxidant activities. Further, linkage analysis and NMR were used to characterize the structures of ALF1. Linkage and NMR data comprehensively showed that ALF1 mainly contained six kinds of linkage type units as →4)-β-D-Manp→, 1,3-α-Fucp→, α-L-Araf-C1→, →6)-β-D-Galp-C1→, →4)-α-D-GlcAp-(1→ and →3)-β-D-Glcp(1→. In addition, ALF1 had good bioactivities such as anticancer and antioxidant activities. ALF1 was proven to be able to inhibit tumor cells without affecting the normal cells. Besides, ALF1 improved the activities of SOD, GSH-Px and CAT, and decreased the production of MDA which result in protecting PC12 cells against H₂O₂-induced oxidative stress. ALF1 decreased ROS production, and stabilize mitochondrial membrane potential. The findings indicated that the fermentation liquid of Floccularia luteovirens could be used as a potential natural source of antioxidant.

Bioactive exopolysaccharide from Neopestalotiopsis sp. strain SKE15: Production, characterization and optimization

Fungal exopolysaccharides are powerful resources of medicinal applications. Neopestalotiopsis sp. SKE15 was isolated and identified according to phenotypical and genotypical analyses (GenBank Accession No. MG649986). The exopolysaccharide (EPS) was produced by cultivation of mycelia in broth culture and extracted. The production was optimized to 2.02 g/l after selection of agitation, temperature, FeSO₄ and K₂HPO₄ concentrations as the most influencing factors using Placket-Burman design and then by applying response surface methodology. Analytical Tools showed that the EPS is composed of a polysaccharide (1.5-2.1 × 10⁶ Da) and its probable low molecular weight derivatives, in a wide range of chain lengths, among them an oligosaccharide of about 1970 Da was dominant. GC-MS (Gas chromatography-mass spectrometry) analysis revealed the EPS was mainly constructed from d-glucose, sorbitol and D-galactose. The EPS showed antibacterial activity against Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633 and Pseudomonas aeruginosa ATCC 27853. DPPH (1,1-diphenyl-2-picryl-hydrazyl) and hydroxyl radical scavenging activity assays showed strong antioxidant activity of the EPS. A challenge with three different cancerous cell lines showed cytotoxic activity of the EPS at final concentration of 100 and 200 μg/ml. Further investigation on medicinal applications of the biopolymer is promising.

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.

Anticancer, antithrombotic, antityrosinase, and anti-α-glucosidase activities of selected wild and commercial mushrooms from Pakistan

Mushrooms have been accepted as nutraceutical foods because of their high nutritional and functional values. They have also gained interest due to their medicinal properties, economic importance, and organoleptic merit. In this study, wild Ganoderma lucidum and four commercial mushrooms, that is, Pleurotus ostreatus, Volvariella volvacea, Hericium erinaceus, and Lentinus edodes from Pakistan were screened for their biological activities such as anticancer, antityrosinase, anti-α-glucosidase, and antithrombotic activities from their methanol, ethanol, and water extracts. Enzyme inhibition assay showed that selected mushrooms are potent inhibitors with %age inhibition ranging from 19.00% to 80.91%, and 32.85% to 83.38% for tyrosinase and α-glucosidase, respectively. The best tyrosinase inhibition was shown by P. ostreatus whereas L. edodes was found best as α-glucosidase inhibitor. These mushrooms were tested against cancer cell lines including HT-29 colon and H-1299 lungs carcinoma cell lines. G. lucidum showed 29% and 24% viability of cells against HT-29 and H-1299 cell lines, respectively. This antiproliferative effect was in dose-dependent manner, and the maximum inhibition was observed at 200 μg/ml. Mushrooms extracts were also found effective against clot lysis. The percentage of clot lysis was in the range of 27%-29%. The research would provide knowledge to the people of Pakistan about the importance of locally available commercial mushrooms and wild mushrooms for health improvement and prevention against different kinds of diseases.

Antioxidant hydrolyzed peptides from Manchurian walnut (Juglans mandshurica Maxim.) attenuate scopolamine-induced memory impairment in mice

BACKGROUND

Walnut protein, which is obtained as a by-product of oil expression, has not been used efficiently. Although walnuts are beneficial for cognitive functioning, the potential of their protein composition in strengthening learning and memory functions remains unknown. In this study, the inhibition of memory impairment by the Manchurian walnut hydrolyzed peptide (MWHP) was evaluated.

