Advancing green extraction of bioactive compounds using deep eutectic solvent-based ultrasound-assisted matrix solid-phase dispersion: Application to UHPLC-PAD analysis of alkaloids and organic acids in Coptidis rhizoma

Rosemary is a medicinal powerhouse, but how do we unlock its full potential? A new study pits four extraction techniques against each other to find the greenest, most effective way to harvest its health-boosting compounds.

Rosemary has long been revered for its medicinal properties, but extracting its bioactive compounds efficiently remains a challenge. In a recent study, scientists compared four extraction methods: stirring extraction (STE), pulsed electric field-assisted extraction (PEF), ultrasound probe-assisted extraction (UPAE), and ultrasound bath-assisted extraction (UBAE). Each technique was fine-tuned using the Plackett–Burman design before being applied under optimal conditions.

The results revealed a clear trade-off. UBAE achieved the highest total polyphenol content (TPC) at ~17 mg gallic acid equivalents per gram of dry weight (dw) and the strongest antioxidant activity via DPPH (~143 µmol ascorbic acid equivalents per gram dw). Meanwhile, UPAE excelled at recovering ascorbic acid (~20 mg/g dw) and showed a favorable chlorophyll-to-carotenoid ratio of 2.98, similar to UBAE's 2.96, indicating potential health benefits.

Interestingly, STE delivered the highest TPC (~19 mg GAE/g dw) but lagged in antioxidant capacity, while PEF produced the lowest yields overall. The choice of extraction method depends on which compound you prioritize and the environmental footprint you're willing to accept. This study underscores that there is no one-size-fits-all solution, but rather a strategic decision guided by your goals.

Key Points

• UBAE yields highest polyphenols and DPPH antioxidant activity.
• UPAE best for ascorbic acid recovery (~20 mg/g dw).
• Extraction choice depends on target compound and environmental impact.