Supreeya Yuenyongsawad and Supinya Tewtrakul

pp. 497 - 502

Abstract

The essential oil distilled from the leaves of Coleus parvifolius Benth. (Labiatae) was studied by gas
chromatography and mass spectrometry (GC-MS). The main components were found to be (E)-phytol
(42.77%), followed by eicosatrienoate (16.39%), n-tetradecanoic acid (14.42%), octoil (6.54%), 2-methyl-7-
octadecyne (5.97%), nonadecane (3.25%), germacrene-D (2.19%) and α-humulene (1.42%), respectively.
Regarding biological activities, the ethanolic extract of C. parvifolius showed potent antimicrobial activity
against gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and B. cereus) with inhibition zones
of 7-11 mm at a concentration of 10 mg/disc and moderate activity against gram negative bacteria (Salmonella
typhi, S. enteritidis and Escherichia coli) with inhibition zones of 9-11 mm at 100 mg/disc, whereas it was
inactive against fungus, Candida albicans at a concentration of 100 mg/disc. The extract also exhibited strong
antioxidant activity (ED₅₀ = 5.87±0.03 µg/ml) three times higher than that of butylated hydroxytoluene
(BHT, ED₅₀ = 18.08±0.43 µg/ml). Moreover, it was non-toxic to brine shrimp with LC₅₀ value > 1,000 µg/ml.