Quality and Functionality of Saffron: Quality Control, Species Assortment and Affinity of Extract and Isolated Saffron Compounds to NMDA and σ₁ (Sigma-1) Receptors

Abstract

Extracts from saffron, the dried stigmata from Crocus sativus L., are being used more and more in preclinical and clinical trials for the treatment of cancer and depression. Because of the known quality problems of saffron, HPLC methods on RP₁₈ 2.5 μm and monolithic RP₁₈ material have been developed and validated for quality control including the quantification of crocins 1 to 5, crocetin, picrocrocin and the degradation products, the cis-crocins. Additionally, a GC-MS method has allowed detection and quantification of the volatile compounds from the pentane extract of saffron. Both systems together allowed the comprehensive characterisation of saffron herbal material and extracts for clinical/preclinical trials. For effective preparation of the respective reference standards, a fast centrifugal partition chromatography (FCPC) method was developed allowing the quick isolation of crocins 1, 2, 5 and picrocrocin in good yields. Using these chromatographic methods and the reference standards, a representative survey of saffron from the global market indicated a high variability of quality, especially concerning the amounts of volatile compounds in saffron samples. A specification for high-quality saffron of > 20 % crocins, > 6 % picrocrocin and not less than 0.3 % of volatiles, calculated as sum of safranal, isophorone and ketoisophorone, was developed. Because no detailed pharmacological studies are available to explain the clinical effects of saffron for the treatment of cancer and depression, receptor binding studies were performed. Saffron extracts and crocetin had a clear binding capacity at the PCP binding side of the NMDA receptor and at the σ₁ receptor, while the crocins and picrocrocin were not effective. These data could give biochemical support for the above-mentioned pharmacological effects of saffron.

Key words

Crocus sativus L. - Iridaceae - saffron - NMDA receptor - σ₁ (sigma-1) receptor - crocins

References

• 1 Schmidt M, Betti G, Hensel A. Saffron in phytotherapy: pharmacology and clinical uses.  Wien Med Wochenschr. 2007;  157/13 - 14 315-9
• 2 Hensel A, Rösing M. Crocus. In: Blaschek W, Ebel S, Hackenthal E, Holzgrabe U, Seller U, Reichling J, editors HagerRom: Hagers Handbuch der Drogen und Arzneistoffe. Heidelberg (Germany); Thieme Publishers 2006, Springer Electronic Media
• 3 Abdullaev F, Frenkel G D. Saffron in biological and medical research. In: Negbi, M, editor Saffron. Crocus sativus. Amsterdam; Harwood Academic Publishers 2005: 103-13
• 4 Akhonzadeh S, Tahmacebi-Pour N, Noorbala A A, Fallah-Pour H, Jamshidi A H, Khani M. Crocus sativus L. in the treatment of mild to moderate depression: a double-blind, randomized and placebo-controlled trial.  Phytother Res. 2005;  19 148-51
• 5 Noorbala A A, Akhondzadeh S, Tahmacebi-Pour N, Jamshidi A H. Hydro-alkoholic extract of Crocus sativus L. versus fluoxetine in the treatment of mild to moderate depression: a double-blind, randomized pilot trial.  J Ethnopharmacol. 2005;  97 281-4
• 6 Abe K, Saito H. Effects of saffron extract and its constituent crocin on learning behaviour and long-term potentiation.  Phytother Res. 2000;  14 149-52
• 7 Abe K, Sugiura M, Shoyama Y, Saito H. Crocin antagonizes ethanol inhibition of NMDA receptor-mediated responses in rat hippocampal neurons.  Brain Res. 1998;  787 32-8
• 8 Hosseinzadeh H, Sadeghnia H R. Protective effect of safranal on pentylenterazol-induced seizures in the rat: involvement of GABAergic and opioids systems.  Phytomedicine. 2007;  14 256-62
• 9 Bowen W D. Sigma receptors: recent advances and new clinical potentials.  Pharm Acta Helv. 2000;  74 211-8
• 10 Hayashi T, Su T P. Sigma1 receptor ligands: potential in the treatment of neuropsychiatric disorders.  CNS Drugs. 2004;  18 269-84
• 11 Maurice T, Lockhart B P. Neuroprotective and anti-amnesic potentials of sigma receptor ligands.  Prog Neuropsychopharmacol Biol Psych. 1997;  21 69-102
• 12 Wintherhalter P, Straubinger M. Saffron-renewed interest in an ancient spice.  Food Rev Int. 2000;  16 39-59
• 13 Li N, Lin G, Kwan Y W, Min Z D. Simultaneous quantification of five major biologically active ingredients of saffron by high-performance liquid chromatography.  J Chromatogr A. 1999;  849 349-55
• 14 Carmona M, Zalacain A, Sánchez A M, Novella J L, Alonso G L. Crocetin esters, picrocrocin and its related compounds present in Crocus sativus stigmas and Gardenia jasminoides fruits. Tentative identification of seven new compounds by LC-ESI-MS.  J Agric Food Chem. 2006;  54 973-9
• 15 Text on Validation of Analytical procedures - ICH Harmonized Tripartite Guideline. ICH; ICH-Q2A. Available at http://www.fda.gov/cder/guidance/ichq2a.pdf. Accessed March 06, 2008. 
• 16 Validation of Analytical Procedures: Methodology - ICH Harmonized Tripartite Guideline. ICH; ICH-Q2B. Available at http://www.fda.gov/cder/guidance/1320fnl.pdf. Accessed March 06, 2008. 
• 17 Wirt U, Schepmann D, Wünsch B. Asymmetric synthesis of 1-substituted tetrahydro-3-benzazepines as NMDA receptor antagonists.  Eur J Org Chem. 2007;  1 462-75
• 18 Straubinger M, Bau B, Eckstein S, Fink M, Winterhalter P. Identification of novel glycosidic aroma precursors in saffron (Crocus sativus L.).  J Agric Food Chem. 1998;  46 3238-43
• 19 Straubinger M, Bau B, Eckstein S, Jezussek M, Winterhalter P. Isolation of new saffron constituents using counter-current chromatography. In: Herderich M, Humpf HU, Schwab W, editors Natural product analysis: chromatography - spectroscopy - biological testing, 1st. edition. Wiesbaden; Vieweg Publishers 1998: 27-34
• 20 Straubinger M, Jezussek M, Waibel R, Winterhalter P. Novel glycosidic constituents from saffron.  J Agric Food Chem. 1997;  45 1678-81
• 21 Berthod A, Hassoun M, Ruiz-Angel M J. Alkane effect in the Arizona liquid systems used in countercurrent chromatography.  Anal Bioanal Chem. 2005;  383 327-40
• 22 Xi L, Qian Z, Du P, Fu J. Pharmacokinetic properties of crocin (crocetin digentiobiose ester) following oral administration in rats.  Phytomedicine. 2007;  14 633-6