Parsley

Scientific Name(s): Petroselinum crispum (Mill.) Nyman ex A. W. Hill. Family: Apiaceae (carrots)

Common Name(s): Parsley , rock parsley , garden parsley

Uses

Parsley, in addition to being a source of certain vitamins and minerals, has been used in the treatment of prostate, liver and spleen diseases, as well as anemia, arthritis, and microbial infections. It has also been found useful as a diuretic and laxative. However, there have been no clinical trials to confirm these uses.

Dosing

Parsley has been used at daily doses of 6 g, however, no clinical studies have been found that support this dose. The essential oil should not be used because of toxicity.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Generally recognized as safe or used as food. Safety and efficacy for dosages above those in foods are unproven and should be avoided. Emmenagogue and abortifacient effects in higher doses.

Interactions

None well documented.

Adverse Reactions

Adverse effects from the ingestion of parsley oil include headache, giddiness, loss of balance, convulsions, and renal damage.

Toxicology

While no major toxicities have been reported with the use of parsley, pregnant women should not take parsley because of possible uterotonic effects.

Botany

Parsley is an annual herb indigenous to the Mediterranean region, but now cultivated worldwide. It has erect stems and bright green leaves. Two cultivars of parsley exist, a curly leaf type and a flat leaf type. 1 Parsley produces an umbel of tiny flowers and characteristic ribbed seeds. 1

Caution must be used when gathering wild parsley because of the general similarity of its leaves and flowers to those of 3 common poisonous plants. The first, Aethusa cynapium (dog poison, fool's parsley, small hemlock) can be distinguished from parsley by the shiny yellow-green underside of the leaves, which are dull in parsley, and the white flowers, which are yellowish in parsley. Similarly, collectors should be aware of Conium maculatum (poison hemlock, water hemlock, poison parsley) and Cicuta maculata (water hemlock). Poison hemlock is a much larger plant than common parsley. Poisonings have occurred when the leaves of Conium were mistaken for parsley and the seeds for anise. Symptoms of Conium and Cicuta poisoning include vomiting, diarrhea, weakness, paralysis, weak pulse, dilated pupils, convulsions, and death.

History

Parsley leaves and roots are popular as condiments and garnish worldwide. In Lebanon, parsley is a major ingredient in the national dish called tabbouleh. An average adult may consume as much as 50 g of parsley per meal. 2

Parsley seed was used traditionally as a carminative to decrease flatulence and colic pain. The root was used as a diuretic and the juice to treat kidney ailments. Parsley oil has also been used to regulate menstrual flow in the treatment of amenorrhea and dysmenorrhea, and is purported to be an abortifacient. Bruised leaves have been used to treat tumors, insect bites, lice, skin parasites, and contusions. 3 , 4 Parsley tea at one time was used to treat dysentery and gallstones. 3 Other traditional uses reported include treatment of diseases of the prostate, liver, and spleen, in the treatment of anemia, arthritis, and cancers, as an expectorant, antimicrobial, aphrodisiac, hypotensive, laxative, and as a scalp lotion to stimulate hair growth. 3 , 5

Chemistry

The concentration of parsley oil varies throughout the plant. The roots contain 0.1% oil, whereas the leaf contains about 0.3%. 6 The fruit contains the largest percentage of oil, between 2% to 7%. 6 The oil contains 2 components, apiol and myristicin, which are pharmacologically active. Myristicin is chemically related to apiol and has also been identified in nutmeg. More than 30 varieties of parsley are recognized and their relative content of apiol and myristicin vary. For example, “German” parsley oil contains about 60% to 80% apiol, whereas “French” parsley oil contains less apiol but more (50% to 60%) myristicin. 7 Parsley has a high carotenoid content, with 25.7 mg per 100 g edible portion. 8

Parsley contains psoralen and related compounds that can induce photosensitivity (see Toxicology); these include ficusin, bergapten, majudin, and heraclin. 9 The plant also contains several antimicrobial furocoumarins: psoralen, 8-methoxypsoralen, 5-methoxypsoralen, oxypeucedanin, and isopimpinellin. 10 Parsley contains the estrogenic flavone glycosides, 6″-acetylapiin and petroside. 11

Uses and Pharmacology

Apiol and myristicin may be responsible for the mild diuretic effect of the seed and oil. 12 Rats given an aqueous parsley seed extract in place of drinking water eliminated a higher volume of urine compared with controls. 13 An in situ kidney perfusion technique also supports this finding. 13 Research suggests that the diuretic effect of parsley is mediated through an inhibition of the Na+-K+ pump. 13 The laxative effect of parsley seed extract is also attributed to the inhibition of sodium and of the Na+-K+ pump. 14

Research reveals no clinical data regarding the use of parsley as a diuretic or laxative.

Apiol is an antipyretic and, like myristicin, is a uterine stimulant. Apiol was once available in capsules for use as an abortifacient. Although the effectiveness of this compound as a uterotonic has not been substantiated, a Russian product containing about 85% parsley juice has been used to stimulate uterine contractions during labor. 15 Data regarding the safety and efficacy of this product are not readily available.

A methanolic extract of the aerial parts of parsley showed potent estrogenic activity in the MCF-7 breast cancer cell line. 11 The activity was attributed to two different compounds, 6″-acetylapiin and petroside. The estrogenic activities of these compounds are very similar to the isoflavones found in soybeans. 11

Parsley extracts have shown slight antibacterial and antifungal activity when tested in vitro, 16 but is not known to what extent this activity is retained in vivo. Furocoumarins extracted from 4 varieties of fresh and freeze-dried parsley leaves inhibited Escherichia coli 0157:H7, Listeria monocytogenes , Erwinia carotovora , and L. innocua . 10

Nutritionally, parsley is a good natural source of vitamins and minerals. These include: calcium, iron, carotene, ascorbic acid, and vitamin A. 3 , 6

Myristicin, a compound found in parsley oil, is suggested to be in part responsible for the hallucinogenic effect of nutmeg. It is not known whether parsley oil induces hallucinations, but the practice of smoking parsley as a cannabis substitute was well known during the 1960s. Parsley may have been smoked for a euphoric effect or as a carrier for more potent drugs such as phencyclidine. 17

Dosage

Parsley has been used at daily doses of 6 g, however, no clinical studies have been found that support this dose. The essential oil should not be used because of toxicity. 18

Pregnancy/Lactation

Generally recognized as safe or used as food. Safety and efficacy for dosages above those in foods are unproven and should be avoided. Emmenagogue and abortifacient effects in higher doses. 19

Interactions

One study indicates that parsley extracts may affect the pharmacodynamic activity of certain drugs. Parsley juice may alter the activity of drugs affected by the cytochrome P450. 20 A decrease of cytochrome P450 in liver homogenate was observed in mice administered parsley juice 2 hours prior to decapitation. 20

Adverse Reactions

Adverse effects from the use of parsley are uncommon. Persons allergic to other members of the Apiaceae family (ie, carrot, fennel, celery) may be especially sensitive to the constituents in the flowers of parsley. Because of the potential uterotonic effects, parsley oil, juice, and seed should not be taken by pregnant women. Adverse effects from the ingestion of the oil have included headache, giddiness, loss of balance, convulsions, and renal damage.

The psoralen compounds found in parsley have been linked to a photodermatitis reaction found among parsley cutters. The skin reaction is usually only evident if the areas that have contacted the juice are exposed to very strong sunlight; it can be minimized by the use of protective clothing and sunscreens. 21

Toxicology

Research reveals little or no information regarding toxicology with the use of this product.

Bibliography

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