LC-DAD-MS (ESI+) analysis and antioxidant capacity of Crocus sativus petal extracts

In this study, various fractions isolated from the petals of Crocus sativus were assessed at first for their phenolic content both qualitatively and quantitatively and secondly for their antioxidant activity. The phytochemical analysis was carried out by LC-DAD-MS (ESI(+)) whereas the antioxidant potential was evaluated by applying two methodologies, the DPPH(center dot) radical scavenging activity test and the Co(II)-induced luminol chemiluminescence procedure. According to data obtained from these antioxidant tests, the diethyl ether, ethyl acetate and aqueous fractions demonstrated the strongest antioxidant capacity. Interestingly, the major constituents identified in these fractions correspond to kaempferol, quercetin, naringenin and some flavanone and flavanol derivatives glycosylated and esterified with phenylpropanoic acids. In addition, the presence of some nitrogen-containing substances, as well as other phenolics and phenylpropanoic derivatives was also traced. The identification and structural elucidation of all substances isolated in this study was achieved by both comparing available literature data and by proposed fragmentation mechanisms based on evaluating the LC-DAD-MS (ESI(+)) experimental data. The quantitative analysis data obtained thus far have shown that Crocus sativus petals are a rich source of flavonoids. Such a fact suggests that the good antioxidant capacity detected in the various fractions of Crocus sativus petals could be attributed to the presence of flavonoids, since it is already known that these molecules exert antioxidant capability. The latter, along with the use of Crocus sativus in food and pharmaceutical industry is discussed.