Radioprotective activity of neutral polysaccharides isolated from the fruiting bodies of Hohenbuehelia serotina

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.

Exploring Natural Products as Radioprotective Agents for Cancer Therapy: Mechanisms, Challenges, and Opportunities

Radiotherapy is an important cancer treatment. However, in addition to killing tumor cells, radiotherapy causes damage to the surrounding cells and is toxic to normal tissues. Therefore, an effective radioprotective agent that prevents the deleterious effects of ionizing radiation is required. Numerous synthetic substances have been shown to have clear radioprotective effects. However, most of these have not been translated for use in clinical applications due to their high toxicity and side effects. Many medicinal plants have been shown to exhibit various biological activities, including antioxidant, anti-inflammatory, and anticancer activities. In recent years, new agents obtained from natural products have been investigated by radioprotection researchers, due to their abundance of sources, high efficiency, and low toxicity. In this review, we summarize the mechanisms underlying the radioprotective effects of natural products, including ROS scavenging, promotion of DNA damage repair, anti-inflammatory effects, and the inhibition of cell death signaling pathways. In addition, we systematically review natural products with radioprotective properties, including polyphenols, polysaccharides, alkaloids, and saponins. Specifically, we discuss the polyphenols apigenin, genistein, epigallocatechin gallate, quercetin, resveratrol, and curcumin; the polysaccharides astragalus, schisandra, and Hohenbuehelia serotina; the saponins ginsenosides and acanthopanax senticosus; and the alkaloids matrine, ligustrazine, and β-carboline. However, further optimization through structural modification, improved extraction and purification methods, and clinical trials are needed before clinical translation. With a deeper understanding of the radioprotective mechanisms involved and the development of high-throughput screening methods, natural products could become promising novel radioprotective agents.

A novel sulfated mannan-carboxymethyl-5-fluorouracil-folic acid conjugates for targeted anticancer drug delivery

CFP₂ is a sulfated polysaccharide isolated from Codium fragile that shows excellent immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), CFP₂ was used as a macromolecular carrier to react with carboxymethyl-5-fluorouracil (C-5-FU) to form CFP₂-C-5-FU, which further reacted with folic acid (FA) via an ester bond to form novel conjugates (CFP₂-C-5-FU-FA). CFP₂-C-5-FU-FA was confirmed by nuclear magnetic resonance (NMR) analysis. In vitro drug release results showed that the cumulative release rate of C-5-FU was 49.9% in phosphate buffer (pH 7.4) after 96 h, which was much higher than that of the other groups, indicating that CFP2-C-5-FU-FA showed controlled drug release behavior. CFP₂-C-5-FU-FA also exhibited enhanced apoptosis and cellular uptake in vitro. Further, intravenous administration of CFP₂-C-5-FU-FA in an HCT-116 cell-bearing xenograft mouse showed that the conjugates were safe and effective drug delivery systems. These results suggest that folate-targeted conjugates can be used effectively for efficient chemotherapy of colorectal cancer.

Neutral Polysaccharides From Hohenbuehelia serotina With Hypoglycemic Effects in a Type 2 Diabetic Mouse Model

Neutral polysaccharides (NHSPs) from the mushroom Hohenbueheliaserotina were purified by D301/D152 resin ion-exchange chromatography and DEAE-cellulose anion exchange chromatography. The weight-average molecular weight (M_W) and number-average molecular weight (Mn) of NHSP were 1,821 and 820.55 kDa, respectively. A monosaccharide component analysis showed that NHSP was composed of glucose, galactose, and mannose in molar ratio 2.6:2.1:1.0. FT-IR and NMR (¹H and HSQC) spectroscopic analyses revealed that NHSP contained mainly 1,3-linked β-D-glucose, 1,4-linked β-D-glucose, 1,6-linked β-D-mannose, 1,6-linked α-D-mannose, and 1,6-linked β-D-galactose. The thermogravimetric analysis (TGA) showed that NHSP has good thermal stability below 250°C. NHSP notably reduced the blood glucose level (hypoglycemic effect) at dose 200 mg/kg for 21 days in a type 2 diabetic mouse model. NHSP reduced the liver index significantly, suggesting that it may help prevent hepatic steatosis or hepatomegaly.

