Structural Analysis of a Non-Starch Polysaccharide Derived from Red Rice Bran and Its Immunomodulatory Properties
Juan Liu1, Dagang Chen1, Xinqiao Zhou1
1Rice Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs/Guangdong Key Laboratory of Rice Science and Technology, Guangzhou 510640, China.
Foods (Basel, Switzerland)
|July 28, 2026
Summary
Red rice bran polysaccharide (RRBP) is a unique glucan that activates macrophages and stimulates pro-inflammatory responses, showing potential for immune-modulating functional foods.
Area of Science:
- Food Science
- Immunology
- Biochemistry
Background:
- Polysaccharides from natural sources are increasingly investigated for their biological activities.
- Red rice bran (Oryza sativa L.) is a rich source of bioactive compounds.
- Understanding the immunomodulatory potential of red rice bran polysaccharides (RRBP) is crucial for functional food development.
Purpose of the Study:
- To characterize the structure of RRBP extracted from red rice bran.
- To investigate the immunomodulatory effects of RRBP on macrophage cells.
- To explore the potential application of RRBP in functional foods.
Main Methods:
- Extraction and structural characterization of RRBP using methylation analysis, UV, and FT-IR spectroscopy.
- Assays with RAW264.7 macrophage cells to measure nitric oxide (NO) and cytokine (IL-6, TNF-α, IL-12) production.
- Gene expression profiling to analyze the transcription of inflammatory genes.
- Cytotoxicity assays.
Main Results:
- RRBP is a hyperbranched glucan (51.4 kDa) primarily composed of glucose with specific linkage patterns.
- RRBP stimulated NO and pro-inflammatory cytokine (IL-6, TNF-α) production in a concentration-dependent manner.
- RRBP promoted M1 macrophage activation and enhanced the transcription of iNOS and pro-inflammatory cytokine genes.
- RRBP exhibited no cytotoxicity, indicating biocompatibility.
Conclusions:
- RRBP is a structurally distinct glucan with selective pro-inflammatory immunostimulant properties.
- RRBP can activate macrophages and modulate immune responses.
- RRBP holds potential for development into functional food products for targeted immune system modulation.
