Abstract
The polyphenol profiles of strawberry leaves (Fragaria × ananassa cvs. Marisol and Festival), cultivated in the tropical highlands of Costa Rica, were analyzed using high-field (750 MHz) and benchtop (60 MHz) Nuclear Magnetic Resonance (NMR) spectroscopy. Soluble and insoluble fractions were examined, revealing differences in the aromatic (6.0─8.0 ppm) and sugar (3.0─5.5 ppm) regions. High-field NMR provided sharper, more resolved signals, allowing for the identification of glycosylated polyphenols, flavonoids, and phenolic acids. Marisol exhibited a higher diversity and intensity of glycosylated polyphenols compared to Festival. In the insoluble fractions, both cultivars showed a unique peak at 2.0 ppm, absent in the soluble fractions, likely corresponding to lipids or matrix-bound compounds. The benchtop NMR spectra, though lower in resolution, confirmed key spectral patterns and cultivar differences. This study demonstrates the complementary use of high- and low-field NMR for polyphenol profiling and highlights the potential of strawberry leaves as a valuable source of bioactive compounds, contributing to the understanding of underutilized plant materials and their applications in health-related fields.