Two new compounds from edible mushroom Sarcomyxa edulis

Chemical investigation of the edible mushroom Sarcomyxa edulis led to the isolation of one new highly degraded sterol (1), and one new β-carboline alkaloid (2), along with nine known compounds (3-11) for the first time from this mushroom. The structures of new compounds were elucidated using HR-ESI-MS data and NMR spectroscopy. In addition, anti-inflammatory activity of new compounds was evaluated against lipopolysaccharide-induced NO production in RAW 264.7 macrophages. Compound 2 exhibited a good anti-inflammatory activity with IC₅₀ value of 9.88 ± 0.48 μM, and compound 1 exhibited a weak inhibitory effect with IC₅₀ value of 71.36 ± 5.11 μM.

Lanzhou Lily polysaccharide fragment protects human umbilical vein endothelial cells from radiation-induced DNA double-strand breaks

Background

Radiotherapy is widely used in the treatment of tumors. However, while killing tumor cells, radiation may also cause damage to the surrounding normal tissues. Therefore, it is very important to find safe and effective radiation protection agents.

Purpose

To investgate the radiation protection effect of Lanzhou Lily polysaccharide fragments (LLP). Methods: The crude polysaccharides of Lanzhou Lily were extracted from the dried bulb powder of Lilium lilium by ultrasonic-assisted hot water method, and then five different fragments were separated from the polysaccharides by DEAE-52-cellulose column. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, neutral comet and immunofluorescent staining were used to investigate the effect of LPe fragment on Human Umbilical Vein Endothelial Cells (HUVEC) survival and the possible radioprotective mechanism.

Results

The LPe fragment (composing of mannose and glucose, with a ratio of 5.5:2.9, and the average molecular weight is 8629.8 Da), significantly promoted the proliferation of HUVECs and protected cells from X-ray-induced double-strand breaks (DSBs) in DNA, in which pretreatment with the LPe fragment at 100 μg/mL showed the most pronounced protection. In addition, the occurrence of X-ray-induced γH2AX foci was significantly reduced by treatment with the LPe fragment at 50, 100, and 200 μg/mL. Furthermore, caffeine or wortmannin in combination with the LPe fragment at 25 μg/mL significantly reduced the number of X-ray-induced γH2AX foci, indicating phosphoinositide-3 kinases (PI3K) is involved in H2AX phosphorylation in HUVECs.

Conclusion

These results indicate the LPe fragment has a protective effect against radiation-induced DSBs and may be used as a natural antioxidant agent.

Potential of natural products as radioprotectors and radiosensitizers: opportunities and challenges

Natural products can be used as natural radiosensitizers and radioprotectors, showing promising effects in cancer treatments in combination with radiotherapy, while reducing ionizing radiation (IR) damage to normal cells/tissues. The different effects of natural products on irradiated normal and tumor cells/tissues have attracted more and more researchers' interest. Nonetheless, the clinical applications of natural products in radiotherapy are few, which may be related to their low bioavailability in the human body. Here, we displayed the radiation protection and radiation sensitization of major natural products, highlighted the related molecular mechanisms of these bioactive substances combined with radiotherapy to treat cancer, and critically reviewed their deficiency and improved measures. Lastly, several clinical trials were presented to verify the clinical application of natural products as radiosensitizers and radioprotectors. Further clinical evaluation is still needed. This review provides a reference for the utilization of natural products as radiosensitizers and radioprotectors.

Radioprotective effects and mechanisms of animal, plant and microbial polysaccharides

Ionizing radiation is increasingly used to successfully diagnose many human health problems, but ionizing radiation may cause damage to organs/tissues in the living organisms such as the spleen, liver, skin, and brain. Many radiation protective agents have been discovered, with the deepening of radiation research. Unfortunately, these protective agents have many side effects, which cause drug resistance, nausea, vomiting, osteoporosis, etc. The polysaccharides extracted from natural sources are widely available and low in toxicity. In vivo and in vitro experiments have demonstrated that polysaccharides have anti-radiation activity through anti-oxidation, immune regulation, protection of hematopoietic system and protection against DNA damage. Recently, some studies have shown that polysaccharides were resistant to radiation. In the review, the anti-radiation activities of polysaccharides from different sources are summarized, and the anti-radiation mechanisms are discussed as well. It can be used to develop more effective anti-radiation management drugs.

