Directly related to : Corn Parsley Petroselinum segetum [which is in the same Genus]
Not to be semantically confused with :
Cow Parsley Anthriscus sylvestris, Upright Hedge-Parsley Torllis japonica,
Spreading Hedge-Parsley Torilis arvensis, Fools Parsley Aethusa cynapium,
Milk-parsley Thyselium palustre,
Cambridge Milk-parsley Selinum carvifolia [all of which are members of the same Carrot Family as is Garden Parsley, but which may be in-edible or toxic].
Nor should it be semantically confused with :
Parsnip [a cultivated plant with edible tuber and similar name belonging to the same family]. Nor with Wild Parsnip (Pastinaca sativa), a similar plant. The inflated rootstock of Garden Parsley looks similar to the root-stocks of both of these plants, the Parsnip, but is smaller. The two taste very different, but the 'Hamburg' variety is often grown for the root vegetable, although it is not eaten in the UK. Nor with
Great Water-Parsnip (Sium latifolium) or Lesser Water-Parsnip (Berula erecta). [These too are members of the same Carrot Family as is Garden Parsley, but which may be in-edible or toxic].
Easily mistaken for : Fools Parsley Aethusa cynapium which belongs to a differing Genus and un-like Garden Parsley has 3 to 4 thin long upper bracts hanging down underneath each small sub-umbel. Leaves are similar and pinnate, but are mostly planar and less curled/crisped.
The Genus Petroselinum derives from the Greek πετρα (petra) meaning stone or rock and σελινον (selinon) the latin name for
Celery (which is Apium graveolens, not Petroselinum graveolens). Why parsley seems to be confused with Celery is unclear, except that both are Umbellifers. In particular, it has nothing to do with petrol, selenium or the Moon. There are 37 varieties or Cultivars of Parsley, reportedly the most valuable of which is 'Curled Leaf'.
When crushed Parsley has a pleasant odour due to the essential oils that it contains. The above photographs show the 'Triple Curly' variety. There are many other varieties, but the 'Italian' variety has much flatter leaves but has the better flavour. There are also 'German' and 'French' varieties. The flat leaf varieties more closely resemble the wild variety of Garden Parsley. The proportion of Apiole to Myristicin varies between varieties, as well as the total toxin content.
One of the toxins within Garden Parsley is the FuroCoumarin
Garden Parsley is a biennial herb often grown as an annual. It is eaten as a side-salad or garnish to a main meal. It is toxic to various degrees, depending on the concentration of two toxins that are present in it, the toxicity varying considerably between variety. The essential oil contains both
Apiole and Myristicin, the latter being the poisonous principle first found in Nutmeg. Apiol is also known as Parsley Apiol. Both are toxic and uterine stimulants, accounting for the use of the volatile oil of Parsley as an emmenagogue and its abuse as an abortifacient. It reinstates the menstrual cycle. Apiole (also known as Parsley Camphor) in particular has a desirable parsley aroma. It is also found in
Celery. Parsley is also used as an aid to digestion and as a diuretic. The volatile oil concentration is lowest in the roots at 0.1%, three times higher in the leaves, and between 2% to 7% in the fruits. Both Apiol and Myristicin are similar both chemically and in their physiological action; both are toxic and in high doses can damage the liver and kidneys. A lot of parsley would have to be eaten before any toxic effects are noticed, which is why it is only eaten as a garnish rather than as a vegetable, and even then, it is seldom eaten, just used to brighten up the plate. The fruits should not be eaten, as they contain much higher concentrations of toxins. Pregnant women should refrain from eating parsley. the essential oil is used in cosmetics, hair shampoos, perfumes, skin lotions and soaps.
Apiol is related to Dillapiole which is found in
Dill and in the roots of Fennel.
The characteristic parsley flavour and odour of crushed leaves is due to the presence of an unusual volatile monoterpene,
1,3,8-p-MenthaTriene. Other compounds present include β-
Apiole, Terpinolene, and
1-methyl-4-isopropylbenzene as major components. The Curly Moss variety of Parsley contains up to 85% of the poisonous Myristicin in its essential oil, the poisonous constituent of
Terpinolene (aka δ-
Terpinene) is another monoterpene, part of a group of four similar Terpinene isomers, α, β, γ and δ, which all occur naturally in some plant or other apart from β-Terpinene.
A CHLORINATED FUROCOUMARIN
Saxalin is a chlorinated furocoumarin (based on Psoralen) which is contained in several plants of the Carrot Family especially
Parsley. It was first discovered in the roots of Angelina saxatilis, and is also found in two species of Hogweed: Heracleum granatense and Heracleum pyrenaicum (but none of these are native to the UK).
Other (non-chlorinated) furocoumarins, such as
OxyPeucedanin, Bergapten, Xanthotoxin,
Marmesin and Heraclenol, and the Coumarin
Graveolone have also been reported as major coumarins in some varieties of Parsley, but un-like Saxalin, none are chlorinated.
Marmesin (aka Nodakenetin) is a linear FuroCoumarin.
OxyPeucadanin looks very similar to Heraclenin until you realise that the long side-branch is on the opposite side (topside instead of bottomside in this depiction).
The furocoumarins are responsible for dermatitis when the sap of the plant containing them is got on the skin and then that area of skin is subsequently exposed to the ultraviolet light in sunlight; they are photoactive compounds.
Graveolone is an unusual coumarin (a PyranoCoumarin) which is also found in
Dill (Anethum graveolens) and has a dimethyl- chromenene moiety rather than a furanone fused to the opposite end. Lacking the furanone moiety it is not a furocoumarine.