A ‘Low‐Level’ Chemotaxonomic Analysis of the Plant Family Apiaceae: The Case of Scandix balansaeReut. ex Boiss. (Tribe Scandiceae)

Abstract

Analyses by GC and GC/MS of an essential-oil sample obtained from dry fruits of Scandix balansae Reut. ex Boiss. allowed the identification of 81 components, comprising 91.4% of the total oil composition. Interestingly, the major identified volatile compounds were medium-chain-length n-alkanes, i.e., tridecane (6.7%), pentadecane (13.4%), and heptadecane (19.3%), and a long-chain homolog nonacosane (7.6%). A number of minor oil constituents, among them tetradecyl 3-methylbutanoate, and octadecyl 2-methylpropanoate, 3-methylbutanoate, and pentanoate, turned out to have a restricted natural occurrence not only in umbellifers but also in the Plant Kingdom, whereas the last ester is a new natural compound in general. The identity of these rare plant constituents that present excellent chemotaxonomic marker candidates for Scandix species was unambiguously confirmed by co-injection of the oil sample with appropriate standards, which were synthesized for this purpose and fully characterized ((1) H- and (13) C-NMR, IR, MS). To explore the possible applicability of the essential oils' compositional data in the taxonomy of Apiaceae, the herein studied and additional 58 oils obtained from Scandiceae taxa were compared using multivariate statistical analyses (MVA). MVA demonstrated that the evolution of the volatiles' metabolism of Scandiceae taxa was neither genera-specific nor follows their morphological evolution.

Synthesis of small libraries of natural products: New esters of long‐chain alcohols from the essential oil of Scandix pecten‐veneris L. (Apiaceae)

“…Except for tridecyl and octadecyl 2-methylpropanoates, and tetradecyl, hexadecyl and octadecyl 3-methylbutanoates, and all 2-methylbutanoates from Table 2, all other esters were for the first time found to be secondary plant metabolites. All of the synthesized esters, with the exception of tetradecyl and octadecyl 3-methylbutanoates and octadecyl 2-methylpropanoate described in a previous report, [3] were fully spectrally characterized ( 1 H-and 13 …”

“…Other relatively intense peaks (at m/z 101, 85, 57 and 43) were in general agreement with the fragmentation pattern known for pentanoates (Figure 1a). [15] The mass spectral data of the compounds belonging to another series of the oil constituents were characterized by the base peak at m/z 43 [C 3 + ] that could be connected to the presence of butanoic or 2-methylpropanoic acids in these molecules (Figure 1b).…”

“…The IR measurements (ATR-attenuated total reflectance) were carried out using a Thermo Nicolet model 6700 FTIR instrument (Waltham, USA 13 C at 100 MHz). All NMR spectra were measured at 25°C in CDCl 3 with tetramethylsilane (TMS) as the internal standard. Chemical shifts are reported in ppm (δ) and referenced to TMS.…”

“…These revealed a series of minor (up to 3.3%) constituents that were tentatively identified as long-chain esters of butanoic and pentanoic acids. Up to now the isomeric esters of butanoic and pentanoic acids of straight-chain alcohols with 6-23 carbon atoms (identity hinted by the MS fragmentation patterns in the preliminary analyses of the mentioned oils) were either new or very rare [3][4][5] in the Plant Kingdom and were more characteristic of insect or animal species. [6][7][8] There are only two previous reports concerning the composition of the essential oil of S. pecten-veneris.…”

“…ex Boiss. (Apiaceae, tribe Scandiceae) [3] provided sufficient motivation for a reinvestigation of the essential oil of a much more widespread species from this genus -Scandix pecten-veneris L. Standard GC and GC-MS analyses of several samples of the essential oils of S. pectenveneris were performed. These revealed a series of minor (up to 3.3%) constituents that were tentatively identified as long-chain esters of butanoic and pentanoic acids.…”