High- and low-pressure fixed bed extraction behaviors to obtain phenolic compounds from barbatimão (Stryphnodendron adstringens) bark

Abstract

Stryphnodendron adstringens, also known as barbatimão, is a native tree from the Brazilian Cerrado recognized for being rich in bioactive compounds and traditionally used as an antiinflammatory, analgesic, and antimicrobial agent. The main phenolic compounds in barbatimão are tannins, flavonoids, and phenolic acids. The diversity of compounds present in this medicinal plant provides a range of applications in the pharmaceutical, cosmetic, and food industries, among others. This work aimed to obtain extracts from barbatimão bark by applying extraction techniques such as fixed bed percolation (PE), ultrasound-assisted percolation (UAP), percolation in cycles (PC) and pressurized liquid extraction (PLE). The extracts were evaluated in terms of global yield (X0), total phenolic content (TPC), tannin content (TTC), flavonoid content (TFC), and ferric reducing antioxidant power (FRAP). Regarding the PE, the best performance condition in TPC was 50% ethanol at 55 °C in 90 min of extraction (485 ± 10 mg TAE/g of dry raw material), obtaining a X0 equal to 51 ± 5%. In terms of TPC, ultrasound didn't show significant improvement (348 ± 36 mg TAE/g of dry raw material), while PC extracted more than four times the TPC (2057 ± 72 mg TAE/g of dry raw material). PLE was statistically equivalent to PE in terms of TPC (472 ± 15 mg TAE/g of dry raw material). The results presented in this work revealed PC and PLE as accessible, cheap, and green extraction techniques able to recover high phenolic content from barbatimão bark.