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

Zhan, J., M., E., & A., A. (2010). Structure determination of two new monocillin I derivatives. Natural Product Communications, 5(5), 801-804.

PMID: 20521550;Abstract:

Biotransformation of monocillin I (1) by Beauveria bassiana ATCC 7159 was investigated. Two new derivatives 2 and 3 were isolated and identified on the basis of the spectroscopic data. Compounds 2 and 3 are synthesized by hydration at 10,11-double bond and hydrolysis of 14,15-epoxide, respectively. The R configuration of 11-OH in 2 was established by the modified 2-methoxy-2- trifluoromethylphenylacetic acid (MTPA) method. The conversion of 1 to 2 and 3 was reconstituted in an acid solution, indicating that the formation of 2 and 3 is an acid-catalyzed instead of an enzymatic process.

Kamal, G. M., Gunaherath, B., A., A., Uvais, M., Sultanbawa, S., & Balasubramaniam, S. (1982). Dulcitol and (-)-4′-O-methylepigallocatechin from Kokoona zeylanica. Journal of Natural Products, 45(2), 140-142.

Abstract:

A phytochemical investigation of the methanolic extract of the inner root bark of Kokoona zeylanica Thwaites (Celastraceae) has resulted in the isolation and identification of dulcitol and (-)-4′-O-methylepigallocatechin. The chemotaxonomic significance and biological activity of dulcitol are discussed.

M., E., Bashyal, B. P., Gunatilaka, M. K., Arnold, A. E., & A., A. (2010). Maximizing chemical diversity of fungal metabolites: Biogenetically related heptaketides of the endolichenic fungus Corynespora sp. (1). Journal of Natural Products, 73(6), 1156-1159.

PMID: 20521776;PMCID: PMC3372999;Abstract:

In an attempt to explore the biosynthetic potential of the endolichenic fungus Corynespora sp. BA-10763, its metabolite profiles under several culture conditions were investigated. When cultured in potato dextrose agar, it produced three new heptaketides, 9-O-methylscytalol A (1), 7-desmethylherbarin (2), and 8-hydroxyherbarin (3), together with biogenetically related metabolites scytalol A (4), 8-O-methylfusarubin (5), scorpinone (6), and 8-O-methylbostrycoidin (7), which are new to this organism, and herbarin (8), a metabolite previously encountered in this fungal strain. The use of malt extract agar as the culture medium led to the isolation of 6, 8, 1-hydroxydehydroherbarin (9), and 1-methoxydehydroherbarin (10), which was found to be an artifact formed during the extraction of the culture medium with methanol. The structures of all new compounds were determined by interpretation of their spectroscopic data and chemical interconversions. © 2010 The American Chemical Society and American Society of Pharmacognosy.

Zhan, J., Burns, A. M., Liu, M. X., Faeth, S. H., & A., A. (2007). Search for cell motility and angiogenesis inhibitors with potential anticancer activity: Beauvericin and other constituents of two endophytic strains of Fusarium oxysporum. Journal of Natural Products, 70(2), 227-232.

PMID: 17286429;PMCID: PMC3361905;Abstract:

Wound-healing assay-guided fractionation of an EtOAc extract of the fungal strain Fusarium oxysporum EPH2RAA endophytic in Ephedra fasciculata afforded beauvericin (1), (-)-oxysporidinone (2), and two new N-methyl-2-pyridones, (-)-4,6′-anhydrooxysporidinone (3) and (-)-6-deoxyoxysporidinone (4). Beauvericin (1) inhibited migration of the metastatic prostate cancer (PC-3M) and breast cancer (MDA-MB-231) cells and showed antiangiogenic activity in HUVEC-2 cells at sublethal concentrations. Cytotoxicity-guided fractionation of an EtOAc extract of F. oxysporum strain CECIS occurring in Cylindropuntia echinocarpus afforded rhodolamprometrin (5), bikaverin (6), and the new natural product 6-deoxybikaverin (7). All compounds were evaluated for cytotoxicity in a panel of four sentinel cancer cell lines, NCI-H460 (non-small-cell lung), MIA Pa Ca-2 (pancreatic), MCF-7 (breast), and SF-268 (CNS glioma), and only beauvericin (1) and bikaverin (6) were active, with 1 and 6 showing selective toxicity toward NCI-H460 and MIA Pa Ca-2, respectively. Interestingly, 6-deoxybikaverin (7) was completely devoid of activity, suggesting the requirement of the C-6 hydroxy group of bikaverin for its cytotoxic activity. © 2007 American Chemical Society and American Society of Pharmacognosy.

Gunatilaka, A., Sriyani, H., & Sotheeswaran, S. (1984). Quaesitol, a phenol from Garcinia quaesita. Phytochemistry, 23(11), 2679-2681.

Abstract:

The petrol extractives of the bark of Garcinia quaesita gave hermonionic acid, its decarboxylated product and a new phenol, quaesitol. © 1984.