Enhancing the yield of emodin from Cassia alata L. leaves using ultrasound-assisted deep eutectic solvent extraction

What if the key to unlocking a medicinal compound's full potential lies in a green, tailor-made solvent? Scientists have found a way to boost emodin yield from Cassia alata leaves using a deep eutectic solvent—an eco-friendly alternative to traditional methods.

Emodin, a bioactive compound in Cassia alata leaves, holds promise for various pharmacological effects. Yet, conventional extraction methods yield disappointingly low amounts. Enter deep eutectic solvents (DES)—a class of green solvents with remarkable properties. Researchers screened several DES combinations and zeroed in on lactic acid:choline chloride in a 2:1 molar ratio. Using response surface methodology with Box-Behnken design, they optimized the extraction conditions. The highest total anthraquinone content was achieved at 53°C, 19 minutes, and a solid-to-solvent ratio of 1:20 g/mL. To ensure accurate quantification, they validated a method using LC-UV with a C-18 column, an isocratic mobile phase of 2% acetic acid:methanol (30:70), a flow rate of 0.8 mL/min, and detection at 288 nm. The DES extract contained higher emodin and total anthraquinone levels than ethanol extracts under the same conditions. This study demonstrates that DES is not only more effective but also more efficient, offering a sustainable path to enhance emodin yield from Cassia alata leaves.

Key Points

• DES (lactic acid:choline chloride 2:1) boosts emodin yield.
• Optimal conditions: 53°C, 19 min, 1:20 g/mL solid-to-solvent.
• DES outperforms ethanol in extraction efficiency.