Polysaccharides in Siraitia grosvenori flowers and herbal tea

Abstract

Siraitia grosvenori fruits are used as a sweetener and in traditional medicine. Their composition is more frequently studied contrary to flowers or herbal tea made of this plant. Infusions or decoctions of S. grosvenori flowers and herbal tea, commercially available products for daily use, are ingested into our body in terms of herbal medicine with potentially health beneficial impact. Mogrosides are supposed to be responsible for biological activities of S. grosvenori; however, it is well known that polysaccharides can also exhibit interesting biological activities. Composition of purified polysaccharidic complex matrices, isolated from S. grosvenori flowers and herbal tea by infusion and decoction, was the target of our study performed mainly by GC–MS and NMR. Characteristic NMR spectral features allowed an identification of the arabinogalactan type II and acidic biopolymers, homogalacturonan and highly esterified homogalacturonan in infusions of the herbal tea and flower and decoction of flowers. In the decoction sample of herbal tea inulin was found as the dominant polysaccharide. Comparison of compositional and linkage analyses data with those of 2D NMR spectra allowed an identification of fine structural elements of arabinogalactan polymers.