RESULTS

Small-molecular-weight MWHP (<3 kDa) achieved the optimal antioxidative activity. Therefore, MWHP (<3 kDa) was subjected to the following mice trials to evaluate its attenuation effect on memory impairment. In the Morris water maze test, MWHP shortened the total path for searching the platform, reduced the escape latency, and increased the dwelling distance and time in the coverage zone. MWHP also prolonged the latency and diminished errors in the passive avoidance response tests. These behavioral tests demonstrated that MWHP could inhibit scopolamine-induced memory impairment. MWHP improved memory by reducing oxidative stress, inhibiting apoptosis, regulating neurotransmitter functions, maintaining hippocampal CA3 pyramidal neurons, and increasing calmodulin-dependent protein kinase II levels in brain tissues.

CONCLUSION

Experimental results proved that MWHP exhibits potential in improving memory and should be used to develop novel functional food. © 2018 Society of Chemical Industry.

Evaluation of the effect of soluble polysaccharides of palm kernel cake as a potential prebiotic on the growth of probiotics

This paper deliberates the extraction, characterization and examination of potential application of soluble polysaccharides of palm kernel cake (PKC) as a prebiotic. The PKC was defatted and crude polysaccharide was obtained through water, citric acid or NaOH extraction. The physiochemical properties of the extracted polysaccharides viz. total carbohydrates, protein content, solubility rate, monosaccharides composition, structural information and thermal properties were also determined. The extracted soluble polysaccharides were further subjected to a digestibility test using artificial human gastric juice. Finally, their prebiotic potential on two probiotics, namely Lactobacillus plantarum ATCC 8014 and Lb. rhamnosus ATCC 53103 were evaluated in vitro. It was observed that PKC contained ash (5.2%), moisture (7.4%), carbohydrates (65.8%), protein (16.5%) and fat (5.1%). There were significant differences (P < 0.05) between the values of NaOH-extracted crude polysaccharides (8.73%) and that of water (3.03%) and citric acid (3.07%)-extracted polysaccharides. The extracted polysaccharides composed of mannose, galactose, glucose, arabinose, xylose and rhamanose, with highest percentage of mannose (62.49%) and galactose (25.42%) in SP_CA. Total carbohydrate content in SCP_W, SCP_CA and SCP_N are 57.11%, 56.94% and 50.95%, respectively. The polysaccharides from PKC in this study were found to be highly soluble (> 95%). Protein content in SCP_W, SCP_CA and SCP_N are 0.72, 0.40 and 0.58, respectively, and the peaks which indicated the presence of protein were observed at approximately 1640 cm^-1 (amide I). FTIR spectroscopy revealed that the polysaccharides extracts were linked to β and α-glycosidic bonds and thermal analysis using differential scanning calorimeter (DSC) showed the main degradation temperature of SP is about 121 to 125 °C. The SP were found to be highly resistance (> 96%) to hydrolysis when subjected to artificial human gastric juice. The prebiotics potentials of the polysaccharides on probiotics in vitro demonstrated an increase in proliferation of Lb. plantarum ATCC 8014 and Lb. rhamnosus ATCC 53103 with decrease in the pH of the medium and producing organic acids.All the above findings strongly indicated that polysaccharides extracted from PKC, an industrial waste, have a potential to be exploited as novel prebiotics.

Phytochemical, Free Radical Scavenging and Antifungal Profile of Cuscuta campestris Yunck. Seeds

This work was conceptualized with the goal to investigate the phytochemical, free radical scavenging and antifungal profile of Cuscuta campestrisYunck. seeds. Total phenolics, amino acid and carbohydrate contents were evaluated in ethanolic, acetone and chloroform extract. Effective antioxidant activity was evaluated throughout seven antioxidant methods. The antifungal activity was assessed against eight fungal strains and Candida albicans. The results showed total phenol, flavonoid, flavonols and phenolic acids contents in amount of 1.51 - 6.35 mg GAE/mL, 78 - 425 μg RU/mL, 1.04 - 2.98 mg QU/g and 12.01 - 30.58 μg CAE/mL, respectively. The total amino acids and carbohydrates content ranged from 8.29 to 185.45 μg Gly/mL and from 0.05 to 0.12 μg Glu/mL. The ethanolic extract showed the best antioxidant activity in phosphomolybdenum, DPPH free radical scavenging, ferric reducing power and lipid peroxidation assays. The best activity in ferrous ion chelating and H₂ O₂ assays had the acetone extract, whereas the best hydroxyl radical scavenging activity was observed with the chloroform extract. The ethanolic extract at a concentration of 6 mg/mL proved to be the most effective antimycotic, since it inhibited the growth of all tested fungi except Penicillium verrucosum. The obtained results indicate that C. campestris seeds could be attributed to a potential source of natural antioxidants in food and pharmaceutical products.

