Epicuticular wax of Panicum virgatum

Leaf and stem wax of Panicum virgatum contains hydrocarbons (4%), esters (3%), free acids (2%), free alcohols (1%), triterpene alcohols (2%), β-diketones (69%) and hydroxy β-diketones (6%). Principal free alcohols range in chain length from C₂₆ to C₃₂. β-Diketones consist almost entirely of tritriacontane-12,14-dione and the hydroxy β-diketone consists only of 5(S)-5-hydroxytritriacontane-12,14-dione. The configuration of the hydroxyl group is the same as that of hydroxy β-diketones from festucoid grasses but opposite to that of the hydroxy β-diketone from Andropogon species.     

Latex extractables of Calotropis gigantea

The hexane and methanol soluble extract of the latex coagulum of Calotropis gigantea afforded two new triterpene esters, viz. 3′-methylbutanoates of α-amyrin and ψ-taraxasterol, besides the known 3′-methylbutanoates of three triterpene alcohols. The compositions of the alkane fraction, total triterpene alcohol fraction, and free, acetyl and 3′-methylbutanoyl triterpene alcohol fractions of the extract were determined.     

Epicuticular waxes of Secale cereale and Triticale hexaploide leaves

Wax on leaves of rye and of hexaploid Triticale (60–70-day-old plants) contains hydrocarbons (6–8%), esters (10%), free alcohols (14-8%), free acids (3%), hentriacontane-14,16-dione (39–45%), 25 (S)-hydroxyhentriacontane-14,16-dione (13–11%) and unidentified (14–15%). Diesters (1–3%) are also present in rye wax. Compositions of hydrocarbons (C₂₇-C₃₃) and esters (C₂₈,C₅₈) are similar for both waxes. Free and combined alcohols of rye wax are mainly hexacosanol but alcohols of Triticale wax are mainly octacosanol. The composition of Triticale wax is close to that of its wheat parent Triticum durum (cv. Stewart 63). Esters of wax from ripe rye contain 58% of trans 2,3-unsaturated esters. *NRCC No. 14033.     

Wax composition of sargassum fulvellum

Sixty-seven compounds were characterized in the wax of Sargassum fulvellum. Characteristic components were the 5-methylhexyl esters of octanoic, decanoic, lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic, and the 2-ethylhexyl esters of the same acids. The wax of S. fulvellum contains hydrocarbons (1.6%), esters (21.8%), free acids (74.9%) and free alcohols (0.3%). The principal free alcohols range in chain length only from C₆ to C₇.     

Free and ester-bound triterpene alcohols and sterols in cellular subfractions of Calendula officinalis flowers

In the chromoplast fraction and in the chromoplast-free fraction, obtained from Calendula officinalis ligulate flowers, the contents of individual free and ester-bound triterpene alcohols and sterols as well as the fatty acid components of the ester form were determined. It was shown that all sterols and triterpene monols in both forms occur in the two subtractions investigated, whereas all diols are localized only in the chromoplast fraction. The compositions of the fatty acids esterifying monols and sterols were similar to those esterifying diols in the chromoplasts. However, the fatty acids esterifying extra-chromoplast monols and sterols were different. This result indicates that triterpene monol esters are substrates for the biosynthesis of 3-monoesters of diols.     

Leaf wax of Triticum aestivum

Leaf waxes from spring wheat varieties Selkirk and Manitou contain hydrocarbons (6%, 10%), long chain esters (14%, 13%), free acids (5%, 8%), free alcohols (19%, 21%), β-diketone (16%, 20%), hydroxy β-diketones (8%, 10%), unidentified gum (29%, 16.5%) and minor amounts of diol diesters, glycerides and aldehydes. The major hydrocarbon is nonacosane and major esters are octacosyl esters of C₁₄–C₃₂ acids but C₂₀ and C₂₂ alcohol esters of trans 2-docosenoic and tetracosenoic acids are also present (Selkirk 20%, Manitou 10% of total esters). Previously unknown trans 2-docosen-1-ol is present as an ester (Selkirk 5%, Manitou 2.5% of total esters). Free acids are C₁₄–C₃₂ acids and trans 2-docosenoic and tetracosenoic acids (Selkirk 30%, Manitou 9% of free acids). Octacosanol is the principal free alcohol. Hentriacontane-14,16-dione is the β-diketone and the hydroxy β-diketones are a 1:1 mixture of 8- and 9- hydroxyhentriacontane-14,16-diones.     

