Floral bio-residues of Crocus sativus L. as a potential source of anthocyanins

Saffron (Crocus sativus L.) flower is composed of six purple tepals, three yellow stamens and a white phylliform style ending in a stigma with three threads. Saffron is cultivated for its stigma, which corresponds to the most valued spice worldwide [1]. The production of a single kg of this spice originates about 63 kg of floral bioresidues without any known utilization. These bio-residues have been reported as having high phenolic content with bioactive properties [2] and, therefore, the study of their anthocyanin composition is worthwhile. Accordingly, saffron petals were extracted with acidified (trifluoracetic acid) methanol and further purified with Cl8 SepPak® Vac 3 cc cartridges (Phenomenex), followed by filtration (0.22-f!m disposable LC filter disk) . Samples were analyzed in a Hewlett-Packard 1100 HPLC (Agilent Technologies) with a quaternary pump and a diode array detector (DAD) coupled to an HP Chem Station data-processing. Double detection was carried out by DAD, using 520 nm as the preferred wavelength, and MS detection, performed in an API 3200 Qtrap (Applied Biosystems) equipped with an ESI source and a triple quadrupole-ion trap mass analyzer (Analyst 5.1 software). The anthocyanin profiles presented three main peaks identified as glycosylated derivatives of delphinidin and petunidin di- 0-glucosides, and cyanidin 0-rutinoside, based on their chromatographic, UV and mass spectral characteristics. As far as we know the presence of this later is reported for the first time in Crocus spp. Delphinidin di-0-glucoside (Fig. lA) was the major anthocyanin in saffron petals. According to the detected amounts, floral bio-residues of C. sativus might be considered as a valuable natural source of anthocyanins with potential industrial applications.