Stigmas and Petals of <i>Crocus sativus</i> L. (Taliouine, Morocco): Comparative Evaluation of Their Phenolic Compounds, Antioxidant, and Antibacterial Activities

Abstract

The dried stigmas of <i>Crocus sativus</i> L. produce saffron, a precious spice used for its culinary and medicinal properties since ancient times, while its petals are considered the main by-product of saffron production. The present study aimed to comparatively evaluate the phenolic content, antioxidant capacity, and antibacterial activity of methanolic extracts of stigmas and petals of <i>Crocus sativus</i> L. from Taliouine. The polyphenol content was measured using the Folin-Ciocalteu method, the antioxidant activity was determined using the DPPH free radical scavenging method, and the well-diffusion method was used to assess antibacterial activity against seven pathogenic bacterial strains (<i>Bacillus subtilis, Escherichia coli, Listeria monocytogenes, Proteus vulgaris</i>, <i>Pseudomonas aeruginosa, Salmonella enterica</i>, and <i>Staphylococcus aureus</i>). Furthermore, the minimum inhibitory concentration (MIC) of the extracts was determined using the microdilution broth test. Our findings revealed that stigmas and petals contained phenolic compounds at the rate of 56.11 ± 4.70 and 64.73 ± 3.42 mg GAE/g, as well as DPPH radical scavenging capacity with IC₅₀ of 1700 <i>µ</i>g/ml and 430 <i>µ</i>g/ml, respectively. Petal extract showed more effective antibacterial activity, with inhibition diameters ranging from 10.66 ± 0.57 to 22.00 ± 1.00 mm and MIC values ranging from 2.81 to 5.62 mg/ml, compared to the stigma extract, which displayed inhibition diameters from 10.00 ± 0.00 to 18.67 ± 0.76 mm and MIC from 2.81 to 11.25 mg/ml, against five of the seven bacterial strains tested, including S. aureus, E. coli, P. vulgaris, P. aeruginosa, and <i>S. enterica</i>. Statistical analyses were performed to determine the significance of these results. Thus, stigmas and petals of <i>Crocus sativus</i> L. might serve as a suitable source of natural antioxidant and antimicrobial agents for application in the food and pharmaceutical industries.