Phytochemical profiling, antibacterial and antioxidant properties of Crocus sativus flower: A comparison between tepals and stigmas

Abstract

Several studies have demonstrated that stigmas of Crocus sativus contain several bioactive compounds with potential health-promoting properties. However, during the processing of stigmas, large amounts of floral bio-residues are normally discarded as by-products. In this study, using untargeted metabolomics, the comprehensive phytochemical composition of C. sativus stigma and tepals was investigated. Moreover, the antibacterial and anti-biofilm properties of the extracts of C. sativus stigmas and tepals were compared. The study was carried out using two methicillin-resistant staphylococcal reference strains (i.e., Staphylococcus aureus ATCC 43300 and Staphylococcus epidermidis ATCC 35984), representing important Gram-positive biofilm-forming human pathogens. The antibacterial properties were correlated with total polyphenol content, total terpenoid content, and in vitro antioxidant properties of tepals and stigmas. The results demonstrated that stigma and tepal extracts, at the sub-toxic concentrations, were able to interfere with biofilm formation by ATCC 43300 and ATCC 35984. Besides, the higher antibacterial activity of tepals than stigmas was associated with higher levels of phycompounds. Therefore, our results demonstrated that C. sativus stigmas and bio-residues, such as tepals, are potential antioxidant sources and good candidates as antibacterial agents to prevent biofilm formation. Taken together, these findings showed that C. sativus could be used as functional ingredient by the food and pharmaceutical industries.

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

“…However, the values obtained appear higher than those reported by Asgarpanah et al for methanolic extracts of Iranian saffron petals (4.09 to 17.34 mg GAE/g MS) [ 40 ]. Although some studies have shown that petals of Crocus sativus L. contain more polyphenols than stigmas [ 39 , 41 ], other studies have reported the opposite, with a concentration of 97.99 mg GAE/g for stigmas and 69.18 mg GAE/g for petals [ 42 ]. Thus, there is no clear consensus as to which of these floral parts of Crocus sativus L. contain the highest polyphenol content.…”

Extracts from Frangula alnus Mill. and Their Effects on Environmental and Probiotic Bacteria

“…Therefore, for more polar compounds, an attempt could be made to dilute plant samples in the case of the need of usage selected extractants for the process of extracting bioactive compounds from a given plant [ 1 , 31 , 32 ]. A good example is the separation of an isopropanol-based extract [ 33 , 34 ], which is less polar than methanol but still belongs to compounds with a high dipole momentum.…”

Bioactive Components and Biological Activities of Crocus sativus L. Byproducts: A Comprehensive Review

“…Further analysis showed significant reductions in the numbers of bacterial cells, and when the pathogens were incubated with saffron stamen extracts at 6 °C, a synergistic effect was observed. 11 Bellachioma et al 55 compared the antimicrobial activities of saffron petal and stigma extracts, and reported that the antimicrobial activity of the petal extracts was stronger than stigma extracts. Asgarpanah et al 88 also observed that methanol extracts of saffron petals had stronger antimicrobial activity against certain pathogens, including Staphylococcus aureus, Salmonella enterica, and Shigella dysenteriae, when compared with stigma extracts.…”

“…The antioxidant properties of different parts of the saffron plant also differ. Generally, petal extracts show good antioxidant activity, even higher than extracts of the stigma or stamen. ,, Mir et al reported that petals had the highest antioxidant activity, followed by leaves, stamens, and styles. Serrano-Díaz et al demonstrated that the stamens showed the strongest scavenging ability for LOO • and OH • free radicals, even higher than propyl gallate.…”

“…Generally, the phytochemical components in saffron bioproducts can kill or inhibit the growth of bacterial cells in various ways, including (1) disruption of the cell membrane, (2) modulation of efflux pumps, (3) inhibition of virulence factors, (4) inhibition of quorum sensing, (5) inhibition of fatty acid synthase, (6) inhibition of peptidoglycan cross-linking, (7) inhibition of dipeptide synthesis, (8) inhibition of bacterial biofilm formation, (9) alteration in oxidative phosphorylation, and (10) inhibition of oxygen uptake (Figure ). ,,− Molecular docking studies of flavonoids showed that flavonoids and their derivatives have significant affinity for binding with certain receptors, suggesting the reason for their good antimicrobial activity …”