Beyond sweetness: Unveiling the antioxidant and the antimicrobial potential of Lebanese carob pod extract

Highlights • Carob extract exhibited high phenolic content and strong antioxidant activity. • Exhibited broad-spectrum antibacterial activity against Gram-positive and negative bacteria (MIC 22.5 mg/mL; MBC 45–90 mg/mL). • Completely inhibited Aspergillus spp. growth and AFB1/OTA production at 90 mg/mL. • Represents a promising natural preservative with combined antioxidant and antimicrobial functions. Ceratonia siliqua L. (carob), a tree native to the Mediterranean basin, shows great potential in nutraceutical and therapeutic applications due to its rich load of bioactive compounds. This study examined the biological properties of an extract obtained from Lebanese carob pod powder using ultrasound bath. The antioxidant activity of the extract was assessed using DPPH scavenging capacity, FRAP, and CUPRAC assays. The extract showed a total phenolic content ranging from 16.68 to 20.71 mg GAE/g DM, which underscores its important antioxidant potential. Additionally, the antibacterial activity of the extract was assessed against a panel of bacterial strains, encompassing both Gram-positive ( L. monocytogenes and S. aureus ) and Gram-negative ( E. coli and Salmonella spp .) bacteria using MIC and MBC methods. It exhibited an antibacterial activity against all bacteria, demonstrating bacteriostatic effects at lower concentrations (22.5 mg/ml) and bactericidal effects at higher levels (45-90 mg/ml). Finally, its antifungal activity against Aspergillus flavus and Aspergillus carbonarius was evaluated. A notable fungistatic and fungicidal activities against both fungal species was observed in a dose-dependent manner . These results suggest that carob pod powder extract could serve as a valuable natural source for food preservation and applications in the health sector, subject to further research and development.