Oleoresin terpenoids

About 50% of spruce oleoresin consists of resin acids, 20-30% are volatile monoterpenes, and the remainder, terpenoids and fatty acid esters. Pine oleoresin contains a higher percentage of resin acids, about 70-80%, than spruce oleoresin. 

The content of extractives and their composition vary greatly among different wood species and also within the different parts of the same tree (cf. Appendix). Wood extractives can be divided into three subgroups aliphatic compounds (mainly fats and waxes), terpenes and terpenoids, and phenolic compounds. Parenchyma resin is rich in aliphatic components and the oleoresin is mainly composed of terpenoids. Characteristic of the heartwood is the accumulation of phenolic compounds. 

Terpenes are flammable unsaturated hydrocarbons, existing in liquid form. They are found in essential oils, resins or oleoresins. They are used as intermediate for the synthesis of sesquitrepenes and terpenoids. They are classified as mono, di or triterpenoids. 

Conifer chemical ecology includes many other herbivores, predators and pathogens, aside from the bark beetles, weevils, sawflies, or budworms, and in these diverse interactions, terpenoid volatile emissions as well as accumulated oleoresin terpenes are likely to play many important roles in signaling and defense. 

Our recent research suggests organ-, tissue-, and cell-specific localization of constitutive and induced terpenoid defense pathways in conifers. For example, linalool synthase (PaTPS-Lin) seems to be preferentially expressed in needles of Norway spruce and Sitka spruce with little or no expression in sterns. ft is also likely that expression of PaTPS-Lin in spruce needles is not associated with resin ducts but could reside in other cells involved with induced terpenoid emission. In contrast, we can speculate that most other mono-TPS and di-TPS are associated with epithelial cells of constitutive and induced resin ducts. The possible localization of conifer sesqui-TPS is difficult to predict. Furthermore, the exact spatial and temporal patterns of terpenoid pathway gene expression associated with traumatic resin duct development in the cambium zone and outer xylem remain to be studied at the tissue and cell level. In situ hybridization and immuno-localization of TPS will address these open questions. These methods have worked well in identifying cell type specific gene and protein expression of alkaloid formation in opium poppy Papaver somniferum) As the biochemistry of induced terpene defenses and the development of traumatic resin ducts have been well described in spruce, this system is ideal for future studies of tissue- and cell-specific localization of transcripts and proteins associated with oleoresin defense and induced volatile emissions in conifers. In addition, the advent of laser dissection microscopy techniques presents a fascinating means by which to further address RNA and protein analysis in a tissue-and cell-specific manner. These techniques, when applied to the cambium zone, xylem mother cells, and the epithelial cells that surround traumatic resin ducts, and will allow a temporal and spatial analysis of cellular functions occurring in the traumatic resin response. 

Southern pine beetles, Dendroctonua frontalis, were assayed for susceptibility to 16 terpenoids from pine oleoresin (15). The LDcq of d-limonene was 0.47 pg/insect, while i-limonene was slightly less toxic (0.55 /lig/insect), as was myrcene (0.62 /jg/insect). The most toxic chemical tested was limonene dioxide (0.24 /ig/insect), indicating that oxidation of limonene may be an activation process (15). 

Rakhmatullaev TU, Yunusov SYu (1972a) Alkaloids of Dipsacus azureus. Chem Nat Compd 8(3) 401 Rakhmatullaev TU, Yunusov SYu (1972b) Alkaloids of Gentiana Olivieri. Chem Nat Compd 8(3) 344—345 Raldugin VA, Demenkova LI, Pentegova VA (1991) Terpenoids of the oleoresin of the Schrenk spruce. Chem Nat Compd 27(3) 279-282 Raskin I, Ripoll C (2004) Can an apple a day keep the doctor away ... 

Mono- and sesquiterpenes are the main constituents of the essential oils, while the other terpenes are constituents of balsams, resins, waxes, and rubber. Oleoresin is a roughly equal mixture of turpentine (85 % Cio-monoterpenes and 15 % C15- sesquiterpenes) and rosin (C2o-diterpene) that acts in many conifer species as a toxic material to invading insects and their pathogenic fungi [12]. A number of angiosperm species have inducible terpenoid defensive compounds (phytoalexins) [13]. These include both sesquiterpenoid and diterpenoid t)pes. Isoprenoid units are also found within the framework of other natural molecules. Thus, indole alkaloids, several quinones (vitamin K), alcohols (vitamin E, vitamin A formed from p-carotene), phenols, and isoprenoid alcohols (also known as terpenols or polyprenols) also contain terpenoid fragments. The biogenesis. 

Monoterpenoids (derived from geranyl diphosphate, GPP) are a subgroup of terpenoids consisting of two isoprene units (IOC). Monoterpenoids may be acyclic or contain rings in their structures. Monoterpenoids usually exist as an oily liquid with distinctive aromas and flavors, such as essential oils, turpentine, and oleoresins of coniferous plants. Important examples of this class include menthol used as topical pain reliever, bomeol as disinfectant or deodorant, and camphor as counterirritant, anesthetic, expectorant, antipruritic, etc. 

Gupta A S, Sukh Dev 1971b Higher terpenoids. I. Triterpenoids from the oleoresin of Dipterocarpus pilosus hollongdione and dipterocarpolic acid. Tetrahedron 27 823-834... 

Misra R, Pandey R C, Sukh Dev 1979 Higher terpenoids. VIII. Diterpenoids from the oleoresin of Hardwickia pinnata. Part I hardwickiic acid. Tetrahedron 35 2301-2310... 

Bol shakova VI, Khan VA, Dubovenko ZV, Shmidt EN et al. 1980 Terpenoids of the oleoresin of the larch growing in Kamchatka. Khim Prir Soedin 16 340-343... 

Khan VA, Pankrushina NA, Shmidt EN, Dobovenko ZHV et al. 1984 Terpenoids of the oleoresin of Abies semenovii. Khim Prir Soedin 20 115-116... 

Shmidt EN, Khan VA, Isaeva ZA, Drebushchak TD et al. 1982 Terpenoids of the oleoresins of Picea orientalis and Abies normanniana growing in the Caucasus. Khim Prir Soedin 18 189-194... 

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