This study investigated the structural composition and antioxidant properties of pectic polysaccharides extracted from Rohdea japonica (Thunb.) Roth. Pectins, which belong to a complex category of acidic polysaccharides, possess a wide range of biological effects stemming from their distinctive structural domains. The polysaccharides were extracted using water, and were subsequently purified through ion exchange and gel permeation chromatography. In order to elucidate their structural features, Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance techniques were applied. Two specific polysaccharides, WRJP-A2a and WRJP-A3b, with molecular weights of 42.7 kDa and 64.1 kDa, respectively, were identified to contain varying proportions of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II domains. Regarding antioxidant capacity, WRJP-A3b exhibited superior scavenging capabilities against DPPH, ABTS, and hydroxyl radicals, potentially attributed to its higher galacturonic acid content and abundance of homogalacturonan domains. These results enhance our comprehension of the structure–activity interplay of pectic polysaccharides sourced from Rohdea japonica (Thunb.) Roth and their potential utility in the healthcare and functional food sectors.

This research explores the structural composition and antioxidant abilities of pectins extracted from Adenophora tetraphylla (Thunb.) Fisch. Pectins, which are a complex group of acidic polysaccharides, exhibit various biological activities due to their unique structural domains. Following aqueous extraction, the pectins underwent sequential purification using ion exchange and gel permeation chromatography techniques. FT-IR and NMR techniques were used to elucidate their structural characteristics. The structural investigation was enhanced through the application of multiple characterization methods: Congo red binding analysis, circular dichroism measurements, and scanning electron microscopy imaging. Among the isolated pectins, WATP-A2b (22.5 kDa) and WATP-A3b (49.8 kDa) demonstrated significant variations in their structural domain organization, comprising different ratios of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II. WATP-A3b displayed the most potent antioxidant performance among the tested pectins, effectively scavenging all three free radical species, which may be correlated with its higher galacturonic acid proportion and substantial rhamnogalacturonan I domain presence. These experimental results provide valuable insights into the correlation between structural characteristics and biological functions of pectins derived from Adenophora tetraphylla and their potential applications in healthcare.

To address the instability of conventional selenium fertilizers, we developed Phellinus igniarius polysaccharide-stabilized selenium nanoparticles (SH-SeNPs). These ~90 nm nanoparticles exhibited excellent stability and enhanced antioxidant capacity compared with native polysaccharides. Foliar application significantly promoted the early growth and biomass of rice without inducing oxidative stress. Specifically, treatment with 5 mg/L SH-SeNPs increased the root length from 5.22 ± 0.78 cm (control) to 5.91 ± 0.50 cm, while the 45 mg/L treatment increased the shoot length from 1.63 ± 0.27 to 1.89 ± 0.35 cm during germination. Mechanistically, SH-SeNPs maintained redox homeostasis through selective enzymatic regulation. Metabolomic analysis indicated a potential strategic metabolic reprogramming: SH-SeNPs appeared to induce the diversion of carbon–nitrogen flux from free amino acids toward the shikimate and phenylpropanoid pathways. This proposed “efficient defense–robust growth” balance suggests that SH-SeNPs may act not merely as a nutrient source but also as a metabolic regulator. These findings provide insights into the mechanisms through which polysaccharide-stabilized SeNPs regulate growth and metabolism in rice during early growth stages, highlighting their potential as nano-biostimulants for seedling establishment.

The flooded rice rhizosphere is a continuous reactive interface composed of sediment, porewater, root-surface oxic microdomains, and iron plaque, where redox processes and Fe cycling regulate Cd/As speciation, bioavailability, and plant accumulation. Engineered nanomaterials (ENMs) have shown potential for reducing Cd/As uptake in rice, but the coupled roles of microbial community responses, iron-plaque gating, and cross-interface elemental migration remain insufficiently integrated. This review synthesizes the current evidence on ENM transformation and partitioning at flooded rhizosphere microinterfaces, focusing on front-end speciation changes, root-surface retention, microbial functional regulation, and plant sequestration or transport. Correlative evidence suggests that rhizosphere microorganisms are associated with altered redox conditions, Fe cycling, As methylation potential, and metabolite secretion, which may influence Cd/As partitioning and cross-interface migration. However, direct causal validation of the complete ENM transformation–microbial response–Fe cycling–Cd/As flux–grain accumulation sequence within a single integrated system remains lacking. We further discuss how elevated CO₂, micro-/nanoplastics, Fe/DOM dynamics, and water management regimes may modify this framework, and we identify Sb as a theoretical boundary case because direct ENM–rice evidence remains limited. Finally, we highlight the need to integrate spatial tracing and imaging methods, including persistent luminescence tracing, LA-ICP-MS, NanoSIMS, and µ-XRF/µ-XANES, with metaomics to connect particle localization, microbial function, and contaminant fate.