About Tribulus terrestris L.
Tribulus terrestris L. is a taprooted herbaceous plant that grows as a summer annual in temperate climates. Fine rootlets branching from its taproot allow the species to survive in arid conditions. It can grow in almost any type of soil, but thrives in dry, loose, sandy soils, and even grows in sand or deserts. It can also grow well in heavier soils, especially when these soils are fertile or moist, and on compacted soils along roadsides. T. terrestris is currently widespread globally between latitudes 35°S and 47°N. It is distributed across the warm temperate and tropical regions of southern Europe, southern Asia, all of Africa, New Zealand, and Australia. It is also present across southern North America, and in Central and South America. Over the 20th century, it appeared in California and spread northward, eventually reaching British Columbia, Canada, where it is classified as a noxious weed. It is widely naturalized in the Americas and in Australia south of its native range. In some U.S. states, it is considered a noxious weed and an invasive species. In South Australia, it is a "declared plant": its transportation and sale are prohibited, and landowners may be required to control it. Toxic compounds found in this plant are known to cause liver damage if ingested at harmful dosages. When T. terrestris is ingested, phylloerythrin accumulates in the blood as a byproduct of chlorophyll degradation, but adverse reactions to this have not been confirmed in humans. In sheep, consuming T. terrestris causes tribulosis, also called 'geeldikkop', which is a form of photodermatitis. Two beta-carboline alkaloids, harman (harmane) and norharman (norharmane), appear to cause limb paresis (staggers) in sheep that eat the plant. The total alkaloid content of dried T. terrestris foliage is approximately 44 mg/kg. The leaves and shoots of this plant are eaten in East Asia. Its stems have been used as a thickener, added to diluted buttermilk to give it the appearance of undiluted buttermilk. There is some evidence that T. terrestris was used in traditional medicine.
