Barbara Timmermann

List of Published Work in PubMed

A. Personal Research Statement

I have built successful extramurally funded research programs almost 40 years at the University of Arizona (UA) and the University of Kansas (KU). Trained as a biologist and as a natural products chemist, I have applied my extensive experience with natural products chemistry to a number of interdisciplinary programs and centers supported by the NIH and other federal agencies as well as mentoring undergraduate and graduate students, post-doctoral research associates and junior faculty. At UA, I was the PI/PD of a NIH/National Center for Complementary and Alternative Medicine (NCCAM)/Office of Dietary Supplements (ODS)-sponsored P-50 grant Arizona Center for Phytomedicine Research (2000-2005), which examined turmeric and ginger’s traditional uses as anti-inflammatory botanicals. This multi-disciplinary center conducted pre-clinical in vitro and in vivo studies, proving efficacy and identifying mechanisms of action in rheumatoid arthritis (RA). Findings from this original pre-clinical turmeric/arthritis studies served as the basis to evaluate the chemistry and therapeutic potential of turmeric dietary supplements as preventive or adjuvant treatment for breast cancer bone metastases. My leadership and administrative capabilities are also demonstrated through my activities as PI/PD of the NIH-funded International Cooperative Biodiversity Groups Program (ICBG) for drug lead discovery from plant biodiversity (1993-2003); the USAID- funded University Development Linkages Program (1993-2000) and the NIH-funded Minority International Research Training (MIRT) Program (2000-2005). More recently, I completed a 10-year NIH-supported Center grant as PI/PD, the NIH/GM Center for Biomedical Research Excellence (COBRE) Center for Cancer Experimental Therapeutics (CCET) [2006-2015] where I mentored KU-Lawrence, KU Medical Center and Kansas State University faculty who have received Pilot Project grants and also directed two Core Laboratories (Medicinal Chemistry and High Throughput Screening) in the area of cancer research.  As part of my administrative duties as Chair of the Department of Medicinal Chemistry at KU (2005-2012) I completed the Senior Administrative Fellow Program (2010-2011). Other funded projects (i.e., Kansas Bioscience Authority) allowed me to be the major advisor of graduate students who were pursuing their Ph.D. degrees in medicinal chemistry or natural products chemistry. I also mentor post-doctoral research associates who complete a two to three years training program of research in my laboratory.  My research interests include safety and efficacy studies of botanical dietary supplements, biodiversity prospecting for drug lead discovery from plants; isolation and chemical characterization of biologically active molecules (e.g., terpenoids, alkaloids, phenolics); method development to improve purification and characterization of complex botanical products; chemotaxonomy and interaction of natural products with organic anion transporter proteins in hepatocytes and enterocytes. I am the author or co-author of more than 210 publications in peer-reviewed scientific literature and numerous research reviews, a co-editor of two proceeding volumes and 20 book chapters, and the co-author of the book “Sesquiterpene Lactones: Chemistry, NMR and Distribution”.

• Yoshioka, H., T.J. Mabry and B.N. Timmermann. Sesquiterpene Lactones, Nuclear Magnetic Resonance, Chemistry and Distribution. The University of Tokyo Press, Tokyo, 1972, 544 pp.

• Timmermann, B.N., C. Steelink and F.A. Loewus. Recent Advances in Phytochemistry, Vol. 18. Phytochemical Adaptations to Stress. Plenum Press, New York, 1984, 334 pp.

• Timmermann, B.N. and Funk, J.  “Multidisciplinary Studies of Anti-Inflammatory Botanicals: Ginger and Turmeric.”  Phytochemicals: Health Promotion and Therapeutic Potential. C. Carkeet, K. Grann, R.K. Randolph, D.S. Venzon and S.M. Izzy (Editors).  CRC Press, Taylor & Francis Group, Boca Raton, FL, 47-72, 2013.

• 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 International Cooperative Biodiversity Groups Program: The First Five Years. Pharm. Biol. 37, Supplement, 35-5.

• Zhang, H., A.K. Samadi, M.S. Cohen, and B.N. Timmermann. 2012. Antiproliferative withanolides from the Solanaceae: A structure–activity study.  Pure Appl. Chem., Vol. 84(6): 1353–1367.

• Zhang, H., B.N. Timmermann. 2014.  Phytochemical compendium of Withania somnifera (Solanaceae):1965-2014. Current Topics in Phytochemisry. 12: 41-68.

