Cynoglossum (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Cynoglossum L.

Protologue: Sp. pl. 1: 134 (1753); Gen. pl. ed. 5: 168 (1754).

Family: Boraginaceae

Chromosome number: x= 12;C. amabile: 2n= 24,C. lanceolatum: 2n= 24

Cynoglossum comprises about 70 species, and has a worldwide distribution, from tropical to temperate regions. In the Malesian region, 13 species have been found, but several are only known from a single collection.

The roots and aerial parts of Cynoglossum are used in traditional medicine in various parts of the world, e.g. to treat cough, scrofula, tuberculosis, wounds, ulcers and eye infections. Information on medicinal applications in South-East Asia is very limited, but Cynoglossum is more commonly used in China and eastern Africa.

The roots of C. officinale L. have been used in Europe as a sedative, phlegm-discharging and mildly constipating remedy, to treat pulmonary tuberculosis and cough, and to stop bleeding. These uses are now largely abandoned because of the presence of toxic alkaloids. The foliage may repel moles in gardens and protect stored fruit and vegetables from rodents. The root juice of C. wallichii G. Don is applied in India to check vomiting in children.

Some species are occasionally planted as an ornamental in gardens, e.g. C. amabile .

Cynoglossum is highly toxic for horses and cattle, mainly during the early growth stage (rosette stage), due to the presence of pyrrolizidin alkaloids with a strong hepatotoxic activity. The contamination of green fodder with Cynoglossum can be a serious problem, as well as the presence of toxicants in milk. Five pyrrolizidine alkaloids have been recorded from C. amabile : supinine, amabiline, rinderine, echinatine and 3’-O-acetylechinatine. Altogether, 14 pyrrolizidine alkaloids have been isolated and separated from C. officinale , and 13 from C. creticum Miller. The roots of C. officinale also contain bitter substances, choline and tannins, the leaves mucilage, traces of essential oils and bactericidal compounds, and the seeds a number of lipids and fatty acids.

A gallic acid salt of the cynoglossophin-heliosupine alkaloid (cyngal) has been isolated from C. officinale . This compound showed a high stimulatory activity on the gastro-intestinal motor function in tests with dogs and rats.

Furthermore, the isohexenylnaphthazarins, more commonly known as alkannins, are lipophilic red pigments found in the outer layer of the roots of many Boraginaceae , including Cynoglossum . They have pronounced antibacterial, wound-healing and antitumour activities.

Annual, biennial or perennial herbs. Leaves alternate, simple and entire, basal leaves usually already withered at flowering time, basal and lower stem leaves usually long petiolate, upper stem leaves often sessile; stipules absent. Inflorescence a terminal and axillary cyme, bracteate or ebracteate. Flowers bisexual, regular, 5-merous, pedicellate; calyx deeply divided, enlarged in fruit; corolla cylindrical, campanulate to funnel-shaped or rotate, with 5 distinct scales in the throat, white, blue or purple; stamens inserted on corolla below the scales, included, filaments very short; ovary superior, 4-parted, style long or short, with or without a distinct stigma. Fruit consisting of 4 nutlets attached to the conical receptacle, covered by glochids.

The flowers are pollinated by various groups of insects, also depending on the species. The nutlets have barbid bristles which adhere to the fur of mammals and are thus dispersed.

Cynoglossum usually occurs in meadows on hillsides, roadsides, river banks and in open forest.

Management Formerly, the roots of C. officinale were collected in Europe in autumn, and dried rapidly.

The Cynoglossum species treated here are the more common ones in South-East Asia (at least locally), except C. amabile , which is only planted in Java. About half of the Malesian species are only known from few collections, and field studies are needed to determine the threats for these species. Large ex situ germplasm collections of Cynoglossum do not exist.

Very little is known about Cynoglossum in South-East Asia. However, studies in species from elsewhere showed interesting properties, e.g. wound healing and antibacterial activities. Research on these aspects in South-East Asia is desirable, and might enhance the medicinal importance in the region.

247, 331, 720.

• '

• '

Ch.B. Lugt & R.H.M.J. Lemmens