Supercritical extraction of neolignans from Piper regnelli var. pallescens

The aim of this study was to compare the yield and biological potential of Piper regnellii extracts obtained by supercritical fluid extraction (SFE) and by conventional method. The extracts were characterized by the HPLC technique according to the structure type of conocarpan and eupomatenoid-5 neolignans. SFE was performed at temperatures of 313 and 333 K and at pressures ranging from 10.92 to 25.00 MPa. An investigation of antioxidant and antibacterial activities was performed as well. Higher levels of neolignans were found in the extracts obtained by SFE. The results indicate that these extracts showed higher antioxidant activity than those obtained by Soxhlet extraction. All extracts showed low total phenolic contents. The extracts obtained by SFE showed minimal inhibitory concentrations (MIC) ranging from 1.95 to 7.81 μg/cm3 against oxacillin-sensitive Staphylococcus aureus (OSSA) and MICs from 0.98 to 7.81 μg/cm3 against oxacillin-resistant S. aureus (ORSA). The second-order mathematical model used to describe the extraction kinetics was quite satisfactory.

Calculated and experimental kinetic curves of extraction from the leaves of Piper regnellii. Solvent flow rate 3 × 10−6 m3/min. (□) 10.92 MPa/313 K, (▵) 24.41 MPa/333 K, (○) 25.00 MPa/313 K and (–) second-order model.Figure optionsDownload as PowerPoint slideHighlights
► Supercritical and conventional extractions were used to obtain neolignans from the leaves and stems of Piper regnellii.
► Conditions for the extraction using supercritical CO2 were 313 and 333 K, with pressures ranging from 10.92 to 25.00 MPa.
► Supercritical extraction proved to be more selective in terms of conocarpan and aupomatenoid-5.
► Satisfactory antioxidant activity results were observed by the DPPH method for the extracts.