A New β-Carboline Alkaloid From the Aerial Part of Hedyotis capitellata

A new β-carboline alkaloid, 10-hydroxy-capitelline (1) together with three known anthraquinones, hedanthroside B (2), hedanthroside C (3), and rubiadin (4) were isolated from the aerial part methanol extract of Hedyotis capitellata. Their structures were established by spectroscopic data (one-dimensional, two-dimensional nuclear magnetic resonance (1D, 2D-NMR) and high-resolution-electrospray ionization-mass spectrometry, HR-ESI-MS) and comparison with those reported in the literature. The anti-inflammatory activity of the isolated compounds is evaluated by their inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. At a concentration of 20 µM, compounds 1 to 4 showed weak inhibitory effects on NO production with inhibitory values ranging from 1.2% to 23.9% compared to a value of 74.5% for the positive control compound, NG-monomethyl-L-arginine (L-NMMA).