The star of the show in a subzi that my mother makes with spring onions, and one of the 5 components of paanchphoran, an aromatic spice mixture used in Bengali cuisine, kalaunji has a nice mild flavor.
The small black seeds that make up this spice are obtained from the Nigella Sativa plant. Variously referred to as black cumin, black caraway, and black sesame in English (none of those names are accurate, though when a Bengali talks of “kala jeera” she is in fact talking of nigella sativa seeds), they are also sometimes mistakenly defined as onion seeds. One more name- a nice one- for this plant is “love in the mist” !
In India kalaunji is used to flavor breads such as naan, pickles, vegetables, and of course the afore-mentioned paanchphoran.
Like many other spices, this one too has been used since ancient times in many parts of the world for its medicinal properties. In the Middle East it is known as the “Habbatul Barakah’, or the seed of blessing.
The active compounds -nigellone and thymoquinine- in the seeds and the oil have been shown in studies to have antioxidant , anti-inflammatory, anti-allergy, anti-microbial and anti-tumor properties. Perhaps this is why both the seeds and the oil find use in traditional remedies for the symptoms of a range of diseases such as asthma, bronchitis, stomach ailments and skin conditions such as eczema and dandruff.
Nigella Sativa is a rich source of polyunsaturated fatty acids and protein, and it is also thought to help keep cholesterol and blood sugar levels low. The former may be due the high level of betasitosterol , a common plant sterol, that is present in this plant.
The sources I browsed:
One quite detailed article about nigella sativa which lists all its sources, is here: http://www.answers.com/topic/black-cumin-seed-extract