Antioxidant and antimicrobial activities of sustainable Salvia hispanica L. seed extracts against gram-positive and gram-negative bacteria

Chia seeds are more than a superfood trend—they might just be the next eco-friendly weapon against foodborne bacteria.

Forget synthetic preservatives. Scientists are turning to nature's own chemistry, and chia seeds are stepping into the spotlight. Researchers in Algeria compared two green extraction methods—aqueous Soxhlet and ethanolic maceration—to pull out bioactive compounds from dark chia seeds. The goal? To see if these extracts can fight off both Gram-positive and Gram-negative bacteria that spoil food and threaten health.

The aqueous Soxhlet extract won on phenolics, showing a strong antioxidant punch: 88% DPPH inhibition at just 400 μg/mL. Meanwhile, the ethanolic maceration extract was richer in flavonoids and displayed moderate, dose-dependent antimicrobial activity. When tested against nine microbial strains, Gram-positive bacteria like Staphylococcus aureus and Listeria monocytogenes were the most vulnerable, with inhibition zones up to 12 ± 1 mm.

But the surprises didn't stop there. Klebsiella pneumoniae, a notoriously tough Gram-negative bacterium, showed a remarkable 15 ± 1 mm zone at 15 mg/mL, while Candida albicans—a fungal foe—was also highly susceptible at 14 ± 1 mm. These results suggest that green-extracted chia seed extracts could serve as natural preservatives, offering a sustainable alternative for food safety and agro-industrial applications.

Key Points

• Aqueous Soxhlet extract: 88% DPPH inhibition at 400 μg/mL
• Gram-positive bacteria most sensitive (up to 12 ± 1 mm)
• Klebsiella pneumoniae: 15 ± 1 mm zone at 15 mg/mL