Background: Gum Arabic (GA) is a natural polysaccharide widely recognized for its antioxidant and anti-inflammatory properties; however, its functional behavior as a biopolymeric gel and the mechanisms underlying its selective effects on cancer-related redox microenvironments remain insufficiently characterized. It is imperative to note that the interaction between its physicochemical properties and its biological activity in colorectal cancer remains to be fully clarified. Methods: This study aimed to evaluate the antineoplastic potential of GA in human colorectal cancer (CRC) cell lines (HT-29 and HCT-116) compared to normal fibroblasts (MRC-5) using the MTS assay. Oxidative stress-related molecular responses were assessed by quantitative PCR analysis of GPX4, GSTA2, CAT, NFKB, and SOD1 expression. In parallel, extracellular concentrations of key metal ions (Fe²⁺, Zn²⁺, Mn²⁺, Mg²⁺, Cu²⁺, and Al³⁺) were quantified following GA exposure. To establish its functional gel characteristics, rheological measurements were performed to assess viscosity and shear-dependent behavior, and USP-compliant in vitro kinetic studies were conducted to evaluate time-dependent release properties. Results: GA induced dose-dependent cytotoxicity in HT-29 and HCT-116 colorectal cancer cells, while MRC-5 fibroblasts exhibited comparatively higher viability across the tested concentration range, indicating reduced sensitivity in normal cells. Rheological analysis revealed concentration- and ion-dependent viscoelastic behavior, identifying a 10% (w/w) GA formulation as optimal due to its balanced low-shear viscosity and controlled shear-thinning properties. Kinetic studies demonstrated a defined, diffusion-governed release profile under physiologically relevant conditions. At the molecular level, significant upregulation of GPX4 and GSTA2 was observed in both cancer cell lines, whereas NFKB expression increased selectively in HT-29 cells, with no notable changes in CAT or SOD1 expression. Additionally, GA treatment resulted in marked increases in Fe²⁺, Zn²⁺, and Mn²⁺ levels, indicating modulation of the redox–ionic microenvironment. Conclusions: These findings demonstrate that GA functions as a natural, ion-responsive biopolymeric system with defined rheological and kinetic properties, capable of selectively targeting colorectal cancer cells through coordinated genetic and ionic regulation of oxidative stress. Collectively, the results position GA as a promising functional gel-based platform for future redox-modulated therapeutic strategies in colorectal cancer.

Probiotic quality and safety require strain-specific characterization supported by controlled production and comprehensive evaluation. This study aimed to integrate controlled fermentation and biomass production, downstream processing and lyophilization, microbiological quality control, batch reproducibility, whole-genome characterization, in vitro functional and safety-related assessment, real-time stability monitoring, and OECD-compliant in vivo safety evaluation of the human-derived Limosilactobacillus reuteri strain ATA-LTC-Lr050600. The strain was produced under controlled fermentation conditions, followed by harvesting, protective formulation, and lyophilization. Product quality was assessed by standardized microbiological testing, whole-genome sequencing, and in vitro assays evaluating acid and bile tolerance, adhesion to a fibroblast cell model, hemolytic activity, and cytotoxicity. Real-time stability was monitored during storage, and safety was further evaluated using OECD-compliant acute and repeated-dose oral toxicity studies. The production process generated a lyophilized preparation with consistent microbiological quality and reproducible manufacturing characteristics. Whole-genome sequencing confirmed strain identity and did not detect acquired antimicrobial resistance determinants. The strain tolerated simulated gastrointestinal conditions, adhered to the evaluated fibroblast cell model, and showed no detectable hemolytic activity or cytotoxicity under the experimental conditions. Product viability and microbiological quality were maintained throughout the monitored storage period. In the in vivo studies, no treatment-related adverse effects were identified, and the repeated-dose study established a no-observed-adverse-effect level of 1000 mg/kg/day under the conditions examined. Collectively, these integrated findings provide a basis for further strain-specific evaluation and support the continued development of L. reuteri ATA-LTC-Lr050600 as a well-characterized probiotic candidate under the conditions examined.

Background: Lactiplantibacillus plantarum is a widely studied probiotic species; however, probiotic characteristics and safety profiles are strain-specific, requiring independent evaluation. This study characterized Lactiplantibacillus plantarum ATA-LPC98052 as a candidate probiotic raw material. Methods: ATA-LPC98052 was evaluated for hemolysis, acid/bile tolerance, Caco-2 adhesion, cytotoxicity, and storage stability. Subacute oral safety was assessed in Wistar rats by gavage for 28 days at 1.2 × 10¹¹ CFU/kg/day; the study design incorporated selected principles of OECD Test Guideline 407. Clinical, hematological, biochemical, organ-weight, and macroscopic endpoints were evaluated. Fecal microbiota was analyzed by 16S rRNA sequencing; WGS was used for taxonomic confirmation and genomic safety screening. Results: ATA-LPC98052 was γ-hemolytic and maintained 60% viability at pH 1.5 and 96% at pH 5.0, while viability ranged from 74% to 82% across 0.1–0.5% bile salt concentrations. Caco-2 cell viability was 99%, adhesion exceeded 90%, and the lyophilized preparation remained stable for 15 months, maintaining 9.6 log₁₀ CFU/g. Repeated oral administration caused no mortality or consistent treatment-related toxicological pattern. Longitudinal microbiota analysis showed no significant treatment × time effects on alpha diversity or Bray–Curtis community structure, and no genus-level MaAsLin2 association was FDR-significant. WGS confirmed L. plantarum identity and no contamination; ResFinder detected no acquired antimicrobial resistance determinants meeting specified thresholds, whereas CARD/RGI identified low-identity qacJ and vanY homologs requiring cautious interpretation. Conclusion: ATA-LPC98052 demonstrated favorable in vitro probiotic characteristics, technological stability, gut microbiota-modulating potential, and a favorable subacute safety profile under the tested conditions; however, microbiota findings were exploratory, and phenotypic MIC testing remains warranted.