Ultrasound-assisted natural deep eutectic solvents for green extraction of flavonoids from Citri Reticulatae Pericarpium: Extraction optimization and attenuation of ulcerative colitis

Imagine a chronic gut disease with no cure—now picture a humble citrus peel, transformed by green chemistry, stepping up as a potential hero. This study turns old wisdom into new science.

Ulcerative colitis is a stubborn inflammatory bowel disease, and current treatments often fall short. But a familiar kitchen staple—Citri Reticulatae Pericarpium, or Chenpi—has long been used for digestive complaints. Now, scientists have finally unpacked its hidden potential.

Using ultrasound-assisted extraction paired with natural deep eutectic solvents (DESs), the team screened ten solvent combinations. Choline chloride with methylurea won the race, outperforming traditional solvents. Optimization via response surface methodology pinpointed the sweet spot: a liquid-to-solid ratio of 20 mL/g, 400 W ultrasonic power, 52 minutes, and 65% water content.

In mice with DSS-induced colitis, Chenpi extracts worked wonders. Disease activity scores dropped, the intestinal barrier was restored, and inflammatory cytokines were suppressed. The extracts also rebalanced redox status—a key to calming inflammation.

The real magic? Chenpi inhibits three specific enzymes—MPO, Elane, and PAD4—which are tied to neutrophil extracellular traps, a driver of colitis. This green extraction method not only boosts efficiency but also offers a promising lead for future UC therapies.

Key Points

• Chenpi flavonoids extracted via ultrasound-assisted DESs, choline chloride/methylurea best.
• Optimal extraction: 20 mL/g, 400 W, 52 min, 65% water.
• Chenpi alleviates colitis by inhibiting MPO, Elane, PAD4.