Abstract Detail

Ecophysiology

Hildebrand, Terri [1], Tufte, Mary [2], Manwill, Preston [3], Kansagra, Harsh [3].

Antimicrobial Properties of Essential Oils Isolated from Anthoxanthum (Poaceae) Against Soil Bacteria.

Anthoxanthum hirtum is a native grass with a long history of traditional ceremonial, medicinal, and ornamental uses. The active compound that elicits the sweet fragrance of the grass is produced by coumarin, a secondary metabolite used today both medicinally and commercially. Plants most often produce secondary metabolites, or essential oils, as a defense against pathogens, but these antimicrobial properties have not been widely investigated in Anthoxanthum species. Our research developed a new protocol that isolated and concentrated the oils from closely related European commercial diploid and polyploid Anthoxanthum strains (A. odoratum), as well as plants from a native (A. hirtum) population. Using Kirby-Bauer diffusion tests, we determined if the oils inhibited the growth of various soil bacteria associated with each strain. Our preliminary results have shown that inhibition zones do occur when A. hirtum oils were tested against bacteria closely associated with its roots, but significantly fewer zones were formed against bacteria isolated from soils associated with the commercial strains (p < 0.001). Further Kirby-Bauer testing of oils isolated from the A. odoratum strains is ongoing and results will be presented. We also analyzed the components of oils produced by each strain using mass spectrometry and determined the % weight/volume (%wt/vol) of coumarin present in each. Polyploid A. odoratum plants produced the greatest % wt/vol of coumarin (µ = 23.2%) whereas diploid A. odoratum and A. hirtum plants were not significantly different in the level of coumarin contained in their oils (16.2% and 15.5% wt/vol, respectively). Interesting trends were observed among other naturally occurring metabolites isolated and noted from mass spectrometry results, including the known photoactive furan compounds 2,3-dihydrobenzofuran and 4,4,7a-trimethyl-5,6,7,7a-tetrahydrobenzofuran. Our results are discussed in light of the evolutionary processes that may have selected for essential oil production in Anthoxanthum as well as its ability to inhibit the growth of soil microbes that occur in the plant’s immediate surroundings. Future studies will investigate these properties in other species of Anthoxanthum native to North America and how these antimicrobial response phenotypes may have played a role in the evolution and distribution of species within the genus.

Broader Impacts:

1 - Southern Utah University, Biology, 351 W University Boulevard, Center for Health & Molecular Sciences 213, Cedar City, UT, 84720, USA
2 - Southern Utah University, 351 W University Boulevard, Science Center 117, Cedar City, UT, 84720, United States
3 - Southern Utah University, 351 W University Boulevard, Cedar City, UT, 84720, United States

Keywords:
soil microbes
essential oil
Kirby Bauer Diffusion Test.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PEP012
Abstract ID:924
Candidate for Awards:Physiological Section Best poster presentation,Physiological Section Physiological Section Li-COR Prize