Alkaloids
Lobelia plants contain alkaloids, flavonoid glycosides, saponins, amino acids, etc. Plants of this genus mainly contain piperidine alkaloids. Before the 1970s, research on the isolation of alkaloids was mainly focused on. Lobeline, Lobeline, Lobelanine, and Isolobelanine, etc. Because alkaloids have central stimulant effects, research on them was once active in the early years, but later fell into disuse due to the failure to produce clinical drugs. With the development of separation and analysis methods, Zhang Mingzhe of Peking University and others isolated eight alkaloid components from the whole plant of Lobelia hybrida produced in Yunnan, among which dehydro lelobanonoline is As for the new compound, Zhang Mingzhe and others isolated another new alkaloid, L elobanono line, from Lobeliadavidii Frarch. Both new compounds contain piperidine rings.
Polyynes
Kanji Ishimaru et al., in their study of secondary metabolites in hairy root culture of medicinal plants, found that from the hairy root tissue culture of Lobelia inflata L. In addition to the expected product alkaloid Lobeline, two new polyacetylenic compounds, Lobetyolin and Lobetyol, were also isolated from the compound. Both of them contain a ****-conjugated diyne structure. The research team also isolated Lobelia inflata L. A new polyacetylenic compound, Lobetyolin, was again isolated from the root culture, containing a glucobiose unit in the molecule. Prior to this, there has never been any report of polyacetylenic components with anticancer activity isolated from Lobelia plants.
Saponins
With the rapid development of separation methods and spectroscopic technology, the research on the chemical components of Lobelia plants has been extended to the isolation and identification of saponins. In 1977, Yoshitama isolated a complex anthocyanin pigment from the blue-violet petals of Lobeliaerinus. This pigment is very unstable in neutral aqueous solution. Later, Tadao Kondo and others isolated two anthocyanin pigments from flowers. Contrary to the compounds, these two pigments can exist stably in neutral aqueous solutions and may exist through intramolecular sandwich overlap.
This genus contains a variety of lobelia alkaloids, which have central stimulant effects and are important neurocholine receptor agonists. Lobeline is a central nervous system stimulant, clinically used to treat respiratory failure, such as neonatal asphyxia, anesthetic poisoning, etc. The effect is short-lived, non-accumulating, and can be injected repeatedly. Its pharmacological effect is quite similar to that of nicotine. It can excite carotid artery chemoreceptors, reflexively deepen and speed up breathing. Larger doses can directly excite the respiratory center, and can also excite the vagus center of the brain oblongata (causing heart rate slowdown) and vomiting. The central nervous system first excites and then paralyzes the ganglia. It has a curare-like effect on striated muscle. Oral administration can cause vomiting, so deaths from poisoning are rare. A small amount has an expectorant effect and has been used to treat respiratory diseases (excited breathing). In guinea pig experiments, it has the effect of inhibiting platelet aggregation caused by ADP, etc. It has been reported that a long-acting tablet was made and applied for a patent as a smoking cessation drug. The traditional Chinese medicine Lobelia has a significant and long-lasting diuretic effect, which can increase urine output and water excretion. It also has the effect of detoxifying and reducing swelling. It is clinically used to treat late-stage schistosomiasis ascites, cirrhosis of the liver, poisonous snake bites, sores, and swelling. It has also been reported that palm B-amyrin ester isolated from the lobelia plant L.inflata has been shown to have antidepressant activity similar to mianserin through studies on its effects on the central nervous system of mice.