The phenolic leaf extract of Ptilostemon casabonae (L.) Greuter after in vitro simulated gastrointestinal digestion

For centuries, plants have played a central role in traditional medicine and have been used for the treatments of numerous diseases. They are still important for healthcare today, because many modern medicines derive from plant compounds. This study is focused on Ptilostemon casabonae (L.) Greuter, an endemic species in Sardinia. This wild, thistle-like plant is traditionally consumed for its flavor and biological effects. It is harvested and eaten either raw or cooked and is used medicinally to treat liver disorders and for its diuretic and digestive properties [1]. The aim of this work was to evaluate the complex digestion process of the hydroalcoholic extract obtained from the leaves of P. casabonae by applying an in vitro simulation model, to determine if there were quali-quantitative differences in the extract after in vitro simulation of gastrointestinal digestion. The INFOGEST protocol was used for this purpose [2]. Primarily, HPLC-PDA combined with MS was utilized to characterize and quantify the compounds present. The HPLC-PDA-MS/MS analysis revealed a complex polyphenolic fraction. In agreement with existing reports on related species, flavonoids, especially O-glycosides of quercetin, and derivatives of caffeoylquinic acid were found [1]. Chromatograms obtained in PDA mode revealed both qualitative and quantitative variations in the profile after in vitro digestion of the extract. In the intestinal phase, notable differences were observed for chlorogenic and cryptochlorogenic acids, as well as dicaffeoylquinic acids, with the appearance of new compounds and variations in their abundances, probably due to isomerization and degradation phenomena caused by changes in pH, high temperatures and stirring [4], [5]. Based on the phytochemical composition, antioxidant properties were evaluated by spectrophotometric methods such as ABTS and DPPH, [3] showing that the digested extract had lower antioxidant activity than the undigested extract.