Molecular Targets and Mechanisms of 6,7-Dihydroxy-2,4-dimethoxyphenanthrene from Chinese Yam Modulating NF-κB/COX-2 Signaling Pathway: The Application of Molecular Docking and Gene Silencing

The lipase inhibitory effect of mulberry leaf phenolic glycosides: The structure-activity relationship and mechanism of action

The present study found for the first time that phenolic glycosides were an important material basis for mulberry leaves to inhibit lipase. The corresponding IC50 for hyperoside, rutin, astragalin and quercetin were 68, 252, 385 and 815 μg/mL respectively. The inhibitory effect was ranked as monoglycosides > phenolic hydroxyl groups > disaccharides on the benzone ring. Hyperoside bound to lipase in competitive inhibition type with one binding site, while the others bound to lipase in a mixed inhibition type by two similar sites. All four compounds altered the microenvironment and secondary conformation of lipase through static quenching. The docking score, stability, and binding energy were consistent with the compound inhibitory activity. The main binding between compounds and lipase amino acid residues were spontaneously though hydrophobic interactions and hydrogen bonding. The strong hydrogen bonds formed with SER-152 inside the lipase pocket, might be important for the strong inhibitory activity of hyperoside.

Targeted and non-targeted metabolic characteristics of 6,7-dihydroxy-2,4- dimethoxyphenanthrene during simulated gastrointestinal digestion

6,7-dihydroxy-2,4-dimethoxyphenanthrene (PC4), isolated and identified from Chinese yam, was one of the important characteristic active ingredients. The present study established simulated gastrointestinal digestion and caco-2 intestinal epithelial models to investigate the digestive and metabolic characteristics of PC4. The results indicated that PC4 was mainly digested and metabolized in the intestine, with a digestion rate of 94 %, producing active characteristic metabolites including 2,6-dimethoxy-4-phenanthrenol (MC1) and 1-methoxyphenanthrene (MC2). Molecular docking indicated that the COX-2 enzyme inhibitory activity of MC1 might be superior to that of the prototype PC4. During 24 h co-incubation of PC4 with caco-2 monolayer epithelial, the signal pathway related to lipid decomposition was up-regulated within 0-12 h, while the diabetes complications AGE-RAGE was inhibited just in 0-6 h period significantly. The research database provided scientific basis for the digestion and metabolism of PC4, and laid theoretical foundation for the scientific development of Chinese yam functional foods.

Bisdemethoxycurcumin, a curcumin derivative, ameliorates adjuvant-induced arthritis by suppressing inflammatory reactions and macrophage migration

Rheumatoid arthritis (RA) is a highly prevalent and chronic inflammatory synovial joint disease manifested by hyperplasia and continuous inflammation. Curcumin (Cur) has been studied for alleviating RA. However, poor stability and oral bioavailability restrict its therapeutic value. Bisdemethoxycurcumin (BDMC), a curcumin (Cur) derivative, exerts better stability and oral bioavailability than Cur. However, the efficacy of BDMC on RA has not been fully clarified. The aim of the study was to investigate the therapeutic effects and underlying mechanisms of BDMC on RA. The in-vivo anti-arthritic activity of BDMC was determined via adjuvant-induced arthritis (AIA) rat model. Paw swelling, body weight, arthritic index, and histopathological assessments were performed. RAW264.7 cell was stimulated by lipopolysaccharides (LPS) in vitro. The cell viability were determined by CCK8 assay, while the migration ability was determined using cell wound healing and transwell assays. Furthermore, in-vivo and in-vitro levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) were assayed by ELISA, and that of IκBα, p-NF-κB, NF-κB, and COX-2 were assessed via Western blot or immunofluorescence. In AIA rat model, it suggested a higher anti-arthritic activity of BDMC than Cur, including amelioration of swelling in hind paws, reduced arthritic index, and alleviated histopathological injury in rats. Furthermore, BDMC also substantially decreased the levels of the aforementioned pro-inflammatory cytokines in both in-vivo and in-vitro, inhibited the IκBα degradation, down-regulated the COX-2 levels and p-NF-κB/NF-κB ratio in AIA rats and LPS-stimulated RAW264.7 cells. Additionally, BDMC showed an inhibitory effect on the migration of LPS-stimulated RAW264.7 cells. BDMC could effectively ameliorate RA by suppressing inflammatory reactions and inhibiting macrophage migration, more potentially than Cur.