![ORGIN , HISTORY AND INTRODUCTION
• THE TERM “ALKALOID” [ALKALI-LIKE] IS COMMONLY USED TO DESIGNATE BASIC HETEROCYCLIC
NITROGENOUS COMPOUNDS OF PLANT ORGIN THAT ARE PHYSIOLOGICALLY ACTIVE
• The term alkaloid of pflanzenlkalien was coined by Meissner a German Pharmacist in 1819
• The mankind has been using alkaloid for various purposes like poisons, medicines, teas etc.
• The French scientist Derosne in 1803 isolated Narcotine](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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ALKALOIDS.pptx
- 1. ALKALOIDS CLASSIFICATION,PHYSICAL AND CHEMICAL PROPERTIES,CHEMISTRY
- 2. ORGIN , HISTORY AND INTRODUCTION • THE TERM “ALKALOID” [ALKALI-LIKE] IS COMMONLY USED TO DESIGNATE BASIC HETEROCYCLIC NITROGENOUS COMPOUNDS OF PLANT ORGIN THAT ARE PHYSIOLOGICALLY ACTIVE • The term alkaloid of pflanzenlkalien was coined by Meissner a German Pharmacist in 1819 • The mankind has been using alkaloid for various purposes like poisons, medicines, teas etc. • The French scientist Derosne in 1803 isolated Narcotine
- 3. DISTRIBUTION IN PLANTS 1. LEAVES: TOBACCO 2. LATEX : OPIUM 3. FRUIT : BLACK PEPPER 4. ALL PARTS: DATURA
- 4. DISTRIBUTION AND OCCURANCE • Rare in lower plants • Dicots are more rich in alkaloids than monocots • Families rich in alkaloids : APOCYNACEAE,RUBIACEAE,SOLANACEAE AND PAPAVERACEAE
- 5. FUNCTION IN PLANTS • They may act as protective against insects and herbivorous due to their bitterness and toxicity. • Act as source of nitrogen in the case of nitrogen deficiency. • They sometimes act as growth regulators in certain metabolic system. • They may be utilised as a source of energy in the case of deficiency in carbon dioxide assimilation. • In certain cases they are final products of detoxification.
- 6. EFFECT OF ALAKLOID IN HUMANS • High biological activity • Produce varying degree of physiological and psychological responses. • Largely interfering with neurotransmitters. • In large dose-highly toxic or fatal • In small dose –many have therapeutic value eg.painkillers
- 8. CLASSIFICATIONS A. TRUE (TYPICAL) ALKALOIDS that are derived from amino acids and have nitrogen in a heterocyclic ring eg. Atropine B. PROTOALKALOIDS that are derived from amino acids and do not have nitrogen in a heterocyclic ring eg. Ephrdrine C. PSUEDOALKALOIDS that are not derived from amino acid but have nitrogen in a heterocyclic ring eg. Caffeine D. FALSE ALKALOIDS are non alkaloids give false positive reaction with alkaloidal reagents.
- 9. PHYSICAL PROPERTIES • COLOURLESS • CRYSTALLINE SOLIDS • INSOLUBLE IN WATER • SOLUBLE IN ORGANIC SOLVENTS • TASTE : BITTER • OPTICALLY ACTIVE (MOSTLY LEAVO ROTATORY)
- 10. CONDITION • Most alkaloids are crystalline solids. • Few alkaloids are amorphous solids eg. Emetine • Some are liquids that are either (A) VOLTILE eg. Nicotine and coniine (B) NONVOLATILE eg.pilocarpine and hyoscine COLOUR • The majority of alkaloids are colourless • EXEPTIONS : Colchicine and Berberine are yellow Canadine is orange SOLUBILITY • Both alkaloidal bases and their salts are soluble in alcohol • Generally the bases are soluble in organic solvents and insoluble in water. • Exceptions: Bases soluble in water : caffeine ,ephedrine ,codeine Bases insoluble or sparingly soluble in certain organic solvents : morphine in ether • Salts are usually soluble in water and insoluble or sparingly soluble in organic solvents • Exceptions: Salt insoluble in water – quinine monosulphate Salts soluble in organic solvents – iobeline and apotropine hydrochlorides are soluble in chloroform.
- 11. CHEMICAL PROPERTIES • In addition to carbon ,nitrogen, and hydrogen most alkaloids contains oxygen in their molecules. • Few alkaloids are oxygen free such as nicotine and coniine. • Due to their basic character alkaloids with acids make salts. • Strong bases form salts with very weak acids. • Weak bases require strong acids • Very weak bases form unstable salts. • Amphoteric alkaloids can form salts with both acids and alkalies • Alkaloids showing acidic character do not form salts with acids eg. rianine
- 12. CHEMICAL TEST 1. WAGNERS TEST : REDDISH BROWN PERCIPITATE 2. MAYERS TEST: CREAMY PERCIPITATE WITH TRUEALKALOIDS 3. HAGGERS TEST:YELLOW PERCIPITATE WITH TRUEALKALOIDS 4. DRAGENDOFF TEST : REDDISH BROWN PERCIPITATE
- 13. . • CHEMICAL CHARECTORS THE UNSHARED ELECTRON PAIR ON THE NITROGEN ATOM IS RESPONSIBLE FOR ALKALOID BASICITY SOME ALJKALOIDS LOSE WATER MOLECULES TO FORM THE ANHYDRO-OR APOALKALOIDS EG. MORPHINE AND APOMORPHINE N OR O DEMETHYLATIONS OF CERTAIN ALAKLOIDS CAN TAKE PLACE UPON HEATING WITH MINERAL ACIDS EG. QUININE , NARCOTINE • EFFECT OF HEAT AND ACID ON ALKALOID STABILITY • HEAT: ALAKALOIDS GENERALLY DECOMPOSE ON HEATING WHILE SOME OF THEM SUBLIME EG.CAFFINE • ACID: COLD CONCENTRATED ACID MAY CAUSE DRAMATIC CHANGES IN ALKALOIDS