|Fredrickson, Ed - USDA ARS BIOLOGICAL CONTR|
Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 15, 2001
Publication Date: November 12, 2001
Citation: TELLEZ, M.R., ESTELL, R.E., FREDRICKSON, E., POWELL, J.E., WEDGE, D.E., SCHRADER, K., KOBAISY, M.M. EXTRACTS OF FLOURENSIA CERNUA (L): VOLATILE CONSITUENTS AND ANTIFUNGAL, ANTIALGAL, AND ANTITERMITE ACTIVITIES. JOURNAL OF CHEMICAL ECOLOGY. 2001. V.27(11). P.2275-2287. Interpretive Summary: Many of the currently used synthetic pesticides are in the process of being phased out or of facing severe limitations on their use. Finding new pesticides from natural sources will not only help replace synthetic pesticides lost to regulatory processes but will help in finding more environmentally benign pesticides that might be even more apt at treating pesticide resistant pests. We have isolated components from the tarbush shrub and evaluated them for possible use against termite, fungi and algae. We have shown that some of these components contain useful products against termites, fungi, and the algae responsible for off-flavor problems in the catfish farming industry. We also established the distribution of chemicals in these components, which might help in the range management of this invasive shrub.
Technical Abstract: The chemical components of 36 kg of tarbush (Flourensia cernua) leaves were fractionated by extracting successively with hexanes, diethyl ether, and ethanol. Volatile profiles of each fraction were identified using GCMS. The hexanes fraction was found to contain mostly monoterpenoids while the ethanol fraction volatiles were primarily sesquiterpenoids. The crude fractions were tested for activity against fungi, algae, and termites. Application of as little as 1 æg of the essential oil obtained from the hexanes fraction was sufficient to provide visible antifungal activity in bioautography assays. The diethyl ether fraction showed selective activity against the cyanobacterium responsible for 2-methylisoborneol induced off- flavor sometimes associated with catfish farming operations. All three fractions exhibited a high degree of antitermite activity.