Alkaloids are small nitrogen-containing molecules found primarily in plants. To date, approximately 27,000 alkaloids have been reported, 21,000 of which are from plants. Since most alkaloids are highly biologically active, they are the main components of many herbal medicines. Some alkaloids are also used as medicines. Due to the positive charges in the nitrogen atoms, alkaloids have electrostatic interactions with proteins, which facilitates binding to the negative charges of proteins. Drug alkaloids, in particular, tend to bind to receptors in the nervous system.

Tropane alkaloids (TAs) are a class of bicyclic alkaloids structurally composed of a pyrrole ring and a piperidine ring. Tropane alkaloids are secondary metabolites containing a tropane ring in their chemical structure and are found in many plants, such as Solanaceae, Cocaaceae, and Convolvulaceae. Typical tropane alkaloids include hyoscyamine, scopolamine, cocaine, etc., all of which have medicinal activity and can be used as anticholinergics or stimulants.

Classification

Tropane alkaloids (TA) are valuable secondary plant metabolites found mainly in high concentrations in the Solanaceae and Rosewood families. TAs are characterized by their unique bicyclotropane ring system and can be divided into three major categories: hyoscyamine and scopolamine, cocaine, and scopolamine. Although all TAs have the same basic structure, their biological, chemical and pharmacological properties vary greatly. Scopolamine, also known as scopolamine, has the largest legal drug market for its treatment of nausea, vomiting, motion sickness, and smooth muscle spasms, while cocaine is the second most commonly consumed illicit drug worldwide. This review provides a comprehensive overview of TAs, highlighting their structural diversity, applications in pharmacotherapy from both historical and contemporary perspectives, their natural biosynthesis in plants, and the emerging use of these compounds in tissue culture and microbial biosynthesis. production possibilities.

Common tropane alkaloids

• Hyoscyamine

Hyoscyamine is one of the belladonna alkaloids isolated from the traditional Chinese medicines Henbane and Amaranthus japonica. Its structure is an ester formed by the condensation of hyoscyamine and hyoscyamic acid. Hyoscyamine is a parasympathetic nerve inhibitor with pharmacological effects similar to atropine, but it is more toxic and has less clinical application. Hyoscyamine has analgesic and antispasmodic properties, and has a good effect on sciatica. It is sometimes used to treat epilepsy, seasickness, etc.

• Scopolamine

Scopolamine is a typical scopolane-type alkaloid found in plants of the Solanaceae family. The pharmacological effects of scopolamine are similar to those of atropine. Its mydriasis and inhibition of gland secretion are stronger than those of atropine. It has an exciting effect on the respiratory center, but has a significant inhibitory effect on the cerebral cortex. In addition, it can expand capillaries, improve microcirculation, and resist inflammation. Seasickness and motion sickness. Scopolamine is the most powerful alkaloid in belladonna. It can be used to block parasympathetic nerves and can also be used as a central nervous system depressant.

• Cocaine

Cocaine is also called cocaine, and its chemical name is benzyl ecgonine. In medical treatment, it is used as a local anesthetic or vasoconstrictor. Due to its good anesthetic effect and strong penetrating power, it is mainly used for topical anesthesia. However, it is not suitable for injection due to its strong toxicity. At the same time, it can be used as a strong natural central stimulant, and its stimulating effect on the central nervous system can lead to abuse.