Acridine Alkaloids

2.2.3 Acridine Alkaloids

The origin of the acridine-ring-system is by virtue of an extension of the process that essentially involves the combination of anthranilic acid and acetate/malonate as shown in the following sequence of reactions; whereas, a rather more direct route to the above leads to the quinoline-ring-system discussed in Section 7.2.2.2 earlier.

There are a few typical examples of the acridine alkaloids, such as: Rutacridone, Acronycine and Melicopicine.

A. Rutacridone

Biological Source The fresh and dried leaves of Ruta graveolens L. (Rutaceae) (Rue, Garden Rue, German Rue).

Chemical Structure

Uses

1. In Chinese medicine rue is considered as an emmenagogue, hemostat, intestinal antispasmodic, sedative, uterine stimulant, vermifuge, rheumatism, cold and fever.

2. In Poland, it is used as an aphrodisiac and choleretic.

3. The herb is used medicinally as a bitters, an aromatic stimulant, ecbolic and in suppression of the menses.

The chemical structures of acronycine and melicopicine are given below:

Biosynthesis of Rutacridone, Acronycine and Melicopicine The anthraniloyl-CoA is observed to act as a starter-unit for the extension of chain via one molecule of malonyl-CoA, and formation of amide ultimately generates the heterocyclic system, that would adopt finally the more stable 4-hydroxy-2-quinolone form as shown in the following sequence of reactions. Interestingly, the position C-3 is highly nucleophilic; and, therefore, is susceptible to alkylation, especially via dimethylallyl diphosphate in the instance of all the three alkaloids, namely: rutacridone, acronycine, and melicopicine. This seems to allow the formation of additional six-membered oxygen containing heterocyclic ring system (acronycine); and five-membered oxygen containing heterocyclic ring system (rutacridone).
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar