A total of 38 phytochemicals were detected but only 36 chemical
constituents were identified (99.87%). The number of identified
components in this study was small as compared with the previous
study in which a total of 75 compounds were identified representing
99.8% of Omani basil oil[5]. Linalool was identified as the major
component (69.87%), followed by geraniol (9.75%), p–allylanisole
(6.02%), 1,8–cineole (4.90%), trans–琢–bergamotene (2.36%) and
neryl acetate (1.24%).
Although there was a difference in number and concentration of the
basil oil constituents in both studies, linalool (69.87%) was identified
as the major component with almost similar concentration present
in Omani basil oil in both studies. In our study, the concentration
of p–allylanisole was found to be approximately ten times of the
value observed in Omani basil oil by Hanif et al[5]. This difference
could be due to seasonal variation and stage of plant growth. Two
compounds with retention time of 13.40 min (0.074%) and 31.38
min (0.045%) could not be identified by GC–MS analysis.
The basil volatile oil primarily consisted of oxygenated monoterpenes,
monoterpene hydrocarbons, sesquiterpene hydrocarbons, oxygenated
sesquiterpenes and diterpene hydrocarbon.
3.2. Antibacterial activity
The antimicrobial activity of the basil essential oil was tested
against three Gram–positive and four Gram–negative pathogenic
bacterial strains. The results of the antibacterial activity reported
as diameter of zone of inhibition (mm) are shown in Table 2.