Triterpenoids from the fruits and leaves of the blackberry (Rubus allegheniensis) and their inhibitory activities on foam cell formation in human monocyte-derived macrophage

From the methanol extract of the fruits of the blackberry (Rubus allegheniensis Port.), four triterpenoids - pomolic acid (1), tormentic acid (2), euscaphic acid (3) and 1β-hydroxyeuscaphic acid (4) - were isolated, while six triterpenoids - 2, 3, myrianthic acid (5), ziyu glycoside II (6), sericic acid (7) and 19-hydroxy-2,3-secours-12-ene-2,3,28-trioic acid 3-methyl ester (8) - were obtained from the methanol extract of the leaves of this plant. Their structures were determined on the basis of spectral data. Compounds 1-8 were examined for their inhibitory activities on foam cell formation in human monocyte-derived macrophages induced by acetylated low-density lipoproteins at a 50 μM concentration. Among the tested compounds, 1 showed the strongest activity, with the inhibitory effect being 90%. The inhibitory activities of 2-8 were evaluated to be 30%, 32%, 33%, 4%, 48%, 4% and 24%, respectively. Further, the structure-activity relationship of these compounds was investigated.

Rubus allegheniensis; blackberry; foam cell; macrophage; triterpenoid.