Easily confused with : Dame's-Violet but Honesty never has lilac coloured flowers as does Dame's-Violet. Honesty also has heart-shaped (cordate) leaves on the upper stem (but more rounded to ovate lower down the stem) that are also well-toothed whereas Dame's-Violet has lanceolate un-toothed leaves. Honesty has flat coin-shaped seed pods that turn silvery when ripe, whereas Dame's-Violet has long thin cylindrical seed pods typical of mustards.
Distinguishing Feature : the flat and papery-thin seed pods which are shiny and silvery in Summer.
Some similarities to: Perennial Honesty (Lunaria rediviva) from Europe escapes from gardens but that has ice-blue flowers and long, narrow elliptical fruits. This grows year in year out by means of underground runners, something which Honesty lacks. Perennial Honesty also has very elongated flat seed pods rather than the almost disc shaped of Honesty. Despite the binomial name of Honesty incorporating 'annua' Honesty is usually a biennial, or only occasionally annual but rarely perennially, so its binomial name is a misnomer. Honesty is species which is most commonly grown in gardens and which is the more likely to escape, rather than Perennial Honesty.
The flowers are four-petalled and, on separate plants, are either purple or white, never lilac. They are a favourite cottage-garden wild flower. You are much more likely to find this plant either in a garden itself, or nearby houses than growing in the wild.
The rounded thin coin-shaped seed pods, when ripe in summer, turn from green to shiny silver. These are used as decoration in indoor dry-flower arrangements.
Honesty also contains 12 Glucosinolates, the 5 major ones being
Hex-5-Enyl Glucosinolate - they were identified by their breakdown product. The main glucosinolate degradation products of these are
BenzoPropane Nitrile (2.3%) and
2-PhenylEthyl IsoThioCyanate at 0.8%.
4-Pentenyl Glucosinolate) is isolated from
Rape (Brassica napus) and other species of Brassicaceae. It has a 6-valent sulfur atom in the sulfate moiety. It is an AlkenylGlucoSinolic Acid.
GlucoPutranjivin is very similar to Epi Progoitrin (on the Sea Kale page). The 'Putr' portion of the chemical name seems to refer to the putrid smell which this molecule might possess.
GlucoAlyssin has three atoms of Sulfur, and all three are utilised in different ways. The topmost sulfur atom is a sulfoxide produced by the oxidation of a MethylThioEther group which was there before and exhibits valence 4, the one on the right (the Sulfate moiety) valency of 6 and the lower one (contributing the requisite NCS portion of the molecule for an
isothiocyanate) exhibits a valency of just 2. It is one of the flavour compounds produced during the cooking of species of Brassica vegetables.
GlucoAlyssin is a Thia-GlucoSinolic Acid. It is an extremely strong acidic compound and is also found in Chinese Cabbage, Pak-Choi (Brassica rapa ssp. pekinensis) Turnip, Horseradish and all other Brassicaceae.
2-PhenylEthyl IsoThioCyanate is used as a food-grade flavour ingredient in cooking and is mainly found in brassicaceae species vegetables. It is the main compound which is responsible in brassica species roots for the nematicidal effect on nematode worms around the roots. It is thus a promising ingredient for soil fumigants against nenatodes.
The oil obtained from its seeds is most unusual, containing a high proportion (21%) of
cis-15-TetraCosenoic Acid, aka
C24-Monoetenoid Acid aka
Nervonic Acid, the highest proportion of this oil in any seeds found so far. they contain other oils too, together totalling 30 to 35% oil. It is used on a small scale as an industrial lubricant as well as a source of
Nervonic Acid which is used both pharmaceutically and Nutraceutically.
Nervonic Acid (aka
Selacholeic Acid or
cis-15-TetraCosenoic Acid) is a long-chain monounsaturated fatty acid which is found in the mammalian brain. Lignoceric Acid is its fully saturated equivalent (meaning with the same number of carbon atoms [24 in this case] in the same chain but without any double bonds). Nervonic acid is involved in the synthesis of the myelin sheath, the sheath which in mammalian brains wraps around nerve fibres to both protect them and speed up the transmission of nerve impulses along them. The myelin sheath normally has gaps in it every so often (presumably for the return current to flow around - your Author guesses using his background in electronics). The destruction of the myelin sheath by the body's own immune system gone awry is responsible for the symptoms of multiple schlerosis.
Nervonic Acid is also found in breast milk where presumably it helps the development of the brains of infants. This acid also regulates the double-positive Calcium ion (Ca2+) channel which is in the membrane of nerve tissues, thus controlling calcium levels in the intercellular fluid (cytosol).
BENZO-FURAN SPERMIDINE ALKALOIDS
Lunarine is an alkaloid based upon a benzofuran (the three fused lower rings) and Spermidine. The Spermidine forms part of a large 20-membered ring straddling part of the benzofuran. Note that Spermidine is not symmetrical, but has four carbon atoms one side of the 'central' nitrogen atom, and only three on the other side of it. Which brings us to Lunaridine, where the molecule of Spermidine is attached the other way around (4-3 instead of 3-4), which would make no difference if Spermidine were symmetrical. This form of juxtaposition is unusual from a plant synthesis perspective. It shows, in this instance, that it can get hold of either end of the stick.
Spermidine itself is shown for comparison, although it seems to be ubiquitous throughout many Genera and must also be present in Honesty. Note that it is asymmetrical, with four carbon atoms on one side and only three on the other.
LBX is identical to Lunarine apart from a CH2 bridge spanning the two nearer nitrogen atoms, thus making a six-membered ring with two nitrogen atoms in it at the meta positions (being
pyrimidine, compare with the two isomers
pyrazine where the nitrogen atoms are at the para position and with
pyridazine with the nitrogen atoms at the ortho position.
LBY is identical to LBX apart from the ketone part of the benzofuran rings being replaced by ⋅H⋅OH.
Initially there was considerable confusion caused by the unusual multi-membered rings of the Lunaria alkakoids, confusion which may persist to the present day. Rumours of further alkaloids within Honesty such as Lunariamine and Numismine cannot be substantiated by any readily-found structural formulae. Although the reports are ubiquitous, no structural formulae are to be found, only empirical formulae.