Barbara N. Timmermann,
Regents' Professor of Pharmacology and Toxicology, Ph.D., University of Texas, 1980
btimmer@pharmacy.arizona.edu

Natural products chemistry; biodiversity prospecting for drug discovery; antioxidant chemistry; catechins in cancer prevention; safety and efficacy studies of botanical dietary supplements.

Research Activities

The research interest of my laboratory is natural products chemistry with specific emphasis on the discovery of bioactive molecules from natural sources for the development of pharmaceutical agents and studies on safety and efficacy of botanical dietary supplements.

As the Principal Investigator/Project Director of an International Cooperative Biodiversity Groups (ICBG) Project, my group's major efforts involve the discovery of novel molecules from plant and microbial biodiversity for the development of prescription drugs in the areas of oncology, infectious diseases, inflammation, cardiovascular, central nervous system and women's health. This experimental effort for research into biodiversity prospecting, conservation, economic development and drug discovery consists of public institutions of higher education, private pharmaceutical corporations, and governmental and environmental organizations in the U.S.A., Argentina, Chile and Mexico.

Since September 2000, I became the Director of the Arizona Center for Phytomedicine Research (ACPRx). This center promotes the scientific study of botanicals available to the public as dietary supplements in order to advance the quality and quantity of scientific information about these products. The center is concentrating its initial efforts on several botanicals purported to be helpful in the treatment of arthritis and other chronic inflammatory conditions, including respiratory diseases such as asthma. The multidisciplinary research team includes scientists from the University of Arizona's Colleges of Pharmacy, Medicine and Agriculture & Life Sciences.

Additional areas of interest include research for the prevention of UV-induced skin carcinogenesis by catechins from dietary sources as well as the study of antioxidant mechanism to prevent oxidative damage in biological systems and the development of novel molecules for preventing and treating cancer.

In addition to funding from the National Institutes of Health (NIH) and the National Science Foundation (NSF), my projects are supported by other federal agencies (US Agency for International Development, US Department of Agriculture), the state of Arizona (Arizona Disease Control Research Commission), the John D. and Catherine T. Mac Arthur Foundation, as well as private corporations (Sumitomo Chemical Company and Wyeth-Ayerst Research Laboratories).

Along with biomedical research, my laboratory is involved in several collaborations in other areas such as insect neurobiology and electrophysiology, chemical ecology, plant physiology and chemotaxonomy.

Publications (Query PubMed for this investigator)

Whitman, S., Gezginci, M., Timmermann, B.N., and Holman, T.R. 2002. Structure-Activity Relationship Studies of Nordihydroguaiaretic Acid Inhibitors toward Soybean, 12-Human, and 15-Human Lipoxygenase. J. Nat. Prod. 45(12), 2659-2961.

Mata, R., Rivero-Cruz, I., Rivero-Cruz, B., Bye, R., and Timmermann, B.N. 2002. Sesquiterpene Lactones and Phenylpropanoids from Cosmos pringlei. J. Nat. Prod., 65(7), 1030-1032.

Gutierrez-Lugo, M-T., Singh, M.P., Maiese, W.M., and Timmermann, B.N. 2002. New Antimicrobial Cycloartane Triterpenes from Acalypha communis. J. Nat. Prod., 65(6), 872-875.

Inoue, M.B., Inoue, M., Quintus, F., Valcic, S. and Timmermann, B.N. 2002. Potentiometric and 1H NMR studies of complexation of A1 3+ with (-)-epigallocatechin gallate a major constituent of green tea. J. Inorganic Biochemistry:88, 7-13.

Wachter, G., S. G. Franzblau, G. Montenegro, J.J. Hoffmann, W. M. Maiese and B. N. Timmermann. 2001. Inhibition of Mycobacterium tuberculosis growth by saringosterol from Lessonia nigrescens. J. Nat. Prod. 64 (11): 1463-1464.

Montenegro, G., G. Patrick, P. Echenique, M. Gomez and B.N. Timmermann. 2001. Mechanisms towards a sustainable use of Chorizanthe vaginata Benth. var. maritima Remy: a medicinal plant from Chile. Phyton: 91-106.

Waechter, G., S. Valcic, S. Franzblau, E. Suarez, and B.N. Timmermann. 2001. Antitubercular activity of triterpenoids from Lippia turbinata. J. Nat. Prod. 64(1): 37-41.

Lambert, J.D., R.O. Meyers, B.N. Timmermann, and R.T. Dorr. 2001. Pharmacokinetic analysis by high-performance liquid chromatography of intravenous nordihydroguaiaretic acid in the mouse. J. Chromatography B, 754: 85-90.

Munoz, O., R.C. Pena, E. Ureta, G. Montenegro and B. N. Timmermann. 2001. Propolis from Chilean matorral hives . Z. Naturforsch. 56c: 269-272.

Munoz, O., R.C. Pena, E. Ureta, G. Montenegro, C. Caldwell and B. N. Timmermann. 2001. Phenolic compounds of propolis from the central Chilean matorral. Z. Naturforsch. 56c: 273-277.

Mata, R., Martinez, E., Bye, R., Morales, G. Singh, M.P., Janso, J.E., Maiese, W., and Timmermann, B.N. 2001. Biological and mechanistic activities of Xanthorrizol and 4-(1',5'-Dimethylhex-4'-enyl)-2-methylphenol Isolated from Iostephane heterophylla, J. Nat. Prod. 64: 911-914.

