Sparassis crispa is an edible mushroom recently cultivable in Japan. Polysaccharide fractions were prepared from the cultured S. crispa by repeated extraction with hot water (SCHWE), cold NaOH (SCCA), and then hot NaOH (SCHA). HWE was further separated by 1 volume (SCHWE1v) or 4 volumes (SCHWE4v) of ethanol-precipitable fractions. By chemical, enzymic, and NMR analyses, the primary structures of SCHWE1v, SCCA, and SCHA were 6-branched 1, 3-β-glucan, having one branch in approximately every third mainchain unit. All of these fractions showed antitumor activity to the solid form of Sarcoma 180 in ICR mice with strong vascular dilation and hemorrhage reaction. These fractions also showed enhanced hematopoietic response to cyclophosphamide induced leukopenic mice following intraperitoneal or peroral administration.

Agaricus blazei is a medically important mushroom widely eaten and prescribed in Japan. Polysaccharide fractions were prepared from cultured A. blazei by repeated extraction with hot water (AgHWE), cold NaOH (AgCA), and then hot NaOH (AgHA). By chemical, enzymic, and NMR analyses, the primary structures of AgHWE, AgCA, and AgHA were mainly composed of 1,6-beta-glucan. Among these fractions, the NaOH extracts showed antitumor activity against the solid form of Sarcoma 180 in ICR mice. To demonstrate the active component in these fractions, several chemical and enzymic treatments were applied. These fractions were found to be i) neutral beta-glucan passing DEAE-Sephadex A-25, ii) resistant to periodate oxidation (I/B) and subsequent partial acid hydrolysis (I/B/H), iii) resistant to a 1,3-beta-glucanase, zymolyase, before I/B, but sensitive after I/B/H. In addition, after I/B/H treatment of the neutral fraction of AgCAE, a signal around 86 ppm attributable to 1,3-beta glucosidic linkage was detectable in the 13C-NMR spectrum. These facts strongly suggest that a highly branched 1,3-beta-glucan segment forms the active center of the antitumor activity.

The black yeast Aureobasidium pullulans produces abundant soluble β-1,3-1,6-glucan—a functional food ingredient with known health benefits. For use as a food material, soluble β-1,3-1,6-glucan is produced via fermentation using sucrose as the carbon source. Various functionalities of β-1,3-1,6-glucan have been reported, including its immunomodulatory effect, particularly in the intestine. It also exhibits antitumor and antimetastatic effects, alleviates influenza and food allergies, and relieves stress. Moreover, it reduces the risk of lifestyle-related diseases by protecting the intestinal mucosa, reducing fat, lowering postprandial blood glucose, promoting bone health, and healing gastric ulcers. Furthermore, it induces heat shock protein 70. Clinical studies have reported the antiallergic and triglyceride-reducing effects of β-1,3-1,6-glucan, which are indicators of improvement in lifestyle-related diseases. The primary and higher-order structures of β-1,3-1,6-glucan have been elucidated. Specifically, it comprises a single highly-branched glucose residue with the β-1,6 bond (70% or more) on a backbone of glucose with 1,3-β bonds. β-Glucan shows a triple helical structure, and studies on its use as a drug delivery system have been actively conducted. β-Glucan in combination with anti-inflammatory substances or fullerenes can be used to target macrophages. Based on its health functionality, β-1,3-1,6-glucan is an interesting material as both food and medicine.

In this report, we describe the convergent synthesis of β(1,3) oligosaccharides containing an aminoalkyl group. The branched heptadecasaccharide and linear hexadecasaccharide acted as ligands of dectin-1 whose binding affinity was only 10-fold weaker than that of natural SPG and exhibited dectin-1 agonist activity.