Structural elucidation and bioactivity of novel secondary metabolites from Carex distachya

Four new carexanes and a new seco-derivative metabolite have been isolated and characterized from the herbaceous plant Carex distachya Desf. All of the structures have been elucidated on the basis of spectroscopic data. These compounds derive from the cyclization of prenylate stylbenoid precursors. The seco-carexane is formed by a further oxidative cleavage of the C-7-C-8 bond. The absolute configurations have been determined by Mosher's method using appropriate chemical correlations. All of the carexanes A-H have been tested for their phytotoxicity against Lactuca sativa. The bioassays showed an inhibitory effect on seed germination for all compounds described in this report.

Graphical Abstract