Preparation and antitumor activity of selenium-modified glucomannan oligosaccharides

Synthesis of glucosamine-selenium compound and evaluation of its oral toxicity and in vitro anti-hepatitis B virus activity

Selenium supplements are beneficial to human health, however, concerns regarding the toxicity of inorganic selenium have stimulated research on safer organic compounds. The main objective of this study was to develop a novel glucosamine-selenium compound (Se-GlcN), clarify its structure, and subsequently investigate its oral toxicity and in vitro anti-hepatitis B virus (HBV) activity. Electron microscopy, infrared, ultraviolet spectroscopy, nuclear magnetic resonance and thermogravimetric analyses revealed a unique binding mode of Se-GlcN, with the introduction of the Se-O bond at the C6 position, resulting in the formation of two carboxyl groups. In acute toxicity studies, the median lethal dose (LD50) of Se-GlcN in ICR mice was 92.31 mg/kg body weight (BW), with a 95 % confidence interval of 81.88-104.07 mg/kg BW. A 30-day subchronic toxicity study showed that 46.16 mg/kg BW Se-GlcN caused livers and kidneys damage in mice, whereas doses of 9.23 mg/kg BW and lower were safe for the livers and kidneys. In vitro studies, Se-GlcN at 1.25 μg/mL exhibited good anti-HBV activity, significantly reducing HBsAg, HBeAg, 3.5 kb HBV RNA and total HBV RNA by 45 %, 54 %, 84 %, 87 %, respectively. In conclusion, the Se-GlcN synthesized in this study provides potential possibilities and theoretical references for its use as an organic selenium supplement.

Hemicellulose and unlocking potential for sustainable applications in biomedical, packaging, and material sciences: A narrative review

Hemicellulose, a complex polysaccharide abundantly found in plant cell walls, has garnered significant attention for its versatile applications in various fields including biomedical, food packaging, environmental, and material sciences. This review systematically explores the composition, extraction methods, and diverse applications of hemicellulose-derived materials. Various extraction techniques such as organic acid, organic base, enzyme-assisted, and hydrothermal methods are discussed in detail, highlighting their efficacy and potential drawbacks. The applications of hemicellulose encompass biodegradable films, edible coatings, advanced hydrogels, and emulsion stabilizers, each offering unique properties suitable for different industrial needs. Current challenges in hemicellulose research include extraction efficiency, scalability of production processes, and optimization of material properties. Opportunities for future research are outlined, emphasizing the exploration of new applications and interdisciplinary approaches to harness the full potential of hemicellulose. This comprehensive review aims to provide valuable insights for researchers and industry professionals interested in utilizing hemicellulose as a sustainable and functional biomaterial.

Chemical modification of bacterial exopolysaccharides: Antioxidant properties and health potentials

In recent years, there has been a burgeoning interest in the utilization of microbial exopolysaccharides (EPS) because of the added advantage of their renewable, biocompatible, and biodegradable nature in addition to intended applications. The endowed properties of bacterial EPS make them valuable candidates for a wide array of industrial applications. Modification of native EPS is known to enhance various physico-chemical and functional properties. Various modifications such as physical, chemical, biological, and enzymatic modifications were practiced improving the bioactivity of EPS. This paper comprehensively aims to review the most recent chemical modification techniques employed to modify the physico-chemical and functional changes of bacterial EPS in comparison with the unmodified forms. Chemical modification entails strategic alterations to the structure and properties of EPS through various synthetic and semi-synthetic methodologies. Emphasis is given to the antioxidant potential and functional role of these EPS derivatives in human health. Antioxidant properties reveal a significant augmentation in activity compared to their native counterparts. Such enhancement holds a strong promise for potential benefits and therapeutic applications. Chemical derivatives of EPS with overwhelming functional benefits could surely encourage EPS application, particularly as potential hydrocolloids in industrial and biomedical contexts.

