Amounts Of Limonene Research Articles

Limonene production in tobacco with Perilla limonene synthase cDNA.

Limonene synthase (LS) catalyses the stereo-specific cyclization of geranyl diphosphate (GPP) to form a monocyclic monoterpene, limonene. In an attempt to engineer monoterpene biosynthesis, three expression constructs of LS cDNA of Perilla frutescens, which were designed to be localized in either the plastid, the cytosol or the endoplasmic reticulum (ER), were introduced into tobacco in order to examine differences in enzyme activity and the productivity of limonene. High and moderate enzyme activity, respectively, was observed for plastid- and cytosol-localized LS, whereas no enzyme activity was seen for ER-localized LS, suggesting that the plastid is the preferred compartment for LS, while LS may also have an active form in the cytosol. The formation of limonene in vivo was confirmed by gas chromatography-mass spectrometry (GC-MS) in leaf extracts of both plastid- and cytosol-localized LS transgenic plants. The amount of limonene in plastid-localized LS transgenic plants was 143 ng g-1 fresh wt, whereas that in the cytosol-type was 40 ng g-1 fresh wt, and these limonene contents increased by 2.7-fold and 3.0-fold, respectively, with the addition of methyl jasmonate. The headspace analyses showed that the plastid- and the cytosol-localized LS transgenic plants (12 cm high) emitted 390 ng and 515 ng limonene per month, respectively. The possibility of genetically engineering monoterpene production is discussed.

The Leaf Essential Oils and Taxonomy of Juniperus centrasiatica Kom., J. jarkendensis Kom., J. pseudosabina Fisch., Mey. & Ave-Lall., J. sabina L. and J. turkestanica Kom. from Central Asia

The leaf essential oils of Juniperus centrasiatica Kom., J. jarkendensis Kom., J. pseudosabina Fisch., Mey. & Ave-Lall., J. sahina L., and J. turkestanica Kom. have been analyzed by GC/MS. The oils were very similar and were dominated by α-pinene, sabinene and cedrol with moderate amounts of limonene, terpinen-4-ol and elemol. On the basis of the oils and morphological observations, it is concluded that J. centrasiatica, and J. turkestanica is conspecific with J. pseudosabina. Comparisons were made with the leaf oil of a shrub form of Juniperus indica Bertol from Nepal. Juniperus indica (shrub form) from Nepal was found to be very distinct from J. centrasiatica, J. pseudosabina and J. turkestanica. In addition, J. jarkendensis oil was found to be very similar to J. sabina oil (Tian Shan Mtns. China).

COMPARATIVE STUDY OF LEAF ANATOMY AND ESSENTIAL OILS OF THE HYBRID MENTHA X VILLOSO-NERVATA AND ITS PARENTAL SPECIES M. LONGIFOLIA AND M. SPICATA

Leaves of the hybrid Mentha x villoso-nervata are covered with nonglandular trichomes of intermediate length between those of its parental taxa M. longifolia and M. spicata. Glandular trichomes producing essential oils are more numerous on the lower leaf surface than on the upper one in all three mints. Their number per mm2 is higher in M. spicata and it decreases in M. longifolia and M. x villoso-nervata. Stomata are also more numerous on the lower leaf surface of the three taxa, with M. longifolia predominating. The leaf lamina of M. x villoso-nervata is ca. 83% thicker than that of M. longifolia and ca. 9% thicker than that of M. spicata. The number of chloroplasts per mm2 of mesophyll section (leaf cross section) is higher in M. X villoso-nervata. In leaf paradermal sections, the sizes of the epidermal, palisade, and spongy parenchyma cells of M. X villoso-nervata have intermediate values between those of its parental species M. longifolia and M. spicata. M. x villoso-nervata leaves are the lowest in essential oil content. As concerns the essential oil composition, the hybrid resembles one parent, M. longifolia, in the derivatives of piperitenone and piperitone, and the other parent, M. spicata, in the high amount of limonene. It differs, however, from its parental species in that it contains a higher amount of germacrene D.

Essential Oil of Carissa edulis Vahl. from Benin

The root oil of Carissa edulis from Benin was analyzed by GC/MS and six components were identified. The main constituent was 2-acetylphenol (92.7%) with lesser amounts of limonene (1.2%), γ-eudesmol (1.2%), α-pinene (0.3%), sabinene (0.3%) and myrcene (0.8%).

The Leaf Oil of Juniperus gracllior Pilger var. urbaniana (Pilger & Ekman) R.P.Adams: Comparison with Other Caribbean Juniperus Species

The composition of the leaf oil of Juniperus gracilior var. urbaniana from Haiti was analyzed and compared to the composition of the other Caribbean junipers. The oil was dominated by bornyl acetate (38.4%) with moderate amounts of limonene (12.2%), sabinene (12.2%) and camphor (5.8%). J. gracilior var. urbaniana appeared to be most closely related to J. gracilior var. ekmanii and J. gracilior. The evolution of the Caribbean junipers is discussed.

Analyses of the Leaf and Resin Essential Oils ofPinus sibirica(Rupr.) Mayr from Mongolia

ABSTRACT The leaf and resin essential oils of Pinus sibirica were analyzed by GC/MS. The leaf oil was dominated by α-pinene (57.2%), β-phellandrene (19.7%), and β-pinene (7.7%) with lesser amounts of limonene (2.2%), myrcene (2.1%), terpinolene (1.3%) and camphene (1.3%). The resin oil contained α-pinene (39.1%), δ-3-carene (23.0%), and β-pinene (9.1%) with moderate amounts of cembrene (4.9%), β-phellandrene (2.1%), camphene (1.7%) and terpinolene (1.3%).

Composition of the Essential Oils of Fruits from Polyploid Types ofThapsia villosaL.: Chemotaxonomic Evaluation

ABSTRACT Fruits of tetraploid (2n=44) and hexaploid (2n=66) specimens of Thapsia villosa collected at different locations have been investigated for their essential oil components. Analysis of the essential oils by means of GC and GC/MS has shown that their chemical composition is slightly affected by the chromosome number of die plants. Both tetra- and hexaploid specimens have limonene and methyl eugenol as main constituents. However, the amount of limonene is reduced in the hexaploid plants (14–26% vs 31–55% in the tetraploids) which are also characterized by discrete amounts of elemicin (trace-30.11%).

The essential oils of choricarpia leptopetala (f. muell.) domin and c. subargentea (c.t. white) l.a.s. johnson (myrtaceae)

AbstractThe leaf essential oils of the two species of Choricarpia were examined. Choricarpia subargentea (C.T. White) L.A.S. Johnson produced an oil in which the major components were α‐pinene (30‐76%), limonene (2‐55%) and 1,8‐cineole (2‐20%). The oil also contained the aromatic ketone jensenone (2,4,6‐trihydroxy‐3,5‐diformyl‐isopentyrophenone) in amounts of up to 5%. Choricarpia leptopetala (F. Muell.) Domin produced an oil which also contained α‐pinene, as principal component. There were varying (though less than 20%) amounts of limonene, p‐cymene and 1,8‐cineole present. Small amounts (less than 3%) of methyl eugenol, methyl isoeugenol and elemicin were also detected in the oil. Jensenone was not present in this oil.