Antibacterial Activity and Molecular Docking of Compounds from Avicennia marina Leaves Extracts: Obtained by Natural Deep Eutectic Solvents

Could a simple mix of citric acid and glucose unlock nature's own antibiotic arsenal? A new study on mangrove leaves says yes—and the key ratio might surprise you.

Mangroves are tough survivors, but their chemical defenses are even tougher. Scientists extracted compounds from young and old leaves of Avicennia marina using a natural deep eutectic solvent—a green, biodegradable mix of citric acid and glucose. By tweaking the molar ratios from 1:1 to 4:1, they found the sweet spot at 4:1, which produced the strongest antibacterial punch against both Staphylococcus aureus and Escherichia coli. Old leaves showed inhibition zones of 27.47 mm and 37.73 mm, while young leaves followed closely with 28.69 mm and 30.99 mm. Using paper-disk assays in vitro and molecular docking in silico, the team targeted peptide deformylase (ID 6JFQ), a key bacterial enzyme. Among six phytochemicals identified via LC-MS, diosmetin 7-O-β-D-glucuronide stood out with a binding affinity of −9.4 kcal/mol—a promising lead for drug development. The authors stress that purification is still needed to isolate pure compounds from the crude extracts, but the path forward is clear: nature's chemistry, guided by green solvents, might soon join the fight against resistant bacteria.

Key Points

• Best antibacterial ratio: citric acid:glucose 4:1
• Old leaves: 27.47-37.73 mm inhibition zones
• Diosmetin glucuronide binds −9.4 kcal/mol to 6JFQ