Water-soluble polysaccharides from finger citron fruits (Citrus medica L. var. sarcodactylis)

• Four homogeneous polysaccharides were extracted and purified from finger citron fruits.
• Acid hydrolysis, methylation, IR spectra, GC–MS, as well as NMR spectra were used for structure analyses.
• Structure analyses showed that they were heteropolysaccharide (FCp-1), galacturonan (FCp-2 and FCp-4) and glucan (FCp-3).
• FCp-3 may have further use as immunomodulatory agents.

Four water-soluble polysaccharides, FCp-1, FCp-2, FCp-3, and FCp-4 were obtained from finger citron fruits (Citrus medica L. var. sarcodactylis) by hot-water extraction and ethanol precipitation, followed by routine separation procedure. Based on the calibration curve, molecular weights of them were estimated to be 113.9, 32.6, 140.3, and 177.1 kDa respectively. The acid hydrolysis, methylation, IR, GC–MS, and NMR experiments were used for composition analysis. FCp-1 was a heteropolysaccharide composed of arabinose, galactose, glucose, rhamnose, and xylose, with a molar ratio of 3.0:7.0:4.1:1.0:1.5. FCp-2 and FCp-4 were →4)-α-d-GalpA(1→ linking galacturonan differ in molecular weights. FCp-3 was a →6)-α-d-Glcp(1→ linking glucan. According to the results of in vitro assays, FCp-3 showed significantly and moderately enhancing capacities toward the proliferation of splenocytes and thymocytes respectively. Thus, FCp-3 or analogs may have further use as immunomodulatory agents.

Four water-soluble polysaccharides were obtained from finger citron fruits (Citrus medica L. var. sarcodactylis Hort) for the first time, and their structures were determined by a combination of chemical modification and spectroscopic methods. One polysaccharide, FCp-3, significantly enhanced the proliferation of splenocytes and moderately enhanced the proliferation of thymocytes, suggesting FCp-3 or analogs may have further use as immunomodulatory agents.Figure optionsDownload as PowerPoint slide