Major Extractable Components in Asclepias linaria (Asclepiadaceae) and Ilex verticillata (Aquifoliaceae), Two Potential Hydrocarbon Crops

The major extractable components of two species identified as having high oil or polyphenol contents were characterized in detail.Asclepias linaria, a desert milkweed, contains 30.3% extractable material on a dry-weight basis, andIlex verticillata contains 41.5% extractable material on a dry-weight basis. Important components inA. linaria oil fractions are triterpene alcohols and esters, wax, and natural rubber; fatty acid triglycerides were nearly absent.Ilex verticillata oil fractions were predominantly triglycerides with some triterpene fatty acid esters. The more polar polyphenol fraction contained sugars and sugar esters of fatty acids and triterpene acids. The polyphenol fraction from these plants is better described as a saponin fraction. Because the crude saponin fraction represents 10.7% of the dry weight of A. linaria and 18.9% of the dry weight ofI. verticillata and because the saponin fractions showed good emulsifying properties, the refined extract of these plants might be used as a biodegradable surfactant.     

Epicuticular wax of Agropyron intermedium

Wax on leaves of Agropyron intermedium contains hydrocarbons (11%, C₂₇–C₃₃), esters (11%, C₃₂–C₆₀), free alcohols (180%, C₂₆) 25-oxohentriacontane-14,16-dione (17%), 10-oxohentriacontane-14,16-dione (5y%), 25-hydroxyhentriacontane-14,16-dione (12%) and 26-hydroxyhentriacontane-14,16-dione (2%). Wax on spikes contains additional components, C₂₅–C₃₃cis 9-alkenes (32% of hydrocarbons), and more β-diketones, 25-hydroxy (17%) and 26-hydroxy (3%) hentriacontane-14,16-diones, 10,25-dioxohentriacontane-14,16-dione (1%) and 4-hydroxy-25-oxo-(2%), 25-hydroxy-10-oxo-(1.3%) and 26-hydroxy-10-oxo-(0.7%) hentriacontane-14,16-diones; free alcohols were very minor components (1%, C₂₄–C₃₂).     

Epicuticular waxes from Agropyron dasystachyum,agropyron riparium and Agropyron elongatum

Epicuticular waxes from whole plants of Agropyron dasystachyum var. psammophylum, A. riparium and A. elongatum contain hydrocarbons (5–8 %), long chain esters (12–15%) and free acids (2–5%). The major esters are C₃₄C₅₆ esters derived from C₁₆C₃₀ acids and alcohols (1-hexacosanol is the major alcohol) but C₃₁, C₃₃ and C₃₅ esters (3–11%) are also present. The latter esters are C₁₈ and C₂₀ acid esters of C₁₃ and C₁₅ 2-alkanols. A. dasystachyum wax contains 2% free alcohols, that of A. riparium contains 17% and that of A. elongatum 11% (1-hexacosanol is the major alcohol in each). Diesters (2%), C₈C₁₂ diols esterified by (E)-2-alkenoic acids, are present in A. riparium wax. Hentriacontane-14,16-dione is present: 29% in A. dasystachyum wax and 32% in A. riparium wax, but only 5% in A. elongatum wax. 25-Oxohentriacontane-14,16-dione forms 14% of A. dasystachyum wax and 27% of A. elongatum wax but the oxo β-diketones of A. riparium wax (5%) consist of both 10-oxo- and 25-oxohentriacontane-14,16-diones in the ratio 4:1. Hydroxy β-diketones of the waxes are 25- and 26-hydroxyhentriacontane-14,16-diones; in A. dasystachyum (20%) the ratio is 3:1, in A. elongatum (20%) the ratio is 9:1 but in A. riparium (5%) it is ca 1:2. The configuration of the hydroxyl group in the 26-hydroxy β-diketone is opposite to that in the 25-hydroxy derivative. The unusual composition of the oxygenated β-diketones of A. riparium confirms that this species should be regarded as separate from A. dasystachyum. Wax from A. elongatum also contains 4-hydroxy-25-oxohentriacontane-14,16-dione (4%) and an unusual oxo-β-ketol, 18-hydroxy-7,16-hentriacontanedione (2%), both these components are probably derived biosynthetically from the 25-oxo β-diketone which is the major component of this wax. Syntheses of racemic 18-hydroxy-7,16-hentriacontanedione and of a model β-ketol, 12-hydroxy-10-pentacosanone, are described.     

Epicuticular waxes of Andropogon hallii and A. Scoparius

Leaf waxes of Andropogon hallii and A. scoparius contain hydrocarbons (2%, 2%), esters (4%, 2%), free acids (3%, 4%), free alcohols (1%, 0.2%, major component dotriacontanol) β-diketones (67%, 80%) and hydroxy β-diketones (16%, 5%). β-Diketones of A. hallii consist mainly of tritriacontane-12,14-dione and hentriacontane-12,14-dione (86:8) and of A. scoparius of tritriacontane-12,14-dione and hentriacontane-10,12-dione (67:29). Hydroxy β-diketones of A. hallii are composed mainly of 5-hydroxytritriacontane-12,14-dione and 5-hydroxy-hentriacontane-12,14-dione (90:8); wax of A. scoparius contains only 5-hydroxytritriacontane-12,14-dione. The hydroxyl group of the major hydroxy β-diketone has the R-configuration opposite to that of all previously described hydroxy β-diketones.     

