New ent-kaurane diterpenoid dimer from Pulicaria inuloides

A new naturally occurring ent-kaurane diterpenoid dimer, 15, 15-oxybis (ent-kaur-16-en-19-oic acid) (1) along with six known compounds, 15-hydroxy-ent-kaur-16-en-19-oic acid (2), 15-hydroxy-ent-kaur-16-en-19-oate--d-glucopyranoside (3), 6-hydroxykaempferol-3, 7-dimethyl ether (4), quercetagetin 3, 7, 3-trimethyl ether (5), -sitosterol (6) and -sitosterol glucoside (daucosterol) (7) were isolated from the aerial parts of Pulicaria inuloides DC. Compounds 2-5 were isolated for the first time from genus Pulicaria. The structures of compounds 1-7 were established on the basis of extensive 1D and 2D NMR spectroscopic techniques in combination with ESI-MS. The antimicrobial activity of the isolated compounds was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. Sulphorhodamine B cytotoxic assay against HepG2 (liver cancer) cell line and ABTS antioxidant assay were carried out. [GRAPHICS] .