Abstract
Essential oil composition of Plectranthus asirensis grown in Saudi Arabia was chemically analysed for the first time by various gas chromatography techniques (GC-MS, GC-FID, Co-GC, LRI determination and database and literature searches) using two different stationary phase columns (polar and nonpolar). This analysis led to the characterisation of a total of 124 components representing 98.5% of the total oil composition. The results revealed that P. asirensis oil was mainly dominated by monoterpenoids (90.7%) in which most representative constituents were thymol (66.0 +/- 0.36%), -terpinene (14.0 +/- 0.18%), p-cymene (5.2 +/- 0.06%) and -caryophyllene (3.0 +/- 0.03%). It is worth mentioning here that this is the first report on the phytochemical constituents of P. asirensis.
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