JEOR: Analysis of the Essential Oil of Indonesian Patchouli (Pogostemon cablin Benth.) Using GC/MS (EI/CI)

Analysis of the Essential Oil of Indonesian Patchouli (Pogostemon cablin Benth.) Using GC/MS (EI/CI)

Bure, Corinne M

Introduction

Patchouli oil is obtained by steam distillation of the non-fermented dried leaves of the plant Pogostemon cablin (Benth.) (syn. P. patchouli Hook.) (family Lamiaceae) where cyclic sesquiterpenes were accumulated. Patchouli oil is a dark orange or brownish colored viscous liquid. Because of its oriental notes and its strong fixative properties (1), it is one of the most important essential oils utilized in the perfumery and cosmetic products industries where it is used in products such as soaps, detergents or deodorants (1).

The study of the structure relationships of patchouli odor has been the subject of numerous investigations. Most were mainly on the odor relationships of patchoulol and norpatchoulenol. Teisseire et al. (2) were the first to show that the odor of patchouli comes from norpatchoulenol. Nikiforov et al. (3,4) proved that (-)-patchoulol was the predominant odor component of patchouli oil by using chiral phase gas chromatography combined with a ‘sniffing-technique.’ More recently, Maurer (5) indicated that some nitrogenous compounds contributed to the odor of patchouli oil.

Pogostemon cablin is grown mainly in Indonesia, Malaysia, China, Brazil and India. Various natural and/or controllable factors could affect the yield, the exact character and the quality of the oil such as growth under sun and shade condidons (6), soil heterogeneity (7), quality of planting material (8) and cultivation practices (9).

This diversity has induced some variation in the chemical composition and physical properties of the oil (6-7). As a result, the composition of patchouli oil has been the subject of a large number of studies (10-18).

The present study was undertaken in order to improve the knowledge of the chemical composition of patchouli oil. In this paper, we report the qualitative and quantitative analysis of the volatile components of Indonesian patchouli oil. Four new compounds were characterized from this oil; namely, [gamma]-gurjunene, germacrene D, aciphyllene and 7-epioc-selinene.

Experimental

Materials: The Indonesian patchouli oil used was given by Jean Niel Society (Grasse, France). Authentic compounds, which were used to identify the oil’s components by coinjection in gas chromatography, were obtained from commercial industries such as Fluka-Sigma-Aldrich (Saint-Quentin Fallavier, France) and Interchim (Asnieres, France).

Gas chromatography (GC): GC analysis of the oil was performed on Varian 3400 (Varian, Les Ulis, France) with an FID and an electronic integrator. The instrument was fitted with a 30 m × 0.25 mm non-polar CP-Sil-5-CB-MS column, film thickness 0.25 µm (Clirompack, Les Ulis, France). Oven temperature was programmed from 80°-120°C at 5°C/min, held at 120µC for 10 min and then programmed from 120°-220°C at 3°C/min. Injector and detector temperature were 250°C. Carrier gas was helium. One µL of oil dissolved in acetone was introduced into the gas Chromatograph with a split mode ratio of 1:100.

Gas chromatography/mass spectrometry (GCIMS): This method was used for identification of the components detected. GC/MS analysis was carried out with a Varian 3300 (Varian, Les Ulis, France) coupled with a Nermag R10-10C quadrupole mass spectrometer (Quad Service, Argenteuil, France) controlled by Ezscan System. Positive and negative ion chemical ionization (PCI and NCI) were achieved with ammonia and deuterated ammonia as reagent gases at a pressure of 2.10^sup -4^ Torr. The electronic impact (EI) was carried out at a pressure of 2.10^sup -6^ Torr. Mass spectra were obtained with an MS ionization voltage of 70 eV (EI) or 90 eV (CI) and with an ion source temperature of 250°C. The chromatographic conditions used were the same as those given above for the GC analysis.

Identification of components: The identification of compounds was based on the comparison of the fragmentation pattern of the mass spectra with those reported in the literature (19-21) and those available on NIST (National Institute of Standards and Technology) and WILEY libraries. We used also the ESO 2000 Database system (22). Components were also identified comparing their retention indices (RI) on a CP-Sil-5-CB-MS column (19-20). The identification of components was confirmed by comparison of their RI and the fragmentation pattern of their mass spectra with those of authentic compounds analyzed by co-injection in GC/MS whenever it was possible. The quantitative analysis was achieved with a flame ionization detector (FID).

Results and Discussion

The constituents of patchouli oil are listed in Table I according to their elution order on the CP-Sil-5-CB-MS column. The chromatogram of the oil indicated 41 peaks of which 28 were identified. The nature and the chemical functions of the 13 non-identified compounds were determined by the use of deuterated ammonia (23) ND^sub 3^ as a reagent gas in positive ion chemical ionization. Among these ones, we found seven sesquiterpene hydrocarbons (2.0%) and six sesquiterpene alcohols (3.0%).

Acknowledgments

We are grateful to Antoine de Bontigny, jean Niel Society, for his gift of patchouli essential oil of Indonesia.

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