Preparation, characterization and evaluation of polysaccharides from Rosa roxburghii Tratt. fruit on ameliorating senior osteoporosis in rats induced by d-galactose and low calcium diet.

BACKGROUND

Senior osteoporosis (SOP) represents a significant health concern that impacts quality of life among the elderly population. Calcium supplementation is the most common treatment for those diagnosed with osteoporosis. However, the administration of inorganic calcium supplements is often associated with adverse effects, including constipation and nephrolithiasis. The fruit of Rosa roxburghii, commonly known as 'Ci Li' in Chinese, is both a medicine and a food. It aids in digestion, strengthens the spleen and stomach, and improves intestinal inflammation. The polysaccharides from R. roxburghii (RRFP) also exhibit activities such as enhancing immunity, managing diabetes, and regulating intestinal function. The current methods for RRFP extraction either have low extraction rates or are not conducive to scale-up applications; in addition, the effect of RRFP on improving SOP is unclear.

RESULTS

RRFP with molecular weights ranging from 50 to 100 kDa was enriched by ultrafiltration, and was composed of fucose, rhamnose, arabinose, galactose, glucose, xylose, and galacturonic acid. The functional groups of polysaccharides were confirmed by Fourier transform infrared spectroscopy. Scanning electron microscopy revealed that RRFP exhibited a porous morphology. Notable increases in antioxidant capacity, dry femur weight, femur bone mineral density, and femur calcium levels were observed in RRFP group rats. Protein expression of keap1 decreased while HO-1 and Nrf2 increased after RRFP-Ca treatment. RRFP altered the composition of the intestinal microbiota in rats.

CONCLUSION

RRFP could enhance calcium absorption to improve SOP by activating the Nrf2/HO-1 pathway and modulating the gut microbiota, especially by altering the abundance of Lachnospiraceae. © 2026 Society of Chemical Industry.