Very-long-chain 3-hydroxy fatty acids, 3-hydroxy fatty acid methyl esters and 2-alkanols from cuticular waxes of Aloe arborescens leaves

Identification of In-Chain-Functionalized Compounds and Methyl-Branched Alkanes in Cuticular Waxes of Triticum aestivum cv. Bethlehem

“…All six compounds in A yielded TMS derivatives with common diagnostic MS fragment m/z 73 [(CH 3 ) 3 Si] + , homolog-dependent M-15 and M-90 ions, due to loss of methyl radical and (CH 3 ) 3 SiOH, respectively, and no m/z 147 [(CH 3 ) 2 SiOSi(CH 3 ) 3 ] + (Fig 1A), together confirming the secondary alcohol structure [15,19,42]. Each homolog, in its TMS derivative mass spectrum, also displayed a pair of α-fragments, with one ion m/z 257 common to all homologs indicative of a hydroxyl group on C-12, and a second fragment varying with chain length ( m/z 397 for the C 33 homolog in Fig 1A).…”

“…In many plant species, wax secondary alcohols were identified with hydroxyl groups exclusively on even-numbered carbon atoms, such as 10-nonacosanol on Malus domestica fruit [51], 10-heptacosanol, 10-nonacosanol and 12-nonacosanol on Osmunda regalis fronds [52], or C 23 -C 33 2-alkanols from Aloe arborescens leaves [19]. It has been proposed that such secondary alcohols, with functional groups on every other rather than adjacent carbons, may be derived from β-hydroxyacyl-CoA intermediates of fatty acid elongation instead of P450 hydroxylation [17,19]. …”

“…Among these new structures, many have multiple functional groups, combining chain-end and in-chain functionalities (primary and secondary functional groups, respectively). Thus, they include diols [12–15], hydroxyaldehydes [16,17], ketols [14], ketoaldehydes [18], hydroxyacids [19], hydroxyesters [19,20] and ketoesters [18]. In many cases, the nature of the functional groups, their relative positions and the chain length profiles within respective homologous series could be used to infer the biosynthetic origin of functional groups or entire molecules.…”

Smart water channelling through dual wettability by leaves of the bamboo Phyllostachys aurea

“…Since such metamers could not be chromatographically resolved and thus quantified by GC-FID, their distributions were determined instead based on abundances of characteristic fragments in the mixed mass spectrum associated with the GC peak of each ester homolog. 23,31,32,33,34,35 Three different patterns of isomer distributions could be discerned depending on overall ester homolog chain length, Figure 5. In young Phyllostachys aurea leaves, the shorter ester homologs (C36-C42) were formed primarily by C20 alcohol and C16-C22 acids, the mid-range esters (C42-C44) included a large portion of isomers formed by C26-C28 alcohols and C16 acid, while the longer esters (C44-C52) contained mainly C22-C30 alcohols and C22 acid.…”

Identification of Polyketides in the Cuticular Waxes of Triticum aestivum cv. Bethlehem

“…Such primary/secondary bifunctional compounds were reported, for example, as alkanediols, ketoaldehydes, ketoalcohols and ketoalkyl esters in the wax of Osmunda regalis fronds [20], or δ-lactones in leaf wax of Cerinthe minor [21]. 1,3-Alkanediols and 3-hydroxyaldehydes were detected in leaf wax of Ricinus communis [22], further alkanediols in Pisum sativum leaves [23], 1,5-alkanediols and 5-hydroxyaldehydes in Taxus baccata needles [16], 1,3-and 1,2-alkanediol acetates in Cosmos bipinnatus petals [24], 3-hydroxyacid derivatives in Aloe arborescens [25], and 3-hydroxyacid and alkanediol esters in Funaria hygrometrica [26].…”