Untargeted metabolomic profiling was performed on aqueous extracts using GC-EI-MS, and metabolite identification was achieved through four free deconvolution tools: MZmine, MS-DIAL, "eRah", and MSHub/GNPS. A total of 205 metabolites were annotated at three confidence levels. Age-specific metabolite abundance revealed significantly higher levels of vanillin, hexacosane, hydroquinone, and others in 4-6-year-old plants; benzeneacetaldehyde, 2-aminophenol, dihydro-3-oxo-β-ionol, and palmitic acid in 6-8-year-olds; and 5,5-dimethylpyrrolidin-2-one, cyclotene, and methylcatechol in 8-10-year-olds. Regarding light conditions, phenolic compounds such as 4-propenylsyringol, catechol, and syringol were significantly more abundant under light exposure, while lipids such as 1-hexadecanol, 1-tetradecanol, and phytol predominated in shaded plants. Metabolic pathway analysis revealed that both plant age and light exposure significantly influenced metabolites involved in tentative pollutant degradation, phenylpropanoid biosynthesis, tyrosine metabolism, and fatty acid degradation. These findings provide new insights into the biochemical plasticity of I. guayusa and its potential for developing natural products enriched in specific classes of bioactive compounds.
Pastuña-Fasso et al. (Wed,) studied this question.