Quality control of saffron (Crocus sativus L.) via a novel HPLC method

Saffron, the dried stigmata of Crocus sativus L., finds various applications in TCM. Here, a novel HPLC protocol was developed and applied for the analysis of saffron samples not only from different places of origin but also from several harvest seasons. One of the main active constituents of saffron, crocin, is also found in Gardenia jasminoides J.Ellis which is used by counterfeiters in order to make faked saffron preparations pass pharmacopoeial tests. HPLC was performed with a ZorBax-XDB-C18 column and with a linear gradient (45 min; 254nm; 1.0 mL/min) of methanol (0.5% acetic acid) and water (0.5% acetic acid). Authentic saffron samples from different regions and years, instead of their effective constituent contents being slightly different, all displayed relatively similar basic chromatograms with 8 typical, well separated peaks, three of which could be identified as crocin-I, crocin-II, and gardenoside, respectively. Accordingly, the crocin-I peak was chosen as the specific chromatogram reference peak in the presented HPLC method. Besides the determination of the content of active constituents, this method was also very favourable for the determination of potential adulterations with G. jasminoides. While in the case of pure saffron the peak ratio (gardenoside/crocin-I) always exhibited values significant below 0.5. The peak ratio was significant above this value for all adulterated samples, with the exact amount rising with the degree of adulteration. Thus, this new HPLC method is easy, quick, precise, and displays high reproducibility so that it can be used for quality control and identification of saffron.

Keywords: Saffron, Crocus sativus, Gardenia jasminoides, quality control, HPLC.