Ulises G. Castillo is a Researcher (Master of Science) at the University of El Salvador, affiliated with the Department of Pharmacy and Pharmaceutical Technology. ResearchGate He works in the Laboratory of Natural Product Research (Marvin J. Nuñez’s lab) where his research focuses on phytochemistry, natural products, medicinal-pharmaceutical chemistry, and chromatographic techniques for the study of plant secondary metabolites. ResearchGate To date, he has co-authored 13 publications. Some of his notable recent works include: “Remarkable anti-Trypanosoma cruzi activity in selected Salvadoran plant species” (May 2025), in which he and colleagues screened 114 plant species from El Salvador for in-vitro activity against the parasite that causes Chagas disease. ResearchGate “Anti-trypanosomal lignans isolated from Salvadoran Peperomia pseudopereskiifolia” (April 2024), where five lignan-type compounds — including three novel ones — were isolated and their configurations determined. ResearchGate His work contributes to the search for bioactive compounds in Salvadoran flora with potential medicinal and pharmacological applications, including antiparasitic and antimicrobial properties. ResearchGate Ulises is recognized for his expertise in phytochemistry, natural product chemistry, and analytical techniques, and he continues to contribute to research at the intersection of Botany, Pharmacognosy, and Pharmaceutical Sciences.