Ultrasound assisted deep eutectic solvent-based extraction of Montepulciano d’ Abruzzo grape seeds for the recovery of the grape seed oil and its biological evaluation

Grape seeds are by-products of vinification process. In this work, a green ultrasound-assisted extraction of grape seeds oil was performed by using the natural volatile deep eutectic solvent (NADES) menthol: thymol 1:1. The obtained oil was compared to that deriving from UAE with n-hexane in terms of fatty acids composition and biological activities. The content of linoleic acid was low for the DES extracted oil; the content of linolenic acid increased from 0.53 % to 5.18 %. The grape seeds oil extracted with DES showed the best total phenolic (18.65 mg GAE/g) and flavonoid (0.73 mg RE/g) contents and the highest results in FRAP, CUPRAC, MCA and Phosphomolybdenum assays. The oil extracted by DES also showed a higher amylase inhibition (0.57 mmol ACAE/g) than n-hexane extract (0.47 mmol ACAE/g). Finally, the anti-inflammatory activity was assessed in vivo through tree different assays, suggesting that their different fatty acids composition could be partially responsible for the significant anti-inflammatory effect of the grape seed oil extracted by NADES.