Characterization of the Macrolide Fraction of Angelica Root Oil and Enantiomeric Composition of 12-Methyl-13-tridecanolide

Essential Oils and Supercritical CO2 Extracts of Arctic Angelica (Angelica archangelica L.), Marsh Labrador Tea (Rhododendron tomentosum) and Common Tansy (Tanacetum vulgare)-Chemical Compositions and Antimicrobial Activities

Traditionally, arctic Finnish Angelica (Angelica archangelica L.), marsh Labrador tea (Rhododendron tomentosum, syn. Ledum palustre) and common tansy (Tanacetum vulgare) have been used as medicinal herbs in folklore medicine. However, these underutilised plants are a source of, e.g., oil-based compounds, which could benefit many modern applications implemented by the green chemistry extraction methods, as well. We extracted Angelica, marsh Labrador tea and common tansy by non-toxic and recyclable extraction methods, i.e., hydrodistillation and supercritical carbon dioxide (scCO₂) extraction; characterised the essential oils (EOs) and scCO₂ extracts by combination of gas chromatography and mass spectrometry (GC-MS), and in addition, analysed the antimicrobial properties. As expected for Angelica root and common tansy inflorescence, the scCO₂ extraction method produced less amount of volatile compounds compared to hydrodistillation. On the other hand, more coumarins, alkanes, fatty alcohols and fatty acids were obtained. Additionally, sesquiterpenoids palustrol and ledol were predominant compounds in both marsh Labrador tea EO and scCO₂ extract. According to our results, however, all the EOs and scCO₂ extracts showed broad spectrum of antimicrobial activities against the selected microbes, but the effects were extract-specific. The strongest and broadest antimicrobial activities were performed by marsh Labrador tea scCO₂ extract, which showed extremely strong effect on Staphylococcusaureus subsp. aureus and strong effect on Candida albicans.

Flow Chemistry under Extreme Conditions: Synthesis of Macrocycles with Musklike Olfactoric Properties

Starting from small cyclic ketones, continuous flow synthesis is used to produce medium-sized rings and macrocycles that are relevant for the fragrance industry. Triperoxides are important intermediates in this process and are pyrolyzed at temperatures above 250 °C. The synthesis is carried out in two continuously operated flow reactors connected by a membrane-operated separator. The practicality of flow chemistry is impressively demonstrated in this work by the use of hazardous reagent mixtures (30% H₂O₂, 65% HNO₃) and the pyrolysis of no less problematic peroxides. All new macrocycles were tested for their olfactory properties in relation to musk.

Understanding the phytochemistry and molecular insights to the pharmacology of Angelica archangelica L. (garden angelica) and its bioactive components

Plant-derived molecules have enduring usefulness in treating diseases, and herbal drugs have emerged as a vital component of global therapeutic demand. Angelica archangelica L. (A. archangelica), commonly known as garden angelica, is an aromatic food plant used in culinary procedures as a flavoring agent. In the traditional medicine system, it is regarded as an "Angel plant" due to its miraculous curative power. This review aims to provide a comprehensive summary of the plant's taxonomic profile, ethnopharmacology, Phytochemistry, and pharmacological activities. Various in vivo and in vitro experiments have validated that the plant possesses broad pharmacological potential. The biological activities attributed to the plant include anti-anxiety activity, anti-convulsant activity, cognition enhancer, antiviral activity, cholinesterase inhibitory potential, antiinflammatory activity, gastroprotective activity, and radioprotective activity. The beneficial effects of the plant are credited to its bioactive components, that is, coumarins and volatile oils. The review summarizes the pharmacological activities of crude extract and its bioactive fractions and has also explored their target-oriented effects. This review will be of value in undertaking further investigations on the plant with regard to exploring mechanism-based pharmacological approaches on A. archangelica.

Fluorine in fragrances: exploring the difluoromethylene (CF2) group as a conformational constraint in macrocyclic musk lactones

The CF2 group is incorporated into specific positions within the lactone ring of the natural musk lactone, (12R)-(+)-12-methyl-13-tridecanolide, a constituent of Angelica root oil, Angelica archangelica L. The approach is taken as it was anticipated that CF2 groups would dictate corner locations in the macrocycle and limit the conformational space available to the lactone. Three fluorine containing lactones are prepared by organic synthesis. One (8) has CF2 groups located at the C-6 and C-9 positions, another (9) with CF2 groups at the C-5 and C-9 positions, and a third (10) with a CF2 group at C-8. Two of the fluorine containing lactones (8 and 10) were sufficiently crystalline to obtain X-ray crystal structures which revealed that the CF2 groups do adopt corner locations. All three lactones were subject to computational analysis at the B3LYP-D3/6-311+G** level to assess the relative energies of different conformers. In all cases, the global minima and most of the lowest energy minima have squared/rectangular geometries and located the CF2 groups at the corners. The lowest energy structures for 8 and 10 closely approximated the observed X-ray structures, suggesting good convergence of theory and experiment in determining relevant low energy conformations. All three compounds retained a pleasant odour suggesting the rings retained sufficient conformational flexibility to access relevant olfactory conformations.