Epicuticular wax of Eragrostis curvula

Epicuticular wax of Eragrostis curvula contains hydrocarbons (6%), esters (13%), acids (3%), alkanols (4%), tritriacontane-12,14-dione (47%), 5(S)-5-hydroxytritriacontane-12,14-dione (14%) as major components. The esters consist of triterpenol esters (42%) as well as alkanol esters. The free alkanols consist principally Of C₁₆C₃₂ components, resembling those of waxes from panicoid, and some other eragrostoid, grasses. Minor components are triterpenols (0.7%), triterpenones (0.5%), triacylglycerols (0.3%), secondary alkanols (0.1%) and 5-oxotritriacontane-12,14-dione (0.1%).     

Variations in sterol and triterpene contents of developing Sorghum bicolor grains

The free, esterified and glycosylated sterols and the pentacyclic triterpene esters of developing Sorghum bicolor grains were analysed by GLC and GC-MS. All the pentacyclic triterpenes were completely esterified but were not detected until 24 days after anthesis. Lupanol, multiflorenol, α-amyrin and isoarborinol were identified in the mature grains as components of the triterpene fraction but no 4,4-dimethylsterols could be found at any stage of development. A sixfold increase in total sterol per grain occurred during development. At 8 days after anthesis, 28-isofucosterol was found to be the second most abundant steryl ester. Campesterol was the major steryl glycoside and obtusifoliol was the major 4-monomethylsterol.     

Structural elucidation of twelve novel esters composed of five fatty acids and three new branched alcohols together with four monoterpenoids from Sancassania shanghaiensis (Acari: Acaridae)

A total of 12 novel esters and four monoterpenoids (rosefuran, (2R,3R)-epoxyneral, and alpha- and beta-acaridials) were detected by GC/MS analyses as the opisthonotal gland components of Sancassania shanghaiensis. The acidic fraction after hydrolysis was composed of five common fatty acids (palmitic, stearic, oleic, linoleic and arachidic acid), while the alcoholic fraction consisted of two major components (C6 and C8 alcohols with branched methyls), together with a trace amount of C9 alcohol. The two major alcohols were identified as new alcohols [(S)-2-methylpentanol and (2S,4S)-2,4-dimethylhexanol] by comparing the physico-chemical data of their 3,5-dinitrobenzoates with those of regio-selectively synthesized alcohols. The C9 alcohol was suggested as (2S,4S)-2,4-dimethylheptanol, based on a structural and biogenetic analogy to the C6 and C8 alcohols. Five of the compounds were each identified by GC to be (S)-2-methylpentyl esters from five fatty acids, and the other five components likewise as (2S,4S)-2,4-dimethylhexyl esters. The remaining two were suggested as (2S,4S)-2,4-dimethylheptyl stearate and linolate.     

Biosynthesis of pentacyclic triterpenoids in leaves of Ilex aquifolium L.

Ilex leaves can utilize sucrose and mevalonate for the synthesis of triterpene esters. Mevalonate is also used for the synthesis of free triterpenoid alcohols, but sucrose is not. The selectivity of precursor utilization indicates separate sites for triterpenol and triterpenol-ester synthesis. The sites of synthesis are not found at the main locations of accumulation of triterpenols (the epicuticular wax) or triterpene esters (the cytoplasmatic lipid globules). Transport from the site of synthesis to the lipid globules, and especially towards the epicuticular wax, is slow.Abbreviations MVA mevalonic acid lactone - TLC thin layer chromatography     

Surface lipids of Sphaerotheca fuliginea spores

The major components (50%) of the surface lipid extract of fungal spores (5.6% of dry spore wt) of Sphaerotheca fuliginea are esters of primary alcohols and fatty acids. Esters (15%) of primary alcohols and a Δ^2t acid are present. The major acid moieties of the alkyl esters are C₂₂ and C₂₄ and of the Δ^2t alkyl ester is Δ^2t C₂₂; for both classes eicosanol is the major primary alcohol. The major ester of each class was concluded to be eicosanyl docosanoate and eicosanyl trans-2-docosenoate. Minor components are saturated and Δ^2t methyl and diol diesters and free fatty acids. The major acid moieties of the diol diesters are C₂₂ and C₂₄ and the major diol is 1,12-dodecanediol.     

