Constituents of the Rhizome Oil of Hedychium cylindricum Ridl.

Journal of Essential Oil Research: JEOR, Jul/Aug 2004 by Ahmad, Fasihuddin bin, Jantan, Ibrahim bin, Jalil, Juriyati

Abstract

The chemical composition of the rhizome oil of Hedychium cylindricum Ridl. was determined by GC retention indices (on two columns of different polarity) and GC/MS. Forty-nine compounds were identified with monoterpernoids accounting for more than 88% of the oil. The major constituents of the oil were terpinen-4-ol (40.5%), sabinene (9.9%), p-cymene (8.5%), limonene (6.0%), [gamma]-pinene (5.6%), [alpha]-terpinene (4.5%), and [alpha]-terpineol (2.2%).

Key Word Index

Hedychium cylindricum, Zingiberaceae, essential oil composition, terpinen-4-ol.

Introduction

Hedychium cylindricum Ridl., Zingiberaceae, is a rhizomatous herb that grows wild on Borneo Island. It is usually about 0.9-1 m high and is found on rocks and fallen logs along river banks (1). The leaves are glabrous while the fruits are dehisced and orange in color within, and the rhizomes are fleshy and very aromatic. In Sabah, Malaysia, the ground rhizome is used in traditional medicine as a febrifuge, antirheumatic, tonic and also as a treatment for wounds and skin diseases (2).

Chemical studies of the oils of some Hedychium species have been reported (3-8). The rhizome oils of H. coronarium Koenig from different countries showed compositional differences, suggesting the existence of chemical varieties. 1,8-Cineole (40-41%) was the most abundant constituent of the oils of the Indian and Tahitian species, but the concentrations of other main components such as [beta]-caryophyllene and [beta]-pinene varied (3,4). The Egyptian species was found to contain methyl eugenol, methyl salicylate and methyl anthranilate, which were absent in the species from the other locations (5). 1,8-Cineole was also the major component of the rhizome oil of H. acuminatum Roscoe (6). The rhizome oil of H. aurantiacum Roscoe was found to be a potential source of linalool (81%) (7). The rhizome oil of H. gardnerianum Roscoe contained about 30% sesquiterpenes, mainly cadinane derivatives (8).

There does not appear to be any prior report on the nature of the rhizome oil of H. cylindricum. The present paper reports on the chemical constituents of the rhizome oil of H. cylindricum collected from Sabah, Malaysia.

Experimental

Plant material: Fresh rhizomes of H. cylindricum were collected from Mahua, Crocker Range, Sabah, Malaysia, in October 1999. Voucher specimens were deposited at the Herbarium of the Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia.

Isolation of the essential oils: Fresh rhizomes, finely chopped (200 g), were subjected to water distillation in a Clevenger-type apparatus for 8 h. The oily layers obtained were separated and dried over anhydrous sodium sulphate. The yields were averaged over two experiments and calculated based on the dry weight of the plant materials.

Analysis of the oil: GC analysis was performed using a Shimadzu GC 14A capillary Chromatograph equipped with an FID detector using a DBS (30 m x 0.25 mm; 0.25 �m film thickness) capillary column. The samples were dissolved in n-hexane and injected in split mode, using pressured controlled helium as carrier gas at a linear velocity of 50 cm/s. Injector and detector temperature were maintained at 250�C. The oven temperature was programmed at 75�C (10 min) to 230�C at 3�C/min. The oil was also examined using an S E 30 capillary column (25 m x 0.25 mm; 0.25 � film thickness) under the following program condition: initial temperature 60�C for 10 min, then 3�C/min to 180�C for l min. Peak areas and retention times were measured by electronic integration. The relative amounts of individual components were based on peak areas obtained, without FID response factor correction. Temperature program linear retention indices of the compounds were also determined relative to n-alkanes (9).

GC/MS analyses were carried out on a Hewlett Packard GC/MSD 5890 series, EI electron impact ion source, 70 eV using a BPX5 (30 m x 0.25 mm; 0.25 �m film thickness) with similar conditions as described in GC programs. Identification of the chemical components was based on the comparison of their mass spectral data with the existing Wiley library, comparison of calculated retention indices with literature values and co-chromatography of some constituents with authentic components on the DB 5 capillary column (10-12).

Results and Discussion

Water distillation of the fresh rhizomes of//, cylindricum yielded 1.5% oil (calculated on a dry weight basis). The gas chromatogram of the oil revealed the presence of at least 55 components, of which 47 were identified (Table I). From the analysis of the mass fragmentation patterns, the unidentified components (3%) that were each present in minute quantities were sesquiterpenes hydrocarbons and their oxygenated derivatives.

The oil was characterized by its richness in monoterpenoids (> 88%) where terpinen-4-ol (40.5%) was the most abundant compound. The oil may be used as a good source of this compound which is widely used in the perfume industry. Other major monoterpenoids in the oil were sabinene (9.9%), p-cymene (8.5%), limonene (6.0%), [beta]-pinene (5.6%), [gamma]terpinene (4.5%), and [alpha]-terpineol (2.2%). 1,8-Cineole and linalool, which were the major components in the other Hedychium species, were only present in minute quantities at 0.1% and 1.3%, respectively (3-8). Sesquiterpenoids constituted only 5.4% of the oil and all of the 16 Sesquiterpenoids identified were present in minute quantities (not more than 0.5%) except for longifolene which was present at 1.0% concentration.