[Histonet] Re: Safran du Gatinais

[rsrichmond <@t> aol.com]

 Lynne Cates in Durham NC asks about buying saffron in bulk for histologic use.

Saffron, a culinary spice and coloring agent most familiarly used in paella, consists of the stigmas of the flowers of Crocus sativus. The spice has a very strong odor, and also contains a dye of some histologic interest. Because of its labor-intensive production (do YOU want to spend your days picking the sex organs out of itty bitty flowers?) saffron's extremely expensive.

Saffron is used histologically as a connective tissue stain, traditionally in one of the many techniques attributed to Dr. Masson, and in the Movat pentachrome stain. It dyes collagen a yellow-orange color that contrasts subtly with eosin. 

Saffron has a Colour Index number (75100) and is described in the 9th edition (I don't have the 10th) of Conn's Biological stains. The active coloring matter is called crocin, composed of crocetin and gentobiose.

To prepare the stain, the dye is extracted from the crude spice with ethanol. Because saffron is so expensive, the WHO tumor fascicles (in the 1960's) suggested extracting the dye into ethanol using a reflux condenser to achieve maximum yield. This alcohol extract has an obnoxious medicinal smell. 

A look-alike, safflower (Carthamus tinctorius), sometimes called dyer's saffron or bastard saffron, is odorless and contains a different dye, carthamin or carthamone, chemically unrelated. I have never seen safflower referred to as a histologic stain. Safflower is sometimes referred to as saffron, and I'd be careful not to buy it for histologic use - remember it's odorless. (Safflower is grown commercially as an oil seed.)

Saffron was historically grown in France and Spain. It is still grown commercially in Spain, but most of it is grown in India. The traditional histologic designation "safran du Gâtinais" referred to the French product, which I think is no longer available. (Saffron was grown in England centuries ago, hence the place name Saffron Walden.)

I checked a high-end spice dealer, Penzeys Spices (disclaimer - my wife orders a box of spices from them about once a month), and found saffron for US$10 to 15 a gram, retailed in gram quantities, depending on the source. I suspect it could be ordered from India, perhaps through an Indian grocery store, for less, but I'd want to be awfully careful I was getting Crocus sativus. Apparently lower grades of saffron can be bought in bulk for a dollar or two a gram.

The Wikipedia article on saffron is worth reading.

According to Wikipedia the coat of arms of Saffron Walden is "Vert within a representation of town walls having two towers and a Gateway between towers Argent three Saffron Flowers issuant from the battlements of the gateway blown and showing the stamens proper And for the Crest On a Wealth of the Colours Upon a Chapeau Gules turned up Ermine a Lion rampant Azure grasping in the dexter paw a representation of the Ancient Mace of the Borough of Saffron Walden proper."

Bob Richmond
Samurai Pathologist, histoantiquarian and occasional blazoner wannabe
Knoxville TN

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