Antioxidant action and protective and reparative effects of lentinan on oxidative damage in HaCaT cells

BACKGROUND

Lentinus edodes is one of the largest edible fungi. Lentinan, extracted from its fruiting body has clinically significant anticancer, antibacterial, antiviral, and anticoagulant effects; however, its preventive effects on skin oxidative damage are unclear.

AIMS

We aimed to evaluate the in vitro antioxidation capability of lentinan and its protective and reparative effects on a model of cell oxidative damage.

METHODS

We evaluated the in vitro antioxidant potential of lentinan by assessing its free-radical quenching ability using DPPH and ABTS and superoxide anions. Using the HaCaT cell line as the experimental system, we tested the protective and reparative effects of lentinan on a model of H₂ O₂ -induced cellular oxidative damage through assessment of cell survival rate, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity.

RESULTS

Lentinan displayed high antioxidant potential: DDPH and ABTS quenching rates were above 60%; superoxide anions, approximately 18%. Furthermore, lentinan could dose-dependently prevent the reduction of activity in HaCaT cells by H₂ O₂ , reduce MDA formation, and increase SOD activity. Moreover, lentinan showed not only a protective effect against oxidative damage but also reparative effects to a certain extent, in HaCaT cells.

CONCLUSIONS

Our findings demonstrated the ability of lentinan to enhance cellular tolerance to oxidative damage, stress resistance, and to have protective and reparative effects on damaged cells. Therefore, with L. edodes as a source for antiaging substances, cosmetics with homology to foods have great potential clinical applications.

Nutritional composition in the chia seed and its processing properties on restructured ham-like products

Low-fat meat products always have harder texture, lower juiciness, and worse flavor. Due to their higher water-holding, water absorption, and organic molecule absorption, chia seeds (CHIA) have been applied in powders, nutrition bars, breads, and cookies. Hence, the objectives of this study were to: (1) analyze the nutritional compositions in CHIA; and (2) look for the possible application of CHIA on restructured ham-like products. CHIA has high amounts of α-linolenic acid, crude polysaccharides, and also contains essential amino acids, minerals, and polyphenols. Regarding processing properties of CHIA, a combination of CHIA and carrageenan (CA) increased (p < 0.05) production yield of restructured ham-like products. A scanning electron microscope observation indicated that CHIA and CA addition can assist an emulsification in this ham-like product. Addition of 0.5% CA and 1.0% CHIA in this ham-like product showed the similar overall acceptance as products with added fat. Following storage at 4°C, higher (p < 0.05) purge and centrifugation losses, as well as hardness of this ham-like product can be improved by adding CHIA and CA. CHIA addition also resulted in lower (p < 0.05) lipid and protein oxidation, especially a 1.0% addition. In summary, due to both nutritional addition and improvements on physicochemical and sensorial properties of restructured ham-like products, CHIA seeds have great potential on the development of healthy and good-quality meat products.

Hypolipidemic Activity of Camellia euphlebia Flower Extract in High-fat-fed Mice

Camellia euphlebia (family, Theaceae) has been used for the prevention and treatment of cardiovascular diseases in Southern China. However, there has been no report on the hypolipidemic activity of Camellia euphlebia flower. This study evaluated the hypolipidemic activity of different preparation of Camellia euphlebia flower extracts using in vivo models. Mice intragastrically administered aqueous extract at 400 mg/kg dose or ethanol extract at 100 and 400 mg/kg doses of Camellia euphlebia flower for 28 days exhibited significant decreases in the levels of total cholesterol, triglycerides and low-density lipoprotein cholesterol, while displaying increased level of high-density lipoprotein cholesterol in the serum. The Camellia euphlebia flower extracts also improved the antioxidant ability of hyperlipidemic mice as well as protecting the animals against liver damage by lowering the level of glutamic-pyruvic transaminase activity. Furthermore, 400 mg/kg ethanol extract effectively down-regulated the mRNA levels of fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and glycerol-3-phosphate acyl transferase, suggesting that Camellia euphlebia flower extract may potentially inhibit lipid accumulation in the liver by regulating the expression of fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and glycerol-3-phosphate acyl transferase. These results provided support for the potential hypolipidemic activity of Camellia euphlebia flower and could partly explain the basis of using Camellia euphlebia for the treatment of hyperlipidemia.

Biological activities and chemical compositions of slime tracks and crude exopolysaccharides isolated from plasmodia of Physarum polycephalum and Physarella oblonga

BACKGROUND

The myxomycetes derive their common name (slime molds) from the multinucleate trophic stage (plasmodium) in the life cycle, which typically produces a noticeable amount of slimy materials, some of which is normally left behind as a "slime track" as the plasmodium migrates over the surface of a particular substrate. The study reported herein apparently represents the first attempt to investigate the chemical composition and biological activities of slime tracks and the exopolysaccharides (EPS) which cover the surface of the plasmodia of Physarum polycephalum and Physarella oblonga.

