Khella - Ammi visnaga (in the Umbelliferae or Parsley family)
Parts used: Seeds.
Taste/smell: Bitter, slightly aromatic.
Dosage: Infusion: 1 teaspoon of crushed seeds per cup of water, infused for 25 minutes; or 1:3 dry liquid extract: 20-60 drops 1-4 times per day in a little water.
Use: (a) Diuretic, (b) Antispasmodic with specific action as a coronary vasodilator, bronchodilator, and urinary tract antispasmodic.
Khella improves blood supply to the myocardium and makes myocardial metabolism more efficient. The antispasmodic activity may be partially due to the calcium antagonist effect. Khella is used to treat mild forms of angina, mild obstructive pulmonary disease and as an antispasmodic for cases of acute urinary tract stones and for interstitial cystitus.
It contains coumarins and furanochromones, (psoralens) such as khellin and visnagin, and a small amount of volatile oil. Khellin has been used in treatment of skin diseases like vitiligo and psoriasis.
Contraindications: It decreases the toxicity of the cardiac glycoside, digitoxin, due to the coronary vasodilator and antiarrhythmic effects. Khella is also contraindicated in pregnancy due to the emmenagogue and uterine stimulating activity of khellin.