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Piperidine alkaloids (2018)

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Piperidine alkaloids (2018)

  1. 1. Ph. D. Ahmed Metwaly
  2. 2. • Pepper alkaloids. • Conium alkaloids. • Lobelia alkaloids. • Pomegranate alkaloids.
  3. 3. * Piperidine Nucleus can be obtained by hydrogenation of pyridine using Nickel as catalyst. * Piperidine Alkaloids are biosynthesized from L-Lysine amino acid. Piperidine N Pyridine N H Nickel Piperidine Alkaloids L-Lysine H2NH2N O OH L-Lysine
  4. 4. Piperine Pepper Conium Coniine e.g. Lobelia Lobeline Lobelanine Lobelanidine e.g. Pomegranate Pelletierine Isopelletierine Methylpelletierine Pseudopelletierine Piperidine Alkaloids
  5. 5. Occurrence: Fruits of Piper nigrum, (Fam. Piperaceae) (E, E)-1-[5-(1, 3-Benzodioxol-5-yl)-1-oxo-2, 4-pentadienyl] piperidine (C17 H19NO3). Pepper alkaloids
  6. 6. ◘The amount of piperine varies from 1–2% in long pepper, to 5–10% in black peppers ◘ Piperine is a weak basic alkaloid, does not form stable salts. ◘ It is tasteless at first, but has a burning after taste. ◘ It is decomposed easily with alcoholic KOH to yield piperidine and piperic acid. Color test: Piperine + H2SO4  red color. Uses: ◘ Condiment, Tonic and rubefacient. ◘ In traditional medicine, used as stimulant, carminative & tonic.
  7. 7. Actions • Anti-inflammatory; It reduces the levels of cytokines that promote inflammation (IL-1b,TNF-α, and PGE2) and increases the levels of cytokines that reduce inflammation (IL-10). • Increasing bioavailability of many drugs and supplements; The primary value of piperine in health supplements is its ability to enhance the bioavailability of some other vitamins and minerals. By inhibiting the detox enzymes that break down drugs (such as CYP3A4) and increasing drug/substance absorption in the gut (increase blood supply), piperine increases the body’s ability to make effective use of many other compounds. • Antioxidant; It acts directly as a hydroxyl and superoxide radical scavenger. • Increasing catecholamines in the brain – these help improve mood, cognitive function, and fight of neurodegenerative diseases. • Increasing muscle metabolism by increasing ATPase activity. This increases the use of energy by the muscles and helps in weight loss.
  8. 8. Gorgani, Leila, et al. "Piperine—the bioactive compound of black pepper: from isolation to medicinal formulations." Comprehensive Reviews in Food Science and Food Safety 16.1 (2017): 124-140.
  9. 9. Drug interactions; It enhances the effect of many drugs (including those metabolized by CYP3A4 and CYP2E1 enzymes): Diclofenac (nonsteroidal anti-inflammatory drug) Ibuprofen (nonsteroidal anti-inflammatory drug) Fexofenadine (an allergy drug) Carbamazepine (anti-epileptic) Chlorzoxazone (muscle relaxant) Ampicillin trihydrate Norfloxacin (antibiotic) Domperidone (anti-emetic drug) Docetaxel (anti-cancer drug) Glimepiride (anti-diabetic) Nateglinide (anti-diabetic) Metformin (anti-diabetic) Piperine also enhances the effect of supplements such as beta-carotene, curcumin, and resveratrol.
  10. 10. The low solubility of piperine in water and its poor dissolution is the rate‐controlling step in the absorption process of piperine. The pharmaceutical activities of piperine are limited due to its low water solubility and because use of it at high concentrations can be toxic for the central nervous and reproductive systems.
  11. 11. Occurrence: The hemlock fruits, Conium maculatum, (Fam. Umbelliferae) Conium alkaloids Coniine
  12. 12. Properties: Coniine and  -Coniceine are non-oxygenated, volatile, liquid alkaloids Coniine is a colorless oily liquid, with mice-like odor and a burning taste. Violet or blue color Color test: Coniine + sodium nitroprusside solution Red color CH3O
  13. 13. Uses: ◘ Coniine is used as a local analgesic, mostly in external preparations, due to its high toxicity. ◘ It is used as an ointment for treatment of hemorrhoids and anal fissures. Coniine is very poisonous, lethal dose 120-300 mg, death may occur after ½ hr. (or may prolong to 3 –12 hrs.)
  14. 14. Lobelia alkaloids Dried aerial parts of Lobelia inflata (Fam. Campanulaceae) ◘ These alkaloids contain piperidine rings with alternative ( C6-C2 ) side chains derived from phenylalanine via cinnamic acid.
  15. 15. Lobeline: ◘ a tertiary base alkaloid. ◘ It is a keto-alcohol. ◘ It forms a monooxime monoester. ◘ Lobeline HCl salt is soluble in CHCl3 Lobelanine: Is a diketonic compound, therefore it forms a dioxime. Lobelanidine: (ketonic group absent). It does not form any oxime Properties:
  16. 16. Tests for identification of lobeline: Lobeline gives with: ◘ Marqui`s reagent  red violet color ◘ Erdmann`s reagent  faint green color ◘ Froehd's reagent  rose red color  blue ◘ Rosette crystals with KCN or Na2CO3 solution.
  17. 17. Uses of Lobelia ◘ Respiratory stimulant. ◘ Expectorant. ◘ Relieve asthma. ◘ Lobeline sulfate was formerly incorporated in tablets or lozenges, that were intended to aid in breaking the tobacco habit (smoking deterrents).
  18. 18. Chewing the plant produces effects like that of nicotine, such as sensation to the tongue and stomach, as well as CNS effects. Structural similarity to nicotine exerts nicotine-like effects on choline receptors Recent studies of Lobeline have found that lobeline reduces the cytosolic pool of dopamine and therefore diminishing methamphetamine evoked dopamine release Due to this mode of action there are current studies developing drug therapies for methamphetamine abuse. The Classical mechanism of action had been categorized as a nicotinic receptor agonist at the nicotinic acetylcholine receptor (nAChR) but with a weaker effect, recent studies suggest it to be an antagonist effect. Ingestion of lobeline may cause nausea, vomiting, diarrhea, coughing, dizziness, visual disturbances, hearing disturbances, mental confusion, weakness, slowed heart rate, increased blood pressure, increased breathing rate, tremors, and seizures. Lobeline has a narrow therapeutic index; the potentially beneficial dose of lobeline is very close to the toxic dose As smoking deterrent: daily oral dose of 6 mg (3*2 mg),
  19. 19. ◘ The fruit rind as well as the root and stem barks of Pomegranate [Punica granatum, Fam. Punicaceae]. Pomegranate alkaloids N H C O H N H CH3 C O N CH3 C O H N OCH3 Pelletierine Isopelletierine N-methylpelletierine Pseudopelletierine Liquid alkaloid s Solid alkaloid Strong basic Weak basic
  20. 20. Isopelletierine Pseudopelletierine
  21. 21. Pomegranat e
  22. 22. Properties:
  23. 23. Uses: ◘ Pelletierine is highly toxic to tape worms ◘ Anthelmintic against pork tape worms and Ascaris. ◘ It is also used as a Taenifuge.
  24. 24. Ph. D. Ahmed M. Metwaly Assistant professor, Pharmacognosy department, Faculty of Pharmacy, Al-Azhar University. ametwaly@azhar.edu.eg