• Zhang, H., B.N. Timmermann. Withanolide structural revisions by 13C NMR spectroscopic analysis inclusive of the γ gauche effect. 2016. J. Nat. Prod. 79: 732-742.

B. Contribution to Science: Peer-reviewed publications (selected from a total of 210 publications)

1. Exploring and discovering new drug leads from plant and microbial biodiversity.  It has long been recognized that plants, microbes and their natural products offer great benefit to human health and wellness. We have only taped into a small fraction of the rich and diverse array of medically valuable natural products. As PI/PD, we have conducted a 15-year NIH-funded International Cooperative Biodiversity Groups program in search of new drug leads against diseases of developed and developing countries. Bioprospecting in Latin America identified new and know natural products with anti-proliferative, anti-TB, anti-microbial and other important biological activities.

• Mata, R., I. Morales, O. Perez, I. Rivero-Cruz, L. Acevedo, I. Enriquez-Mendoza, R. Bye, S.G. Franzblau, and B.N. Timmermann. 2004. Antimicobacterial Compounds from Piper sanctum. J. Nat Prod 67(12): 1961-1968.

• Gutierrez-Lugo, M.T., J.D. Deschamps, T.R. Holman, E. Suarez and B.N. Timmermann. 2004. Lipoxygenase inhibition by anadanthoflavone, a new flavonoid from the aerial parts of Anadenanthera colubrina. Planta Medica 70(3): 263-265.

• Woldemichael, G.M., G. Waechter, M. Singh, W.M. Maiese and B.N. Timmermann. 2003. Antibacterial diterpenes from Calceolaria pinnifolia Cav.  J. Nat. Prod. 66(2): 242-246.

• Lambert, J.D., R.T. Dorr, and B.N. Timmermann. (2004). Nordihydroguaiaretic Acid: A Review of its Numerous and Varied Biological Activities.  Pharmaceutical Biology.  42(2):149 - 158.
• Roy, A., P. McDonald, B.N. Timmermann, M. Gupta and R. Chaguturu. 2019. Bioactivity profiling of plant biodiversity of Panama by High Throughput Screening. Nat. Prod. Comm. 14(1):71-74.

2. Studying safety and efficacy of botanical dietary supplements with an emphasis on anti- inflammatory natural products. Botanical medicines are complex mixtures of natural products as opposed to pharmaceutical drugs that contain single molecular entities.  There is a great health need to understand the chemistry and mechanisms of action of botanicals widely consumed in the US and categorized as dietary supplements. As PI/PD of a NIH-funded Botanical Research Center, my group has investigated the anti-inflammatory chemistry and mechanisms of action of turmeric and ginger and their effects against rheumatoid arthritis, colitis and inflammatory bowel disease (IBD). Our group has also examined the brain-protective effects of turmeric in stroke.  This translational significant work has been patented and published extensively in the peer-reviewed literature.

• Billerey-Larmonier, C., J.K. Uno, N. Larmonier, A.J. Midura, B.N. Timmermann, F.K. Ghishan, & P.R. Kiela. 2008. Protective effects of dietary curcumin in mouse model of chemically-induced colitis are strain dependent. J Inflamm Bowel Dis, 14(6):780-793.

• Uno, J.K., O.I. Kolek, E.R. Hines, H. Xu, B.N. Timmermann, P.R. Kiela and F.K. Ghishan. 2006. The role of tumor necrosis factor in down-regulation of osteoblast Phex gene expression in experimental murine cholitis. Gastroenterology 131 (2): 497-509.

• Funk, J.L., J.B. Frye, J.N.  Oyarzo and B.N. Timmermann. 2009. Comparative effects of two gingerol-containing Zingiber officinale extracts on experimental rheumatoid arthritis. J Nat Prod, 72(3): 403-407.

