In Vitro Immuno-Modulatory Potentials of Purslane (Portulaca oleracea L.) Polysaccharides with a Chemical Selenylation

Effects of selenylation on Chinese yam polysaccharides: Structure, antioxidant, and digestive properties

Natural polysaccharides have unsatisfactory properties in production and processing due to structural limitations. Recent studies have shown that chemical modifications can improve the physicochemical and functional properties of plant polysaccharides. Herein, the effect of selenylation on the structure, functional properties, and in vitro digestion characteristics of yam polysaccharide (YP) was investigated. Selenylated products with different selenium contents (YP-LSe and YP-HSe) were prepared by controlling the addition of sodium selenite, and all samples were identified as acidic polysaccharides. Selenylation induced alterations in the chemical composition of YP. FT-IR spectral analysis revealed that YP-LSe and YP-HSe exhibited characteristic vibrational absorption peaks associated with selenium-containing groups. Microstructure analysis showed that YP-LSe and YP-HSe presented stacked leaf-like structures with sphere attachments. Moreover, selenylation significantly enhanced the emulsion capacity, foaming capacity, and antioxidant capacity of YP. In the simulated digestion process, YP-LSe and YP-HSe exhibited greater resilience against the gastrointestinal environment than YP. This study provides a theoretical basis for the development and utilization of selenylation of YP in the field of functional foods.

Exploring the therapeutic potential of polysaccharide from Portulaca oleracea L.: A review of phytochemistry and immunomodulatory effect

Portulaca oleracea L., a plant with both edible and medicinal properties, is traditionally valued for its diuretic, antipyretic, antiseptic, antispasmodic, and anthelmintic functions in folk medicine. P. oleracea polysaccharide (POP), a pivotal bioactive component, has various biological activities. Notably, their immunomodulatory capabilities have emerged as a significant area of research. The extraction, purification, monosaccharide composition, structure characterization, and biological activity of POP have been extensively investigated to identify the active components and to clarify their pharmacological actions and underlying molecular mechanisms. It aims to delineate the pharmacological mechanisms and molecular pathways associated with these polysaccharides, thereby underscoring their therapeutic promise and nutritional significance. Furthermore, the review critically examines the current research landscape of POP, identifying gaps and proposing innovative perspectives to enrich the scientific discourse surrounding these bioactive compounds.

Review of isolation, purification, structural characteristics and bioactivities of polysaccharides from Portulaca oleracea L

Portulaca oleracea L., also known as purslane, affiliates to the Portulacaceae family. It is an herbaceous succulent annual plant distributed worldwide. P. oleracea L. is renowned for its nutritional value and medicinal value, which has been utilized for thousands of years as Traditional Chinese Medicine (TCM). The extract derived from P. oleracea L. has shown efficacy in treating various diseases, including intestinal dysfunction and inflammation. Polysaccharides from P. oleracea L. (POP) are the primary constituents of the crude extract which have been found to have various biological activities, including antioxidant, antitumor, immune-stimulating, and intestinal protective effects. While many publications have highlighted on the structural identification and bioactivity evaluation of POP, the underlying structure-activity relationship of POP still remains unclear. In view of this, this review aims to focus on the extraction, purification, structural features and bioactivities of POP. In addition, the potential structure-activity relationship and the developmental perspective for future research of POP were also explored and discussed. The current review would provide a valuable research foundation and the up-to-date information for the future development and application of POP in the field of the functional foods and medicine.

Extraction, Purification, Structural Characteristics, Biological Activity and Application of Polysaccharides from Portulaca oleracea L. (Purslane): A Review

Portulaca oleracea L. (purslane) is a widely distributed plant with a long history of cultivation and consumption. Notably, polysaccharides obtained from purslane exhibit surprising and satisfactory biological activities, which explain the various benefits of purslane on human health, including anti-inflammatory, antidiabetic, antitumor, antifatigue, antiviral and immunomodulatory effects. This article systematically reviews the extraction and purification methods, chemical structure, chemical modification, biological activity and other aspects of polysaccharides from purslane collected in the Chinese Pharmacopoeia, Flora of China, Web of Science, PubMed, Baidu Scholar, Google Scholar and CNKI databases in the last 14 years, using the keywords "Portulaca oleracea L. polysaccharides" and "purslane polysaccharides". The application of purslane polysaccharides in different fields is also summarized, and its application prospects are also discussed. This paper provides an updated and deeper understanding of purslane polysaccharides, which will provide useful guidance for the further optimization of polysaccharide structures and the development of purslane polysaccharides as a novel functional material, as well as a theoretical basis for its further research and application in human health and manufacturing development.

