Insights into the structural characterisations,bioactivities and their correlations with water-soluble polysaccharides extracted from different pomelo (Citrus maxima Merr.) tissues

Pomelo (Citrus maxima Merr.), known as a famous fruit and folk medicine, is widely cultivated in China. Nonedible pomelo tissues contain peels, seeds, and segment membranes, which generally being discarded. Polysaccharides relationships among different pomelo tissues remain uncertain. Four water-soluble polysaccharides, PPPs, PSPs, FPPs and SMPs, were extracted from pomelo peels, seeds, pulps and segment membranes, respectively. Molecular structure and conformation were investigated by a combination of chemical and instrumental analyses. PPPs and FPPs were consisted of Ara, GalA, GlcA, Rha, Glc, Xyl and Gal, while PSPs and SMPs did not contain GalA and Gal. The average molecular weight (Mw) of PPPs, PSPs, FPPs and SMPs was 4.604 × 10⁵, 10.85 × 10⁵, 5.795 × 10⁵ and 16.06 × 10⁵ Da, respectively. PPPs, PSPs and SMPs all showed totally spherical structures, while FPPs primarily comprised linear chains. The structures–bioactivities correlations analysis revealed that low-Mw polysaccharides had strong DPPH•, OH• scavenging and HeLa cells inhibiting activities. These data revealed that the bioactivities of pomelo tissues polysaccharides were not a function of a single factor but a combination of various characteristics.