Chemical structure of native and modified sulfated heterorhamnans from the green seaweed Gayralia brasiliensis and their cytotoxic effect on U87MG human glioma cells

Recent advances in polysaccharide-based drug delivery systems for cancer therapy: a comprehensive review

Cancer has a high rate of incidence and mortality throughout the world. Although several conventional approaches have been developed for the treatment of cancer, such as surgery, chemotherapy, radiotherapy and thermal therapy, they have remarkable disadvantages which result in inefficient treatment of cancer. For example, immunogenicity, prolonged treatment, non-specificity, metastasis and high cost of treatment, are considered as the major drawbacks of chemotherapy. Therefore, there is a fundamental requirement for the development of breakthrough technologies for cancer suppression. Polysaccharide-based drug delivery systems (DDSs) are the most reliable drug carriers for cancer therapy. Polysaccharides, as a kind of practical biomaterials, are divided into several types, including chitosan, alginates, dextran, hyaluronic acid, cyclodextrin, pectin, etc. Polysaccharides are extracted from different natural resources (like herbal, marine, microorganisms, etc.). The potential features of polysaccharides have made them reliable candidates for therapeutics delivery to cancer sites; the simple purification, ease of modification and functionalization, hydrophilicity, serum stability, appropriate drug loading capacity, biocompatibility, bioavailability, biodegradability and stimuli-responsive and sustained drug release manner are considerable aspects of these biopolymers. This review highlights the practical applications of polysaccharides-based DDSs in pharmaceutical science and cancer therapy.

Semisynthesis of new sulfated heterorhamnan derivatives obtained from green seaweed Gayralia brasiliensis and evaluation of their anticoagulant activity

Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.