Common Heliotrope, Heliotropium europaeum

This is a variable, low to short, erect or spreading, hairy annual. Leaves are oval to elliptical, gray-green in color. Flowers are white, with a yellow eye, 2 – 4.5 mm (4/50 – 9/50 in), borne in one-sided, forked, spiraled spikes; they are, generally speaking, unscented.

It is interesting to note that the genus name, Heliotropium, is derived from the Greek words "helios", meaning sun, and "tropaios", meaning turning back or turning towards the sun.

Like most plants of the Borage family, the Common Heliotrope contains pyrrolizidine alkaloids (PAs). These alkaloids, according to a report published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization, are found in plants growing in most environments and all parts of the world. The main sources are the families Boraginaceae (all genera), Compositae (tribes Senecionae and Eupatoriae), and Leguminosae (genus Crotalaria), and the potential number of alkaloid-containing species is as high as 6,000, or 3% of the worldrs flowering plants (Culvenor, 1980).

They have long been known to be a health hazard for livestock, at least since 1902 (Schoental, 1963), and loss of livestock in various parts of the world has been traced to their grazing on certain plants growing in pastures, especially following periods of drought or in arid climates. They have been found to be toxic for all species of animals tested (Schoental, 1963), though some species, notably the guinea-pig, are resistant (Chesney & Allen, 1973a; White et al., 1973).

Human disease caused by PA toxicity has been known to be endemic in the central Asian republics of the USSR, at least since the early thirties (Ismailov, 1948a,b; Mnushkin, 1949) when several outbreaks occurred, and the cause was discovered to be the seeds of plants of Heliotropium species (Dubrovinskii, 1947, 1952; Khanin, 1948), which contaminated the staple food crops. A spate of reports followed, mostly from the West Indies, of acute and chronic liver disease (Bras et al., 1954, 1961; Bras & Hill, 1956; Stirling et a1., 1962), associated with the ingestion by people of herbal infusions for the treatment of certain ailments. Schoental (1961) and Davidson (1963) suggested that, in view of the evidence of the hepatotoxicity of PAs, consumption of plants containing them could be of etiological significance in human 1iver disease, especially in developing countries.

The "Health and Safety Guide No. 26", a companion volume to the aforesaid report published by the same organizations, states, in respect of the effects of pyrrolizidine alkaloids on human health, that although all age groups are affected, children are particularly vulnerable. The symptoms, which are generally acute in onset, are characterized by upper abdominal discomfort that develops rapidly and progresses to swelling of the abdomen, resulting in increased girth, sometimes accompanied by a reduction in the quantity of urine excreted and swelling of the feet. The disease is called veno-occlusive disease (VOD) because of the characteristic obstruction of the small venous blood channels that carry blood from the liver back to the heart. The disease often progresses rapidly and mortality is high. There may be vomiting of blood in advanced stages of the disease. While many patients recover, the disease may continue for a long time in others resulting in a severely scarred liver - a condition called cirrhosis. Some patients may have only vague symptoms and the only sign of the disease may be persistent enlargement of the liver.

The liver is usually the target organ but, in an epidemic caused by contamination of the staple cereal with the seeds of Trichodesma, the brain and the nervous system were mainly affected.

Chromosome aberrations have been reported in the blood cells of children affected by VOD but, as yet, there is no evidence pointing to an increased incidence of cancer of the liver or other organs or congenital anomalies in the newborn offspring of patients exposed to PAs.

According to WEED ID / MANAGEMENT, an Australian site, the Common Heliotrope becomes quickly established in fallows, stubbles and lightly grassed pastures. Infestations extract nitrogen and other nutrients from the ground and deny the following season's crop or pasture of any stored moisture from summer rainfall events. Plants are also toxic to stock and if grazed excessively can cause liver damage-induced copper poisoning in sheep, cattle and horses. On the positive side, the site states that large populations could assist in reducing soil erosion, in addition to providing a source of nectar and pollen for bees.

Due to its toxicity, the plant doesn't have many medicinal uses, however the HYpermedia for Plant Protection site states that the Common Heliotrope is desiccative, resolvent and detergent.

Type of plant
Variable, short annual.

Flowering Season
February - June

Known Hazards
Contains pyrrolizidine alkaloids (PAs), which are a known health hazard for livestock and are toxic to humans, mainly affecting the liver.

Known Uses
Could be used as a soil stabilizer. The plant has desiccative, resolvent and detergent properties.

Habitat
Cultivated, fallow and waste ground, roadsides.

Distribution
Italy and the Balkans eastwards, including Cyprus. Has been introduced to Australia, quite probably elsewhere, as well.

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Taxonomy

Kingdom: Plantae (Plants); Subkingdom: Tracheobionta (Vascular plants); Superdivision: Spermatophyta (Seed plants); Division Magnoliophyta (Flowering plants); Class: Magnoliopsida (Dicotyledons); Subclass: Asteridae; Order: Lamiales; Family: Boraginaceae (Borage family); Genus: Heliotropium; Species: europaeum