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Updated: Jun 17, 2026

Quantification of Hypopigmentation Activity In Vitro
Published on: March 6, 2019
Melanin-concentrating hormone-1 receptor binding activity of pheophorbides isolated from Morus alba leaves
Byung Koo Oh1, Kwang-Seok Oh, Kwang-il Kwon
1Bio-Organic Science Division, Korea Research Institute of Chemical Technology, Yuseong, Daejeon, Republic of Korea.
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.
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