Molecular Characteristics of Water-Soluble Extracts from Hypsizigus marmoreus and Their in Vitro Growth Inhibition of Various Cancer Cell Lines and Immunomodulatory Function in Raw 264.7 Cells

Abstract

Water-soluble extracts isolated from Hypsizigus marmoreus and fractionated by ion-exchange chromatography were investigated to determine their molecular characteristics and biological activities. The crude and fractionated water-soluble extracts (F₁, F₂ and F₃) consisted mostly of carbohydrates (55.8–98.9%) with varied protein contents (1.1–23.0%). Their monosaccharide levels were significantly different, including the glucose content (67.0–100%) and galactose content (0–33.0%). The backbone of each fraction was mainly glucose molecules connected with 1,4-glycosidic linkages which contained considerable amounts of glucose and/or galactose connected through 1,6-glycosidic linkages. The average molecular weight (M_w) of the extracts varied considerably, ranging from 1,665×10⁴ to 19×10⁴ g/mol. Little cytotoxicity was apparent in cancer cell lines from the addition of these extracts; however, they significantly stimulated Raw 264.7 cells to release nitric oxide (NO) and prostaglandin E₂ (PGE₂), suggesting their potential immunomodulating activities.