Nigella probably originated in western Asia but today is cultivated from Egypt to India. Though it’s sometimes called black cumin, it’s unrelated to cumin; the black cumin mentioned in the Old Testament may actually be nigella, which has been found in the Giza pyramid and in the tomb of King Tutankhamen.
Confusingly, nigella is also known as onion (or wild onion) seed because the two look similar, although only nigella is used as a spice.
The seeds contain numerous esters of structurally unusual unsaturated fatty acids with terpene alcohols (7%); furthermore, traces of alkaloids are found which belong to two different types: isochinoline alkaloids are represented by nigellimin and nigellimin-N-oxide, and pyrazol alkaloids include nigellidin and nigellicin.