alpha-bulnesene and guaiene

Patchouli is used as an incense material and essential oil. The characteristic odor of patchouli leaves results from the drying process used in their production; however, there have to date been no reports on the changes in the odor of patchouli leaves during the drying process. We investigated the aroma profile of dried patchouli leaves using the hexane extracts of fresh and dried patchouli leaves. We focused on the presence or absence of the constituents of the fresh and dried extracts, and the differences in the content of the common constituents. Fourteen constituents were identified as characteristic of dried patchouli extract odor by gas chromatography-olfactometry analysis. The structures of seven of the 14 constituents were determined by gas chromatography-mass spectrometry (α-patchoulene, seychellene, humulene, α-bulnesene, isoaromadendrene epoxide, caryophyllene oxide, and patchouli alcohol). The aroma profile of the essential oil obtained from the dried patchouli leaves was clearly different from that of dried patchouli. The aroma profile of the essential oil was investigated by a similar method. We identified 12 compounds as important odor constituents. The structures of nine of the 12 constituents were determined by gas chromatography-mass spectrometry (cis-thujopsene, caryophyllene, α-guaiene, α-patchoulene, seychellene, α-bulnesene, isoaromadendrene epoxide, patchouli alcohol, and corymbolone). Comparing the odors and constituents demonstrated that the aroma profile of patchouli depends on the manufacturing process.

Topics: Azulenes; Chromatography, Gas; Gas Chromatography-Mass Spectrometry; Hexanes; Liquid-Liquid Extraction; Odorants; Oils, Volatile; Olfactometry; Plant Extracts; Plant Leaves; Plant Oils; Pogostemon; Polycyclic Sesquiterpenes; Sesquiterpenes; Sesquiterpenes, Guaiane; Terpenes

The enhanced sample collection capability of a heart-cutting three-dimensional GC-prep system is reported. In its original configuration, a highly pure component can be usually collected after the last (3D) column outlet by means of a dedicated preparative station. The latter is located after the last chromatographic column, and this poses the requirement for multiple heart cuts even for those components showing satisfactory degree of purity after the first (or second) separation dimension. The feasibility to collect pure components after each chromatographic dimension is here described, employing a three-dimension MDGC system equipped with high-temperature valves, located inside the first and second GC ovens, with the aim to improve the productivity of the collection procedure. In addition to a commercial preparative collector located at the 3D outlet, two laboratory-made collection systems were applied in the first and second dimension, reached by the effluent to be collected trough a high-temperature valve switching the heart-cut fraction between either the detector (FID), or the collector. Highly pure sesquiterpene components were collected, namely: patchouli alcohol after the first column [poly(5% diphenyl/95% dimethylsiloxane)], α-bulnesene after a second column coated with high molecular weight polyethylene glycol, and α-guaiene after an ionic-liquid based column (SLB-IL60), used as the third dimension. Purity levels ranging from 85 to 95% were achieved with an average collection recovery of 90% (n=5). The following average amounts were collected per run: 160μg for α-guaiene, 295μg for α-bulnesene, and 496μg for patchouli alcohol.

Topics: Azulenes; Chromatography, Gas; Dimethylpolysiloxanes; Polyethylene Glycols; Sesquiterpenes; Sesquiterpenes, Guaiane

Deuterium-labeled guaiane derivatives and their precursors, namely, d5-2R-rotundol (11a), d5-2S-rotundol (11b), d5-bulnesone (14), d5-2R-bulnesol (16), d7-α-guaiene (10), and d7-α-bulnesene (15), were synthesized in good yields as GC-MS internal standards for comparing the behavior of α-guaiene (1) and α-bulnesene (5) under autoxidative conditions. It was found that approximately 99% of α-guaiene coated onto filter paper and exposed to air at ambient temperature was autoxidized after 48 h and up to 7% of rotundone (3) and 0.6% of rotundols (2a/b) were formed during this period. Autoxidation of α-bulnesene (5) was considerably slower, with approximately 80% remaining after 2 days and yielding less than 1.5% of α-bulnesone (7) and 0.3% and 0.9% of bulnesols 6a and 6b, respectively, after 5 days. The results indicate the feasibility of rapid changes of aroma profiles of herbs and other plant materials over time when exposed to air.

Topics: Azulenes; Flavoring Agents; Odorants; Oxidation-Reduction; Sesquiterpenes; Sesquiterpenes, Guaiane