Radioprotection of EGCG based on immunoregulatory effect and antioxidant activity against 60Coγ radiation-induced injury in mice

Excessive reactive oxygen radicals (ROS) produced by ionizing radiation (IR) can cause human body to serious oxidative damage, leading to oxidation-reduction (REDOX) system imbalance and immune system damage. Here, the radioprotection of EGCG was studied through a model of oxidative damage in ⁶⁰Coγ radiation mice. Firstly, the weights and the main organs indexes of mice, including the liver index, spleen index and pancreas index, indicated preliminarily the safety and protection of EGCG. Then, the radioprotection of EGCG based on immune-regulation on radiation mice was further investigated. Results suggested that EGCG could prevent significantly the immune system damage caused by ⁶⁰Coγ via increasing the immune organ index, inducing the transformation of spleen cells into T- and B-lymphocytes, and enhancing the macrophage phagocytosis, compared with model group. In addition, EGCG could also protect spleens of radiation mice from ⁶⁰Coγ-induced the imbalance of REDOX system by enhancing the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), increasing the level of glutathione (GSH), suppressing lipid peroxidation (Malondialdehyde, MDA). The antioxidant enzymes activities of serum and livers were also increased markedly. Taken together, our results indicated that EGCG possessed the excellent potential to serve as a natural radioprotector against IR-induced damage.

Whole body radioprotective effect of phenolic extracts from the fruits of Malus baccata (Linn.) Borkh

This study was designed to evaluate the radioprotective effect of phenolics extracted from the fruits of Malus baccata (Linn.) Borkh. (MBP-3b) against damage induced by (60)Co γ-irradiation in vivo. MBP-3b could significantly improve the activity of endogenous antioxidant enzymes and the T-AOC, as well as reduce the MDA level in the liver and kidneys of irradiated mice. In addition, pretreatment with MBP-3b at a dose of 150 mg per kg bw could significantly enhance immunomodulation activity by promoting the proliferation of spenocytes and monocyte phagocytosis. The administration of MBP-3b prevented the decline induced by radiation of haematological parameters (WBC, RBC, PLT and HGB). Furthermore, MBP-3b could protect spenocytes from radiation-induced damage by inhibiting cell apoptosis. The results indicated that MBP-3b possesses strong whole body radioprotective and immunomodulatory activities. The main constituents of MBP-3b were tentatively identified as delphinidin-3,5-diglucoside, cyanidin-3-glucoside, chlorogenic acid, proanthocyanidin C1, quercetin-3-galactoside, quercetin-3-glucoside, quercetin-3-xyloside/arabinoside, phloretin-2-xyloseglucoside, quercetin-3-rhamnoside and phlorizin. MBP-3b could be used as a probable radioprotector against gamma radiation induced oxidative damage.

Mushroom Polysaccharides: Chemistry and Antiobesity, Antidiabetes, Anticancer, and Antibiotic Properties in Cells, Rodents, and Humans

More than 2000 species of edible and/or medicinal mushrooms have been identified to date, many of which are widely consumed, stimulating much research on their health-promoting properties. These properties are associated with bioactive compounds produced by the mushrooms, including polysaccharides. Although β-glucans (homopolysaccharides) are believed to be the major bioactive polysaccharides of mushrooms, other types of mushroom polysaccharides (heteropolysaccharides) also possess biological properties. Here we survey the chemistry of such health-promoting polysaccharides and their reported antiobesity and antidiabetic properties as well as selected anticarcinogenic, antimicrobial, and antiviral effects that demonstrate their multiple health-promoting potential. The associated antioxidative, anti-inflammatory, and immunomodulating activities in fat cells, rodents, and humans are also discussed. The mechanisms of action involve the gut microbiota, meaning the polysaccharides act as prebiotics in the digestive system. Also covered here are the nutritional, functional food, clinical, and epidemiological studies designed to assess the health-promoting properties of polysaccharides, individually and as blended mixtures, against obesity, diabetes, cancer, and infectious diseases, and suggestions for further research. The collated information and suggested research needs might guide further studies needed for a better understanding of the health-promoting properties of mushroom polysaccharides and enhance their use to help prevent and treat human chronic diseases.