Ammi visnaga is a species of flowering plant in the carrot family known by many common names, including bisnaga, toothpickweed, and khella. It is native to Europe, Asia, and North Africa, but it can be found throughout the world as an introduced species. This is an annual or biennial herb growing from a taproot erect to a maximum height near 80 centimeters. Leaves are up to 20 centimeters long and generally oval to triangular in shape but dissected into many small linear to lance-shaped segments. The inflorescence is a compound umbel of white flowers similar to those of other Apiaceae species. The fruit is a compressed oval-shaped body less than 3 millimeters long. This and other Ammi species are sources of khellin, a diuretic extract. Khella was used in Ancient Egypt as a herbal remedy for renal colic.
Traditionally A. visnaga tea has been used for kidney stones. Ancient Egyptian and Indian writings describe vitiligo treated with psoralen-containing plants such as Ammi majus and exposed to sunlight. There have been a number of European research papers investigating this ancient folk use of the plant. For example, studies of the extract in diseased rats have shown prevention of renal crystal deposition.
- Vanachayangkul P., Chow N., Khan S.R., Butterweck V. (2010). "Prevention of renal crystal deposition by an extract of Ammi visnaga L. and its constituents khellin and visnagin in hyperoxaluric rats". Urological Research 39 (3): 1–7. DOI:10.1007/s00240-010-0333-y. PMID 21069311.
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- Lee JK, Jung JS, Park SH, Park SH, Sim YB, Kim SM, Ha TS, Suh HW (2010-11-30). "Anti-inflammatory effect of visnagin in lipopolysaccharide-stimulated BV-2 microglial cells". Archives of Pharmacal Research 33 (11): 1843–1850. DOI:10.1007/s12272-010-1117-1. PMID 21116788.
- Khan, Z. A., et al. (2001) Inhibition of oxalate nephrolithiasis with Ammi visnaga (AI-Khillah). International Urology and Nephrology 33:4 605-8.