Labdane diterpenoids from Salvia reuterana

Three labdane diterpenoids, 14 alpha-hydroxy-15-chlorosclareol (1), 14 alpha-hydroxy-15-acetoxysclareol (2), and 6 beta-hydroxy-14 alpha-epoxysclareol (3), together with the known diterpenoids sclareol (4), 6 beta-hydroxysclareol (5), and 14 alpha-epoxysclareol (6), as well as other common plant constituents were isolated from the n-hexane extract of aerial parts of Salvia reuterana. The structures of the new compounds were established by extensive 1D and 2D NMR spectroscopic techniques. Compound 1 is the first example of a halogenated terpenoid in the genus Salvia. Compounds 1-6 were also tested for their inhibitory activity toward HeLa and MCF-7 cell lines. Preliminary structure-activity relationship studies indicated that double bond moiety in sclareol is an essential feature for activity and modification of this moiety significantly decreased the cytotoxic activity of the resulting compounds. (c) 2014 Elsevier Ltd. All rights reserved.