Partial depolymerization of tamarind seed xyloglucan and its functionality toward enhancing the solubility of curcumin

Fully biosourced amphiphilic block copolymer from tamarind seed xyloglucan and solanesol: synthesis, aqueous self-assembly, and drug encapsulation

This study aims to explore the development of natural bio-based amphiphilic block copolymers for drug delivery applications. We investigated block copolymers derived from tamarind seed xyloglucan and solanesol, focusing on their synthesis, structural analysis, aqueous self-assembly, and drug encapsulation. Specifically, xyloglucan hydrolysate segments with number-average degrees of polymerization (DPs) of between 8 and 44 (XOS8, XMS10, XMS16, XMS28, and XMS44) were used as the hydrophilic blocks, whereas plant-sourced solanesol was selected as the hydrophobic segment. These two segments were linked via click chemistry to create novel XOS-b-Sol and XMS-b-Sol copolymers, where XOS refers to a xyloglucan oligosaccharide (DP < 10), and XMS denotes a megalosaccharide, defined as a larger xyloglucan polymer with a DP >10. XMS10- and XMS16-b-Sol self-assembled in aqueous media to form predominantly narrowly dispersed spherical micelles, while XOS8-b-Sol exhibited a combination of short wormlike structures and spherical micelles. Small-angle X-ray scattering, multi-angle dynamic light scattering, and transmission electron microscopy revealed the XMS28- and XMS44-b-Sol micelles are morphologically diverse. XMS10-b-Sol solubilized quercetin, a water-insoluble flavonoid, highly effectively, highlighting its potential as an environmentally benign drug carrier.

Fabrication of zein-tamarind seed polysaccharide-curcumin nanocomplexes: their characterization and impact on alleviating colitis and gut microbiota dysbiosis in mice

In this work, a zein-tamarind seed polysaccharide (TSP) co-delivery system was fabricated using an anti-solvent precipitation method. The formation mechanism, characterization, and effect on alleviating colitis and gut microbiota dysbiosis in mice of zein-TSP-curcumin (Z/T-Cur) nanocomplexes were investigated. Hydrogen bonding and the hydrophobic effect played a key role in the formation of Z/T-Cur nanocomplexes, and the interactions were spontaneous and driven by enthalpy. The encapsulation efficiency, loading capacity, and bioavailability increased from 60.8% (Zein-Cur) to 91.7% (Z/T-Cur1:1), from 6.1% (Zein-Cur) to 18.3% (Z/T-Cur1:1), and from 4.7% (Zein-Cur) to 20.0% (Z/T-Cur1:1), respectively. The Z/T-Cur significantly alleviated colitis symptoms in DSS-treated mice. Additionally, the prepared nanocomplexes rebalanced the gut microbiota composition of colitis mice by increasing the abundance of Akkermansia. Odoribacter and Monoglobus were rich in the Z-T-Cur treatment group, and Turicibacter and Bifidobacterium were rich in the zein-TSP treatment group. This study demonstrated that the TSP could be helpful in the targeted drug delivery system.

Partial enzymolysis affects the digestion of tamarind seed polysaccharides in vitro: Degradation accelerates and gut microbiota regulates

Two hydrolyzed fractions of tamarind seed polysaccharide (TSP), denoted ETSP1 (176.68 kDa) and ETSP2 (34.34 kDa), were prepared by partial degradation via endo-xyloglucanase, and then characterized and evaluated by simulated gastrointestinal digestion in vitro. The results showed that the hydrolyzed TSPs remained indigestible in gastric and small intestinal media, and were fermented by gut microbiota, similar to the native TSP (M_w = 481.52 kDa). Although the degradation of hydrolyzed TSPs was accelerated during fermentation with a decreasing degree of polymerization, the content of produced total short-chain fatty acids (SCFAs) decreased. After fermentation, the gut microbiota composition was modified, esp. the Firmicutes/Bacteroidetes ratio decreased (1.06 vs. 0.96 vs. 0.80) with a decreasing degree of polymerization, which implied that the potential anti-obesity prebiotic effect was enhanced. At the genus level, hydrolyzed TSPs maintained similar roles as native TSP, including promoting beneficial bacteria (Bifidobacterium, Parabacteroides, and Faecalibacterium) and inhibiting enteropathogenic bacteria (Escherichia-Shigella and Dorea). Moreover, ETSP1 had additional potential due to abundant Bacteroides vulgatus (LDA = 4.68), and ETSP2 might perform better as related to Bacteroides xylanisolvens (LDA = 4.40). All these results indicated the prebiotic potential of hydrolyzed TSP with detailed information about changes in degradation and gut microbiota based on enzyme-hydrolysis.