• Funk, J.L., J.B. Frye, G. Davis-Gorman, A.L. Spera, M.J. Bernas, M.H. Witte, M.E. Weinand and B.N. Timmermann, P.F. McDonagh, L. Ritter.  2013.  Curcuminoids limit neutrophil-mediated reperfusion injury in experimental stroke by targeting the endothelium.  Microcirculation 20 (6): 544-554.
• Wright, L.E., J.B. Frye, B. Gorti, B.N. Timmermann and J.L. Funk.  2013.  Bioactivity of Turmeric-derived Curcuminoids and related metabolites in breast cancer.   Current Pharmaceutical Design 19 (34): 6218-6225. 
• Funk, J.L., J.B. Frye, J.N. Oyarzo, J. Chen, H. Zhang and B.N. Timmermann. 2016. Anti-inflammatory effects of the essential oils of ginger (Zingiber officinale Roscoe) in experimental rheumatoid arthritis. PharmaNutrition, 4:123-131.

3. Determining mechanisms of action of novel steroidal natural products with anti-cancer activity. Withanolides are C28 ergostane-type steroidal lactones present in the family Solanaceae.  As PI/PD, my group is investigating members of the Solanaceae as sources of natural products with promising in vitro anti-proliferative and in vivo anti-tumor properties. To date, our work on Datura wrightii, Jaborosa caulescens, Physalis hispida, P. longifolia, P. neomexicana, Vassobia breviflora and Withania somnifera has resulted in the isolation of more than 100 withanolides, 40 of which are new, as well as the semi-synthesis of a further 30 withanolides.  We have demonstrated that withanolides are potent novel targeted therapeutic agents against various carcinomas including adrenocortical, head and neck squamous carcinomas, melanoma, thyroid, colon and glioblastomas. More recent work investigates mimetic synthetic HDL-withanolides as a novel treatment strategy for neuroblastoma to improve drug delivery to neuroblastomas and their cancer stem cells through SR-B1 targeting in vitro and in vivo. Patents and numerous publications have resulted from these studies

• Zhang, X., A.K. Samadi, K.F. Roby, B.N. Timmermann and M.S. Cohen. 2012. Inhibition of cell growth and induction of apoptosis in ovarian carcinoma cell lines CaOV3 and SKOV3 by natural withanolide Withaferin A. Gynecologic Oncology 124: 606–612.
• Samadi, A.K., M.S. Cohen, R. Mukerji, V. Chaguturu, X. Zhang, B.N. Timmermann, M.S. Cohen & E.A. Person.  2012. Natural withanolide withaferin A induces apoptosis in uveal melanoma cells by suppression of Akt and c-MET Activation. Tumour Biol 33(4):1179-80.
• Zhang, H., A.K. Samadi, R.J. Gallagher, J.J. Araya, X. Tong, V.W. Day, M.S. Cohen, K. Kindscher, R. Gollapudi, and B.N. Timmermann. 2011. Cytotoxic Withanolide Constituents of Physalis longifolia.  J. Nat. Prod. 74: 2532−2544.

• Samadi, A.K., J. Bazzill, X. Zhang, R. Gallagher, H. Zhang, R. Gollapudi, K. Kindscher, B.N.Timmermann  and M.S. Cohen. 2012. Novel withanolides target medullary thyroid cancer through inhibition of both RET phosphorylation and the mammalian target of rapamycin pathway.  Surgery 152(6): 1238-1247.
• Cao, C., X. Wu, K. Kindscher, L. Xu and B.N. Timmermann. 2015. Withanolides and sucrose esters from Physalis neomexicana. Journal of Natural Products 78: 2488-2493.

• White, P., Subramanian, C., Zhu, Q., Zhang, H., Gallagher, R., Timmermann, B.N., Blagg, B., Cohen, M. 2016. Novel HSP90 inhibitors effectively target function of thyroid cancer stem cell preventing migration and invasion. Journal Surgery 159:142-151.

• Zhang, H., B.N. Timmermann. Withanolide structural revisions by 13C NMR spectroscopic analysis inclusive of the γ gauche effect. 2016. J. Nat. Prod. 79: 732-742.

• Kuai, R., C. Subramanian, P.T. White, B.N. Timmermann, J.J. Moon, M.S. Cohen and J. Schwendeman 2017. Synthetic high-density lipoprotein nanodisks for targeted withalongolide delivery to adrenocortical carcinoma. Intl. J. Nanomedicine 12: 6581-6594.

• Subramanian, C., P.T. Grogan, V.P. Opipari, B.N. Timmermann and M.S. Cohen. 2018. Novel natural withanolides induce apoptosis and inhibition migration of neuroblastoma cells through downregulation of N-myc and suppression of Akt/mTOR/NF-kB activation. Oncotarget 9 (18): 14509-14523.

