Sesquiterpenes wth ten-membered carbon rings.  Review

Šorm, F.

doi:10.1021/jf60178a017

Cited by 26 publications

(9 citation statements)

References 17 publications

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“…The observed decreases of the germacrene-type sesquiterpene hydrocarbons, and the corresponding increases of δ-cadinene, γ-cadinene, α-muurolene, aromadendrene, allo-aromadendrene, globulol, α-cadinol, T-cadinol, T-muurolol and spathulenol at 20 o C could occur due to structural rearrangements and transformations influenced by silica gel and heat, in accordance with previous reports [18][19] . A sharp decrease of bicyclogermacrene occurred (from 0.9 to 0.1%).…”

Section: Changes In Composition Of Yuzu Oil Upon Silica Gel Treatmentsupporting

confidence: 92%

Preparation ofCitrusEssential Oils: Effects of Silica Gel Treatment on Volatile Composition of Yuzu (Citrus junos) Cold-pressed Peel Oil

Njoroge

Sawamura

2004

Journal of Essential Oil Bearing Plants

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The effects of silica gel, a substance commonly used for fractionation of essential oils during preparation, were investigated on cold-pressed peel oil of yuzu (Citrus junos Sieb. ex Tanaka), a sour Citrus fruit. The silica gel treatment was performed for 24 h at 20 o C, 5 o C and -2 o C. The volatile components were determined using GC and GC-MS. Important compositional changes occurred at 20 o C and 5 o C and minimally or virtually absent at -21 o C. The notably decreased groups were monoterpene hydrocarbons (from 95.7 to 75.2%), sesquiterpene hydrocarbons (from 2.1 to 1.0%) and monoterpene alcohols (from 2.2 to 1.7%). The main decreases were of sabinene hydrate and α-terpineol occurred. Artifact compounds including β-copaene, d-camphor, viridiflorol and spathulenol were formed. Use of silica gel for preparative treatment of complex Citrus oils could cause alteration of the original composition. The results could be applicable for quality control at the perfume or Citrus juice factory.

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Section: Changes In Composition Of Yuzu Oil Upon Silica Gel Treatmentsupporting

confidence: 92%

Preparation ofCitrusEssential Oils: Effects of Silica Gel Treatment on Volatile Composition of Yuzu (Citrus junos) Cold-pressed Peel Oil

Njoroge

Sawamura

2004

Journal of Essential Oil Bearing Plants

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“…On p. 3628, the top line of the second column should read,"... found next to the anticodon (U40). In mature tRNA (18) (3), discovery of the naturally occurring cis,-trans-cyclodeca-1,5-diene melampodin (4,5) has necessitated reclassification of the germacranolides into four subgroups The anti-arrangement of CA14 and CA15 seems to be typical for the. conformation of the melampolides (II) and heliangolides (III).…”

Section: Figmentioning

confidence: 99%

Neutron Diffraction Structure of Melampodin: Its Role in the Reclassification of the Germacranolides

Watkins

Fischer

Bernal

1973

Proc. Natl. Acad. Sci. U.S.A.

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The precise crystal and molecular structure of melampodin, C 21 H 24 O 9 , was determined from three-dimensional neutron diffraction data collected by counter techniques and phases by direct statistical methods. Crystals are orthorhombic, P2 1 2 1 2 1 , a = 8,990(9), b = 14.352(14), c = 16.294(16) Å, V = 2102 Å 3 , d(calc.) = 1.328 g·cm -3 , Z = 4 molecules per unit cell. The structural model was refined by full matrix least-squares of 2303 observed independent reflections, with all 54 atoms treated anisotropically, to R(F) = 5.0%. Hydrogen bonds link melampodin molecules together in the solid state. The conformation of the cyclodeca-1,5-diene ring is such that one intraannular hydrogen atom interacts strongly with one double bond, but there is little or no transannular interaction between double bonds. Strain in the ten-membered ring and in the trans -fused lactone ring is discussed, as are chemical implications of the unsymmetric epoxide in the epoxyangelic acid side chain. The previously suggested reclassification of germacranolide sesquiterpene lactones into four subgroups is supported, and a new convention for configurational representations of the four subgroups is proposed.

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“…The observed changes in the constitution of the sesquiterpene hydrocarbons at 20 °C could be explained to some extent by the possible reactions of bicyclogermacrene and germacrene D. The two compounds constituted 55% of the sesquiterpenes in the fresh oil. Germacrene-type hydrocarbons are known to be particularly labile, undergoing oxidization, isomerization, and rearrangement under suitable conditions of air, heat, acid, light, or other agents (Nishimura et al, 1969;Yoshihara et al, 1969;Sorm, 1971). Bicyclogermacrene is thought to be the possible precursor of tricyclic sesquiterpenes (Tressl et al, 1983).…”

Section: Resultsmentioning

confidence: 99%

Changes in the Volatile Composition of Yuzu (Citrus junos Tanaka) Cold-Pressed Oil during Storage

Njoroge

Ukeda

Sawamura

1996

J. Agric. Food Chem.

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The changes of 34 components constituting a relative 97.6% of the total volatiles of yuzu (Citrus junos Sieb. ex Tanaka) cold-pressed peel oil and the possible artifacts during storage at -21, 5, and 20 °C were investigated after 1, 3, 6, 9, and 12 months. Major qualitative changes were found after 12 months at 20 °C. Total monoterpene hydrocarbons underwent a large decrease (from 93.3 to 37.7%), with major loses of limonene, γ-terpinene, myrcene, and R-pinene, while notable increases occurred in p-cymene as well as the monoterpene alcohols (from 2.1 to 13.2%). Bicyclogermacrene, the main sesquiterpene hydrocarbon of the fresh oil (1.0%), was virtually depleted. Sesquiterpene alcohols were formed as dominant artifacts (36.1%) and constituted the second most abundant volatile group of the oil after the monoterpene hydrocarbons. (-)-Spathulenol (decahydro-1,1,7-trimethyl-4-methylene-1H-cyclopropylazulen-7-ol) was the main artifact among the 14 identified. The alcohol constituted the second major component of the oil after limonene from the ninth month and accounted for more than 75% of the sesquiterpenic alcohols at 20 °C. The spathulenol was found for the first time to be an artifact in yuzu oil. The compound could be a useful index for monitoring the quality and freshness of yuzu flavor during storage.

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Sesquiterpenes wth ten-membered carbon rings. Review

Cited by 26 publications

References 17 publications

Preparation ofCitrusEssential Oils: Effects of Silica Gel Treatment on Volatile Composition of Yuzu (Citrus junos) Cold-pressed Peel Oil

Preparation ofCitrusEssential Oils: Effects of Silica Gel Treatment on Volatile Composition of Yuzu (Citrus junos) Cold-pressed Peel Oil

Neutron Diffraction Structure of Melampodin: Its Role in the Reclassification of the Germacranolides

Changes in the Volatile Composition of Yuzu (Citrus junos Tanaka) Cold-Pressed Oil during Storage

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