Crocus sativus L. (saffron), belonging to the Iridaceae family, is a perennial plant reaching up to 25 cm in height that requires for growing a continental Mediterranean climate [1]. Italy is among the major producers of saffron in Europe, after Greece and Spain [2]. The plant is cultivated only to recover the stigmas from its flowers to obtain the spice, which is widely used in the food sector both for particular taste and intense colour. The remaining part of the flower (almost all) is waste. Previous chemical characterization studies of saffron bioresidues revealed the presence of flavonoids such as quercetin and kaempferol glucosides [3,4] known in the literature as bioactive agents, useful for their antioxidant and antiviral properties [5]. The aim of this work was to re-evaluate Tuscan saffron by-products by preparation of a hydroalcoholic extract, followed by its chemical quali-quantitative UHPLC-HR-Orbitrap/ESI-MS analysis and in vitro test of the antiviral effect against SARS-CoV-2. The raw material was provided by the Tuscan "Montegrappa Farm by Anastasia Vecchiarelli" (Grosseto, Italy) and extracted by static maceration with EtOH-H2O 60% v/v immediately after harvesting. Extracts were injected in triplicate solutions into the LC-MS system and the chemical fingerprint was obtained by tentative identification of the components based on HR-MS data. The metabolomic study of saffron by-products extract confirmed the presence of quercetin, kaempferol, isorhamnetin derivatives (as mono- or diglucoside and in acetylated form) and showed the occurrence of crocins. Kaempferol-O-sophoroside resulted the most abundant kaempferol derivative contained in the saffron extract (316.5 ± 5.3 mg/100 g of fresh flower (FF)), followed by kaempferol (14.8 ± 1.4 mg/100 g FF). For the antiviral assay, VERO E6 cells were infected with the SARS-CoV-2 clinical strain VR PV10734 obtained from the Unit of Virology, AOUP, Pisa. The SARS CoV-2 antiviral activity of the saffron extract was evaluated by counting the number of infected cells in the presence and absence of extract (High Content Confocal Microscopy) and by quantifying SARS CoV-2 genomes by Real-Time PCR. Saffron by-products extract reduced SARS-CoV-2 viral genomes and the frequency of cell infection by 2-fold respect to the untreated control. In conclusion, these encouraging results, which fit into a perspective of enhancing the small local agri-food chain, showed the high chemical and biological value of the Tuscan saffron wastes phytocomplex as a good source of health-promoting specialized metabolites.
Re-evaluation of Tuscan Crocus sativus L. wastes by metabolomic fingerprint and in vitro antiviral test against SARS-CoV-2
E. Cioni;M. Di Stasi;E. Iacono;M. Lai;M. De Leo;A. Braca;M. Pistello
2023-01-01
Abstract
Crocus sativus L. (saffron), belonging to the Iridaceae family, is a perennial plant reaching up to 25 cm in height that requires for growing a continental Mediterranean climate [1]. Italy is among the major producers of saffron in Europe, after Greece and Spain [2]. The plant is cultivated only to recover the stigmas from its flowers to obtain the spice, which is widely used in the food sector both for particular taste and intense colour. The remaining part of the flower (almost all) is waste. Previous chemical characterization studies of saffron bioresidues revealed the presence of flavonoids such as quercetin and kaempferol glucosides [3,4] known in the literature as bioactive agents, useful for their antioxidant and antiviral properties [5]. The aim of this work was to re-evaluate Tuscan saffron by-products by preparation of a hydroalcoholic extract, followed by its chemical quali-quantitative UHPLC-HR-Orbitrap/ESI-MS analysis and in vitro test of the antiviral effect against SARS-CoV-2. The raw material was provided by the Tuscan "Montegrappa Farm by Anastasia Vecchiarelli" (Grosseto, Italy) and extracted by static maceration with EtOH-H2O 60% v/v immediately after harvesting. Extracts were injected in triplicate solutions into the LC-MS system and the chemical fingerprint was obtained by tentative identification of the components based on HR-MS data. The metabolomic study of saffron by-products extract confirmed the presence of quercetin, kaempferol, isorhamnetin derivatives (as mono- or diglucoside and in acetylated form) and showed the occurrence of crocins. Kaempferol-O-sophoroside resulted the most abundant kaempferol derivative contained in the saffron extract (316.5 ± 5.3 mg/100 g of fresh flower (FF)), followed by kaempferol (14.8 ± 1.4 mg/100 g FF). For the antiviral assay, VERO E6 cells were infected with the SARS-CoV-2 clinical strain VR PV10734 obtained from the Unit of Virology, AOUP, Pisa. The SARS CoV-2 antiviral activity of the saffron extract was evaluated by counting the number of infected cells in the presence and absence of extract (High Content Confocal Microscopy) and by quantifying SARS CoV-2 genomes by Real-Time PCR. Saffron by-products extract reduced SARS-CoV-2 viral genomes and the frequency of cell infection by 2-fold respect to the untreated control. In conclusion, these encouraging results, which fit into a perspective of enhancing the small local agri-food chain, showed the high chemical and biological value of the Tuscan saffron wastes phytocomplex as a good source of health-promoting specialized metabolites.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
