Research

Dr. Nelson is a broadly trained pharmaceutical chemist specializing in plant-based drug discovery and advanced drug analysis. He received professional research training (J-1 Exchange Visitor Program) at the Department of Medicinal Chemistry, University of Florida, USA, in Prof. Dr. McCurdy’s lab, where he contributed to a NIDA-funded research program investigating the chemistry and central nervous system (CNS) receptor mechanisms of Mitragyna speciosa (Kratom/Ketum) alkaloids. His research primarily focuses on discovering psychoactive and neuroprotective alkaloids from selected plant families, including Rubiaceae, Apocynaceae, and Loganiaceae, with the goal of developing novel therapeutics for drug addiction, pain management, neurological disorders, and neurodegenerative diseases. With over five years of analytical experience, Dr. Nelson specializes in utilizing UPLC-MS/MS for the identification, separation, and quantification of kratom alkaloids, illicit drugs, pharmaceuticals, phytochemicals, and neurochemicals in different matrices. Additionally, he is actively involved in preclinical evaluations of natural products, including herbal standardization, pharmacokinetic profiling, and ADME (absorption, distribution, metabolism, and excretion) studies. As part of his international collaborations, Dr. Nelson engages with researchers from the University of Florida (USA) and the University of South Carolina (USA), working on joint research projects that leverage cutting-edge analytical methodologies, natural products isolation, receptor-radioligand binding assays, and preclinical evaluations to explore novel plant alkaloids for CNS drug development.

Current Research Projects:

• Isolation and characterization of corynanthe-type alkaloids from Mitragyna speciosa (Kratom / Ketum) and Uncaria species using various chromatographic techniques and spectroscopic methods (NMR, MS, IR, UV and ECD).
• Mechanistic studies of analgesic, anti-addiction or neuroprotective activities of kratom and Uncaria alkaloids using cell-based and animal models.
• Development and validation of selective UPLC-MS methods for the separation and quantification of stereoisomeric compounds in plant extracts and biological samples.

People

Current PhD students (as Co-supervisor)

• Tan Ai Fein A/P Ching-Ga
• Yu Hai Long

Current MSc students (as Co-supervisor)

• Chuink Siew Tong
• Sri Yogalakshmi Gunasaykaran

Publications

SELECTED PUBLICATIONS (FROM 2020)

1. 1. Chiang, Y. H., Chear, N. J., Berthold, E. C., Kuntz, M. A., Kanumuri, S. R. R., Senetra, A. S., Ramanathan, S., McCurdy, C. R., & Sharma, A. (2025). Preclinical pharmacokinetic studies of villocarine A, an active Uncaria Drug Testing and Analysis, 17(3), 329–341.
   2. Gunasaykaran, S. Y., Chear, N. J. Y., Ismail, S., Mohammad, N. A., Murugaiyah, V., & Ramanathan, S. (2024). Drug-drug interactions of plant alkaloids derived from herbal medicines on the phase II UGT enzymes: an introductory review. Naunyn-Schmiedeberg's Archives of Pharmacology, 1-18.
   3. Ahad, M. A., Chear, N. J., Abdullah, M. H., Ching-Ga, T. A. F., Liao, P., Wei, S., Murugaiyah, V., & Hassan, Z. (2024). Effects of clitorienolactones from Clitoria ternatea root on calcium channel mediating hippocampal long-term potentiation in rats induced chronic cerebral hypoperfusion. Ageing Research Reviews, 96, 102252.
   4. Ahad, M.A., Chear, N.J., Keat, L.G., Has, A.T., Murugaiyah, V., & Hassan, Z. (2023). Bio-enhanced fraction from Clitoria ternatea root extract ameliorates cognitive functions and in vivo hippocampal neuroplasticity in chronic cerebral hypoperfusion rat model. Ageing Research Reviews, 89.
   5. Chear, N. J., Ching-Ga, T. A. F., Khaw, K. Y., León, F., Tan, W. N., Yusof, S. R., McCurdy, C. R., Murugaiyah, V., & Ramanathan, S. (2023). Natural Corynanthe-Type Cholinesterase Inhibitors from Malaysian Uncaria attenuata: Isolation, Characterization, In Vitro and In Silico Studies. Metabolites, 13(3), 390.
   6. Chear, N. J., León, F., Sharma, A., Kanumuri, S. R. R., Zwolinski, G., Abboud, K. A., Singh, D., Restrepo, L. F., Patel, A., Hiranita, T., Ramanathan, S., Hampson, A. J., McMahon, L. R., & McCurdy, C. R. (2021). Exploring the Chemistry of Alkaloids from Malaysian Mitragyna speciosa (Kratom) and the Role of Oxindoles on Human Opioid Receptors. Journal of Natural Products, 84(4), 1034–1043.
   7. Damodaran, T., Chear, N. J. Y., Murugaiyah, V., Mordi, M. N., & Ramanathan, S. (2021). Comparative Toxicity Assessment of Kratom Decoction, Mitragynine and Speciociliatine Versus Morphine on Zebrafish (Danio rerio) Embryos. Frontiers in Pharmacology, 12, 714918.
   8. Hanapi, N. A., Chear, N. J. Y., Azizi, J., & Yusof, S. R. (2021). Kratom alkaloids: Interactions with enzymes, receptors, and cellular barriers. Frontiers in Pharmacology, 12, 751656.
   9. Domnic, G., Chear, N. J. Y., Rahman, S. F. A., Ramanathan, S., Lo, K. W., Singh, D., & Mohana-Kumaran, N. (2021). Combinations of indole based alkaloids from Mitragyna speciosa (Kratom) and cisplatin inhibit cell proliferation and migration of nasopharyngeal carcinoma cell lines. Journal of Ethnopharmacology, 279, 114391.
   10. Obeng, S., Kamble, S. H., Reeves, M. E., Restrepo, L. F., Patel, A., Behnke, M., Chear, N. J., Ramanathan, S., Sharma, A., León, F., Hiranita, T., Avery, B. A., McMahon, L. R., & McCurdy, C. R. (2020). Investigation of the Adrenergic and Opioid Binding Affinities, Metabolic Stability, Plasma Protein Binding Properties, and Functional Effects of Selected Indole-Based Kratom Alkaloids. Journal of Medicinal Chemistry, 63(1), 433–439.

Chapter in Book (From 2010)

1. Ramanathan, S., León, F., Chear, N. J., Yusof, S. R., Murugaiyah, V., McMahon, L. R., & McCurdy, C. R. (2021). Kratom (Mitragyna speciosa Korth.): A description on ethnobotany, alkaloid chemistry, and neuropharmacology. Studies in Natural Products Chemistry, 69, 195-225.