Composition of Essential Oils of Tagetes patula L. Growing in Northern India

Journal of Essential Oil Research: JEOR, Jul/Aug 2005 by Sagar, D Vidya, Naik, S N, Rout, P K, Rao, Y R

Abstract

The chemical compositions of the essential oils of Tagetes patula leaf, capitula and total above ground herb collected from Farrukhnagar (28°N, 76°E), Haryana, India were subjected to analysis by GC and GC/MS. The major constituents of the oils were limonene (6.2-13.6%), (Z)-β-ocimene (0.3-8.3%), dihydrotagetone (4.5-8.l%), terpinolene (0-11.2%), p-cymen-8-ol (3.4-11.0%), piperitone (6.1-11.9%), piperitenone (2.7-8.1%), β-caryophyllene (2.3-8.0%) and trans-sesquisabinene hydrate (2.0-12.5%).

Key Word Index

Tagetes patula, Asteraceae, essential oil composition, limonene, (Z)-β-ocimene, dihydrotagetone, terpinolene, p-cymen-8-ol, piperitone, trans-sesquisabinene hydrate.

Introduction

Tagetes patula L. (marigold) belongs to the Tagetes genus (Fam. Asteraceae). It is one of the four annual Tagetes species native to Central America but is found throughout the world as an important ornamental plant (1). In India, it is cultivated as a floriculture crop and the flowers are used loose or in garlands for social and religious purposes (2). Recently, commercial cultivation of marigold in India has risen to an estimated 13,000 hectares with annual production of 200,000 tonnes of flowers, the highest for any flower grown in India (3). Tagetes oil in general usually refers to the essential oil from T. minuta, which has been investigated by several workers (4-8). The first chemical investigations on T. patula oil was reported by Igolen (9), who obtained it in 0.3% yield by steam distillation of the entire above ground full flowering plants and reported tagetone as the major constituent. Analysis of the oil has been reviewed by Lawrence (5) and also by Garg et al. (10). Piccaglia et al. reported chemical and antimicrobial activity of essential oils of T. ercta and T. patula (11). Extraction of the capitula with liquid and supercritical carbon dioxide was studied and its composition compared with steam volatile oil (12). More recently, by combination of GC and GC/MS, 22 components have been identified (10) in the capitula oil of T. patula (yield 0.09%). The effect of mineral fertilization on the composition of the oil has also been studied in Bulgaria (13). In addition, lutein and lutein esters in hexane extracts of some types of T. patula have been investigated recently (14). We report here composition of the oils obtained from the distillation of leaves, capitula and above ground parts of T. patula grown in Haryana, India.

Experimental

The plant material and oil recovery: Five kg each of capitula and leaves of T. patula were collected in December 2000 when the crop was in full bloom from Farrukhnagar, Gurgaon district, Haryana, India. The above ground part of plant material was collected in February 2001 almost at the end of the flowering season.

The capitula and leaves were brought to the laboratory and distilled in a Clevenger- type apparatus for 4 h to get 0.1% and 0.4% oil, respectively. The above ground part comprising of flowers, leaf and stems (1 tonne) was distilled in a commercial still to recover about 1.4 kg of oil. The oils were dried over anhydrous sodium sulfate and stored in glass bottles under nitrogen in a refrigerator before analysis.

GC and GC/MS analysis: GC analysis was carried out on a Shimadzu GC 17A gas chromatograph equipped with a flame ionization detector and a 30 m x 0.25 mm WCOT column coated with 0.25 µm 5% diphenyl dimethyl silicone supplied by J &W (DB-5). The carrier gas used was helium at a flow rate of 1.2 mL/min at a column pressure of 42 Kpa. Component separation was achieved following a temperature program of 60°-200°C (2°C/min). Percentage composition was calculated using peak normalization method. The oils were analyzed using a Shimadzu QP5000 GC/MS fitted with the same column and temperature programmed as above. MS parameters: ionization voltage (EI) 70 eV, peak width 20 s, mass range 40-400 amu. Peak identification was carried out by comparison of the mass spectra with mass spectra available on NIST-I, NIST-2 and Adams libraries. The compound identification was supported by comparison of their relative retention indices with literature values (15,16) and the data are presented in Table I.

Results and Discussion

It may be seen from Table I that the T. patula oil is a complex mixture of several compounds, with limonene, (Z)- and (E)-β-ocimene, tagetenone, dihydrotagetone, terpinolene, piperitone and piperitenone, β-caryophyllene andfraos-sesquisabinene hydrate as constituents in significant amounts. Previous work (6,17) on the T. patula oil of Indian origin reported the major constituents to be limonene (23%), β-ocimene (11%), linalool (26%), linalyl acetate (17%) and tagetone (14%). However, in agreement with Garg et al. (9), we have not come across such chemotypes. The presence of irans-sesquisabinene hydrate in significant amounts (2.0-12.5%) is reported for the first time. A total of 71 compounds were reported constituting 85.0%, 77.6% and 77.5% of oils from leaf, flower and aerial parts of the plant, respectively.