Melanin Synthesis Inhibitors from Lespedeza floribunda

Abstract

In the course of our search for new melanin synthesis inhibitors from plants, 40 new flavonoids and 11 known flavonoids were isolated from the roots of Lespedeza floribunda Bunge. The structures of the new compounds were determined by MS and NMR analyses, and the absolute configurations by CD spectra. Many of the compounds inhibited melanin synthesis in normal human epidermal melanocytes (NHEM), and compounds 3, 7, 8, 11, 16, 24, 27, 29, 33, 43, 45, and 51 were particularly inhibitory. Their activities were stronger than that of hydroquinone, which is known as a major skin-lightening drug.

Hypoglycemic Activity and the Potential Mechanism of the Flavonoid Rich Extract from Sophora tonkinensis Gagnep. in KK-Ay Mice

“…et al, 2014), ononin ( 3 ; Yang X.Z. et al, 2014), trifolirhizin 6′-monoacetate ( 4 ; Yang et al, 2014), quercetin ( 5 ; Yi et al, 2002), lespeflorin B4 ( 7 ; Mori-Hongo et al, 2009), dehydrolupinifolinol ( 8 ; Sutthivaiyakit et al, 2009), glabrol ( 9 ; Cho et al, 2012), euchrenone a2 ( 11 ; Mizuno et al, 1988), 6,8-diprenylkaempferol ( 12 ; Meragelman et al, 2001), and sophoranochromene ( 13 ; Li et al, 2008) by comparison with their mass spectrum (MS), UV, and NMR spectra with published reference data. Spectroscopic data of compounds 1–13 could be found in S2 in Supplementary Material.…”

A Novel 3-Arylcoumarin and Three New 2-Arylbenzofurans from Mucuna birdwoodiana

“…3) also supported the structure of 4. Thus, it was characterized as 2-(3,4-dihydroxy-2-methoxylphenyl)-5-methoxylbenzofuran-6-ol and named mucodianin D. Phytochemical study of this plant also resulted in the isolation of four known 2-arylbenzofurans: 6-demethylvignafuran (5), 7) eryvarin L (6), 9) isopterofuran (7), 7) and lespeflorin F 1 (8), 10) which were characterized by comparison of the respective spectral data ( 1 H-, 13 C-NMR, MS) with those found in the literatures.…”

Synthesis of Psoralidin derivatives and their anticancer activity: first synthesis of Lespeflorin I1

“…As discussed earlier, compound 2 is a natural product namely, Lespeflorine I 1 , which shows a mild melanin synthesis inhibitory property in normal human epidermal melanocytes. 13 Following a similar synthetic strategy as described earlier, we needed the phenylacetate derivatives 11 , 33 , 34 and benzoic acids 19 , 35 (Scheme 3). Synthesis of compound 33 was reported in the literature starting from 2,4,5-trimethoxybenzoic acid in six linear steps.…”

“…The compound was isolated from the roots of Lespedeza floribunda Bunge and reported to act as a mild melanin synthesis inhibitor in normal human epidermal melanocytes. 13 The activities of all the synthesized compounds were tested against two different prostate cancer cell lines to get a preliminary idea about the structure-activity relationship of the parent natural product.…”