RESULTS

Chemical analyses indicated that the slime tracks and samples of the EPS consist largely of carbohydrates, proteins and various sulphate groups. Galactose, glucose and rhamnose are the monomers of the cabohydrates present. The slime tracks of both species and the EPS of Phy. oblonga contained rhamnose, but the EPS of Ph. polycephalum had glucose as the major monomer. In term of biological activities, the slime tracks displayed no antimicrobial activity, low anticancer activity and only moderate antioxidant activity. However, EPSs from both species showed remarkable antimicrobial activities, especially toward Candida albicans (zone of inhibition ≥20 mm). Minimum inhibitory concentrations of this fungus were found to be 2560 μg/mL and 1280 μg/mL for EPS from Phy. oblonga and Ph. polycephalum, respectively. These EPS samples also showed moderate antioxidant activities. However, they both displayed cytotoxicity towards MCF-7 and HepG2 cancer cells. Notably, EPS isolated from the plasmodium of Phy. oblonga inhibited the cell growth of MCF-7 and HepG2 at the half inhibitory concentration (IC50) of 1.22 and 1.11 mg/mL, respectively.

CONCLUSIONS

EPS from Ph. polycephalum plasmodium could be a potential source of antifungal compounds, and EPS from Phy. oblonga could be a potential source of anticancer compounds.

Culture broth of Ganoderma lucidum exhibited antioxidant, antibacterial and α-amylase inhibitory activities

Culture broth of Ganoderma lucidum was determined for antioxidant, antibacterial and α-amylase inhibitory activities. The culture broth contained protein as determined by Bradford method equaled to 0.2 mg/ml and total phenol content as 0.078 mg GAE/mg protein (0.557 mg GAE/g extract). It exhibited radicals scavenging activities against ABTS^+· and DPPH^· radicals with a half maximal inhibitory concentration (IC₅₀) less than 1.70 ± 0.02 and 2.28 ± 0.02 µg protein/ml, respectively and reducing power equaled to 4.38 ± 0.02 µmol Trolox/µg protein as investigated by ferric ion reducing antioxidant power method. The culture broth experimented into two approached; (1) treated with pronase and (2) filtered through a membrane with 10 kDa molecular weight cut-off (MWCO). The pronase-treated culture broth exhibited insignificant lower antioxidant activities, but the retained culture broth 10 kDa MWCO resulted in significant decrease in antioxidant activities suggesting that the small proteins might play the key role in antioxidant activity. The culture broth could protect DNA damage from hydroxyl radicals (^·OH) generated by Fenton's reaction. This culture broth showed antibacterial activity towards pathogenic strains Staphylococcus epidermidis and Pseudomonas aeruginosa and also had an interesting α-amylase inhibitory activity. This study suggested that apart from the fruiting bodies and the mycelial of G. lucidum, its culture broth also had potential applications as a value-added ingredient in the product such as in cosmetics and in nutraceuticals.

Defatted coconut residue crude polysaccharides as potential prebiotics: study of their effects on proliferation and acidifying activity of probiotics in vitro

This paper reports on the extraction, partial characterization and the potential application of crude polysaccharides from defatted coconut residue as a prebiotic. The coconut residue was defatted and extracted to obtain the crude polysaccharides and its physicochemical properties were determined. The crude polysaccharides were assessed for monosaccharide composition, total carbohydrate content, reducing sugar concentration and protein content determination. The functional group and structural elucidation of crude polysaccharides was also done using Fourier transform infrared spectra analysis. The product was then subjected to artificial human gastric juice treatment to determine digestibility. Finally, an in vitro proliferation and acid production by two probiotic bacteria namely Lactobacillus casei Shirota and Lactobacillus bulgaricus were included in this study. It was found that the defatted coconut residue contained ash (0.54%), moisture (55.42%), protein (1.69%), crude fat (17.26%) and carbohydrate (25.73%). The percentage of crude polysaccharides extracted was 0.73 ± 0.04. The two fractions of monosaccharides obtained were glucose and fructose. Total carbohydrate content of DCR was 13.35% (w/v). The quantitative value of the reducing sugars obtained was 20.71%. Protein content in the crude polysaccharides was 0.009% and the peaks which indicated the presence of protein were observed at around 1640 cm^-1 (amide I) and 1530 cm^-1 (amide II). DCR crude polysaccharides were highly resistant (88%) to hydrolysis when subjected to artificial human gastric juice. The product was found to markedly stimulate two tested probiotics to proliferate and produce organic acids. All the above findings are supportive of the fact that polysaccharides extracted from DCR, an industrial waste, have a vast potential to be exploited as novel prebiotics.