Sustainable Recovery and Biofunctional Characterization of Polyphenol-Rich Extracts from Norway Spruce, Chestnut Wood, and Pomegranate By-Products

What if the secret to better health was hidden in the bark of trees and the leftovers of your pomegranate juice?

Forget the trash bin—plant by-products are the new treasure chests. Scientists are turning Norway spruce bark, chestnut wood, and pomegranate waste into potent sources of bioactive compounds, all using eco-friendly methods. The study employed microwave and ultrasound-assisted extractions, alone or in sequence, optimizing conditions like solvent, temperature, and power. A simple 50% ethanol solution combined with microwaves proved the champion, unlocking the highest phenolic recovery and antioxidant punch across all materials. Among the trio, pomegranate waste stole the spotlight with the strongest antioxidant activity, as measured by FRAP, ORAC, and DPPH assays. Chemical profiling revealed stilbenes in spruce, ellagic acid in chestnut, and ellagic acid plus punicalagins in pomegranate. But the benefits didn't stop there: spruce bark and pomegranate waste inhibited α-amylase, an enzyme linked to starch digestion, and both showed antimicrobial effects against Gram-positive and Gram-negative bacteria, with pomegranate leading in inhibition and spruce bark offering broad-spectrum action. Even after 21 days, the phenolic content remained stable. This isn't just waste—it's a goldmine for functional foods and medicine, all thanks to sustainable extraction.

Key Points

• Green extraction yields high phenolics from plant by-products.
• Pomegranate waste shows strongest antioxidant and antimicrobial activity.
• Spruce and pomegranate inhibit α-amylase; stable for 21 days.