Assessment of total phenolic content, in vitro antioxidant and antibacterial activity of ruta graveolens L. Extracts obtained by choline chloride based natural deep eutectic solvents

Can a clever mix of natural solvents turn a humble medicinal plant into a powerhouse of antioxidants and antibacterial defense? Researchers are unlocking the hidden potential of rue leaves using designer green solvents.

Rue, scientifically known as Ruta graveolens, has long captured scientific interest for its rich cargo of furanocoumarins and flavonoids. But how you extract these valuable phytochemicals matters immensely. Researchers set out to test how varying extraction temperatures, times, and water content in choline chloride-based natural deep eutectic solvents shape the final crude extracts.

It all comes down to precision. The sweet spot was found at a mild 30 °C, with a 20% water content, over a 90-minute extraction period. At a concentration of 13.3 µg mL−1, this specific extract hit the jackpot, boasting the highest total phenolic content at 38.24 mg GAE per gram of dry matter and a stellar antioxidant activity of 72.53%.

Beyond antioxidant power, this exact formulation proved to be a formidable foe against bacteria. It showed the best antibacterial efficiency across all tested strains, displaying a particularly strong knack for neutralizing the stubborn gram-negative bacterium Pseudomonas aeruginosa.

Key Points

• Optimal extraction at 30 °C, 20% water, and 90 min
• Highest phenolic content reached 38.24 mg GAE g−1 DM
• Best antibacterial efficiency shown against gram-negative P. aeruginosa