Diterpene identification

Diterpenes Ladix kaempfen SiOj CHCI3 + MeOH uv 254 nm Identification 60 CD —T... 

Many nonvolatile and thermally labile allelochemicals can be well separated by liquid chromatography (LC). Identification of the separated components on-line by mass spectrometry (MS) is of great value. Fused-silica LC columns of 0.22 mm ID packed with small-particle material are used in the described LC/MS system. The shape of the column end allows direct connection to a electron impact ion source of a magnetic sector mass spectrometer. Separations by LC are reported and LC/MS mass spectra are shown for monoterpenes, diterpene acids, phenolic acids and cardiac glycosides. The LC/MS system provides identification capability and high-efficiency chromatography with a universal detector. 

Pettitt Jr, B. C. Identification of the diterpene esters in arabica and cane-phora coffees. J Agr Food Chem 1987 35(4) 549-551. 

Shvets, S. A., P. K. Kintya, O. N. Gutsu, and V. 1. Grishkovets. Steroid glycosides of the seeds of Nicotiana tabacum. 11. The structures of nicotianosides C and E. Chem Nat Comp 1995 31(3) 332-335. Shinozaki, Y., T. Tobita, M. Mizutani, and T. Matsuzaki. Isolation and identification of two new diterpene glycosides from Nicotiana tabacum. Biosci Biotech Biochem 1996 60(5) 903-905. 

Tang, X., Y. Ma, and P. Li. 1995. Separation and identification of the anti-inflammatory diterpene from the root cortices of Acanthopanax gracilistylus W. W. Smith. Zhongguo Zhongyao Zazhi 20 231. 

Measurements on these 13C-enriched compounds and the application of common assignment aids [73] led to the total signal identification of the following diterpenes the 13C shifts are outlined in Table 5.42. 

The fatty/waxy products contained the lipophilic substances, including fatty oils, waxes, resins and colorants. Valuable pharmacological effects were proved for some minor constituents of these products (e.g. triterpenes, diterpenes, sterols and carotenoids). Thin layer chromatography and on-line UV-VIS spectroscopy were used for the quick identification and quantity determination of these compounds using authentic samples as standards. The SFE method proved favorable in terras of both extraction yield and speed of carotenoids. The CO2 extracts of the lavandin, clary sage and thyme have been enriched in triterpenic compounds (a-es P-amyrin, oleanic acid, ursolic acid, etc.) and phytosterols. Both free and esterified triterpenoids were present in the extracts of the different samples. Furthermore camosol and other diterpenes were detected in the SFE extract of Lamiaceae plants. The fatty acid composition was only slightly different for extracts obtained by SFE and conventional hexane extraction. 

Novel Diterpene Alkaloid Identification Application of Tandem Mass Spectrometry... 

Identification of new compounds may start with TLC analysis of plant extracts. For instance, Jakupovic et al. [4] isolated and further identified several diterpenes from Euphorbia segetalis. Similarly, chamomile essential oil (Chamomilla reticulata) was analyzed with 11 different development systems and the authors discussed... 

Earlier we described the isolation and identification of two isomeric diterpenes from the leaves of young tobacco plants (Nicotiana tabacum L. cv. Hicks) that significantly (P<0.01) inhibited the growth of etiolated wheat coleoptiles (Triticum floativ m L. cv. Vakeland) in concentrations that ranged from 10 3 to 10 m (1 2). X-ray crystallography confirmed the structures... 

A dereplication example that illustrates the use of microscale derivatization and analysis by GC-MS is an identification of a series of bioactive diterpenes by NCI researchers (35). The extract from Croton cuneatus showed activity in a phorbol dibutyrate receptor, binding assay, and, on analysis, could be separated by HPLC into a group of seven very minor, related components. Following hydrolysis and acetylation, all seven components appeared to give rise to only two peaks, which by GC-CIMS analysis were judged to be phorbol tetraacetates. It was concluded that the seven compounds were probably van-ous esters of 4a-, or 16-hydroxylated phorbol analogs (Fig. 6). 

Aral M, Yamamo Y, SetiawanA,KobayashiM. Identification of the target protein of agelasine D, a marine sponge diterpene alkaloid, as an anti-dortmant mycobacterial substance. Chembiochem 2014 15(l) 117-23. 

Ganjian, L, I. Kubo, and T. Kubota Rapid and Micro Identification of Biologically Active Diterpenes in Rabdosia umbrosus var. excisinflexus (Labiatae) by Reversed-phase High-performance Liquid Chromatography. J. Chromatogr. 200, 250 (1980). 

Cubitermes umbratus is an example of a termite using the second type defense. Soldiers produce four diterpenes, biflora-4,10 (19)-15-triene (156) (522), cembrane A (157) and 3-Z-cembrane A (158) (521) and cubitene (159). More recently, isolation and identification of cube-gene (160), a diterpene with a novel carbon skeleton from C. ugandensis soldiers, has been reported (539). Odontotermes badius also bites with... 

Isolation and Identification of Diterpenes from Termite Soldiers. Methods in Enyz-mol. 110, 417-425 (1985). 

The identification of compounds comprising more than 1 wt% in the oils can be also carried out by C-NMR and computer-aided analysis. " The chemical shift of each carbon in the experimental spectrum can be compared with those of the spectra of pure compounds. These spectra are listed in the laboratory spectral database, which contains approximately 350 spectra of mono-, sesqui-, and diterpenes, as well as in the hterature data. Each compound can be unambiguously identified, taking into account the number of identified carbons, the number of overlapped signals, as well as the difference between the chemical shift of each resonance in the mixture and in the reference. 

Identification of new compounds may start with TLC analysis of plant extracts. For instance, Jakupovic et al. - isolated and further identified several diterpenes from Euphorbia segetalis. Similarly, chamomile essential oil (Chamomilla reticulata) was analyzed with 11 different development systems and the authors discussed both the most efficient (separation power) and the ideal way they are to be used to identify an unknown component in such a complex mixture, using the minimum number of TLC systems.This area of work still has to be investigated, considering the wide variety of the vegetal reign and of potential plant toxins. 

Wang Q, Hillwig ML, Peters RJ (2011) CYP99A3 functional identification of a diterpene oxidase from the momilactone biosynthetic gene cluster in rice. Plant J 65 87-95... 

Bleif S, Hannemann F, Lisurek M, Kries JP, Zapp J, Dietzen M, Antes I, Bernhardt R (2011) Identification of CYP106A2 as a regioselective allylic bacterial diterpene hydroxylase. Chembiochem 12 576—582... 

Orinak, A., Orinakova, R., Arlinghaus, H.F., Vering, G., and Hellweg, S. 2006. Post-chromatographic TOF-SIMS identification of diterpenes. Surf. Interface Anal., 38 599-603. 

Baker, R., Parton, A. H. and Howse, P. E. (1982) Identification of an acyclic diterpene alcohol in the defense secretion of soldiers of Reticulitermes lucifugus. Experientia, 38, 297. 

Robinson, D. R., and West, C. A. (1970). Biosynthesis of cyclic diterpenes in extracts from seedlings of Ricinus communis L. I. Identification of diterpene hydrocarbons formed from mevalonate. Biochemistry 9 70-79. 

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