Efficient and sustainable recovery of bioactive compounds from cashew nut testa shell (Anacardium occidentale L.) using pressurized liquid extraction

What if the secret to a sustainable super-supplement was hiding in the shell of a cashew nut? A new study turns this waste into a goldmine of bioactive compounds using a green, pressurized liquid extraction.

Cashew nut shells are usually tossed aside, but they may hold more value than we think. Scientists have developed a method to recover bioactive compounds from cashew nut testa shells using pressurized liquid extraction—a greener alternative to traditional solvents. The process uses a natural deep eutectic solvent (NADES), specifically a mix of lactic acid and glycerol, which proved to be the most efficient at 60°C with just 4% water. This eco-friendly cocktail achieved a yield of 6.6%, with sulfate and uronic acid contents of 0.170 mg/mg and 0.023 mg/mg, respectively.

The extracted compounds were analyzed using colorimetric methods, FTIR, and NMR to confirm their chemical structure. Antioxidant tests showed promising activity: ABTS scavenging at 25.84%, DPPH at 30.45%, and a ferric reducing power of 690 μg/μg. Even more exciting, cellular assays with L929 fibroblasts revealed that concentrations of 50 and 75 μg/mL boosted cell viability, with colony formation reaching 179% and invasive cells numbering 449—indicating potential benefits for cell proliferation and migration.

This research highlights a win-win scenario: reducing agricultural waste while producing high-value bioactive compounds. The use of NADES as a green solvent not only aligns with sustainability goals but also opens doors for applications in food, cosmetics, and pharmaceuticals. It's a small step for a nut shell, but a giant leap for green chemistry.

Key Points

• NADES (lactic acid + glycerol) extracts bioactive compounds from cashew shells.
• Yield of 6.6% with antioxidant activity (ABTS, DPPH, FRAP).
• Boosts fibroblast viability and migration at 50–75 μg/mL.