The Melanin Synthesis inhibition and Radical Scavenging Activities of Compounds Isolated from the Aerial Part of Lespedeza cyrtobotrya

The EtOAc fraction of Lespedeza cyrtobotrya showed mushroom tyrosinase inhibitory and radical scavenging activity. Four active compounds were isolated based on LH-20 chromatography and HPLC, and the structures were elucidated on the basis of their LC-MS and NMR spectral data, as 2-(2,4-Dihydroxyphenyl)-6-hydroxybenzofuran (1), eriodictyol-7-O-glucopyranoside (2), haginin A (3), and dalbergioidin (4), respectively. 2-(2,4-Dihydroxyphenyl)-6-hydroxybenzofuran (1) showed mushroom tyrosinase inhibitory activity with an IC50 value of 5.2 micronM and acted as a competitive inhibitor. Furthermore, 37.3 micronM of compound 1 reduced 50 % of the melanin content on a human melanoma (MNT-1) cells. The radical scavenging activity of 2-(2,4-dihydroxyphenyl)-6-hydroxybenzofuran (1), eriodictyol-7-O-glucopyranoside (2), haginin A (3), and dalbergioidin (4) was shown with IC50 values of 11.0, 24.5, 9.0 and 36.5 micronM in an ABTS system and with IC50 values of 42.7, 36.0, 37.7 and 61.7 micronM in a DPPH system, respectively. The mushroom tyrosinase inhibitory activity of EtOAc fraction of Lespedeza cyrtobotrya was contributed by compound 1, 3 and 4, and radical scavenging activity of it was contributed by compound 1-4.