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Of 73 essential oils tested for antibacterial activity against Streptococcus pneumoniae R36A (an unencapsulated strain) with a paper disk diffusion assay, three oils were highly inhibitory, fifteen moderately inhibitory and the remainder weakly or non-inhibitory. Three oils from each group were selected and tested with a broth assay in which each oil was added to growing cultures of S. pneumoniae R36A and optical densities (OD) were measured over time. The oils with high antibacterial activity; oregano, thyme and rosewood, induced rapid lysis of R36A as indicated by a decrease in OD, and appearance of dechaining and considerable cell debris within 30 min of addition. The lytic response of R36A to the three oils with moderate activity was variable but all induced some lysis. Oils that were weak inhibitors generally caused slowing of growth but little or no lysis. Several oils were also tested against an encapsulated isolate, S. pneumoniae IC2. Both disk assay and broth results were similar to thos...

The hydrodistilled essential oils from herbal parts of three varieties of Chrysothamnus nauseousus were analyzed by GC and GC/MS. All oils were found to consist of mainly monoterpenes. A total of 51, 46 and 59 compounds were identified from C. nauseousus var. albicaulis, C. nauseousus var. consimilis and C. nauseousus var. glabratus, respectively, representing 97.1%, 96.0% and 96.2% of each of the oils listed. The major constituents of C. nauseousus var. albicaulis were β-pinene (16.8%), limonene (18.6%) and β-phellandrene (26.0%); the main constituents of C. nauseousus var. consimilis were limonene (33.2%), β-phellandrene (18.0%) and (Z)-β-ocimene (14.6%). The major constituents of C. nauseousus var. glabratus were β-pinene (30.3%), myrcene (10.5%), limonene (16.5%) and β-phellandrene (10.9%).

The steam-distilled essential oil from stem part of Bursera graveolens was analyzed by GC and GC/MS. The oil was found to consist of monoterpenes (78.2%) and sesquiterpenes (9.6%). The major constituents of B. graveolens oil were limonene (58.6%), and α- terpineol (10.9%).