Microwave‐ and Ultrasound‐Assisted Extraction of Cucurbita pepo Seeds: a Comparison Study of Antioxidant Activity, Phenolic Profile, and In‐Vitro Cells Effects

What if the humble pumpkin seed holds the key to fighting oxidative stress-related diseases? A new study reveals that a simple green extraction method can unlock its powerful antioxidants.

Forget synthetic additives—nature's pantry is full of bioactive treasures, and pumpkin seeds are no exception. Scientists are increasingly turning to green extraction methods to isolate these compounds, and a recent study compared two: microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE). Both used plain water as the solvent, with two different seed-to-water ratios (1 mg/20 mL and 2.5 mg/20 mL).

The results were striking. The MAE extract at the lower ratio (condition 1) showed the best antioxidant activity in FRAP and DPPH assays, while the higher ratio (condition 2) excelled in ABTS and total phenolic content. The extracts also displayed remarkable scavenging power, particularly against hypochlorous acid (HOCl), with IC50 values as low as 1.88 μg/mL.

Chemical analysis identified 21 phenolic compounds, with catechin, caffeine, and gallic acid leading the pack. When tested on cells, MAE extracts showed no adverse effects on Caco-2 viability, while other conditions slightly reduced NSC-34 viability. Overall, the MAE condition 2 extract emerged as the most promising candidate for nutraceutical development—proof that sometimes, the simplest methods yield the most powerful results.

Key Points

• MAE condition 1 led antioxidant activity (FRAP, DPPH)
• MAE condition 2 excels in ABTS, TPC, and cell safety
• 21 phenolics found; catechin, caffeine, gallic acid dominant