Schizophyllan (Sizofiran)

Schizophyllan (Sizofiran, SPG) is a β-1,3-glucan polysaccharide with β-1,6-glycosidic branching points, produced by the split-gill mushroom Schizophyllum commune. It is primarily valued as a bioactive compound rather than a conventional nutritional source. Key profile: **Primary bioactive compound:** β-1,3/1,6-glucan (schizophyllan), typically extracted at purities of 90–95%, with molecular weight ranging from 450 kDa to over 5,000 kDa depending on preparation. Triple-helix tertiary structure in aqueous solution is critical for biological activity. **Polysaccharide content:** ~85–95% of dry extract weight, predominantly glucose-based polymer linked by β-(1→3) backbone with approximately every third glucose unit bearing a β-(1→6) branch. **Protein content:** Minimal in purified form (<2–5% of dry weight); crude fruiting body of Schizophyllum commune contains approximately 10–15% protein (dry weight), including essential amino acids. **Fiber:** The parent mushroom contains approximately 35–45% total dietary fiber (dry weight), of which schizophyllan constitutes a major soluble fiber fraction. **Lipids:** Trace amounts (<1–3% dry weight in whole mushroom); includes small quantities of linoleic acid and ergosterol (provitamin D2, approximately 0.3–0.8 mg/g dry weight). **Vitamins (whole mushroom source):** Niacin (B3) ~3.5–5.0 mg/100g dry weight; Riboflavin (B2) ~0.3–0.5 mg/100g; Folate ~25–40 µg/100g; Ergocalciferol (vitamin D2) variable, enhanced significantly with UV exposure (up to 10–20 µg/g). **Minerals (whole mushroom):** Potassium ~2,000–3,000 mg/100g dry weight; Phosphorus ~500–800 mg/100g; Magnesium ~100–150 mg/100g; Selenium ~2–15 µg/100g; Zinc ~5–10 mg/100g; Iron ~3–8 mg/100g. **Other bioactive compounds:** Trace amounts of lectins, phenolic compounds (gallic acid, protocatechuic acid at ~0.5–2.0 mg/g dry weight), and ergothioneine (~0.1–0.5 mg/g). **Bioavailability notes:** Oral bioavailability of schizophyllan as a high-molecular-weight polysaccharide is limited; it primarily acts through gut-associated lymphoid tissue (GALT) and Peyer's patches via Dectin-1 and complement receptor 3 (CR3) on macrophages and dendritic cells. Parenteral or intratumoral administration yields significantly higher systemic bioavailability. The triple-helix conformation is essential for optimal receptor binding and immunomodulatory activity; denaturation (e.g., in DMSO or alkaline conditions) reduces bioactivity. Concomitant intake with vitamin C may enhance absorption of iron and phenolic compounds from whole mushroom preparations.