Structure,molecular size and antitumor activities of polysaccharides from Poria cocos mycelia produced in fermenter

摘要

Mycelia of Poria cocos were obtained from a pilot-scale 50-L fermenter by submerged cultivation biotechnology.Six polysaccharide fractions were extracted sequentially from the P.cocos mycelia with 0.9% NaCl (Pi-PCMl),hot water (Pi-PCM2),0.5 M NaOH (Pi-PCM3-I and -II),and 88% formic acid (Pi-PCM4-I and -II).The supernatant of the culture media was spray-dried to obtain the extracellular polysaccharide (Pi-PCM0) produced by the mycelia.The results from Fourier transform infrared spectroscopy,gas chromatography,and 13C NMR revealed that the water-soluble fractions including Pi-PCMO,Pi-PCMl,and Pi-PCM2 were heteropolysac-charides mainly containing glucose,galactose,and mannose,whereas Pi-PCM3-I and Pi-PCM4-I had (1 -> 3)-alpha-D-glucan characteristics.The weight-average molecular mass (M_w) and intrinsic viscosity ([eta]) of the polysaccharide were measured by laser light scattering (LLS) and viscometry,respectively.Results indicated that Pi-PCM 1 and Pi-PCM2 existed as a compact random coil in aqueous solution,close to the global shape.Interestingly,the three water-soluble polysaccharides (Pi-PCMO to Pi-PCM2) all exhibited antitumor activities in vivo (Sarcoma 180 solid tumor implanted in BALB/c mice),and in vitro (HL-60 tumor cell).