Synthesis of Both Enantiomers of 12-Methyl-13-tridecanolide and 14-Methyl-15-pentadecanolide (Muscolide)

Both enantiomers of 12-methyl-13-tridecanolide{( R)-(+)-1 ( S)-(-)-1} and 14-methyl-15-pentadecanolide (muscolide) {( R)-(+)-2 ( S)-(-)-2} were synthesized from either ( S)-(+)- or ( R)-(-)-3-bromo-2-methyl-1-propanol 8 as a chiral building block.

Essential Oil Composition of Wild Growing Apiaceae from Europe and the Mediterranean

In this overview, the essential oil composition of more than 150 species from about 50 genera of the Apiaceae is reviewed. Essential oil components encountered in Apiaceae proved to be very diverse; they include monoterpenes, sesquiterpenes, rarely diterpenes, phenylpropanoids, phthalides, octanol and octyl esters, trimethylbenzaldehydes and aliphatic aldehydes. In assessing the data one has to keep in mind that the essential oil amount and composition is influenced by many factors, including geographic and genetic variation, physiological aspects and environmental conditions. In some species the occurrence of chemotypes could be demonstrated, but in many cases the data available do not allow the evaluation of infraspecific variability.

14-Methylpentadecano-15-lactone (muscolide): a new macrocyclic lactone from the oil of Angelica archangelica L

The chemical composition of seed and root oils from Angelica archangelica L. was investigated. Analyses were performed by GC/MS and GC using two columns of different polarities (polyethylene glycol (DB-Wax) and 5% phenyl/95% polydimethylsiloxane (HP-5)), for the separation of several co-eluting components. A total of 58 compounds were identified, accounting for 96.3% (seed) and 93.5% (root) of the oils, respectively. A high content of beta-phellandrene (74.7%) was found in Angelica seed oil. Root oil contained a larger amount of macrocyclic lactones (1.3%) in comparison to the seed oil (0.4%). Different harvest dates produced only slight changes in the root-oil composition. In root oil harvested in summer, the beta-phellandrene content increased by ca. 36%, but no significant changes in the relative compositions of other components were observed. Fresh root oils were collected in five fractions (constant time intervals) during steam distillation (see Table). The highest-boiling fraction contained 9.3% of macrocyclic lactones such as tridecano-13-lactone (5.0%), 12-methyltridecano-13-lactone (0.4%), tetradecano-14-lactone (0.1%), pentadecano-15-lactone (3.5%), 14-methylpentadecano-15-lactone (1; trace), hexadecano-16-lactone (trace), and heptadecano-17-lactone (0.2%). This is the first report of the occurrence of 14-methylpentadecano-15-lactone (muscolide; 1) in a natural product.

?Brain Aided? Musk Design

This brief review, including new experimental results, is the summary of a talk at the RSC/SCI conference flavours & fragrances 2004 in Manchester, United Kingdom, 12-14 May, 2004. Musk odorants have been a classical domain for computer aided structure-odor relationship (SOR) studies, but, contrary to sandalwood or amber odorants, they belong to structurally very different substance classes, e.g., macrocycles, aromatic polycycles, and nitro arenes. Most SOR computer models are restricted to one class, excluding structural diversity to increase predictability. But even within a musk family, structural similarities are often due to a common synthetic access, and do not reflect binding requirements for the musk receptor. Beyond that, the importance of structural key features can be missed, which is discussed on the example of the (4S)-Me group of Galaxolide. By synthesis and olfactory evaluation of Galaxolide-like shaped macrobicycles as model compounds for conformationally constrained (12R)-12-methyltridecano-13-lactone, it was investigated how likely there is more than one musk receptor. Finally, the new family of so-called linear musks is discussed, especially with respect to the conformational importance of the gem-2',2'-dimethyl moiety in Helvetolide and the additional 2'-carbonyl group of Romandolide--structural features that strongly diminish the musk odor of macrocycles. On the example of 2-methyl-2-[(E)-1,2,4-trimethylpent-2-enyloxy]propyl esters, the 'brain-aided' design and conformational analysis of musk odorants is illustrated. The overview concludes with the synthesis, odor evaluation, and conformational discussion of the new musk odorant 2-(3,3-dimethylcyclohexyl)propanoic acid ethoxycarbonylmethyl ester.

