Ferruginoside D: A Novel Phenylethanoid from Verbascum leiocarpum

A novel phenylethanoid, ferruginoside D, together with fourteen known compounds were isolated from the Verbascum leiocarpum for the first time. Chemical structures of isolated compounds were determined by spectroscopic analysis including HR-ESI-MS and NMR spectra. The antioxidant, α-glucosidase inhibitory properties, and antiproliferative activities against multiple cell lines (A172, C6, HeLa, A2780, SW620, HT29, Beas2B, RPE, and HSF) of the isolated compounds were evaluated in vitro. According to the results, iridoids, flavonoids (luteolin and apigenin), and phenylethanoids (poliumoside and isoverbascoside) with strong antiproliferative potential were also found to have cytostatic effects. Furthermore, the investigation revealed that compounds luteolin, poliumoside, verbascoside, isoverbascoside, ferruginoside C, ferruginoside D, and ursolic acid show potent alpha-glucosidase inhibitory activity, while compounds luteolin, verbascoside, and isoverbascoside exhibit substantial antioxidant activity. The new compound (ferruginoside D) was found moderately active against cancer cell lines, with strong alpha-glucosidase inhibitory activity, and moderate antioxidant properties.