Taxonomic class

Rosaceae

Comman Trade Name

None known

Common forms

Available as decoctum cydoniae, B.P. (decoction from seeds), fruit syrup, and mucilage of quince seeds.

Source

The fruit and seeds of Cydonia oblonga are used in preparing the medicinal products of quince.

Chemical Components

The seeds contain fixed oil, protein, and a small amount of amygdalin, and its coat contains mucilage. The fruit pulp contains malic acid. Beta­D- glucopyranosyl-(1,6) -beta -D-glncopyranoside of 3- hydroxy-beta­ionol has also been isolated in the fruit.

Actions

Tertiary literature suggests astringent, cardiac, demulcent, diuretic, emollient, and restorative effects. A decoction of C. Oblonga has been shown in vitro to have a bactericidal effect against Vibrio cholerae .

A German abstract describes a three-way crossover study examining varying strengths of a mixture of extracts from both Citrus limon and C. oblonga and their effects on nasal mucociliary clearance . The investigators failed to detect a change in nasal mucociliary clearance.

Reported Uses

Traditionally, quince fruit syrup has been commonly added to beverages to treat diarrhea, dysentery, and sore throat. The decoction from the seeds is taken internally in the treatment of dysentery, gonorrhea, and thrush; it is also used as an adjunct in boric acid eye lotions and in skin lotions and creams. Anecdotal data exist for these uses; no clinical human data are available. The mucilage of quince seeds has been used as a suspending agent in such pharmaceutical and toilet preparations as mouthwashes for canker sores, gum problems, and sore throats. Although the quince seeds are thought to be useful in treating cancer probably because of amygdalin’s cyanogenetic action-no studies have confirmed this effect.

Dosage

For diarrhea, dysentery, gonorrhea, and thrush, large quantities of decoctum cydoniae (2 drams of quince seed boiled in 1 pt of water for 10 minutes) P.O.

No dosages have been reported for the external use of mucilage preparations.

Adverse Reactions

None reported .

Interactions

None reported.

Contraindications and Precautions

Avoid using quince in pregnant or breast-feeding patients; effects are ,known.

Speciacial Considerations

• Advise the patient taking quince for GI symptoms that other agents with known safety and efficacy data are available.

Alert Quince seeds are potentially toxic because of their amygdalin (laetrile) content.

• Caution the patient to keep quince out of the reach of children and pets.

Points of Interest

• Other varieties of quinces, especially the Japanese quince, Cydonia illponica, are not used medicinally.
• Japanese quince is a popular ornamental plant that is grown all over the world.

Commentary

Preparations made from the fruit or the mucilage derived from the seed (oat may provide minor relief from diarrhea and sore throat because of their astringent and demulcent properties. Although a quince decoction has been shown to have an in vitro bactericidal effect against V. cholerae there are no clinical reports suggesting its value in treating cholera. The amygdalin (laetrile) component of quince is toxic and ineffective as a cancer treatment and should not be consumed.

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