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PHG 322 Pharmacogonsy II lecture 5 Presented by Assistant Prof. Dr. Ebtesam Alsheddi. بسم الله الرحمن الرحيم. Indole Alkaloids 4 - Rauwolfia Alkaloids ( carboline alk .). Source: Rauwolfia roots ( Rauwolfia serpentina , Fam. Apocynaceae ). Carboline skeleton .
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PHG 322Pharmacogonsy IIlecture 5Presented byAssistant Prof. Dr. EbtesamAlsheddi بسم الله الرحمن الرحيم
Indole Alkaloids4- RauwolfiaAlkaloids (carbolinealk.) • Source:Rauwolfia roots (Rauwolfiaserpentina, Fam. Apocynaceae) Carboline skeleton
Constituents:The most important are Reserpine, Deserpineand Rescinnamine. • Properties: • Reserpine and related alkaloids are weakly basic diester, tertiary alkaloidsand possess a carboxylic group on ring "E".
Alkaline Hydrolysis: 1- Reserpine → reserpicacid + trimethoxybenzoic acid + methanol. 2- Recinnamine → reserpicacid + trimethoxycinnamic acid + methanol. • Its solution acquires a yellow color and a pronounced fluorescence especially after the addition of acids or upon exposure to light. • Tests for reserpine: • Vanillin /HCl reagent: → violet color. • Sodium molybdate in H2SO4 → Yellow → Blue in two minutes. • Uses: • Reserpineand the related alkaloidrescinnamineare mainly used as antihypertensives (250-500 mg daily) and as tranquilizers(0.1- 1mg or more daily).
Imidazole Alkaloids Pilocarpus Alkaloids • Source: Jaborandi leaves (Pilocarpus jaborandi). • Constituents: (+)-Pilocarpine. • Properties: 1- Oily liquid miscible with water. 2- Non-volatile liquid alkaloid. 3- Lactone function. • Test: Helche’s test: Alkaloid + Dil acid + K2CrO7 → violet colour (Pilocarpine dichromate) • Uses: 1- Miotic. 2- Diaphoretic. 3- Hair preparations.
Characters 1. Pilocarpine is oily non-volatile liquid alkaloid. Effects/Uses: • Pilocarpine is a cholinergic agent causing constriction of the pupil (Antagonistic to Atropine). • Pilocarpinesalts are valuable in ophthalmic practice and are used in eye drops as miotics and for the treatment of glaucoma. • Pilocarpine gives relief for dryness of the mouth that results in patients undergoing radiotherapy for mouth and throat cancers.
Tropolone Alkaloids Colchicum Alkaloids • Source: Colchicum Corm. • Constituents: Colchicine. • Properties: 1- Neutral Alkaloid. 2- Amid function. • Test: 1- Red colour with FeCl3. 2- Yellow colour with dil. Mineral acids. • Uses: 1- Treatment of Gout. 2- Anticancer in vitro. 3- Treatment of Mediterranean Sea fever. 4- Polyploidy in Plants.
Alkaloids with Exocyclic Nitrogen(Protoalkaloids- Phenylalkylamines- Biological amines) • This group of alkaloids have the nitrogenatomlocated in an amino group and is not a member of a heterocyclic ring • Many are simple derivatives of Phenylethylamineand as such, are derived from the common amino acids Phenylalanine or Tyrosine. phenylalanine tyrosine • They are sympathomimetic drugs (e.g. rise the blood pressure).
Protoalkaloids includes the alkaloids of: Ephedra alkaloids Khat alkaloids Peyotealkaloids
Alkaloids with Exocyclic Nitrogen(Protoalkaloids- Phenylalkylamines- Biological amines) especially Ephedrasinica(Family Ephedraceae). * 1- Ephedra Alkaloids Source: Ephedra Herb (Ma Huang, Yellow Hemp). Ephedra used as remedy for Asthma in Chinese medicine. (-)-Ephedrine is the major Alkaloid in Ephedra. Ephedrine is a phenylalkylamine with N atom in the side chaine
Ephedrine is similar to adrenaline in structures. • Advantages of Ephedrine over adrenaline: 1- Orally active. 2- Prolonged action Adrenaline is used to treat a number of conditions including: cardiac arrest, anaphylaxis, and superficial bleeding.It has been used historically for bronchospasm and hypoglycemia, but newer treatments for these, such as salbutamol, a synthetic epinephrine derivative, and dextrose, respectively, are currently preferred.[8]
Effects/Uses of Ephedrine • Its pharmacological action resembles epinephrine (adrenaline), but is considerably less active. • Ephedrine can be absorbed orally, unlike epinephrine. • Ephedrine increases blood pressure and heart rate. • It is a potent nasal decongestant due to its vasoconstrictor action on blood capillaries of mucous membranes. • Ephedrine has a longer duration of action.
Chen’stest: Ephedrine HCl in water + 0.1 ml CuSO4 + 1ml NaOH → Violetcolour, shake with Ether→ Ether layer → purple Aqueous layer → blue
2- Cathe Alkaloids (Kat القات) Khat or “ Abyssinian tea” consists of the fresh leaves of Catha Edulis (Family Celastraceae). • CNS stimulant activity • Abused drug.
3- Peyote Alkaloids • Source: Lophophorawilliamsii( is a small, spineless cactus) • Hallucinogenic • Major alkaloid
Purines are derivatives of a heterocyclic nucleus consisting of a six-membered Pyrimidine ring fused to a five-membered Imidazole ring. Purines are Psudoalkaloids (Are not derived from amino acids but have nitrogen in a heterocyclic ring) (True alkaloid- protoalkaloid- pseudoalkaloid)
Chemical test: • Do not give precipitate with Mayer's reagent. • They give a positive Murexide test (special test). * are weak basesform salts only with strong acids
Caffeine: • Is the best CNS stimulant of the purine bases and has weak diuretic action. Source: Coffee seeds – Sеmina CoffeaeArabian coffee tree --CoffeaarabicaFam.–Rubiaceae Added to the analgesics
Theobromine: • Has little CNS stimulant action, but has more diuretic activity, and has smooth muscle relaxant effect. From Theobroma cacao tree
Theophylline: • Has low CNS stimulant action and is an effective diuretic, but it is an important smooth muscle relaxant & used for relief of bronchial spasms. Tea Leaves – Folia TheaeChinese Tea – TheasinensisFamilyTeas – Theaceae
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