Selenium-enriched plant foods: Selenium accumulation, speciation, and health functionality

Selenium (Se) is an essential element for maintaining human health. The biological effects and toxicity of Se compounds in humans are related to their chemical forms and consumption doses. In general, organic Se species, including selenoamino acids such as selenomethionine (SeMet), selenocystine (SeCys₂), and Se-methylselenocysteine (MSC), could provide greater bioactivities with less toxicity compared to those inorganics including selenite (Se IV) and selenate (Se VI). Plants are vital sources of organic Se because they can accumulate inorganic Se or metabolites and store them as organic Se forms. Therefore, Se-enriched plants could be applied as human food to reduce deficiency problems and deliver health benefits. This review describes the recent studies on the enrichment of Se-containing plants in particular Se accumulation and speciation, their functional properties related to human health, and future perspectives for developing Se-enriched foods. Generally, Se's concentration and chemical forms in plants are determined by the accumulation ability of plant species. Brassica family and cereal grains have excessive accumulation capacity and store major organic Se compounds in their cells compared to other plants. The biological properties of Se-enriched plants, including antioxidant, anti-diabetes, and anticancer activities, have significantly presented in both in vitro cell culture models and in vivo animal assays. Comparatively, fewer human clinical trials are available. Scientific investigations on the functional health properties of Se-enriched edible plants in humans are essential to achieve in-depth information supporting the value of Se-enriched food to humans.

Modifications of polysaccharide-based biomaterials under structure-property relationship for biomedical applications

Polysaccharides are well accepted biomaterials that have attracted considerable attention. Compared with other materials under research, polysaccharides show unique advantages: they are available in nature and are normally easily acquired, those acquired from nature show favorable immunogenicity, and are biodegradable and bioavailable. The bioactivity and possible applications are based on their chemical structure; however, naturally acquired polysaccharides sometimes have unwanted flaws that limit further applications. For this reason, carefully summarizing the possible modifications of polysaccharides to improve them is crucial. Structural modifications can not only provide polysaccharides with additional functional groups but also change their physicochemical properties. This review based on the structure-property relation summarizes the common chemical modifications of polysaccharides, the related bioactivity changes, possible functionalization methods, and major possible biomedical applications based on modified polysaccharides.

Identification and characterization of a novel glucomannanase from Paenibacillus polymyxa

Konjac glucomannan oligosaccharide has attracted much attention due to its broad biological activities. Specific glucomannan degrading enzymes are effective tools for the production of oligosaccharides from konjac glucomannan. However, there are still few reports of commercial enzymes that can specifically degrade konjac glucomannan. The gene ppgluB encoding a glucomannanase consisting of 553 amino acids (61.5 kDa) from Paenibacillus polymyxa 3-3 was cloned and heterologous expressed in Escherichia coli BL21 (DE3). The recombinant PpGluB showed high specificity for the degradation of konjac glucomannan. Moreover, the hydrolytic products of PpGluB degrade konjac glucomannan were a series of oligosaccharides with degrees of polymerisation of 2-12. Furthermore, the biochemical properties indicated that PpGluB is the optimal active at 45 to 55 °C and pH 5.0-6.0, and shows highly pH stability over a very broad pH range. The present characteristics indicated that PpGluB is a potential tool to be used to produce oligosaccharides from konjac glucomannan.

Characterization and antitumor activities of polysaccharides obtained from ginger (Zingiber officinale) by different extraction methods

Three different extraction technologies including hot water extraction (HWE), enzyme assisted extraction (EAE) and ultrasonic cell grinder extraction (UCGE) were employed to extract crude ginger polysaccharides (GPs) under their respective best parameters, then crude GPs were purified by DEAE cellulose-52 and Sephadex G-200 size-exclusion chromatography in that order. Five GPs fractions (HGP, EGP1, EGP2, UGP1, and UGP2, respectively) were obtained. The differences of five GPs in chemical composition, characterization and antitumor activities were further compared. The molecular weights were different in five GPs, varying from 11.81 to 1831.75 kDa. Mannose and glucose as the main monosaccharide and the glycosidic linkage of →4)-α-D-Glc(1→ and -α-Manp-(1→ existed in both five GPs. While EGP2 and UGP1 possessed specific structure of →6)-β-D-Galp-(1→ and UGP1 contained more sulfate group. Moreover, UGP1 exhibited strong inhibitory effect on three tumor cells especially the colon cancer. The inhibition rates of UGP1 on H1975, HCT116 and MCF-7 were 23.339 ± 2.285%, 56.843 ± 2.405% and 21.061 ± 1.920% respectively. The study indicated GPs extracted by UCGE could reserve more active structure and inhibit colon cancer more significantly.