khella

Khella, commonly referring to the plant Ammi visnaga, is a flowering herb in the Apiaceae family. It is native to the Mediterranean region and parts of North Africa and the Middle East and has been naturalized in other areas. The plant is an annual or short‑lived perennial, with finely dissected green leaves and umbels of small white flowers. The seeds are the part most often used in traditional practice, and they are brown, ridged, and aromatic.

Chemical constituents of Ammi visnaga include furanochromones such as visnagin and khellin, as well as various essential oils. These compounds contribute to the plant’s pharmacological properties and have historically attracted medical interest.

Traditional and potential uses: In traditional medicine, khella seeds have been employed as a diuretic and antispasmodic and to support urinary tract health, including applications related to kidney stones. In some cultural contexts, it has also been used for bronchial and respiratory complaints. In modern pharmacology, khellin has been studied as a photosensitizer for PUVA therapy (psoralen plus ultraviolet A) in the treatment of conditions such as vitiligo and psoriasis; however, its use has declined due to safety concerns and the availability of other therapies. Research has also explored possible vasodilatory and bronchodilatory effects of khellin and visnagin.

Safety and regulation: The plant contains furanocoumarins that can cause phototoxic reactions when exposed to sunlight, making sun sensitivity a consideration after exposure or ingestion. Users should be aware of potential interactions with other photosensitizing medications and with UV exposure. Pregnant or lactating individuals should exercise caution and seek medical guidance before using khella-derived preparations.

See also: Ammi majus, PUVA therapy, furanocoumarins.