Leslie Gunatilaka

Leslie Gunatilaka

Professor, Natural Resources and the Environment
Director, Natural Products Center
Professor, Pharmacology and Toxicology
Professor, Cancer Biology - GIDP
Professor, Arid Lands Resources Sciences - GIDP
Professor, BIO5 Institute
Contact
(520) 621-9932

Work Summary

Discovery of natural products from plants and their associated microorganisms as potential drugs to treat cancer. Application of medicinal chemistry approach for structure-activity relationship studies and to obtain compounds for preclinical evaluation. Development of alternative agricultural systems for sustainable utilization of natural resources.

Research Interest

Despite many therapeutic successes, cancer remains a major cause of mortality in the US. Natural products (NPs) represent the best source and inspiration for the discovery of drugs and molecular targets. Our aim is to discover effective and non-toxic NP-based anticancer drugs. Working with NCI we have recently discovered a class of plant-derived NPs useful in cancer immunotherapy. The main focus of our current research is to utilize medicinal chemistry approach to obtain their analogues for preclinical evaluation. Leslie Gunatilaka is Professor at the School of Natural Resources and the Environment and Director of the Natural Products Center. He is also Adjunct Professor of Department of Nutritional Sciences, and a member of the Arizona Cancer Center. He is a member of several professional societies, editorial boards, and pharmaceutical company advisory groups. He is a Fellow of the Academy of Sciences for the Developing World (TWAS), Italy, and the National Academy of Sciences, Sri Lanka. Dr. Gunatilaka has over 200 peer-reviewed publications and book chapters and over 150 communications in natural product science to his credit. He is the recipient of the Sri Lankan Presidents’ gold medal for “creating a center of excellence in natural products research at the University of Peradeniya, Sri Lanka” (1987), CaPCURE award for “dedication to ending prostate cancer as a risk for all men and their families” (2000), Research Faculty of the Year Award of the UA College of Agriculture and Life Sciences (2003), the UA Asian American Faculty, Staff and Alumni Association Outstanding Faculty Award (2005), and the UA Leading Edge Researcher Award for Innovative Research (2012). He has delivered over 100 invited lectures worldwide and was the Chief Guest and Plenary Lecturer at the International Herbal Medicine Conference held in Sri Lanka (2005), and the Keynote Speaker and the Guest of Honor at Chemtech-2007, an International Conference organized by the Institute of Chemistry, Ceylon. His current research interests include discovery, identification of protein targets, and structure-activity relationship (SAR) studies of natural product-based drugs to treat cancer, neurodegenerative, and other diseases from plants, and plant- and lichen-associated microorganisms, maximization of chemistry diversity and production of microbial and plant secondary metabolites, and scientific investigation of medicinal plants and herbal supplements. Keywords: Natural Product-Based Drug Discovery, Medicinal Chemistry, Cancer Immunotherapeutic Agents

Publications

Mafezoli, J., Oliveira, M. C., Paiva, J. R., Sousa, A. H., Lima, M. A., Júnior, J. N., Barbosa, F. G., Wijeratne, E. M., & Gunatilaka, A. A. (2014). Stereo and regioselective microbial reduction of the clerodane diterpene 3,12-dioxo-15,16-epoxy-4-hydroxycleroda-13(16),14-diene. Natural product communications, 9(6), 759-62.

The biotransformation of the clerodane diterpene, 3,12-dioxo-15,16-epoxy-4-hydroxy-cleroda-13(16),14-diene (1), obtained from Croton micans var. argyroglossum (Baill.) Mill., was investigated for the first time. Whole cells of Cunninghamella echinulata and Rhizopus stolonifer were used as enzymatic systems, and with both fungi the only biotransformation product obtained was the new ent-neo-clerodane diterpene (3R,4S,5S,8S,9R,10S)-3,4-dihydroxy-15,16-epoxy-12-oxo-cleroda-13(16),14-diene (2a). The absolute stereochemistry of 2a was inferred by comparison of its optical rotation with those of the chemical reduction product of 1 and its quasienantiomer 2c.

Zhan, J., & A., A. (2005). Microbial transformation of curvularin. Journal of Natural Products, 68(8), 1271-1273.

PMID: 16124776;Abstract:

The microbiological transformation of curvularin (1) with Beauveria bassiana ATCC 7159 afforded three new metabolites identified as curvularin-7-O-β-D-glucopyranoside (2), curvularin-4′-O-methyl-7-O- β-D-glucopyranoside (3), and 6-hydroxycurvularin-4′-O-methyl-6-O- β-D-glucopyranoside (4) resulting from hydroxylation, glucosidation, and methylglucosidation of the substrate. Isolation of 6-methyl-2,4-dihydroxyphenyl- 4′-O-methyl-1-O-β-D-glucopyranoside (5) from the fermentation broth of B. bassiana ATCC 7159 without any added substrate suggested that hydroxylase, glucosyl transferase, and methylase are constitutive enzymes of this organism. © 2005 American Chemical Society and American Society of Pharmacognosy.

Tillekeratne, L. M., Jayamanne, D. T., Weerasuria, K. D., & Gunatilaka, A. (1982). Lignans of Horsfieldia iryaghedhi. Phytochemistry, 21(2), 476-478.

Abstract:

A detailed chemical investigation of extracts of the bark, leaf and timber of Horsfieldia iryaghedhi collected in Sri Lanka, led to the isolation of (+)-asarinin, dodecanoylphloroglucinol and (-)-dihydrocubebin. © 1982.

G., D., Chaudhary, A. G., Chordia, M. D., Gharpure, M., A., A., Higgs, P. I., Rimoldi, J. M., Samala, L., Jagtap, P. G., Giannakakou, P., Jiang, Y. Q., Lin, C. M., Hamel, E., Long, B. H., Fairchild, C. R., & Johnston, K. A. (1998). Synthesis and biological evaluation of 2-acyl analogues of paclitaxel (Taxol). Journal of Medicinal Chemistry, 41(19), 3715-3726.

PMID: 9733497;Abstract:

The anticancer drug paclitaxel (Taxol) has been converted to a large number of 2-debenzoyl-2-aroyl derivatives by three different methods. The bioactivities of the resulting analogues were determined in both tubulin polymerization and cytotoxicity assays, and several analogues with enhanced activity as compared with paclitaxel were discovered. Correlation of cytotoxicity in three cell lines with tubulin polymerization activity showed reasonable agreement. Among the cell lines examined, the closest correlation with antitubulin activity was observed with a human ovarian carcinoma cell line.

Gunatilaka, A. L., & Mateos, A. F. (1979). Hydroboration of tricarbonylironergosteryl benzoate. Synthesis of (22R)- and (22S)-3β-benzoyloxyergosta-5,7-dien-22-ol and (23R)-3β- benzoyloxyergosta-5,7-dien-23-ol. Journal of the Chemical Society, Perkin Transactions 1, 935-938.

Abstract:

Hydration of tricarbonylironergosteryl benzoate via hydroboration and subsequent decomplexing affords a mixture of (22R)- and (22S)-3β- benzoyloxyergosta-5,7-dien-22-ol and (23R)-3β-benzoyloxyergosta-5,7-dien- 23-ol. Oxidation gives 3β-benzoyloxyergosta-5,7-dien-22- and -23-one. On reduction these ketones yield (23S)-3β-benzoyloxyergosta-5,7-dien-23-ol in addition to the above three dienols. Stereochemical assignments are on the basis of molecular rotations.