The aromatic genus Ocimum
L. is commercially and medicinally important in the family Lamiaceae
was known by 180 genera and 3500 species spread from tropical to sub-tropical parts of the world, of which O. basilicum
L. prefers both plains and high altitudes. The species is the most important of all as its various subspecies, varieties and chemotypes contain a number of terpenoids and phenols along with many other compounds of high medicinal and commercial values. It is a natural tetraploid (2n = 4x = 48 chromosomes) with almost normal mitosis and meiosis and belongs to the sub-genus Basilicum with basic chromosome number x =12. Free intervarietal hybridization in the species has resulted in a number of viable and stable chemotypes with methyl chavicol, linalool, eugenol, camphor and methyl cinnamate as main constituents of their essential oils, either occurring singly or in different combinations. This feature of the chemotypes has been suggested to be genic in nature as an alteration in their chromosome number and structure is a rare phenomenon. While α-phenylalanine has been found to be the precursor of terpenoids and phenols boch, monoterpenoid linalool has been considered to be the initial terpenoid in the biogenesis of the two compounds. A semblance in the biogenetic pathways of the said main compounds in the various species of the genus Ocimum
, including the one understudy, with those of Mentha
L, looks plausible, which throws light on homogeneity in the family Lamiaceae. Various aspects of the species, such as distribution, cytology, genetics, biogenesis, biotechnology, etc. of the commercially important species have been discussed in detail.