phg 322 pharmacogonsy ii lecture 5 presented by assistant prof. dr. ebtesam alsheddi بسم الله...
TRANSCRIPT
PHG 322PHARMACOGONSY IILECTURE 5PRESENTED BYASSISTANT PROF. DR. EBTESAM ALSHEDDI
الرحيم الرحمن الله بسم
• Source: Rauwolfia roots (Rauwolfia serpentina, Fam. Apocynaceae)
Indole Alkaloids4- Rauwolfia Alkaloids (carboline alk.)
Carboline skeleton
• Constituents: The most important are Reserpine, Deserpine and Rescinnamine.
• Properties: Reserpine and related alkaloids are weakly basic diester,
tertiary alkaloids and possess a carboxylic group on ring "E".
NH
NH3CO
H3COOC OR
R= 3,4,5-trimethoxybenzoic acid ReserpineR= 3,4,5-trimethoxycinnamic acid Recinnamine
E
Alkaline Hydrolysis:1- Reserpine → reserpic acid + trimethoxybenzoic acid + methanol. 2- Recinnamine → reserpic acid + 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: Reserpine and the related alkaloid rescinnamine are 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.
N
N O
CH3
O
Pilocarpine is a cholinergic agent causing
constriction of the pupil (Antagonistic to Atropine).
Pilocarpine salts 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.
Effects/Uses:
8
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.
H3CO
H3CO
OCH3
OCH3
O
NH-CO-CH3
Alkaloids with Exocyclic Nitrogen(Protoalkaloids- Phenylalkylamines- Biological amines)
This group of alkaloids have the nitrogen atom located
in an amino group and is not a member of a
heterocyclic ring
Many are simple derivatives of Phenylethylamine and as
such, are derived from the common amino acids
Phenylalanine or Tyrosine.
CH2 C
H
NH2
COOHOH
phenylalanine tyrosine
CH2 C
H
NH2
COOH
They are sympathomimetic drugs (e.g. rise the blood
pressure).
1) Ephedra alkaloids
2) Khat alkaloids
3) Peyote alkaloids
Protoalkaloids includes the alkaloids of:
Alkaloids with Exocyclic Nitrogen(Protoalkaloids- Phenylalkylamines- Biological amines)
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
especially Ephedra sinica (Family Ephedraceae). *
• 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’s test: Ephedrine HCl in water + 0.1 ml CuSO4 + 1ml NaOH → Violet
colour, shake with Ether →
Ether layer → purpleAqueous 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.
CH CH CH3
NH2
OH
Cathine
C CH CH3
NH2
O
Cathinone
3- Peyote Alkaloids
NH2
H3CO
H3CO
OCH3
Mescaline
• Source: Lophophora williamsii ( 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 Psudo alkaloids (Are not derived from amino acids but have nitrogen in a heterocyclic ring)
(True alkaloid- protoalkaloid- pseudoalkaloid)
Purine alkaloids
xanthine
theophyillinecoffeine theobromine
Purine alkaloids
They are all methyl derivatives of xanthine.
* are weak bases form salts only with strong acids
Do not give precipitate with Mayer's reagent. They give a positive Murexide test (special test).
22
Chemical test:
Caffeine:
Is the best CNS stimulant of the purine bases and has weak
diuretic action.
Source: Coffee seeds – Sеmina CoffeaeArabian coffee tree --Coffea arabicaFam. – 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 – Thea sinensisFamily Teas – Theaceae
Marine Bioactive Agent
• Over 70% of the earth's surface is covered by oceans which contain 95% of the earth's biosphere
• Marine environments are considered more biologically diverse than terrestrial environments
• Ocean contain highly ecological, chemical & biological diversity starting from micro-organisms to vertebrates. This diversity has been the source of unique chemical compounds, which hold tremendous pharmaceutical potential.
• Marine Bioactive Agent, Marine bioactive compounds or Marine natural products (MNPs) are organic compounds produced by microbes, sponges, seaweeds, and other marine organisms. The host organism synthesizes these compounds as secondary metabolites to protect themselves and to maintain homeostasis in their environment.
• Marine organisms are able to generate bioactive compounds to protect themselves from external factors.
• Recently, scientists have explored various health beneficial pharmaceutical bioactives from marine bio resources such as macroalgea, microalgea, fungi, bacteria, actinomycetes, invertebrates and vertebrates.
• The number of potential compounds isolated from marine exceeds to 10000
• with hundred of new compounds still being discovered every year
• A number of promising identified molecules are already in market, clinical trials or preclinical trials