Lignan Glycosides and Flavonoid Glycosides from the Aerial Portion of Lespedeza cuneata and Their Biological Evaluations

Abstract

<i>Lespedeza cuneata</i> (Fabaceae), known as Chinese bushclover, has been used in traditional medicines for the treatment of diseases including diabetes, hematuria, and insomnia. As part of a continuing search for bioactive constituents from Korean medicinal plant sources, phytochemical analysis of the aerial portion of <i>L. cuneata</i> led to the isolation of two new lignan glycosides (<b>1</b>,<b>2</b>) along with three known lignan glycosides (<b>3</b>⁻<b>7</b>) and nine known flavonoid glycosides (<b>8</b>⁻<b>14</b>). Numerous analysis techniques, including 1D and 2D NMR spectroscopy, CD spectroscopy, HR-MS, and chemical reactions, were utilized for structural elucidation of the new compounds (<b>1</b>,<b>2</b>). The isolated compounds were evaluated for their applicability in medicinal use using cell-based assays. Compounds <b>1</b> and <b>4</b>⁻<b>6</b> exhibited weak cytotoxicity against four human breast cancer cell lines (Bt549, MCF7, MDA-MB-231, and HCC70) (IC₅₀ < 30.0 μM). However, none of the isolated compounds showed significant antiviral activity against PR8, HRV1B, or CVB3. In addition, compound <b>10</b> produced fewer lipid droplets in Oil Red O staining of mouse mesenchymal stem cells compared to the untreated negative control without altering the amount of alkaline phosphatase staining.