New Macrocyclic Musk Compounds

The syntheses and olfactory evaluations of eight new macrocyclic musks with a 1,6-dioxa structure (1a-d and 1'a-d) as well as of twelve optically active 3-methyl macrolides (5a-c and 5'a-c) are reported. These macrocycles were synthesized via intramolecular metathesis mediated by the Grubbs catalyst. Despite the absence of a C=O function, the 1,6-dioxa compounds, both unsaturated (1) and saturated (1'), possess musky odors similar to those of macrocyclic ketones and lactones. Especially 16-membered rings were found to display an intense and pleasant musk character. However, in the case of optically active 3-methyl macrolides (5, 5'), only the (R)-configured 15- and 16-membered rings had intense and pleasant musk notes.

Constructing conformationally constrained macrobicyclic musks

To investigate the structure-odor correlation of musks, (12R)-12-methyl-13-tridecanolide (1), a macrocyclic musk, and 13-tridecanolide, its non-musky demethyl analogue, were conformationally constrained by introduction of methylene bridges between C-3 and C-8 or C-9. These [7.5.1]- and [8.4.1]-macrobicycles were synthesized starting from bicyclo[5.3.1]undec-8-en-9-one (3) and bicyclo[4.3.1]dec-7-en-8-one (8), respectively, by a sequence consisting of catalytic hydrogenation, alpha-alkylation with a TBS-protected (tert-butyldimethylsilyl) hydroxy halide, acid-catalyzed cyclization, oxidative cleavage of the formed enol ether double bond, and subsequent reduction of the carbonyl group via its tosylhydrazone. The compound (1R,6R,9R)-(+)-6-methyl-4-oxa-bicyclo[7.5.1]pentadecan-3-one (22) was found to possess the most pronounced musk odor, and this was rationalized by a superposition analysis with the polycyclic aromatic musk odorant (4S,7R)-Galaxolide (2). In its (1S,6R,9S)-(+)-stereoisomer 23 as well as in (1S,6R, 10R)-(+)-6-methyl-4-oxabicyclo[8.4.1]-pentadecan-3-one (18) the (6R)-methyl group seems to hinder the interaction with the musk receptor, while the demethyl compounds 7 and 12 showed only very faint odors.

Enantioselectivity of the musk odor sensation

This brief review, the summary of a talk at the Symposium on Biological Chirality 2000 in Szeged, Hungary, illustrates what chiral recognition tells us about the molecular parameters of the musk odor sensation. While the enantioselectivity of odor perception is strong evidence for the key role of proteinogenic receptors in the molecular mechanism of olfaction, the quantitative and qualitative odor differences of enantiomers are often not very pronounced, as in the case of muscone (17/26). In those cases, however, where there is strong enantiodiscrimination, we find most intense musk odorants with very low odor thresholds, such as (-)-(12R)-12-methyl-9-oxa-14-tetradecanolide (35), (12R;9Z)-12-methyl-14-tetradec-9-enolide [(R)-Nirvanolide, 38], and (-)-(4S;7R)-1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran [(-)-(4S;7R)-Galaxolide, 57], the latter being rather rigid. We thus can assume the geometry of the musk receptor to be fairly complementary to these compounds, which therefore can serve as templates for the design of new musk odorants.

Odds and Trends: Recent Developments in the Chemistry of Odorants Note on trademarks: Words which we know or have reason to believe constitute registered trademarks (R) are designated as such. However, neither the presence nor absence of such designation should be regarded as affecting the legal status of any trademark. Note on perfume analysis: The quoted percentages of perfume raw materials in market products are rounded figures. They are often derived from area percentages from the GC (FID) analysis, and are thus subject to analytical error

Fragrance chemistry is, together with the closely related area of flavor chemistry, one of the few domains, if not the only one, in which chemists can immediately experience structure-activity relationships. This review presents structure-odor correlations and olfactophore models for the main odor notes of perfumery: "fruity", "marine", "green", "floral", "spicy", "woody", "amber", and "musky". New trendsetters and so-called captive odorants of these notes are introduced, and recent activities and highlights in fragrance chemistry are summarized. The design of odorants, their chemical synthesis, and their use in modern perfumery is discussed. Our selection is guided and illustrated by creative fragrances, and features new odorants which encompassed current trends in perfumery. New odorants for grapefruit and blackcurrant, for galbanum, and leafy top notes are presented. Compounds with fashionable marine, ozonic, and aquatic facets are treated, as well as new odorants for classical lily-of-the-valley, rose, and jasmine accords. Compounds with sweet and spicy tonalities are also discussed, as are the most recent developments for woody notes such as sandalwood and vetiver. We conclude with musky and ambery odorants possessing uncommon or unusual structural features. Some odor trends and effects are illustrated by microencapsulated fragrance samples, and areas where there is need for the development of new synthetic materials and methodologies are pointed out. Thus, chemists are invited to explore fragrance chemistry and participate in the design and synthesis of new odorants. This review gives the latest state of the art of the subject.