Essential Oil Composition of Vetiveria nigritana from Mali

Journal of Essential Oil Research: JEOR, Nov/Dec 2006 by Champagnat, Pascal, Figueredo, Gilles, Chalchat, Jean-Claude, Bessière, Jean-Marie

Abstract

An oil was obtained from roots of Vetiveria nigritana (Benth.) Stapf collected in Mali and analyzed by GC and GC/MS. Fifty-four constituents (79.7% of the whole oil) were identified. Prezizanoic acid (15.0%), preziza-7(15)-en-12-ol (9.5%), cedren-8-en-15-ol (6.2%), preziza-7(15)-en-3α-ol (6.0%) and zizanoic acid (5.9%) were the major components of Vetiveria nigritana oil.

Key Word Index

Vetiveria nigritana, Poaceae, essential oil composition, prezizanoic acid.

Plant Name

Vetiveria nigritana (Benth.) Stapf (Poaceae).

Source

Roots of V. nigritana were collected from Koulikouro, near Bamako (Mali, Africa) in March 2002. Plant material was identified by G. Aymonin (Muséum d'Histoire Naturelle, Paris, France). A voucher specimen of the whole plant has been deposited in the Herbarium of the University of ClermontFerrand (France); register number CLF 049699.

Plant Part

The oil was obtained from air dried roots by steam distillation in a Kaiser & Lang-type apparatus for 12 h to produce yellow oil in 2% w/w yield.

Previous Work

The first botanical descriptions of this plant were published in Niger Flora (1) and in Flora of Tropical Africa (2). In some countries of Africa, in particular Senegal, Gabon, Mali and Niger, roots of Vetiveria nigritana were used in the following fields: perfume, cosmetics and medicine. Macerations or infusions of roots were added to drinking water or used as an antidiarrheal for children (3).

In spite of traditional use, there was no work about any components of these roots. Only a few articles were previously published about Angolan root oil by Cardoso et al. (4-6) and Nigam et al. (7). Hutchinson et al. made reference to the variations of percentage of essential oil certainly relating to the soils (8). In the book on genus Vetiveria published in 2002, Maffei (9) reported all studies concerning V. zizanioides, but only mentioned V. nigritana without any comment.

Present Work

GC analyses were performed on a Hewlett Packard HP 6890 equipped with a split/splitless injector (280°C), a split ratio 1:10, using a HP-5 capillary column (25 m x 0.25 mm, film thickness 0.25 µm). The temperature program was 50°C (5 min) rising to 300°C at a rate of 5°C/min. Helium was used as the carrier gas at a flow rate of 1.1 mL/min. The injection of the sample consisted of 1.0 µL of the oil diluted to 10% v/v with acetone.

GC/MS analyses were performed by a Hewlett Packard 5973/6890 system operating in EI mode (70 eV), equipped with a split/splitless injector (280°C), a split ratio 1:10, using two different columns: a fused silica HP-5 MS capillary column (25 m x 0.25 mm, film thickness 0.25 µm), and a HP-Innowax capillary column (60 m x 0.25 mm, film thickness 0.25 µm). The temperature program for the HP-5 MS column was 50°C (5 min) rising to 300°C at a rate of 5°C/min and for the HPInnowax column, 50° -250°C at a rate of 5°C/min. Helium was used as the carrier gas at a flow rate of 1.1 mL/min. Retention indices for all compounds were determined according to the Van den Dool approach (10). The identification of components was based on comparison of their mass spectra with those of Mc Lafferty and Stauffer (11), Adams (12) and Joulain (13) libraries, as well as by comparison of their retention indices with literature data.

The composition of the oil from the roots of V. nigritana is summarized in Table I.

Fifty-seven compounds were detected (90.3% of the oil), amongthose, 54 were identified (79.7%). This oil was principally characterized by the presence of only sesquiterpene compounds. Alcohols and acids were the most important components (33.7% and 31.1%, respectively). Among the alcohols, preziza-7(15)-en-12-ol (9.5%), cedren-8-en-15-ol (6.2%), preziza-7(15)-en-3α-ol (6.0%), were the main compounds. The major acids were prezizanoic acid (15.0%), compound no 56 (7.5%) and zizanoic acid (5.9%). The sesquiterpene hydrocarbons (10.5%) were mainly represented by compound no 4 (2.2%), preziza-7(15)-ene (1.7%) and β-cedrene (1.6%). 12-Nor-preziza-7(15)-en-2-one (2.7%) was the main ketone among a low percentage of total ketones (5.5%). Other components were found to be aldehydes (8.0%) and esters (0.1%).

The composition of oil of V. nigritana was compared to those of oils of V. zizanioides from different countries. Weyerstahl reported the composition of an Haitian oil (14), and more recently, Champagnat et al. studied V. zizanioides oils from nine different geographical origins (unpublished work). The results of these authors are concordant and show that V zizanioides oils from any geographical origin were characterized by the presence of 40-57% alcohols, 15-25% hydrocarbons, 13-16% ketones, approximately 5% aldehydes, a very low amount of esters (

As a result, the composition of the oil of V. nigritana (from Mali) was mainly different from that of V. zizanioides, regarding the hydrocarbon and acid contents of these oils.

Acknowledgment

We are grateful to G. Aymonin (Muséum d'Histoire Naturelle, Paris) for helpful assistance in botanical identification.