Yet another article in the Telegraph: this time Supermarket rocket salad healthier than homegrown. featuring the vegetable kingdom this time:

Changes in rocket salad phytochemicals within the commercial supply chain: Glucosinolates, isothiocyanates, amino acids and bacterial load increase significantly after processing

This is an open access paper which you can read for free.  At the top (like on the pedestal of Ozymandias) these words appear:

•  Glucosinolates, isothiocyanates and amino acids increase significantly over time.

•  Glucoraphanin is not significantly affected by harvesting and processing.

•  Sulforaphane significantly increases after processing in E. sativa cultivars.

•  Bacterial load of leaves is correlated with glucosinolate and amino acid abundance.

•  Commercial processing may increase the nutritional value of E. sativa to consumers.

(Eruca sativa is the botanical name of the commonly cultivated rocket.  Diplotaxis tenuifolia is the perennial wall rocket often known as “wild rocket”.  It is also cultivated, but what you buy in a supermarket at a higher price as “wild rocket” might be either one or other of the two species.)


The particular compound of interest, and which is widely praised for its beneficial qualities (presumed or actual) is Sulforaphane, one of the isothiocyanates.

Looking at the formula give above, the carbon atom at the left has four different atoms attached, so this make the compound chiral, since that atom lacks the type of symmetry which allows it to be superposed on top of its mirror image.  This generally causes compounds like this to rotate the plane of polarized light, either to the right (as in D-glucose, which used to be commonly known as dextrose) or to the left (as in L-amino acids, which form the basis of proteins.)  The version shown here is the  R-enantiomer, according to the newer convention, which according to the Wikipedia article cited, arose as follows:

“The R/S system is an important nomenclature system for denoting distinct enantiomers. Another system is based on prefix notation for optical activity: (+)- and (−)- or d- and l-. The Latin for left and right is laevus and dexter, respectively. Left and right have always had moral connotations, and the Latin words for these are sinister and rectus (straight, proper). The English word right is a cognate of rectus. This is the origin of the D,L and S,R notations, and the employment of prefixes levo- and dextro- in common names.”

If this is true, then here we have a double whammy.  Firstly, in English, words sinister and rectitude/correct have much stronger moral connotations.  Moreover, whoever thought it up has no real understanding of Latin and its place in Western civilization [1]

Most naturally occurring enantiomeric compounds appear in only one form or the other, and many pharmacologically active compounds are only effective in one of the two forms.

Anyway, this compound sulforaphane is the basis of the widely held opinion the broccoli is a ‘superfood’, and will ward off cancer.  But the paper in no way suggested that homegrown is not better, it is simply comparing commercially grown rocket just after harvesting and after several days’ storage in a refrigerator.  So yet another misleading journalistic headline.  But if you continue to grow your own, as in The Good Life (1975 TV series), you are not going against the results of this piece of research.  Though it would not work for me: my fingers are magenta, the complementary colour of green, and it is a rare occasion whenever my attempts to grow vegetables even recoup the cost of the packet of seed.

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[1]  About twenty years ago, I came across an argument that the use of names such as “German”, “Hungarian” as opposed to “Chinese”, “Japanese” implied that Europeans were somehow embedding an attitude of assumed racial superiority over Asians in their languages.  Overlooking the fact that many names referring to Asia such as “Korean” or “Indian” go against this hypothesis, it stems from a lack of understanding of how Latin works.  The purest example of modern Latin practice can be found in Italian, and here in this video, where the inhabitants of the Abruzzo region are laying claim to the best dance routine for keeping fit, reading the karaoke lines we find “-ano” forms in the first verse and “-ese” forms in the second to make the rhyme, and quite possibly the difference dates back 2500 years or more simply because the words flowed more easily off the tongue.