Epicuticular waxes of four eragrostoid grasses

The major components of Sporobolus airoides wax were hydrocarbons (37%, C₂₇–C₃₃), those of Bouteloua curtipendula and Eragrostis trichoides waxes esters (28% and 31%, respectively) and those of Muhlenbergia wrightii wax free alcohols (57%, almost entirely C₂₈). Free alcohols formed 22% of the wax from B. curtipendula, 19 % of the wax from E. trichoides and 10% of the wax from S. airoides; the compositions ranged from C₂₆ to C₃₂ with C₃₂ the major component. These alcohol compositions are similar to those found for other species in the subfamily Eragrostoideae. The esters contain 32–46% of acylated triterpenols, principally α- and β-amyrins. Aldehydes were present in all the waxes except for that from S. airoides.     

Long chain oxoaldehydes and oxoalcohols from esters as major constituents of the surface lipids of Manduca sexta pupae in diapause

Lipid constitutents of diapausing pupae of the tobacco hornworm, Manduca sexta (L), were identified by thin layer and gas-liquid chromatography, IR spectroscopy, and gas-liquid chromatography-mass spectrometry. Surface wax was a mixture of long chain polar compounds: oxoalcohol esters, oxoaldehydes, primary alcohol esters, and oxoalcohols, as listed in descending order of abundance. The distribution of the alcohols and aldehydes was C28 (75-85%), C27 (5%), and C26 (10-15%). The C26 compounds were largely 11-oxo isomers, but the C28 compounds consisted of similar amounts of 11- and 12-oxo isomers. The identities of the oxoaldehydes were confirmed by selective and complete NaBH4 reductions to yield oxoalcohols and diols, respectively. Mass spectral interpretations were verified with mass spectra of the oxoaldehyde, oxoalcohol, and diol synthesized from 12-hydroxystearic acid. Reduction of the total lipids with NaBH4 and hydrolysis of the product with ethanolic KOH gave oxoalcohols (85%), primary alcohols (8%), and oxoacids (5%); 30-40% of the oxoalcohols were derived from NaBH4-reduced oxoaldehydes, 5-10% were from free oxoalcohols, and 50% were from esters. Primary alcohols only existed as esters. Large quantities of fatty oxoalcohols relative to fatty oxoacids in the saponified mixture suggested the presence of esters other than those composed of long chain acids and alcohols. Oxoacids appeared to be mainly oxidation products of the oxoaldehydes.     

Long-chain and very long-chain methyl-branched alcohols and their acetate esters in pupae of the tobacco hornworm,Manduca sexta

Four homologous series of very long-chain methyl-branched alcohols (VLMA, C₃₈ to >C₄₄) were found in the internal lipids of developing male pupae of the tobacco hornworm, Manduca sexta, both as free alcohols and as acetate esters. The four major homologous series, with carbon chain backbones of 36–44 carbon atoms, consisted of a monomethyl, two dimethyls and a trimethyl-branched alcohol series. The major alcohol of each homologous series (with the corresponding alkane obtained by reduction in parentheses) was identified as 24-methyltetracontan-1-ol (17-methyltetracontane), 24,28-dimethyltetracontan-1-ol (13,17-dimethyltetracontane), 22,34-dimethyloctatriacontan-1-ol (5,17-dimethyloctatriacontane) and 22,26,34-trimethyloctatriacontan-1-ol (5,13,17-trimethyloctatriacontane). The minor components of the VLMA had backbones with an odd number of carbon atoms (37, 39, 41 and 43). Methyl branches of the minor components were identified on the 18- and 14,18-positions when numbered from the alkyl end of the chain. Also identified were minor amounts of long-chain methyl-branched alcohols (LMA, C₂₅ to C₃₂). The major components in the “wax ester” TLC fraction were acetate esters of the LMA and VLMA.     

Composition of sugarcane waxes in rum factory wastes

Wastes produced during fermentation and distillation of crude sugarcane juice in rum factories were evaluated as a new source of waxes. The chemical composition of the crude wax extracted from adsorbat of the wastes on fuller's earth was studied by GC-mass spectrometry. Series of linear alkanes (C19-C33), and wax esters constitute the main components. In addition, phytosterols, triterpene methyl ethers, ethyl and methyl esters of fatty acids, and free fatty acids were found as minor components. Acid (predominance of C16 and C18) and alcohol portions (C26-C32) of the wax esters were analysed after saponification.     

The chemical composition of the cuticular wax of cranberry

Cuticular wax of cranberry fruit (Vaccinium macrocarpon var. Howes) was analysed by thin layer and gas-liquid chromatography in conjunction with mass spectrometry and infrared spectroscopy. The wax was shown to contain n-paraffins (10·7%), n-aldehydes (14·3%), n-alcohols (6·5%), n-fatty acids (9·7%), sterols (5·0%) and pentacyclic triterpene alcohols (5·8%), acetates (6·1%) and acids (30·7%).