Triterpenoids from the fruits of Cornus kousa burg. As human acylcoa: Cholesterol acyltransferase inhibitors

The fruits of Cornus kousa Burg. were extracted with 80% aqueous methanol (MeOH) and the concentrated extract was partitioned with ethyl acetate (EtOAc), n-butanol (n-BuOH), and H 2 O. From the EtOAc fraction, 5 triterpenoids were isolated through repeated silica gel (SiO₂), octadecyl silica gel (ODS), and Sephadex LH-20 column chromatography (c.c.). These compounds were determined to be ursolic acid (1), corosolic acid (2), taraxasterol (3), betulinic acid (4), and betulinic aldehyde (5) on the basis of their spectroscopic data including electronic ionization mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. This is the first reported isolation of these compounds from this plant. Also, compounds 1, 3, 4, and 5 show a relatively high inhibitory activity against human acyl-CoA: cholesterol acyltransferase-1 (hACAT-1) with inhibition values of 52.8±0.7, 91.1±0.4, 93.0±0.7, and 96.2±0.2% at a concentration of 100 μM, respectively.