Search

In this study we investigated the inhibitory effects and possible mechanisms of action of 8'-hydroxydaidzein and 3'-hydroxydaidzein, two ortho-dihydroxyisoflavone derivatives from Korean fermented soybean paste, on melanogenesis in B16 murine melanoma cells. The two hydroxydaidzeins reduced melanin synthesis comparably to treatment with kojic acid, a proven whitening agent, in B16 melanoma cells. Furthermore, when in vitro human skin equivalents were treated with the hydroxydaidzeins, the levels of melanogenesis were significantly reduced relative to a kojic acid control. The RT-PCR results demonstrated that depigmentation was due to transcriptional repression of several melanogenesis genes, including microphthalmia-associated transcription factor (MITF), by the hydroxydaidzeins. The immunoblotting results confirmed that diminution of MITF expression subsequently decreased expression of tyrosinase, and tyrosinase-related proteins 1 and 2. Cumulatively, these results suggest that hydroxydaidzeins would be potent attenuators of melanin synthesis as well as effective inhibitors of hyperpigmentation in human skin. Copyright © 2011 John Wiley & Sons, Ltd.

This hydrolytic instability mightbe a crucial drawback of thus designed derivatives in theextreme pH conditions which are often required for theapplications as transport carriers for ionic guests. In thispaper, we would like to report the synthesis and Hg(II)-selective ionophoric properties of the amidine derivative 3,which is designed to enhance the hydrolytic stability and thepreorganization of the ionophore, by means of the competi-tive transport experiments.The amidine derivative was prepared by the condensationof vicinal diaminocatechol derivative with Kemp’s triacid.The 4,5-dinitrocatechol was reacted with 1-bromooctane(Cs

The reaction of hydrophilic amino alcohols with acid chlorides in the presence of magnesium oxide in aqueous organic solution (THF/H2O=4:1) cleanly provided alkanolamides.

Kojic acid, 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4one, is produced from carbohydrate sources in an aerobic process by a variety of microorganisms. It showed broad biological activities such as inhibition of tyrosinase, scavenging of the free radicals, chelating activity of metal ions and prevention of photodamage. Its various activities are due to γ-pyranone structure having enolic hydroxyl group. Recently, enolic hydroxyl group of kojic acid has been focused as an alternative of carboxylic acid in retinoid structure. We synthesized 3,4-methylenedioxy cinnamic acid ester of kojic acid as a new retinoidal compound. In this study, we evaluated biological activities of new kojic acid derivative 1, 2-((3E)-4(2H,3H-benzo[3,4-d]1,3-dioxolan-5yl)-2-oxo-but-3-enyloxy)-5-hydroxy-4H-pyran-4-one.