Polysaccharides from Diaphragma juglandis fructus: Extraction optimization, antitumor, and immune-enhancement effects

This study discusses the optimization of the microwave-assisted extraction of polysaccharides from Diaphragma juglandis (DJPs). One main fraction (DJP-2) was successfully purified by ion-exchange chromatography and gel-permeation chromatography. The results showed that the optimal extraction conditions with DJP extraction yield of 4.7 +/- 0.28% were water to raw material ratio of 20 mL/g, extraction time of 40 min, and microwave extraction power of 400 W. Bioassays indicated that DJP-2 could effectively suppress the proliferation of HepG2 and BGC-82 cell lines. In addition, DJP-2 could significantly enhance phagocytosis; stimulate the production of NO, tumor necrosis factor-alpha (TNF-alpha), and interleukins (IL-6 and IL-1 beta); and promote their corresponding mRNA expression levels in a dose-dependent manner. Meanwhile, CR3, MR, and TLR2 were confirmed to be the major membrane receptors of DJP-2 on RAW 264.7. All these results indicated that DJP-2 could be a potential antitumor and immunomodulatory agent in the field of pharmacology. (C) 2018 Elsevier B.V. All rights reserved.