Discovery of dearomatized isoprenylated acylphloroglucinols with colon tumor suppressive activities in mice via inhibiting NFκB-FAT1-PDCD4 signaling activation.

Dearomatized isoprenylated acylphloroglucinols (DIAPs) are specific natural products mainly distributed in the plants of genus Hypericum. In this study, guided by HPLC-UV screening, 46 DIAPs (approximately 70% of all DIAPs) including 20 new ones and an unprecedented architecture, were discovered from the roots of Hypericum henryi, which were elucidated by comprehensive spectroscopic, X-ray crystallography, and ECD methods. Compounds 1-7, 39, and 41-42 exhibited remarkable cytotoxicities (IC50 = 0.84-5.63 µM) in human colon cancer HCT116 cells, in which 2 and 6 possessed selective cytotoxicities towards colon cancer cells. The preliminary structure-activity relationships of these tested compounds were discussed. In addition, mechanistic investigations demonstrated that 2 and 6 could significantly suppress the expressions of NFκB, FAT1, and promoted novel tumor suppressor gene PDCD4 in HCT116 cells. Furthermore, in HCT116 colon xenograft-bearing mouse model, treatments with 2 and 6 reduced the growth of xenograft tumors in dose-dependent manner. Expressions of FAT1 in tumors were also decreased in mice treated with 2 and 6, suggesting their anti-tumor effects were via FAT1 signaling pathway. In conclusion, this is the first report on the mechanistic and in vivo studies of DIAP, indicating that these metabolites can be considered as a new type of anti-colon cancer lead agents for further drug development.

Isolation, structure characterization, and immunomodulating activity of a hyperbranched polysaccharide from the fruiting bodies of Ganoderma sinense.

A polysaccharide (GSP-6B) with a molecular mass of 1.86 × 106 Da was isolated from the fruiting bodies of Ganoderma sinense . Chemical composition analysis, methylation analysis, infrared spectroscopy, and nuclear magnetic resonance spectroscopy were conducted to elucidate its structure. GSP-6B contains a backbone of (1→6)-linked-ß-D-glucopyranosyl residues, bearing branches at the O-3 position of every two sugar residues along the backbone. The side chains contain (1→4)-linked-ß-D-glucopyranosyl residues, (1→3)-linked-ß-D-glucopyranosyl residues, and nonreducing end ß-D-glucopyranosyl residues. An in vitro immunomodulating activity assay revealed that GSP-6B could significantly induce the release of IL-1ß and TNF-α in human peripheral blood mononuclear cell (PBMC) and showed no toxicity to either PBMC or a human macrophage cell line THP-1. GSP-6B could also activate dendritic cells (DC) by stimulating the secretion of IL-12 and IL-10 from DC.