Intensified aqueous-based processes to obtain bioactive extracts from Plantago major and Plantago lanceolata

Abstract

Subcritical water extraction (SWE) and microwave-assisted water extraction (MAE) have been investigated for the effective recovery of antioxidant compounds from Plantago major and Plantago lanceolata. Subcritical water extractions were carried out at several temperatures ranging from 25 to 200°C and two different extraction procedures have been used: individual and sequential extractions. For comparison purposes, microwave-assisted water extraction was carried out at the same extraction temperatures. The Plantago species’ extracts were characterized in terms of total phenol content by using the Folin-Ciocalteu assay. Antioxidant activity was measured using two different in vitro assays, namely DPPH radical scavenging and TEAC (trolox equivalents antioxidant capacity). The identification of bioactive components was carried out using liquid chromatography coupled to diode array and mass spectrometry (HPLC-DAD-MS). Results indicate the presence of various polyphenolic compounds such as plantamajoside, verbascoside and isoverbascoside and demonstrate that the extraction temperature had a positive influence on both extraction yield and antioxidant activity of the attained extracts. SWE and MAE demonstrated its usefulness as green extraction methods compared to traditional protocols and thus can be successfully employed to obtain bioactive extracts from Plantago species for their use in cosmetic and food industries.