Cutler described its utility in asthma in 1813 and Reece introduced this drug in 1829 to English medical profession.
The herb found indigenous to Eastern and Central U.S.A, and Holland consists of dried aerial parts of Lobelia inflata Linn. (Lobelia BP/USP) of the family Campanulaceae. It is official in British Pharmacopoeia and United States Pharmacopoeia. The Indian herb of lobelia consists of dried aerial parts of Lobelia nicotianae folia Heyne (Lobelia IP) of the family Campanulaceae. Lobelia is also referred as Indian tobacco, Herba lobelia, Lobelia herb or Asthma weed. Lobelia should contain not less than 0.55 percent of total alkaloids, calculated as lobeline.
Lobelia consists of stems, leaves, flowers, fruits and seeds.
Morphological features of Lobelia BP/USP – Stem is green with purple patches. Upper part of stem is cylindrical hairy and the lower part is angular, channeled and less hairy. Leaves are mostly broken and are pale green in color. Leaves are ovate, oblong and irregularly toothed. Water pores are present on teeth and hairs are present on entire lamina especially on veins of lower surface. Flowers are light blue colored, 7mm long with a tubular corolla. Fruit is an inferior capsule and yellowish-green in color and inflated. Seeds are long and broad, reddish-brown colored. Lobelia has a slight irritating smell and taste is unpleasant, acrid and burning.
Morphological features of Lobelia IP – it has thick and thin stems. Thick stem is greenish to yellow, straight, cylindrical and hollow in the middle. Thin stems obtained from twigs are greenish-yellow, cylindrical. Leaves are of two types, lower leaves are bigger, yellowish-green pr greenish-yellow colored and upper leaves are smaller, dull green colored. They are lanceolate to oblong-lanceolate shaped with acute or acuminate apex. Upper surface of leaf is glabrous and lower pubescent (hairy). This drug has tobacco-like odour and acrid nauseating taste. Lobelia pyramidilis is met with as an adulterant of Indian lobelia.