Hee-Jong Lim

Synthesis and evaluation of 4-hydroxyphenylacetic acid amides and 4-hydroxycinnamamides as antioxidants.

4-Hydroxyphenylacetic acid amides and 4-hydroxycinnamamides were synthesized and their antioxidant and neuroprotective activities were evaluated. Among the prepared compounds, 8b, and exhibited potent inhibition of lipid peroxidation in rat brain homogenates, and marked DPPH radical scavenging activities. Furthermore, and exhibited neuroprotective action against the oxidative damage induced by the exposure of primary cultured rat cortical cells to H(2)O(2), xanthine/xanthine oxidase, or Fe(2+)/ascorbic acid. Based on these results, we found that was the most potent antioxidant among the compounds tested.

Suppression of NFAT5-mediated Inflammation and Chronic Arthritis by Novel κB-binding Inhibitors

Nuclear factor of activated T cells 5 (NFAT5) has been implicated in the pathogenesis of various human diseases, including cancer and arthritis. However, therapeutic agents inhibiting NFAT5 activity are currently unavailable. To discover NFAT5 inhibitors, a library of > 40,000 chemicals was screened for the suppression of nitric oxide, a direct target regulated by NFAT5 activity, through high-throughput screening. We validated the anti-NFAT5 activity of 198 primary hit compounds using an NFAT5-dependent reporter assay and identified the novel NFAT5 suppressor KRN2, 13-(2-fluoro)-benzylberberine, and its derivative KRN5. KRN2 inhibited NFAT5 upregulation in macrophages stimulated with lipopolysaccharide and repressed the formation of NF-κB p65-DNA complexes in the NFAT5 promoter region. Interestingly, KRN2 selectively suppressed the expression of pro-inflammatory genes, including Nos2 and Il6, without hampering high-salt-induced NFAT5 and its target gene expressions. Moreover, KRN2 and KRN5, the latter of which exhibits high oral bioavailability and metabolic stability, ameliorated experimentally induced arthritis in mice without serious adverse effects, decreasing pro-inflammatory cytokine production. Particularly, orally administered KRN5 was stronger in suppressing arthritis than methotrexate, a commonly used anti-rheumatic drug, displaying better potency and safety than its original compound, berberine. Therefore, KRN2 and KRN5 can be potential therapeutic agents in the treatment of chronic arthritis.

Synthesis of (3S,4S)-4-aminopyrrolidine-3-ol derivatives and biological evaluation for their BACE1 inhibitory activities

Synthesis, SAR study and BACE1 inhibitory activity of (3S,4S)-4-aminopyrrolidine-3-ol derivatives (2) were described. The compound 7c exhibited more inhibition activity than 11a (IC50: 0.05μM vs 0.12μM, respectively), but the latter was more effective in cell-based assay (IC50: 1.7μM vs 40% inhibition by 7c @ 10μM) due to the relatively higher cell permeability. Most of the compounds showed high selectivity over BACE2 and cathepsin D. This work will provide useful information for further structural modifications to develop potent BACE1 inhibitors in cell.

DPT-Mediated Synthesis of 2-Aminoimidazolidin-4-ones from Thioureas Tethered to Amides

Abstract 2-Aminoimidazolidin-4-ones have been synthesized by using di-2-pyridyl thiocarbonate (DPT), taking the thioureas tethered to amides as the starting materials. Both the primary amides and secondary amides have been subjected to this cyclization method and in general this simple and convenient method was found to ensure good to excellent yields (81–99%). GRAPHICAL ABSTRACT