title: Enhancement of in vitro and in vivo anticancer activities of polysaccharide peptide from Grifola frondosa by chemical modifications.
abstract: BACKGROUND
  Grifola frondosa (Polyporaceae), maitake, is a widely consumed edible mushroom in some Asian countries. The fruit bodies and mycelia of maitake have shown different bioactive compounds with anticancer and other therapeutic properties.
  
  
  OBJECTIVE
  This study evaluated three chemically modified maitake polysaccharide-peptides' (MPSP) adjuvant effect (in vivo) and anticancer activity (in vitro growth inhibitory effect) compared with crude MPSP from G. frondosa.
  
  
  METHODS
  We investigated the possibility of enhancing the adjuvant effect and anticancer effect of crude MPSP by using simple chemical modification methods to convert crude MPSP to phosphorylated, acetylated or esterified MPSPs. The adjuvant effect and growth inhibitory effect were evaluated by C6 cell inoculated rat model with cyclophosphamide (CPA) treatment and in vitro cell viability assay, respectively.
  
  
  RESULTS
  All four tested MPSPs showed significant adjuvant effect to CPA treatment on rats inoculated with C6 cancer cells. In addition, an obvious growth inhibitory effect was observed in C6 cancer cells but not in normal brain cells treated with various forms of MPSPs. Only phosphorylation could significantly (p < 0.05) improve the adjuvant effect (in vivo) and growth inhibitory effect. A same rank order (phosphorylated MPSP > esterified MPSP ≥ acetylated MPSP ≥ crude MPSP) of efficacy was observed in both the in vivo and in vitro assays.
  
  
  CONCLUSIONS
  This study showed chemical phosphorylation could markedly enhance both adjuvant effects and growth inhibitory effects. This study demonstrated the feasibility of enhancing the efficacy of MPSP by using a simple chemical modification method, and this provides a foundation for future study in this area.
authors: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors: Janet Yuen-Yan
authors: JY
authors: Chan
authors: Enoch
authors: E
authors: Chan
authors: Shun-Wan
authors: SW
authors: Chan
authors: Shun-Yin
authors: SY
authors: Sze
authors: Ming-Fai
authors: MF
authors: Chan
authors: Siu-Hung
authors: SH
authors: Tsui
authors: Kit-Yee
authors: KY
authors: Leung
authors: Robbie Yat-Kan
authors: RY
authors: Chan
authors: Ivan Ying-Ming
authors: IY
authors: Chung