Extraction and characterization of bioactive compounds from eggplant peel using ultrasound – assisted extraction

Abstract

This study followed the bioactive compounds extraction and the antioxidant potential of the eggplant peel, using three different solvents (ethanol, methanol and acetone). The successive extraction of total monomeric anthocyanin (TMA), total flavonoids (TFC), and total phenolic compounds (TPC) from eggplant peel was done by using an ultrasound -assisted extraction. The results showed that the highest bioactive compounds content was achieved for the methanol extract, which was characterized by 0.74 g D-3G/g d.w. of TMA, 5.48 g CE /g d.w. of TFC, 14.72 g GAE/g d.w. of TPC, compared to the ethanol and acetone extracts. Moreover, for the methanol extract, six anthocyanins were identified (delphinidin-3-rutinoside, delphinidin-3-glucoside, cyanidin-3-rutinoside, delphinidin-3rutinoside-5-glucoside, malvidin-3-rutinoside-5-glucoside and petunidin-3rutinoside), while for the ethanol extract, five anthocyanins were identified (all without malvidin-3-rutinoside-5-glucoside) and for the acetone extract only two anthocyanins were detected (delphinidin-3-rutinoside, delphinidin-3-glucoside). The antioxidant potential of the eggplant extracts was investigated by DPPH method. Results showed that the methanol extract had the highest antioxidant activity (51% inhibition of DPPH radical at a concentration 27.2 mM TE/g d.w.), followed by the ethanol and acetone extracts (39 % and 33% DPPH radical inhibition rate at a concentration 22.4 and 17.04 mM TE/g d.w., respectively). Ultrasound-assisted extraction is promising because the extracts rich in bioactive compounds can be obtained at low cost.

Eggplant Peels as a Valuable Source of Anthocyanins: Extraction, Thermal Stability and Biological Activities

“…Time significantly influenced the antioxidant activity only for the extract with EtOH 70% at 25 °C ( p < 0.05). Compared to our results, Horincar et al [ 22 ] obtained lower antioxidant activity by eggplant peels ultrasound extraction using EtOH 70% acidified with 1N HCl for 30 min at 40 °C.…”

“…The results exhibited that the exposure for 30 min to ultrasounds is enough to extract a high content of anthocyanins. Horincar et al [ 22 ] also reported lower TAC values from an eggplant peel extract obtained with EtOH 70% acidified with 1N HCl after 30 min at 40 °C. Dumitrascu et al [ 23 ] reported higher TAC for higher EtOH concentrations at 50 °C after 40 min of phenolic compound extraction from cornelian cherry fruits.…”

Value-Added Pastry Cream Enriched with Microencapsulated Bioactive Compounds from Eggplant (Solanum melongena L.) Peel

“…The extraction of phytochemicals from freeze-dried eggplant peel was performed according to the procedure described in our previous study [13]. The resulting eggplant peel extract (EPE) was used for the microencapsulation experiment.…”

“…Other anthocyanins found in the eggplant are delphininidin-3-rutinoside, delphininidin-3glucoside, cyanidin-3-rutinoside, and petunidin-3-rutinoside [11][12][13]. The predominant phenolic compound found in all eggplant varieties is chlorogenic acid [14].…”

Solanum melongena L. Extract Protects Retinal Pigment Epithelial Cells from Blue Light-Induced Phototoxicity in In Vitro and In Vivo Models

“…Eggplant, an edible plant rich in beneficial nutrients such as vitamins, phenols, and antioxidants, has been extensively investigated for its antioxidant properties [ 17 , 18 , 19 ]. In particular, Solanum melongena L. contains high levels of components with strong radical-scavenging activities [ 19 , 20 ].…”