Melanocortin 4 receptors interact with antimicrobial frog peptide analogues.

We have developed fluorescence polarization (FP) assays of human melanocortin 4 receptor (MC4R) in 384-well microtiter plates using TAMRA-NDP-MSH as a tracer. The rank order of potency of agonists and antagonists agrees well relative to the published assays: SHU9119>MTII>NDP alphaMSH>alphaMSH. We have screened libraries of Korean plant extracts and frog peptide analogues in search of MC4R ligands using FP assays and cell-based CRE luciferase reporter assays.

The high throughput screening of neuropeptide FF2 receptor ligands from Korean herbal plant extracts.

We have screened 356 libraries of Korean herbal plant extracts to find potential anti-obesity drugs. We employed the recently developed fluorescence polarization high throughput screening (FP HTS) assays of human neuropeptide FF (NPFF) receptors in 384-well microtiter plates. The primary hits were cherry-picked from the libraries and further analyzed by secondary displacement curve assays, in vitro GTPgammaS binding assays and cell-based CRE luciferase reporter assays.

Cytotoxic dammarane glycosides from processed ginseng.

Steaming ginseng at high temperature increased its cytotoxicity to SK-Hep-1 hepatoma cancer cells. HPLC separation and fractionation followed by MTT assay revealed that ginsenosides Rg3, Rg5, Rk1, Rs5, and Rs4 are the active principles. Their 50% growth inhibition concentration (GI50) values were 41, 11, 13, 37, and 13 microM, respectively.

Mushroom tyrosinase inhibition activity of some chromones.

Currently, aloesin is used in the cosmetic industry as a whitening agent because it inhibits tyrosinase activity. Aloesin is a C-glycosylated chromone compound isolated from aloe, and it is difficult to synthesize because of C-glycosyl moiety in the molecule. The purpose of this study is to search for a new chromone compound which is easy to synthesize and which posesses stronger tyrosinase inhibitory activity than aloesin.