Triterpenoic acids of Prunella vulgaris var. lilacina and their cytotoxic activities in vitro

The column chromatographic separation of the MeOH extract from the aerial parts of Prunella vulgaris var. lilacina Nakai led to the isolation of fifteen triterpenoic acids (2-6, 9-13, 16-20), four flavonoids (14, 21-23), four phenolics (7, 8, 15, 24), and a diterpene (1). Their structures were determined by spectroscopic methods to be trans-phytol (1), oleanic acid (2) ursolic acid (3), 2α,3α,19α-trihydroxyurs-12en-28oic acid (4), 2α,3α-dihydroxyurs-12en-28oic acid (5), maslinic acid (6), caffeic acid (7), phydroxy cinnamic acid (8), 2α,3α,19α,23- tetrahydroxyurs-12en-28oic acid (9), 2α,3α,23-trihydroxyurs-12en- 28oic acid (10), 2α,3β-dihydroxyurs-12en-28oic acid (11), 2α,3β,24-trihydroxyolea-12en-28oic acid (12), (12R, 13S)-2α,3α,24,trihydroxy-12,13-cyclo-taraxer-14-en-28oic acid (13), quercertin 3-O-β-D-glucopyranoside (14), rosmarinic acid (15), 2α,3α,24-trihydroxyurs-12,20(30)-dien-28oic acid (16), 2α,3α,24-trihydroxyolea-12en-28oic acid (17), 2α,3β, 19α,24-tetrahydroxyurs-12en-28oic acid 28-O-Dglucopyranoside (18), 2α,3α,19α,24-tetrahydroxyurs-12en-28oic acid 28-O-D-glucopyranoside (19), prunvuloside A (20), kaempferol 3-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopranoside (21), kaempferol 3-O-β-D-glucopyranoside (22), quercertin 3-O-α-L- rhamnopyranosyl(1→6)-β-D-glucopyranoside (23), and 2-hydroxy-3-(3′,4′-dihydroxyphenly)propanoic acid (24). Compounds 1, 8-12, 17, 21, 23, and 24 were isolated from this plant source for the first time. The isolated compounds were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT15 cells in vitro using the sulforhodamin B bioassay (SRB) method. Compound 3 exhibited moderate cytotoxic activity against A549, SK-OV-3, SK-MEL-2, and HCT15 cells, with ED₅₀ values of 3.71, 3.65, 13.62, and 5.44 μM, respectively.