Fascinating Insights into Alkaloids Derived from Tryptophan in Pharmacognosy
Explore the intricate world of alkaloids derived from tryptophan, a key aspect in pharmacognosy studies. Learn about the biosynthesis, diverse compounds, and pharmaceutical significance of tryptophan derivatives in the synthesis of indole alkaloids. Discover how tryptamine contributes to the creation of medicinal alkaloids and the formation of indole alkaloids. Delve into the pharmaceutical interests and complexities associated with tryptamine-derived alkaloids. Unravel the fascinating connections between tryptophan, its derivatives, and the pharmaceutical applications of indole alkaloids.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
Tishk Tishk International University International University FACULTY OF PHARMACY Department of Pharmacognosy Department of Pharmacognosy Alkaloids derived Alkaloids derived from tyrosine and from tyrosine and tryptophan tryptophan Pharmacognosy Pharmacognosy- -III III Grade Grade 4 4- - Fall Fall semester semester 20 Dr. Dr. Omji Omji Porwal Porwal 2021 21- -202 2022 2
BIOSYNTHESIS OF ALKALOIDS Alkaloids derived from ornithine Alkaloids derived from Lysine Alkaloids derived from phenylalanine, tyrosine and related amino acids Alkaloids derived from tryptophan
Tryptophan Derivatives About 1,200 dissimilar compounds, the entire of which are tryptophan derivatives have been isolated till today. The tryptophan derivatives correspond to 25% of all known alkaloids and many of them are medicinally valuable. Tryptophan and its decarboxylated product (tryptamine) are precursors for the biosynthesis of broad range of indole alkaloids of which the vinca and rauwolfia alkaloids are examples; and also in the alkaloids belonging to families like Apocynaceae, Loganiaceae, and Rubiaceae. D-Tubocurarine, the active components of curare, is also a tryptophan derivative. Tryptamine on condensation with secologanin produces vincoside a nitrogenous glucoside. Some of the indole alkaloids in vinca are formed from vincoside.
With a few minor exceptions, tryptophan and its decarboxylation product, tryptamine, give rise to the large class of indole alkaloids. These bases usually contain two nitrogen atoms; one is the indolic nitrogen and the second is generally two carbons removed from the -position of the indole ring. Of the several alkaloid groups within the indole class, two may be produced, depending on the type of condensation occurring between tryptamine and an aldehyde or keto acid. A Mannich reaction involving the -carbon atom of the indole nucleus affords a -carboline derivative; reaction involving the -position gives rise to an indolenine.
Some examples of alkaloids of pharmaceutical interest, derived from tryptamine. It will be noted that the more complex indole alkaloids contain a non-tryptophan-derived portion of the molecule and this is supplied by mevalonic acid, which in the case of the ergot alkaloids is a C5 - isopentenyl unit and with the alkaloids of the Apocynaceae, Loganiaceae, Rubiaceae etc., a C10 - geraniol (monoterpenoid) contribution. Some 2000 monoterpenoid alkaloids are known.
Ergot and Ergot Alkaloids Ergot (Ergot of Rye) is the dried sclerotium of a fungus, Claviceps purpurea Tulasne (Clavicipitaceae), arising in the ovary of the rye, Secale cereale. Controlled field cultivation on rye is the main source of the crude drug. The most important producers are Czechoslovakia, Hungary, Switzerland and former Yugoslavia. With modern farming the supply of natural ergot is decreasing and fields of rye are devoted to its cultivation. Different selected strains of C. purpurea are used for the production of the alkaloids ergotamine, ergocristine, or ergocornine and ergokryptine. Commercially, ergot of rye is becoming less important and by 1994 UK dealers were trading mainly in ergot of wheat.
The ergoline nucleus is derived from tryptophan and mevalonate, and current work has involved elucidating the biosynthetic relationship between the various clavine alkaloids. Possible biosynthetic routes for lysergic acid involving two isomeric intermediates are given in below slides.
