1Smithsonian Tropical Research Institute, PO Box 2072, Balboa, Ancon, Republic of Panama.
2Technische Universitaet Braunschweig, Pharmazeutische Biologie, Mendelssohnstrasse 1, 38106 Braunschweig, Germany.
Evaluating the ecological role of secondary metabolites very often implies working with
small amount of sample for chemical analysis. We have modified a method1, 2
to quantitatively extract lower terpenoids from plant tissue and insect feculae using amounts
ranging from 10-100 mg of sample. The material is extracted inside a closed vial containing
hexane, a solvent transparent to microwave radiation3. Terpenes in leaf
glandular trichomes are readily released, as micrographs indicate, when fresh material is
utilized. Maceration with glass beads and centrifugation are used for dried samples. However,
the complete procedure is carried out inside the same vial. The lower terpenoid concentration
of commercial Matricaria chamomilla determined with our method was 0.65 ±
0.05%; the reported concentration was 0.63%. Other plant material was additionally
analyzed. The percentage of variation was 9% for the total concentration and 11% for the
main component. Steam distillation of C. curassavica (from Panamá)
yielded less essential oil than our method, which is fast, reproducible, and offers an excellent
alternative to those methods requiring gram quantities of material.
1 J.R.J. Pare, U.S. Patent No. 5,338,557, August 16 (1994).
2 L.J. Clark et al, Plant J., 11 (1997) 1387.
3 Gómez, N. et al., J. Chem. Ecol. (1999) 1007.