Comparative Analysis of Phytochemical Profile and Antioxidant and Antimicrobial Activity of Green Extracts from Quercus ilex and Quercus robur Acorns

Move over, synthetic solvents—green chemistry just found a new hero in acorns. Two oak species are battling it out, and the winner packs a punch against both bacteria and a notorious plant killer.

Forget harsh chemicals—scientists have brewed up a greener way to extract nature's medicine cabinet. Using a medium-scale ambient temperature system, they optimized the process for Quercus ilex acorns, balancing polyphenol yield and antioxidant power while slashing solvent use. The sweet spot? 200 grams of acorn, 100 milliliters of solvent, and a 0.5 dispersant ratio—a recipe for eco-friendly efficiency.

When they applied the same conditions to Quercus robur, the results got interesting. Robur flexed its muscles with a whopping 35,822 mgGAE/L of polyphenols and 234 mmolTE/L of antioxidant capacity, leaving ilex in the dust (25,072 and 162, respectively). But ilex fought back with its own chemical arsenal—procyanidins and catechin—while robur dominated in gallotannins.

The real drama unfolded in the petri dish. Both extracts showed strong antibacterial action, with ilex taking down Staphylococcus aureus at a MIC of just 0.63%. And in a first-ever discovery, acorn extracts halted the growth of Phytophthora cinnamomi, a devastating plant pathogen—robur proved lethal at a mere 0.1% concentration. Who knew acorns were such overachievers?

Key Points

• Green extraction optimized for acorns, cutting solvent use
• Quercus robur hits 35,822 mgGAE/L polyphenols, ilex 25,072
• First proof: acorn extracts inhibit Phytophthora cinnamomi