Structural characterization and anti-inflammatory activity of a novel neutral polysaccharide isolated from Smilax glabra Roxb

Identification and Molecular Mechanism of Novel Two-Way Immunomodulatory Peptides from Ovalbumin: In Vitro Cell Experiments, De Novo Sequencing, and Molecular Docking

The purpose of this study was to identify ovalbumin-derived immunomodulatory peptides by in vitro cell experiments, de novo sequencing, and molecular docking. Ovalbumin hydrolysates were prepared by two enzymes (alkaline protease and papain) individually, sequentially, or simultaneously, respectively. The simultaneous enzymatic hydrolysate (OVAH) had a high degree of hydrolysis (38.12 ± 0.48%) and exhibited immune-enhancing and anti-inflammatory activities. A total of 160 peptides were identified by LC-MS/MS in OVAH. Three novel peptides NVMEERKIK, ADQARELINS, and WEKAFKDE bound to TLR4-MD2 through hydrogen bonds and hydrophobic interactions with high binding affinity and binding energies of -181.40, -178.03, and -168.12 kcal/mol, respectively. These three peptides were synthesized and validated for two-way immunomodulatory activity. NVMEERKIK exhibiting the strongest immunomodulatory activity, increased NO and TNF-α levels by 128.69 and 38.01%, respectively, in normal RAW264.7 cells and reduced NO and TNF-α levels by 27.31 and 39.13%, respectively, in lipopolysaccharide-induced inflammatory RAW264.7 cells. Overall, this study first revealed that ovalbumin could be used as an immunomodulatory source for controlling inflammatory factor secretion.

Characterization and prebiotic potential of polysaccharides from Rosa roxburghii Tratt pomace by ultrasound-assisted extraction

In this study, polysaccharides (RRTPs) were extracted from Rosa roxburghii Tratt pomace by hot water or ultrasound (US)-assisted extraction. The structural properties and potential prebiotic functions of RRTPs were investigated. Structural characterization was conducted through HPAEC, HPGPC, GC-MS, FT-IR and SEM. Chemical composition analysis revealed that RRTPs extracted by hot water (RRTP-HW) or US with shorter (RRTP-US-S) or longer duration (RRTP-US-L) all consisted of galacturonic acid, galactose, glucose, arabinose, rhamnose and glucuronic acid in various molar ratio. US extraction caused notable reduction in molecular weight of RRTPs but no significant changes in primary structures. Fecal fermentation showed RRTPs could reshape microbial composition toward a healthier balance, leading to a higher production of beneficial metabolites including total short-chain fatty acids, curcumin, noopept, spermidine, 3-feruloylquinic acid and citrulline. More beneficial shifts in bacterial population were observed in RRTP-HW group, while RRTP-US-S had stronger ability to stimulate bacterial short-chain fatty acids production. Additionally, metabolic profiles with the intervention of RRTP-HW, RRTP-US-S or RRTP-US-L were significantly different from each other. The results suggested RRTPs had potential prebiotic effects which could be modified by power US via molecular weight degradation.

Structure of a polysaccharide MDP2-1 from Melastoma dodecandrum Lour. and its anti-inflammatory effects

The anti-inflammatory activity of polysaccharides derived from Melastoma dodecandrum Lour. was evaluated in pyretic mice and HEK-Blue™ hTLR4 cells. The testing led to the identification of MDP2-1, which was then investigated for its structural characteristics and anti-inflammatory effects. Results showed that MDP2-1 had a molecular weight of 29.234 kDa and primarily consisted of galactose, arabinose, rhamnose, glucose, glucuronic acid, and galacturonic acid. Its main backbone was composed of →4)-α-D-GalpA-(1→, →2)-α-L-Rhap-(1→, →3,4)-α-D-GalpA-(1→, →2,4)-α-D-GlcpA-(1→, and its side chains were connected by →4)-α-D-Galp-(1→, α-D-Galp-(1→, →4)-β-D-Glcp-(1→, and α-L-Araf-(1→. In vivo experiments on mice demonstrated that MDP2-1 attenuated LPS-induced acute lung injury, and in vitro experiments on RAW264.7 cells showed that MDP2-1 reduced the levels of inflammatory mediators and mitigated LPS-induced inflammatory damage by inhibiting the activation of the TLR4 downstream NF-κB/MAPK pathway. These findings suggest that MDP2-1 is a novel anti-inflammatory agent for therapeutic interventions.

Structural and functional investigation on stem and peel polysaccharides from different varieties of pitaya

Varieties of plant species may affect the composition and structures of the polysaccharides, thus have an impact on their chemical properties and biological activities. Herein, the present study comparatively evaluated the differences in the chemical composition, morphological structures, antioxidant activity, and anti-inflammatory activity of the stem and peel polysaccharides from different varieties of pitaya. The FT-IR and NMR spectra indicated that the six polysaccharides had similar structural features, whereas the physicochemical characterization showed that they differed significantly in terms of the monosaccharide composition, molecular weight, and surface morphology. In addition, different varieties of pitaya polysaccharides exhibited different antioxidant activities and similar anti-inflammatory activities. These data suggested that varietal differences resulted in pitaya stem and peel polysaccharides with different monosaccharide compositions and molecular weights, thus led to different antioxidant activities and protection against oxidative damage, while similar structural features were closely related to their similar anti-inflammatory activities. Therefore, the study of the stem and peel polysaccharides from different varieties of pitaya can help us to better understand the relationship between their composition and structure and their biological activities. In addition, pitaya stem and peel polysaccharides have the potential to act as antioxidants or to treat inflammatory damage.