Microwave-assisted efficient extraction of phenolics from Juglans regia L.: pellicle; kernel unripe fruits; and leaves in different solvents

Abstract

Aim: In the present study, microwave-assisted extraction was compared with conventional approaches for the efficient extraction of phenolics from Juglans regia unripe fruits and leaves. The main objective of this study was to extract phenolic compounds from Jordanian J. regia L. Unripe fruits compared to leaves using microwave and Soxhlet. Materials and Methods: The effects of microwave power; part used and solvent type (ethyl acetate; acetonitrile and acetone) on phenolic content, antioxidant activity, and phytochemical profile. Results and Discussion: Pellicle was the best place for phenolic compounds using ethyl acetate MW closed system with (18%) while the least amount was also in the pellicle (8%) for acetonitrile Soxhlet method. MW closed system used the lowest solvent to solid ratio, but it gives the best phenol content. Kernel Soxhlet/ethyl acetate shows the best free radical scavenger activity IC50 (2.4 * 10−2 μg/ml) while Pellicle MW Open/acetone give the lowest activity IC50 (1.0 μg/ml) but still better than Juglone IC50 (10.21 μg/ml). Conclusion: It’s worthy to go more through the pharmacological activity for this part as anti-inflammatory wound healing and anticancer activity as secondary metabolite profile for this part from walnut not studied extensively.