4. Method development to improve purification and characterization of complex botanical products. We have established several validated, quantitative HPLC and Mass Spectrometry methods in order to determine the presence and quantity of bioactive metabolites in plant extracts for future quality control and related biological applications.

• Araya, J., G. Montenegro, L. Mitscher, and B.N. Timmermann, 2010. Application of Phase-Trafficking Methods to Natural Products Research. J. Nat. Prod. 73: 1568-1572.

• Cao, C-M., H. Zhang, R.J. Gallagher and B.N. Timmermann. 2013. Withanolide artifacts formed in methanol.  J. Nat. Prod. 76: 2040-2046.

• Jiang, H., B.N. Timmermann and D.R. Gang. 2007. Characterization and identification of diarylheptanoids in ginger (Zingiber officinale Rosc.) using high-performance liquid chromatography/electrospray ionization mass spectrometry. Rapid Commun. Mass Spectrom. 21(4):509-518.

• Jiang, H., A. Somogyi, B.N. Timmermann and D.R. Gang. 2006. Instrument dependence of ESI ionization and MS/MS fragmentation of the gingerols. Rapid Comm. Mass Spectrom. 20 (20): 3089-3100.

5. Understanding the interaction of natural products with organic anion transporter proteins (OATPs) in hepatocytes and enterocytes. OATPs are liver-specific transporters that mediate the uptake of a broad range of drugs into hepatocytes, including statins, antibiotics, and many anticancer drugs.  Natural products that alter the transport by OATPs could potentially be used to target drugs to hepatocytes or improve the bioavailability of drugs that are cleared by the liver. We examined the effect of green tea catechins.  We have demonstrated that the green tea compounds ECG and EGCG are substrates for OATP1A2 and OATP1B3 suggesting that these two transporters could be involved in the disposition of these two major catechins.  Because of increasing use of green tea catechins, particularly EGCG, in dietary supplements and because ECG and EGCG can significantly alter the function of OATPs involved in drug disposition, the results of our studies suggest that there is a significant possibility of adverse drug-catechin interactions.

• Roth, M., B.N. Timmermann, and B. Hagenbuch.  2011. Interactions of green tea catechins with organic anion-transporting polypeptides.  Drug Metab. Dispos. 39:920-926.
• Roth, M., J.J. Araya, B.N. Timmermann and B. Hagenbuch. 2011. Isolation of modulators of the liver specific Organic Anion Transporting Polypeptides (OATPs) 1B1 and 1B3 from Rollinia emarginata Schlecht (Annonaceae). J Pharmacology Exp Ther, 339 (2): 624-32.

6. Understanding the interaction of plant natural products with butterflies in plant-insect co-evolution. In the system involving queen and viceroy butterflies, the viceroy is both mimic and co-model depending on the local abundance of the model, the queens. We integrate population surveys, chemical analyses, and predator behavior assays to demonstrate how mimics may persist in locations with low-model abundance.  As the queen becomes less abundant, the viceroy becomes more chemically defended and unpalatable to predators. Our results suggest that mimetic viceroy populations are maintained at localities of low-model abundance through an increase in their toxicity, making biologists rethink old theories about animal mimicry. In separate studies, we have shown in a detailed mechanistic way, that structurally different plant cardiac glycosides can affect specific animal Na⁺/K⁺-ATPases in highly distinct ways. For interactions involving sequestration, such as that between milkweeds and monarch butterflies, both the plant and the animal antagonists must manage toxicity, not only in the pair but also to the third trophic level.

• Prudic, K.L., S. Khera, A. Solyom and B.N. Timmermann. 2007. Isolation, identification, and quantification of potential defensive compounds in the viceroy butterfly and its larval host plant, Carolina willow. J. Chem. Ecol. 33(6): 1149-1159.
• Petschenka, G., C.S. Fei, J.J. Araya, S. Schroder, B.N. Timmermann and A. Agrawal. 2018. Relative selectivity of plant cardenolides for Na⁺/K⁺-ATPases from the Monarch Butterfly and non-resistant insects. Front. Plant Sci. 9 (1424), 1-13.

• Prudic, K.L., B.N. Timmermann, D.R. Papaj, D.B. Ritland and J.C. Oliver. 2019. Mimic advantage varies in relation to the abundance and distribution of its model. Communications Biology (Nature) 2:68.

List of Published Work in PubMed