Green solvent selection and extractin protocol for selective recovery of anti-diabetic components from T. crispa

Abstract

This study systematically explores a green extraction process of T. crispa stems to selectively isolate therapeutic compounds, borapetoside C (BPC) and magnoflorine (MGF), recognized for their anti-diabetic properties. In agreement with Hansen solubility parameters prediction, H2O and EtOH were found to be suitable solvents for extraction of BPC and MGF, respectively, resulting in 33 % and 45 % extractabilities after 60 min. Further investigations demonstrated considerable increase in BPC extractability using 20 % EtOH:H2O mixture at 40 °C, with complete extraction achieved after 60 min. While for MGF, pure-EtOH at 40 °C, was the most suitable solvent, showing the highest selectivity and complete extraction after 100 min. The BPC-rich extract from 20 % EtOH:H2O exhibited higher anti-diabatic activity (IC50 = 0.63 ± 0.03 and 0.72 ± 0.04 mg/mL, respectively, for α-glucosidase and α-amylase enzymes inhibition activity), and considerably lower cytotoxicity to L6 and HepG2 cells, with IC50 = 0.26 ± 0.16 and 0.24 ± 0.02 mg/mL, respectively, compared with the MGF-rich extract obtained with pure-EtOH. Based on these results, a sequential extraction scheme was proposed involving initial pure-EtOH extraction to selectively and completely remove MGF, followed by extraction with a 20 % EtOH:H2O mixture to recover the remaining BPC, which was approximately 80 % of the BPC originally present. The obtained MGF-free BPC-rich extract showed significantly lower cytotoxicity (IC50 = 0.31 ± 0.06 mg/mL against L6 cell) and higher enzyme inhibition activities (IC50 = 0.53 ± 0.32 and 0.52 ± 0.02 mg/mL for α-glucosidase and α-glucosidase enzymes inhibition activity), comparable to acarbose (IC50 = 0.43 ± 0.02 and 0.83 ± 0.03 mg/mL for α-glucosidase and α-glucosidase enzymes inhibition activity), the result that potentially leads to the development of a promising industrial process to harness T. crispa for diabetes prevention and treatment.