Purpose: To determine the antimicrobial and antioxidant activities of
Pulicaria inuloides
and
Ocimum forskolei essential oils.
Methods: Steam distillation of the aerial parts of
P. inuloides and
O. forskolei was performed using a
Clevenger apparatus. Essential oils were analyzed by gas chromatography–mass spectrometry. Total
phenolic content and antioxidant activities were determined by 2,2-diphenyl-1,1-picrylhydrazyl (DPPH)
and β-carotene bleaching assays. Disc diffusion and microtiter broth microdilution assays were
employed to determine antimicrobial activity.
Results: The chemical compounds in
P. inuloides essential oil include 2-cyclohexen-1-one, 2-methyl-5-
(1-methyl) (55.1 %) and benzene, methyl- (20.6 %). The major components identified in
O. forskolei
essential oil included bicyclo [3.1.1] hept-2-ene,2, (22.4 %) and naphthalene 1,2,3,4,4a,5,6, (19.3 %).
P.
inuloides showed a higher total phenol content than
O. forskolei (144 ± 5.32 vs. 54.6 ± 30 mg GAE/g
extract), higher antioxidant activity (92.92 ± 0.10 % vs. 26.76 ± 0.11 % scavenging activity; IC
50, 4.5 ±
0.05 vs. 73.03 ± 0.05) and β-carotene bleaching (90.77 ± 0.21 % vs. 41.03 ± 6.35 % inhibition).
P.
inuloides essential oil inhibited all tested microorganisms except
Salmonella typhimurium
and
Shigella
dysenteriae
with a minimum inhibitory concentration (MIC) of 3.0 μg/mL against
Escherichia coli
.
O.
forskolei essential oil inhibited only
Candida albicans
.
Conclusion: P. inuloides essential oil possesses significant antioxidant and antimicrobial activities.
