Wisteria species: Wisteria

Family

Fabaceae

Common Names

Wisteria, Chinese wisteria (W. sinensis), Japanese wisteria (W. floribunda), Silky wisteria (W. brachybotrys), American wisteria (W. frutescens)

Plant Description

Comprising 10 species native to Asia and North America, Wisteria species are vigorous, deciduous, woody stemmed climbers to 10 - 15m in length. Leaves are pinnate, with 9 - 15 lanceolate or elliptic leaflets. Inflorescences are many, pendant racemes up to 60cm in length, white or purple, pea-like, perfumed flowers (Fig. 401, Fig. 402 and Fig. 403). Fruits are leguminous pods with multiple seeds.

Figure 401. Wisteria sinensis alba.

Figure 402. Wisteria sinensis.

Figure 403. Wisteria sinensis flowers.

Toxic Principle and Mechanism of Action

The seeds and bark contain a toxic glycoprotein lectin which binds to N-acetyl-D-galactosamine and thereby prevents the normal replacement of the mucosal cell layer of the intestinal mucosa [1]. The loss of the mucosal cells results in hemorrhagic gastroenteritis and corresponding clinical signs. Although the flowers are reportedly edible, caution is advisable as all parts of the plants are potentially toxic [2].

Risk Assessment

Wisterias are popular garden plants for growing over arbors and as espaliers. Once mature they produce striking displays of flowers, followed by bean like pods that contain toxic seeds. The seeds are hazardous to children and pets that might consume them.

Clinical Signs

Gastroenteritis, hematemesis, diarrhea, headache, dizziness, and confusion are reported in people who have ingested 5 - 10 seeds [3]. Similar clinical signs can be expected in animals that eat the seeds.

Since vomiting is a common effect of Wisteria poisoning, the seeds are often regurgitated, and treatment must be directed at fluid replacement where dehydration is present.