Chemometrics applied to 1H NMR and UV–Vis spectroscopy as a way to evaluate solid-liquid extraction of leaves of artichoke

Abstract

Artichoke has several biological actions, which are related to the synergistic action of its bioactive compounds. Solid-liquid extraction influence the type and quantity of compounds extracted and, consequently, the biological activity of the plant extract. This study aims to investigate which extraction method (maceration, infusion, or Soxhlet) and which green solvent (ethanol or acetone) would be more suitable to obtain bioactive artichoke extracts. All solid-liquid procedures were carried out in triplicate, using 3.0 g of artichoke leaves and 200 mL of solvent. After drying, samples were analyzed by UV–Vis and 1H NMR. Chemometrics was applied to spectroscopic data, and the PCA analysis showed that they were specially separated according to the solvent extractor. The sesquiterpene lactone cynaropicrin was identified as the major compound of the extracts, and this allowed us to conclude that the best solid-liquid procedure was Soxhlet, using ethanol as solvent.