Saffron, picrocrocin

Greek saffron Picrocrocin, safranal, crocins, kaempferol diglucoside Me0H/H20 A MeOH B H20 with AcOH 250, 308, 440 nm/ ESI (+) ESI interface 22... 

Fig. 2.22. Chromatograms of methanohwater (50 per cent, v/v) saffron extracts from Mancha (a), Rio (b) and Sierra (c) types, simultaneously recorded at 250, 310 and 440 nm, including 4-nitroaniline as internal standard. The mobile and stationary phases were a linear gradient of methanol-water from 20 to 70 per cent in 50min, and an ODS column, respectively. The flowrate was lml/min, temperature 30°C and sample size 50/jl. The following compounds are present picrocrocin (1), HTCC (2), 3-entiobiosile-kaempferol (3), a-crocin (4), crocin 2 (5), crocin 3 (6), safranal (7), crocin 4 (8), crocin 5 (9), crocin 6(10) and internal standard (I>S.). Reprinted with permission from R Lozano et al. [47].

Saffron (Crocus sativus L. Iridaceae) finds use in medicine as well as a flavoring and coloring agent. It has three main chemical compounds. The bright red coloring carotenoids a bitter taste, picrocrocin and a spicy... 

A third type of alkali-sensitive glycoside was described by Kuhn and Lowin 1941.13 Picrocrocin [(—)-4-hydroxy-2,6,6-trimethyl-l-cyclohexene-l-carboxaldehyde-(4 — 1) /3-D-glucopyranoside] (VIII), the bitter principle of saffron, was observed to decompose in aqueous alkali with the formation of D-glucose and the unsaturated aglucon safranal (2,6,6-tri-... 

E.Kayser [74] terms polychroit crocin, and crocin crocetin, and ascribes to the former the formula C44H70O2S, and to the latter C34H48O9. According to him, crocin splits up into crocetin and saffron sugar, CsHi Og, while the ethereal oil is a product of the decomposition of picrocrocin. 

Crocins (II) that are glycosyl esters of crocetin (I) are the major components of saffron. Crocins (trans and cis isomers) belong to the family of carotenoids that are water-soluble. Safranal (III), a monoterpene aldehyde and picrocrocin (IV) precursor of safranal are also main components. 

UV-Vis spectra of saffron components are characteristic picrocrocin [4-(a-D-glycopyranosyloxy)-2,6,6-trimethyl-l-cyclohexen-l-carboxaldehyde] exhibits a characteristic broad absorption band at 250nm Oxidative decarboxylation of picrocrocin gives the precursor isophorone (3,5,5-trimethyl-2-cyclohexen-l-one) that is also a minor component of saffron. 

Responsible for the flavor of saffron, as it has been mentioned, is the bitter tasting glycoside picrocrocin, and its degradation product, safranal. 

In vitro cytotoxic analysis of the main saffron compounds (crocins, crocetin, picrocrocin and safranal) using HeLa (human cervical epitheliod cancer) cells was carried out by Escribano et al [64]. It was found that in terms of LD50 values (dose inducing 50% cell growth inhibition on these cells) safranal has 0.8mM, crocin and picrocrocin 3mM respectively. Furthermore, Escribano et al [65] have also isolated from corms of Crocus sativus a glycoconjugate with cytotoxic activity as well. Experiments with carotenoids from Crocus sativus in HL60 cells were conducted by Tarantilis et al [66] where inhibition and induction of differentiation of these cells was studied. 

As Pfander and Schurtenberger have reported [28] the absence of C20-hydrocarbon precursors of crocetin in saffron supports a degradation pathway for the biosynthesis of crocetin by the occurrence of picrocrocin and safranal. 

Tissue culture of saffron including somatic embryogenesis and shoot regeneration has been first reported by George et al [105], Induction of crocin, crocetin, picrocrocin and safranal synthesis in callus cultures of saffron-Oocws sativus L has been reported by Visvanath et al [106]. Callus cultures were obtained from floral buds on Murashige and Skoog s medium supplemented with 3% sucrose, 2,4-dichlorophenoxy acetic acid... 

Escribano, J. et al, Crocin, safranal and picrocrocin from saffron Crocus sativus L.) inhibit the growth of human cancer cells in vitro. Cancer Lett., 100, 23, 1996. 

Saffron (from Arabic zafaran=to be yellow). The dried, aromatic-smelling flowerheads of the saffron plant Crocus sativus, Iridaceae), indigenous to southern Europe, which contain the yellow pigment crocin (see crocetin) and the bitter principle picrocrocin (saffron bitter, see safranal). Characteristic flavor com-... 

C,oH,40, Mr 150.22, bp. 72 C (4 hPa). A monocyclic monoterpene aldehyde. S. is the odor principle of saffron and is formed from the bitter saffron gluco-side picrocrocin [CisHjjO, Mr 330.38, mp. 156°C, [a]g -58° (H2O)]. S. acts as an androtermone, i.e., the substance determining the male gender of the green alga Chlamydomonas eugametus. S. occurs in saffron oil (Crocus sativus, Iridaceae) and is prepared from, e.g., citral. ... 

Saffron is a mixture of substances. Those that make it desirable as a spice and dye are among the ones the plant uses to attract insects. Two of them, crocetin and crocin, are mainly responsible for its color, another (safrana ) its odor, and another picrocrocin) its taste. The same 20-carbon conjugated polyene unit is the chromophore that gives crocetin and crocin their yellow color. The difference between the two is that crocin is a glycoside in which both carboxylic acid functions of crocetin are attached to a disaccharide igentiobiose) by ester linkages. 

In aroma extract dilution analyses (cf. 5.2.2), a compound with a saffron and hay-like odor, which could be 2-hydroxy-4,4,6-tri-methyl-2,5-cyclohexadien-l-one, gave the highest FD factor. This was followed by the terpene aldehyde safranal and an unknown compound, both of which have a saffron odor. Safranal (XXIV) is probably obtained from the bitter substance picrocrocin (XXII) by hydrolysis and elimination of water (Formula 22.6). 

The ahcycHc monoterpenic aldehyde safranal has a different biochemical origin, and is the main characteristic odorous component of saffron Crocus sativus, Iridaceae). Safranal is classified as a degraded carotenoid (apocarotenoid) as it is produced from zeaxanthin via hydrolysis of the bitter intermediate picrocrocin. Degradation of carotenoids produces a number of other aromatic compounds (see Section 9.9.5.2). A list of the names of major terpenoid aldehydes is shown in Table 8.11. 

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