Occurrence of Benzoic Acid Esters as Putative Catabolites of Prunasin in Senescent Leaves of Prunus laurocerasus

Sendker J, Ellendorff T, Hölzenbein A

Abstract

ABSTRACT:Prunus laurocerasusis an evergreen shrubcontaining large quantities of the cyanogenic glycosideprunasin (1) in its leaves, which decomposes to prunasinamide (2) or glucose-1-benzoate (4) when the leaves becomechlorotic as a result of senescence or pseudosenescence. Thisstudy was aimed at the systematic identification of senescence-associated metabolites to contribute further insight into thecatabolism of1. LC-ESIMS profiles of senescent and greenleaves were analyzed by principal component analysis. Insenescent leaves, the concentrations of 36 compounds wereincreased significantly including several benzoic acid deriva-tives, of which prunasin amide-6′-benzoate (5) and prunasinacid-6′-benzoate (6) were isolated and identified. The observed metabolic changes were also induced by treatment ofP.laurocerasusshrubs with exogenous ethylene. The data presented support an oxidative catabolism of1without release ofhydrogen cyanide and the remobilization of its nitrogen in the course of senescence. The results are discussed in the context offunctional diversification and drug discovery, where senescent plant material represents a widely unexplored source for thediscovery of natural products.