Inhibition of leukemia proliferation by a novel polysaccharide identified from Monascus-fermented dioscorea via inducing differentiation.

Monascus-fermented products offer valuable therapeutic benefits and have been extensively used in East Asia. However, the polysaccharide obtained from Monascus-fermented products has never been investigated. This study evaluated the effects of dioscorea polysaccharide (DPS) and red mold dioscorea polysaccharide (RMDPS) on differentiation of leukemic THP-1 cells. DPS and RMDPS inhibited THP-1 cells proliferation in dose- and time-dependent manners. The differentiation induction (macrophage-like cells) was observed when THP-1 cells were treated with DPS and RMDPS for 5 days. Superoxide anion production, phagocytic capacity, and cytokine secretion confirmed activity for differentiating THP-1 cells. Results indicated that RMDPS elevated reactive oxygen species production and immune activity, including phagocytosis, interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) productions in THP-1 cells, which was greater than that seen with DPS. These results may be attributed to Monascus-fermentation altering the carbohydrate components and polysaccharide structure. RMDPS may serve as a novel material and functional ingredient to exert anticancer capacity.

Monascus-fermented metabolite monascin suppresses inflammation via PPAR-γ regulation and JNK inactivation in THP-1 monocytes.

Fermentation products of the fungus Monascus offer valuable therapeutic benefits and have been used extensively for centuries in Asia. The aim of this study is to investigate the inhibitory effect of the Monascus-fermented metabolite monascin (MS) on the molecular mechanism of ovalbumin (OVA)-induced inflammation in the human THP-1 monocyte cell line. We found that 1, 5, and 25 µM of MS significantly attenuated several proinflammatory mediators, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression as well as nitric oxide (NO) and prostaglandin E(2) (PGE(2)) formation caused by OVA stimulation. Further, 5 and 25 µM of MS significantly reduced the generation of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) at both the protein and mRNA levels. MS (5 and 25 µM) decreased OVA-induced phosphorylation of mitogen-activated protein kinase (MAPK) c-Jun NH(2)-terminal kinase (JNK), but not that of extracellular signal-regulated kinase (ERK) or p38 kinase. We used the peroxisome proliferator activated receptor-γ (PPAR-γ) antagonist GW9662 to show that MS inhibit JNK phosphorylation through increased expression of PPAR-γ. Thus, the metabolites from Monascus fermentation may serve as a dietary source of anti-inflammatory agents.

The Monascus metabolite monascin against TNF-α-induced insulin resistance via suppressing PPAR-γ phosphorylation in C2C12 myotubes.

Chronic inflammation in muscle tissue causes insulin resistance and type-2 diabetes. Peroxisome proliferator-activated receptor (PPAR) ligands are reported to activate the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, including pioglitazone, which belong to the thiazolidinedione (TZD). Monascin (MS), a Monascus metabolite, has been reported to exert anti-inflammatory activity in our recent study. Therefore, the alleviating mechanism of MS on tumor necrosis factor-α (TNF-α; 20ng/mL) induced insulin resistance in C2C12 cells was investigated in this study. Results showed that MS increased the uptake of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) in C2C12 myotubes. This result was associated with both PPAR-γ activity and PI3K/Akt pathway caused by MS inhibited p-JNK activity and prevented PPAR-γ phosphorylation. Moreover, we found that MS may act a PPAR-γ agonist to improve insulin sensitivity, and this issue was further confirmed by PPAR-γ antagonist (GW9662). Briefly, MS as pioglitazone, stabilized PPAR-γ structure and diminished PPAR-γ phosphorylation thereby improving insulin resistance.