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BIOSYNTHESIS OF INDOLE ALKALOIDS

BIOSYNTHESIS OF INDOLE ALKALOIDS. INDOLE ALKALOIDS. Biggest single class of alkaloids - more than 1500 known. Indole alkaloids come from trytophan which originates from the shikimic acid pathway.

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BIOSYNTHESIS OF INDOLE ALKALOIDS

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  1. BIOSYNTHESIS OF INDOLE ALKALOIDS

  2. INDOLE ALKALOIDS Biggest single class of alkaloids - more than 1500 known. Indole alkaloids come from trytophan which originates from the shikimic acid pathway. Many are of mixed-origin using geraniol, a terpene as a precursor.

  3. TRYPTOPHAN SYNTHESIS

  4. ANTHRANILIC ACID :B-Enz glutamic acid :NH3 H+ H+ anthranilic acid chorismic acid Tryptophan

  5. TRYPTOPHAN anthranilic acid imine .. : tautomers phospho- ribosyl PP enamine H+ TRYPTOPHAN enol tautomers PLP serine H+ reverse adol - CO2 - H2O indole keto

  6. ALKALOIDS FROM TRYPTOPHAN

  7. PSILOCYBIN SAM PLP tryptophan tryptamine [O] [O] ATP PLP 5-hydroxytryptamine (5-HT, serotonin) psilocybin

  8. Psilocybe spp

  9. b-CARBOLINE ALKALOIDS tryptophan + an aldehyde tryptophan aldehyde from an amino acid a b-carboline

  10. b-CARBOLINE ALKALOIDS tryptophan + an a-ketoacid tryptophan Mannich Arom Subst an a-ketoacid Oxidative decarboxylation harmine harmaline harman

  11. Ayahuasca Banisteriopsis caapi liana

  12. Yopo Anadenathra peregrina Cohoba snuff a legume

  13. Virola

  14. TERPENOID INDOLE ALKALOIDS

  15. There are a variety of alkaloids that have tryptophan and geraniol as their precursors. The geraniol precursor can yield a variety of skeletal pieces as it rearranges readily via a pathway containing two intermediates called loganin and secologanin. geraniol loganin secologanin

  16. SECOLOGANIN Secologanin has so much functionality that it can open bonds, rotate and make new bonds, easily rearranging the carbon skeleton. Three principal skeleton types are shown below. These combine with tryptamine to form alkaloids (some examples are given). IRIDOIDS IRIDANE SKELTON Corynanthe type akuammicine secologanin Iboga type Aspidosperma type tabersonine catharanthine

  17. Iboga Tabernanthe iboga

  18. Vinca

  19. SUMMARY REPEAT

  20. (+ acetogenin) Shikimate Pathways SHIKIMIC ACID FLAVANOIDS CHORISMIC ACID ANTHRANILIC ACID PHENYL-C3 COMPOUNDS PREPHENIC ACID CINNAMIC ACIDS TYROSINE TRYPTOPHAN PHENYLALANINE PHENYL-C1 COMPOUNDS ALKALOIDS ALKALOIDS ALKALOIDS

  21. Read: ASSIGNMENTS Hesse Alkaloids - Nature’s Cure or Curse , Wiley-VCH (2000) Chapter 7 “Alkaloids and Chemotaxonomy ”, pp 237-256, especially Section 7.2 which discusses the formation of secologanin and other iridoids from geraniol. Schultes, Hofmann and Ratsch, Plants of the Gods, Healing Arts Press (2001) All of these are indole-based alkaloids (b-carbolines and tryptamines) “The Magic Drink of the Amazon”, pp 124-139 (Ayahuasca) “Beans of the Hekula Spirit”, pp116-119 (Yopo) “Seeds of Civilization”, pp 120-123 (Cebil) “Semen of the Sun”, pp 176-181 (Virola, Epena) Ibogamine is fromed from an iridoid intermediate “Guide to the Ancestors”, pp 112-115 (Iboga) Psilocybin mushrooms “Little Flowers of the Gods”, pp 156-163 (Psilocybes) (Yage)

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