Valorization of Tomato Leaves: Optimization of Eco-Friendly Phenolic Extraction and Assessment of Biological Activities

Tomato leaves, usually thrown away, hide a treasure trove of bioactive compounds—and scientists just found a green way to unlock them.

Every harvest, mountains of tomato leaves are discarded, yet these humble greens are packed with phenolic compounds that could power everything from nutraceuticals to sustainable products. In this study, researchers optimized an eco-friendly, water-based extraction using response surface methodology. The winning recipe? Heat a 1:50 solid-to-liquid mixture at 71°C for just 29 minutes—this yielded the highest total phenolic content and antioxidant activity.

The resulting lyophilized tomato leaf extract (TLE) showed dose-dependent antimicrobial effects against Escherichia coli and Candida albicans, but not against Pseudomonas aeruginosa or Staphylococcus aureus. It also exhibited moderate cytotoxicity against MCF-7 breast cancer cells (IC50 = 114.5 µg/mL), and notably reduced intracellular reactive oxygen species in macrophages, hinting at anti-inflammatory power.

Chemical analysis via LC-MS revealed the extract's major players: rutin (45.21%), 4-hydroxycoumarin (13.60%), and α-tomatine (12.37%). These compounds likely drive the observed bioactivities, transforming agricultural waste into a valuable, eco-friendly ingredient for functional products.

Key Points

• Optimal extraction: 71°C, 29 min, 1:50 ratio
• Antimicrobial vs E. coli and C. albicans
• Main compounds: rutin, 4-hydroxycoumarin, α-tomatine