Molecular Characterization of Two Polysaccharides from Phellinus vaninii Ljup and their Cytotoxicity to Cancer Cell Lines

Background: Phellinus vaninii, a medicinal basidiomycete fungus, is often confused with Phellinus igniarius and Phellinus linteus. Polysaccharides extract from P. igniarius and P. linteus are reported to stimulate humoral immunity and inhibit tumor growth However, available literature reviewed no information on the relationship between bioactivities and structures of polysaccharides from the fruit body of P. vaninii.

Methods: Two water-soluble polysaccharides (PV-W, PV-B) were isolated and purified from fruiting bodies of P. vaninii by hot water and sodium hydroxide solution, respectively. The chemical structures of PV-W, PV-B were analyzed by FT-IR, GC-MS analysis and 13C NMR spectra. And, their molecular conformations were analyzed by viscosity method and SEC-MALLS-RI. Finally, their inhibition of cancer cells was investigated using MTT assay.

Results: The results illustrated that PV-W was a heteropolysaccharide, mainly composed of mannose, glucose, arabinose and galactose. PV-B was a β-1, 3-D-glucan branched with β-1, 6-D-glucose. The results of viscometry proved that PV-W and PV-B could be molecularly dispersed in water without aggregation. The results of SECMALLS- RI indicated that the two polysaccharides had the similar Mw but different molecular conformation. That is, PV-W existed as a stable globular shape, while PV-B presented a more expanded flexible random coils conformation. MTT assay indicated that PV-B showed higher inhibition effect on HepG2 and HeLa cells than PV-W in vitro.

Conclusion: This work provided the important information of active components from P. vaninii and its potential applications in the food and medicine industry.

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