Constituents of the Essential Oils from Two Varieties of Cymbopogon distans

Abstract

Cymbopogon distans (Steud.) Wats. (l), unlike other species of the series Citrati, has linear-to-filiform leaf blades and a shallowly concave lower glume of the sessile spikelet (1). Both of the varieties of C . distam reported in the present investigation grow wild in the Himalayan region. In our earlier communication, we had reported the chemical composition of C . distans (2), a species growing around Nainital. We have now identified its major constituent, Cl,H,40, as a-oxobisabolene. The second chemotype of C . distans was collected from Munsiyari, and the results presented herein account for ca. 80% ofthe oil obtained from chis chemotype. Its major constituents were observed to be citral, geranyl acetate, and geraniol; however, aoxobisabolene was not detected in this variety. RESULTS AND DISCUSSIONThe physico-chemical properties and chemical composition of the oils isolated from two morphologically identical varieties of C . distans varied markedly.C . DZSTANS (Nainital collection).-The oil (0.6% by weight offresh aerial part) had a specific gravity of 0.801, an acid value of 1.15, an ester value of 19.6 (ester value after acetylation 80.95), and a carbonyl value of 5.

Repellent Constituents of Essential Oil of Cymbopogon distans Aerial Parts against Two Stored-Product Insects

“…13 It was suggested that several chemotypes of C. distans essential oils have marker compounds R-oxobisabolene-1 (chemotype I); citral, geraniol, and geranyl acetate (chemotype II); piperitone, limonene, and eudesmanediol (chemotype III); and sesquiterpene alcohol (chemotype IV). 13,14 One more chemotype with chemical marker p-menthol (66.5%) was reported later. 24 For the practical application of the essential oil as a novel repellent, further studies on plant cultivation and essential oil standardization will be needed because the chemical composition of the essential oil varies greatly with the plant population.…”

“…19 The above findings suggest that there are great variations in the chemical composition of essential oil of C. distans. 13,14 In fact, C. distans has been reported to occur in nature in the form of several geographical races. 13 It was suggested that several chemotypes of C. distans essential oils have marker compounds R-oxobisabolene-1 (chemotype I); citral, geraniol, and geranyl acetate (chemotype II); piperitone, limonene, and eudesmanediol (chemotype III); and sesquiterpene alcohol (chemotype IV).…”

Effect of Terpenoids and Related Compounds on the Oviposition Behavior of the European Corn Borer, Ostrinia nubilalis (Lepidoptera: Pyralidae)

“…Regardless of the chemical specificity and processing of chemical information during olfactory and/or gustatory reception, O. nubilalis, a highly polyphagous pest (Caffrey and Worthley, 1927), likely uses individual sesquiterpenes as cues for host plant selection. The sesquiterpene, farnesal (1), an intermediate in the pathway of insect juvenile hormone biosynthesis (Sen and Garvin, 1995;Schooley and Baker, 1985), a pheromone for the pyralid moth, Corcya cephalonica (Zagatti et al, 1987), and a widespread phytochemical (Chamblee et al, 1985;Melkani et al, 1985), was an oviposition deterrent to female O. nubilalis. Farnesol (2), a precursor of juvenile hormone, was a deterrent for O. nubilalis, but also is active as a juvenile hormone mimic (Bowers and Thompson, 1963;Schooley and Baker, 1985) and is a gonadotrophic hormone in some adult insects (Slama, 1985).…”

Himalayan Aromatic Medicinal Plants: A Review of their Ethnopharmacology, Volatile Phytochemistry, and Biological Activities

“…The components of the essential oils of C. distans differ with growth conditions and geographical locations [ 393 ]. Thus, for example, the essential oil from Munsyari (Uttarakhand) was composed of citral (neral + geranial) (35.0%), geranyl acetate (15.0%), and geraniol (9.5%) [ 122 ]. Similarly, the essential oil cultivated in Pantnagar, Uttarakhand was made up predominantly of geranial (22.8%), neral (16.9%), geraniol (14.8%), and geranyl acetate (19.5%) [ 394 ].…”

“…Similarly, the essential oil cultivated in Pantnagar, Uttarakhand was made up predominantly of geranial (22.8%), neral (16.9%), geraniol (14.8%), and geranyl acetate (19.5%) [ 394 ]. However, the oil from Nainital (Uttarakhand) was dominated by α-oxobisabolene (68%) [ 122 ], while C. distans var. Loharkhet essential oil was rich in the sesquiterpenoids eudesmanediol (34.4%) and 5- epi -7- epi -α-eudesmol (11.2%) [ 395 ].…”