title: Melanin-concentrating hormone-1 receptor binding activity of pheophorbides isolated from Morus alba leaves.
abstract: The time-resolved fluorescence technique based on melanin-concentrating hormone (MCH) receptor subtype-1 (MCH-1 receptor) binding assay was adopted to carry out a bioassay-guided fractionation of the methanol extract of Morus alba leaves. This fractionation and purification led to the isolation of two compounds identified as pheophorbide a methyl ester and 13(2)(S)-hydroxypheophorbide a methyl ester. These active pheophorbides exhibited potent inhibitory activity in binding of europium-labeled MCH to the human recombinant MCH-1 receptor (IC(50) value; 4.03 and 0.33 microM, respectively). Besides binding activity, the pheophorbides inhibited MCH-mediated extracellular signal-regulated kinase (ERK) phosphorylation in Chinese hamster ovary cells expressing human MCH-1 receptor. These results suggest that pheophorbide a methyl ester and 13(2)(S)-hydroxypheophorbide a methyl ester act as modulators of MCH-1 receptor and MCH-mediated ERK signaling.
authors.affiliation: Bio-Organic Science Division, Korea Research Institute of Chemical Technology, Yuseong, Daejeon, Republic of Korea.
authors.forename: Byung Koo
authors.initials: BK
authors.lastname: Oh
authors.forename: Kwang-Seok
authors.initials: KS
authors.lastname: Oh
authors.forename: Kwang-il
authors.initials: KI
authors.lastname: Kwon
authors.forename: Shi Yong
authors.initials: SY
authors.lastname: Ryu
authors.forename: Young Sup
authors.initials: YS
authors.lastname: Kim
authors.forename: Byung Ho
authors.initials: BH
authors.lastname: Lee
mesh_terms: D000818:Animals; D016466:CHO Cells; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D015394:Molecular Structure; D031625:Morus / Q000737:chemistry*; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D010936:Plant Extracts; D011979:Receptors, Pituitary Hormone; D011994:Recombinant Proteins; C092274:melanin-concentrating hormone receptor; D002734:Chlorophyll; D048049:Extracellular Signal-Regulated MAP Kinases; C032623:pheophorbide a