[Bioassay-guided fractionation of constituents targeting mediators of inflammation from lycii cortex as inhibitors of NF-kappaB].

Lycii Cortex, a popular herb medicine in traditional Chinese medicine, is used to treat different inflammation-related diseases. The aim of our work is to find the key constituents inhibiting NF-kappaB, a key regulator of inflammation. In the investigations of cell-based in vitro assays of extracts, we found that both ethyl acetate extract and methanol extract of Lycii Cortex inhibited the TNF-alpha-induced activation of NF-kappaB. Through bioassay-guided fractionation, we identified 4 phenolic amides including trans-N-(p-coumaroyl) tyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), and dihydro-N-caffeoyltyramine (4). Four phenolic amides showed differently inhibitory activities on TNF-alpha-induced NF-kappaB activation. Trans-N-caffeoyltyramine (3) was identified as the key component with an IC50 of 18.41 micromol x L(-1). It was suggested that the hydroxyl group at C-3 in trans-N-caffeoyltyramine might be a key binding site and its C-7,8-double bond might play an important role on NF-kappaB inhibitory activities as the link of the conjugation of pi electrons leading to a partial planar conformation. It might be inferred that the biological activity of compound 3 is attributed to the structure of Michael reaction acceptor containing alpha, beta-unsaturated ketones and benzene along with hydroxyl group in o-diphenol.

[Effect of Jiangang Yishen Recipe on high insulin induced cell proliferation of human glomerular mesangial cells and the expression of insulin receptor substrate 1 and phosphatidylinositol-3-kinase].

OBJECTIVE: To investigate the effect of Jiangtang Yishen Recipe (JTYSR) on high insulin induced cell proliferation of human glomerular mesangial cells (HMCs) and the expression of insulin receptor substrate 1 (IRS-1) and phosphatidylinositol-3-kinase (PI-3K). METHODS: HMCs were divided into 4 groups, i.e., the negative control group, the high insulin model group, the JTYSR group, and the LY294002 group. The concentration of insulin, JTYSR, and LY294002 was respectively confirmed by pre-experiment. Different culture solution was respectively added for different groups. RPMI1640 culture solution was added for HMCs in the negative control group, while HMCs in the rest 3 groups were cultured by 100 nmol/L insulin for 24 h. Meanwhile, HMCs from the JTYSR group and the LY294002 group were exposed to 125 mg/L JTYSR and 80 micromol/L LY294002 respectively for further 48 h. The proliferation of HMCs was detected by MTT and flow cytometry. The protein expression of IRS-1 and PI-3K in HMC was detected by immunohistochemical assay and Western blot. Results The proliferation of HMCs induced by high insulin could be significantly lowered, and the protein expression of IRS-1 and PI-3K could be down-regulated in the JTYSR group and the LY294002 group (P <0.01). Compared with the LY294002 group, the protein expression of IRS-1 and PI-3K could be slightly down-regulated in the JTYSR group (P <0.05). CONCLUSION: JTYSR could lower high insulin induced proliferation of HMCs, and its mechanism might be related to insulin signaling pathway.