Diethyl-Ether Flower Washings of Dianthus cruentus Griseb. (Caryophyllaceae): Derivatization Reactions Leading to the Identification of New Wax Constituents.

ABSTRACT

Some carnation species (Dianthus spp., Caryophyllaceae) exhibit a strong resistance to drought stress that is connected with the increased surface wax formation. Wax composition is unknown for the majority of Dianthus spp. Herein, mass spectral and gas chromatographic data, in combination with synthesis and chemical transformations (transesterification and synthesis of dimethyl disulfide adducts), enabled the identification of 151 constituents of diethyl-ether washings of fresh flowers of Dianthus cruentus Griseb. from Serbia. The flower wax contained, along with the dominant ubiquitous long-chain n-alkanes, homologous series of n- and branched (iso- and anteiso-) long-chain hexyl alkanoates/alkenoates and alkyl/alkenyl benzoates. The branching position in the mentioned hexyl esters was probed by synthesis of esters of three isomeric hexanols that were spectrally characterized (1 H- and 13 C-NMR, IR, MS). The washings also contained long-chain (Z)- and (E)-alkenes (C23 -C35 ) with several different double bond regiochemistries. Fifty-five of these constituents (eight hexyl esters, two benzoates, and forty-five alkenes) were detected for the first time in Plantae, while ten of these represent completely new compounds. The rare occurrence of these wax constituents makes them possible chemotaxonomic markers of this particular Dianthus sp.