Phytochemical Characterization and High-Speed Countercurrent Chromatography-Assisted Isolation of Flavonoids from...

Talisia esculenta Radlk (Sapindaceae) is a tropical tree species native to Brazil, whose leaves are traditionally consumed as herbal infusions. However, the secondary metabolite composition of its foliage remains poorly characterised. In this study, the phytochemical profile of T. esculenta leaf infusions was investigated using HPLC-ESI-QTOF-MS/MS, leading to the annotation of 20 compounds. Subsequent liquid-liquid partitioning and high-speed counter-current chromatography (HSCCC) enabled the targeted isolation of two major constituents. The analysis revealed a flavonoid-rich profile dominated by glycosylated flavonols, with rutin and quercitrin identified as the principal compounds and structurally confirmed by NMR spectroscopy. They were both quantified in the aqueous infusion of the leaves, being 1.42 ± 0.02% (w/w) and 1.54 ± 0.01% (w/w) for rutin and quercitrin, respectively. The metabolite pattern found is consistent with that reported in other members of the Sapindaceae family and contributes to the chemotaxonomic characterisation of the genus. Fractionation enhanced the enrichment of phenolic constituents and allowed assessment of their functional properties such as antioxidant activity (including DPPH assay: from 43.4% for the aqueous infusion to 92.9% for the ethyl acetate fraction) and inhibition of microbial biofilm formation (from 37.4% for the aqueous infusion to 83.4% for the butanolic fraction at 6.25 µg/mL against Staphylococcus aureus). The MIC and MBC were also calculated for the aqueous infusion (12.5 mg/mL for both), its partitions as well as rutin and quercitrin. Anti-inflammatory effects were also observed, with inhibition of NF-κB activity reaching 56.9% for the aqueous infusion and 47.7% for the butanolic fraction. These findings expand current knowledge of secondary metabolite diversity in T. esculenta and demonstrate the applicability of HSCCC as an efficient technique for flavonoid isolation from complex plant extracts. Overall, this study provides new insights into the phytochemical composition of an underexplored tropical species within the Sapindaceae family.