Structural Characteristics and Antioxidative Capability of the Soluble Polysaccharides Present in Dictyophora indusiata (Vent. Ex Pers.) Fish Phallaceae

Dictyophora indusiata (Vent. ex Pers.) Fish Phallaceae (Chinese name Zhu-Sūn, the bamboo fungi) has been used as a medicinal mushroom to treat many inflammatory, gastric and neural diseases since 618 AD in China. We hypothesize that the soluble polysaccharides (SP) present in D. indusiata and their monosaccharide profiles can act as an important role affecting the antioxidative capability, which in turn would influence the biological activity involving anti-inflammatory, immune enhancing and anticancer. We obtained six SP fractions and designated them as D1, a galactoglucan; D2, a galactan; D3, the isoelectrically precipitated riboglucan from 2% NaOH; D4, a myoinositol; D5 and D6, the mannogalactans. The total SP accounted for 37.44% w/w, their molecular weight (MW) ranged within 801–4656 kDa. D3, having the smallest MW 801 kDa, exhibited the most potent scavenging effect against the α,α-diphenyl-β-picrylhydrazyl, •OH(−), and •O(2) (−) radicals, yielding IC(50) values 0.11, 1.02 and 0.64 mg mL(−1), respectively. Thus we have confirmed our hypothesis that the bioactivity of D. indusiata is related in majority, if not entirely, to its soluble polysaccharide type regarding the MW and monosaccharide profiles.