Gezginci, M.H. and B. N. Timmermann. 2001. A short synthetic route to nordihydroguaiaretic acid (NDGA) and its stereoisomer using Ti-induced carbonyl-coupling reaction.Tetrahedron Letters 42: 6083-6085.

Lambert, J.D., R.O. Meyers, B. N. Timmermann and R.T. Dorr. 2001. Tetra-O-methylnordihydroguaiaretic acid inhibits melanoma in vivo. Cancer Letters 171: 47-56.

Valcic, S., J.A. Burr, B.N. Timmermann, and D.C. Liebler. 2000. Antioxidant Chemistry of Green Tea Catechins. New oxidation products of (-)- epigallocatechin gallate and (-)- epigallocatechin from their reactions with peroxyl radicals. Chem. Res. Toxicol.13(A): 801-810.

Caldwell, C., S.G. Franzblau, E. Suarez and B.N. Timmermann. 2000. Oleanane triterpenes from Junellia tridens. J. Nat. Prod. 63(12): 1611-1614.

Flagg, M.L., G. Waechter, A.L. Davis, G. Montenegro and B.N.Timmermann. 2000. Two novel flavanones from Greigia sphacelata. J. Nat. Prod. 63(12), 1689-1691.

Arora, A., S. Valcic, S. Cornejo, M. Nair, B.N. Timmermann, and D.C. Liebler. 2000. Reactions of Genistein with Alkylperoxyl Radicals. Chem. Res. Toxicol. 13, 638-645.

Miketova, P., K. H. Schram, J. Whitney, M. Li, R. Huang, E. Kerns, S. Valcic, B.N. Timmermann, R. Rourick and S. Klohr. 2000. Tandum mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea. J. Mass Spectrom 35, 860-869.

Timmermann, B.N., G. Wachter, S. Valcic, B. Hutchinson, J. Henzel, C. Casler, S. Ram, F. Currim, R. Manak, S. Franzblau, W. Maiese, D. Galinis, E. Suarez, R. Fortunato, E. Saavedra, R. Bye, R. Mata and G. Montenegro. 1999. The Latin American ICBG: The First Five Years. Pharm. Biol. 37, Supplement, 35-54.

Hutchinson, B., J. Henzel, S. Ram and B.N. Timmermann. 1999. Managing information products for the bioactive agents from dryland biodiversity of Latin American project. IAALD, XLIV, ¾: 163-172.

Wächter, G., G. Montenegro, B. N. Timmermann. 1999. Diterpenoids from Baccharis pingreaea. J. Natural Products. 62(2): 307-308.

Chen, W., Dong, Z., Valcic, S., Timmermann, B.N., Bowden, G.T. 1999. Inhibition of Ultraviolet B-induced c-fos Gene Expression and p38 Mitogen-Activated Protein Kinase Activation by (-)-Epigallocatechin Gallate in a Human Keratinocyte Cell Line. Molecular Carcinogenesis 24(2):79-84.

Dvorakova, K., R. T. Dorr, S. Valcic, B. N. Timmermann, and D. S. Alberts. 1999. Pharmacokinetics of the green tea derivative, EGCG, by the topical route of administration in mouse and human skin. Cancer Chemotherapy and Pharmacology 43:331-335.

Valcic, S., A. Muders, N.E. Jacobsen, D.L. Liebler, B.N. Timmermann. 1999. Antioxidant chemistry of green tea catechins. Identification of products of (-)-epigallocatechin gallate (EGCG) reaction with peroxyl radicals. Chem. Res. in Toxicol. 12(4):382-386.

Miketova, P., K. H. Schram, J. Whitney, E. Kerns, S. Valcic, B. N. Timmermann and K. J. Volk. 1998. Mass spectrometry of selected components of biological interest in green tea extracts. J. Nat. Prod. 61: 461-467.

Glendinning, J.I., S. Valcic and B. N. Timmermann: Maxillary palps can mediate taste-rejection of plant allelochemicals by caterpillars. J. Comp. Physiol. A. 183(1):35-43, 1998.

Valcic, S., G. Montenegro and B. N. Timmermann. 1998. Lignans from Chilean propolis. J. Nat. Prod. 61: 771-775.

Wächter, G., S.G. Franzblau, G. Montenegro, E. Suarez, R.H. Fortunato, E. Saavedra,and B.N. Timmermann. 1998. A New Antitubercular Mulinane Diterpenoid from Azorella madreporica Clos. J. Nat. Prod. 61:965-968.

Barthelman, M., W.B. Bair III, K.K. Stickland, W. Chen, B.N. Timmermann, S. Valcic, Z. Dong, and G.T. Bowden. 1998. (-)-Epigallocatechin-3-gallate inhibition of ultraviolet B-induced AP-1 activity. Carcinogenesis. 19(12): 2201-2204.

He, K., S. Valcic, B.N. Timmermann and G. Montenegro. 1997. Indole Alkaloids from Aristotelia chilensis (Mol.) Stuntz. Intl. J. Pharmacognosy 35 (3): 215-217.

S. Valcic, G.A. Wachter, G. Montenegro, and B.N. Timmermann. 1997. Triterpenoids from Acaena pinnatifida R. et P. Z. Naturforsch 52c, 264-266.

B.N. Timmermann. 1997. A Biodiversity Prospecting Models for Collection Resources: the NIH/NSF/USAID Model" in "Proceedings of the Symposium on Global Genetic Resources: Access, Ownership, and Intellectual Property Rights, K.E. Hoagland and A.Y. Rossman (Eds.), pp 219-234, Association of Systematics Collections, Washington, DC.

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