Journal Article

Optimization of antibacterial and antifungal activities in Moroccan saffron by-products using mixture design and simplex centroid methodology

Asehraou, Abdeslam, Al-Maaqar, Saleh M., Saalaoui, Ennouamane, Jaouadi, Bassem, Haddou, Mounir, Bellaouchi, Reda, El Hachlafi, Naoufal, Addi, Mohamed, Baddaoui, Sanae, Taibi, Mohamed, Baraich, Abdellah, Benabbes, Redouane, Elbouzidi, Amine, AL-Farga, Ammar

2025

Overview

The health risks associated with synthetic preservatives have intensified the search for natural antimicrobial alternatives. Crocus sativus L. (saffron) generates abundant by-products, such as tepals and leaves, which are rich in bioactive compounds with demonstrated antimicrobial potential. Compared to other natural alternatives, saffron by-products offer distinct advantages, including a unique combination of phenolic compounds (e.g., ellagic acid, rutin) and carotenoids (e.g., crocin) that act synergistically against both Gram-positive and Gram-negative bacteria, as well as fungi. Additionally, these by-products represent a sustainable solution, with approximately 63 kg of agricultural waste generated per kg of saffron spice. This study optimized the antibacterial and antifungal efficacy of saffron extracts using a simplex centroid mixture design. Phytochemical analysis using high-performance liquid chromatography with diode-array detection (HPLC–DAD) identified key antimicrobial compounds, including ellagic acid (68.43% in leaves, 50.31% in tepals) and crocin (9.59% in stigmas). Antimicrobial assays against Staphylococcus aureus , Escherichia coli , Candida albicans , and Geotrichum candidum revealed that stigma extracts exhibited superior antibacterial activity (MIC = 25 mg/mL for S. aureus and E. coli ), while tepal and leaf extracts showed promising antifungal effects (MIC = 12.5 mg/mL for G. candidum ). The mixture design approach uncovered synergistic interactions, with an equimolar combination of stigma, tepal, and leaf extracts (33:33:33) demonstrating the strongest antibacterial activity (MIC = 25 mg/mL) and a ternary mixture (34% stigma, 30% leaf, 36% tepal) achieving the lowest antifungal MIC (6.25 mg/mL). These findings highlight saffron by-products as highly effective and sustainable natural antimicrobials, providing a cost-efficient (40–60% reduction compared to conventional extracts) and multi-functional alternative to synthetic preservatives. Their dual functionality (antimicrobial + natural coloring) and agricultural waste origin make them particularly valuable for industrial applications in food preservation, pharmaceuticals, and biopharmaceuticals. The integration of statistical modeling maximizes their potential, meeting the growing demand for safe, natural antimicrobial solutions with clear competitive advantages

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/326/1320 / 631/326/193 / 631/326/22 / 631/326/2522 / 631/326/41 / Acids / Agricultural wastes / Anti-Bacterial Agents - chemistry / Anti-Bacterial Agents - pharmacology / Antibacterial activity / Antifungal activity / Antifungal Agents - chemistry / Antifungal Agents - pharmacology / Antimicrobial agents / Bacteria / Bacteria - drug effects / Bioactive compounds / Biopharmaceuticals / By-products / Byproducts / Carotenoids / Carotenoids - pharmacology / Crocus - chemistry / Crocus sativus L / Design / E coli / Ellagic acid / Escherichia coli / Experimental mixture design / Feeds / Flavonoids / Food / Food industry / Food preservation / Fungi - drug effects / Gram-negative bacteria / Gram-positive bacteria / Health risks / Herbal medicine / High-performance liquid chromatography / Humanities and Social Sciences / Industrial applications / Leaves / Liquid chromatography / Metabolism / Metabolites / Microbial Sensitivity Tests / Minimum inhibitory concentration / Morocco / multidisciplinary / Multidrug resistant organisms / Pathogens / Phenolic compounds / Phytochemicals - pharmacology / Plant extracts / Plant Extracts - chemistry / Plant Extracts - pharmacology / Plant Leaves - chemistry / Polyphenols / Preservatives / Rutin / Science / Science (multidisciplinary) / Solvents / Staphylococcus aureus / Statistical models / Stigma / Stigmas (botany)