Isolation and identification of alectrol as (+)-orobanchyl acetate, a germination stimulant for root parasitic plants

Alectrol, a germination stimulant for root parasitic plants, was purified from root exudates of red clover (Trifolium pratense L.) and identified as a novel strigolactone, (+)-orobanchyl acetate, by 1D and 2D NMR spectroscopy and ESI- and EI-MS spectrometry. Orobanchyl acetate afforded an [M-42]+ ion in EI-MS and thus had been recognized as an isomer of strigol.