Four New Bisabolane-Type Sesquiterpenoids From Sanguisorba officinalis

Sanguisorba officinalis L. (Di-Yu in Chinese) is a traditional herbal plant that belongs to the genus Sanguisorba (Rosaceae). Four new bisabolane-type sesquiterpenoids (1-4) and two known monoterpenoids (5 and 6) were isolated from the roots of S. officinalis. Their structures were identified by nuclear magnetic resonance (NMR) spectra, high-resolution electrospray ionization mass spectroscopy (HRESIMS), density functional theory (DFT) NMR calculations, and electronic circular dichroism (ECD) spectroscopic analysis. All compounds were isolated from the Rosaceae family for the first time. In addition, all the isolated compounds were evaluated for their anti-melanogenic effects in vitro on IBMX-stimulated B16F10 melanoma cells. The result showed that compounds 1, 2, and 5 possessed moderately anti-melanogenic effects at a concentration of 50 µM, respectively.