Research on the Properties of Polysaccharides, Starch, Protein, Pectin, and Fibre in Food Processing

As food components, polysaccharides, starch, protein, pectin, and fibre are often used in the food industry due to their particular functional properties, as well as their efficient, safe, and green characteristics [...].

Chemical Modification, Characterization, and Activity Changes of Land Plant Polysaccharides: A Review

Plant polysaccharides are widely found in nature and have a variety of biological activities, including immunomodulatory, antioxidative, and antitumoral. Due to their low toxicity and easy absorption, they are widely used in the health food and pharmaceutical industries. However, low activity hinders the wide application. Chemical modification is an important method to improve plant polysaccharides' physical and chemical properties. Through chemical modification, the antioxidant and immunomodulatory abilities of polysaccharides were significantly improved. Some polysaccharides with poor water solubility also significantly improved their water solubility after modification. Chemical modification of plant polysaccharides has become an important research direction. Research on the modification of plant polysaccharides is currently increasing, but a review of the various modification studies is absent. This paper reviews the research progress of chemical modification (sulfation, phosphorylation, acetylation, selenization, and carboxymethylation modification) of land plant polysaccharides (excluding marine plant polysaccharides and fungi plant polysaccharides) during the period of January 2012-June 2022, including the preparation, characterization, and biological activity of modified polysaccharides. This study will provide a basis for the deep application of land plant polysaccharides in food, nutraceuticals, and pharmaceuticals.

The Barrier-Enhancing Function of Soluble Yam (Dioscorea opposita Thunb.) Polysaccharides in Rat Intestinal Epithelial Cells, as Affected by the Covalent Se Conjugation

The non-starch yam polysaccharides (YP) are the bioactive substances of edible yam, while Se is an essential nutrient for the human body. Whether a covalent conjugation of Se to YP might cause bioactivity change for the resultant selenylated YP in the intestine is still insufficiently studied, including the critical intestinal barrier function. In this study, two selenylated YP products, namely, YPSe-I and YPSe-II, with corresponding Se contents of 795 and 1480 mg/kg, were obtained by the reaction of YP and Na2SeO3 in the presence of HNO3 and then assessed for their bioactivities to a cell model (i.e., rat intestinal epithelial IEC-6 cells). The results showed that YP, YPSe-I, and YPSe-II at 5–80 μg/mL dosages could promote cell growth with treatment times of 12–24 h. The three samples also could improve barrier integrity via increasing cell monolayer resistance and anti-bacterial activity against E. coli or by reducing paracellular permeability and bacterial translocation. Additionally, the three samples enhanced F-actin distribution and promoted the expression of the three tight junction proteins, namely, zonula occluden-1, occludin, and claudin-1. Meanwhile, the expression levels of ROCK and RhoA, two critical proteins in the ROCK/RhoA singling pathway, were down-regulated by these samples. Collectively, YPSe-I and, especially, YPSe-II were more potent than YP in enhancing the assessed bioactivities. It is thus concluded that this chemical selenylation of YP brought about enhanced activity in the cells to promote barrier integrity, while a higher selenylation extent of the selenylated YP induced much activity enhancement. Collectively, the results highlighted the important role of the non-metal nutrient Se in the modified polysaccharides.

Protective Effects of Polysaccharides in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are characterized by progressive degeneration and necrosis of neurons, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease and others. There are no existing therapies that correct the progression of these diseases, and current therapies provide merely symptomatic relief. The use of polysaccharides has received significant attention due to extensive biological activities and application prospects. Previous studies suggest that the polysaccharides as a candidate participate in neuronal protection and protect against NDs. In this review, we demonstrate that various polysaccharides mediate NDs, and share several common mechanisms characterized by autophagy, apoptosis, neuroinflammation, oxidative stress, mitochondrial dysfunction in PD and AD. Furthermore, this review reveals potential role of polysaccharides in vitro and in vivo models of NDs, and highlights the contributions of polysaccharides and prospects of their mechanism studies for the treatment of NDs. Finally, we suggest some remaining questions for the field and areas for new development.