Comparison of volatile inflorescence oils and taxonomy of certain Cymbopogon taxa described as Cymbopogon flexuosus (Nees ex Steud.) Wats.

The inflorescence oils of four taxa of Cymbopogon flexuosus. RRLJ 1279 is typical while the others, RRLJ 1280, RRLJ 1277 and RRLJ 1752, as unusual chemomorphological taxa of the species have been studied by GC and GC-MS from taxonomic and economic point of view. Seventy-seven constituents representing between 94.3% and 99.05% of the total oils of the taxa were identified. Citral, citronellol, elemicin and methyl eugenol ether were the main constituents of the oils of RRLJ 1279, RRLJ 1280, RRLJ 1277 and RRLJ 1752, respectively. Nine constituents detected in the oils of RRLJ 1279, five in RRLJ 1280, 18 in RRLJ 1277 and ten in RRLJ 1752 were not detected in others. Amongst these oil constituents of individual distinction, neral alone constituted 26.1-26.8% of the total oils in RRLJ 1279, citronellol 30-32.1% in RRLJ 1280, 1-10 diepicubenol 6.6-7.6% in RRLJ 1277 and (E)-methyl isoeugenol 20.7-21.1% in RRLJ 1752. The taxa investigated thus revealed distinct chemical characters and when considered together with their differences in morphology, they warrant recognition as distinct taxa. Recognition of each taxon as a varietal entity would be justified as these taxa have been described as single species, Cymbopogon flexuosus. For all these taxa, the oil yields were registered over 1% level and the oils were also rich in many aroma-chemicals of potential industrial value. Thus, the inflorescence oils of these taxa also need to be reviewed for their commercial use as that of their foliage or vegetative aerial parts. (C) 2002 Elsevier Science Ltd. All tights reserved.