Forsythia

Scientific Name(s): Forsythia suspensa (Thunb.) Vahl
Common Name(s): Forsythia, Golden bells, Lian qiao, Weeping forsythia

Medically reviewed by Drugs.com. Last updated on Sep 13, 2021.

Clinical Overview

Use

Clinical trials are lacking to support a place in therapy for forsythia. Research interest focuses on chemotherapeutic applications.

Dosing

There are no recent clinical studies of forsythia to provide a basis for dosage recommendations.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Documented adverse effects. Uterine stimulant, emmenagogue. Avoid use.

Interactions

None well documented.

Adverse Reactions

Forsythia is contraindicated in pregnancy.

Toxicology

Information is limited.

Scientific Family

• Oleaceae (olives)

Botany

F. suspensa is an attractive deciduous shrub native to China. It is often grown ornamentally in the United States for its bright yellow flowers that appear in early spring. There are numerous horticultural varieties that are vegetatively propagated. The Chinese drug is obtained in the fall from the ripe fruits of the cultivated plant. The related species F. viridissima and F. koreana also are used medicinally.

History

Forsythia fruits are widely used in Chinese traditional medicine for antipyretic and anti-inflammatory activity in the treatment of bacterial infections and upper respiratory ailments. They are commonly combined with honeysuckle flower (Lonicera) and other ingredients. Forsythia fruits are also reputedly used as a diuretic and as a cardiovascular tonic.

Chemistry

Lignans, such as phylligenin and pinoresinol, and their glucosides are major constituents of F. suspensa fruits, while the other species contain related compounds.1 Caffeic acid glycosides with variation in the number of sugars include forsythiaside2 suspensaside3 and a number of forsythosides.4 The reduced cyclohexylethane derivatives rengyol, rengyoxide, and rengyolone5 and their glycosides (rengyosides A-C6 and forsythensides A and B7) have been reported. The distribution of various phenolics among 7 different species of forsythia in leaves and fruits has been studied.8, 9 Rutin is the major flavonoid of all 7 forsythia species.9 Caffeic ester glycosides from related genera of the Oleaceae have been compared.10 Several triterpenes have been isolated from the fruits as well.11 An HPLC assay for major forsythia phenolics has been published.12 The essential oil composition of the fruits has been studied.13

Uses and Pharmacology

Antimicrobial activity

Animal data

Antimicrobial effects, including antiviral activity, have been reported on screening and in vitro studies.3, 4, 14, 25, 26, 27, 28, 29

Clinical data

Research reveals no clinical data regarding the use of forsythia as an antimicrobial agent.