Properties and characterization of pH responsive nanoparticles based on polysaccharides from Bletilla striata as carriers in cancer therapy

Preparation, characterization, and stability of chitosan-tremella polysaccharide layer-by-layer encapsulated astaxanthin nanoemulsion delivery system

In this study, a layer-by-layer (LBL) encapsulated astaxanthin (Ast) nanoemulsion delivery system based on chitosan (CS) and tremella polysaccharide (TP) was successfully developed. The system constructed an Ast-CS-TP emulsion with high encapsulation efficiency and an excellent stability profile by utilizing the opposite charge properties of CS and TP. This study evaluated the effects of different stresses (including temperature, salt addition, pH, UV irradiation, and centrifugal force) on the emulsion's stability. To further investigate the protective mechanism of the emulsions, we performed antioxidant activity experiments after UV treatment. Additionally, an in vitro digestion experiment was conducted to assess the behavior of Ast emulsion under simulated gastrointestinal conditions. The stability correlation coefficients were calculated using the Python database Pandas. The results showed that Ast-CS-TP emulsions exhibited turbidity and enhanced homogeneity with a small particle size of around 400 nm and a high absolute zeta potential of 35 mV and exhibited excellent stability under various stresses. The Ast-CS-TP emulsions also exhibited pH-responsive release at pH ≥ 7, consistent with pH changes in the gastrointestinal tract, and were stable in highly concentrated salt solutions. We found that the CS and TP layers significantly improved the photostability of Ast. CS and TP significantly enhanced Ast's oral bioavailability. The stability correlation coeffcients showed that pH and salt concentration were the largest factors that affected the stability of the emulsion. This study provided important insights into the encapsulation and targeting of Ast, providing a theoretical foundation and technical guidance for the comprehensive utilization of Ast.

Acid-triggered rattan ball-like β-glucan carrier embedding doxorubicin to synergistically alleviate precancerous lesions of gastric cancer via p53 and PI3K pathways

The early intervention of precancerous lesions of gastric cancer (PLGC) is crucial for improving the survival of patients with gastric cancer. Traditional pharmaceuticals for the treatment of PLGC are limited by side effects, thus developing innovative drug carrier that are more efficient but without the undesirable side effects is required. Here, we proposed an acid-triggered mushroom-derived β-glucan carrier embedding doxorubicin (DOX) to circumvent drug cytotoxicity and synergistically alleviate PLGC based on the controlled conformational transformation. The triple helix β-glucan extracted from Dictyophora rubrovolvata (DRP) loaded doxorubicin driven by pH and DMSO regulation, forming two rattan ball-like nanoparticles (DRP-DOX(pH) and DRP-DOX(DMSO)) via its collapse and recombination of triple-helix conformation. The findings revealed that DRP-DOXs achieved acid-triggerable and sustained drug delivery with an average particle size of 500 nm and 550 nm. In vitro evaluation of GES-1 cells showed DRP-DOXs reduced reactive oxygen species (ROS) production and altered mitochondrial membrane potential. Compared to DRP-DOX(DMSO) and DRP, DRP-DOX(pH) could more effectively downregulate cellular oxidative stress and inflammation to eventually alleviate PLGC, by regulating the p53 and PI3K pathways to mitigate gastric mucosa damage. Consequently, the nature-derived β-glucan delivery nanovesicle holds great promising applications in reducing drug toxicity and suppressing the development of PLGC.

Extraction, structural-activity relationships, bioactivities, and application prospects of Bletilla striata polysaccharides as ingredients for functional products: A review

Bletilla striata is a well-known medicinal plant with high pharmaceutical and ornamental values. Polysaccharide is the most important bioactive ingredient in B. striata and has various health benefits. Recently, B. striata polysaccharides (BSPs) have attracted much attention from industries and researchers due to their remarkable immunomodulatory, antioxidant, anti-cancer, hemostatic, anti-inflammatory, anti-microbial, gastroprotective, and liver protective effects. Despite the successful isolation and characterization of B. striata polysaccharides (BSPs), there is still limited knowledge regarding their structure-activity relationships (SARs), safety concerns, and applications, which hinders their full utilization and development. Herein, we provided an overview of the extraction, purification, and structural features, as well as the effects of different influencing factors on the components and structures of BSPs. We also highlighted and summarized the diversity of chemistry and structure, specificity of biological activity, and SARs of BSP. The challenges and opportunities of BSPs in the food, pharmaceutical, and cosmeceutical fields are discussed, and the potential development and future study direction are scrutinized. This article provides comprehensive knowledge and underpinnings for further research and application of BSPs as therapeutic agents and multifunctional biomaterials.