ALKALOIDS.pptx

This is about alkaloids and their classifications their physical and chemical properties ,uses and toxic effects

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 LEAVES: TOBACCO LATEX : OPIUM FRUIT : BLACK PEPPER 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

7. STIMULANTS HALLUCINOGENS TROPANEALKALOIDS MESCALNE LSD DEPPRESENTS MORPHIN CODEINE HEROINE COCAINE EPHEDRINE CAFFEINE PSYCHOACTIVE ALKALOIDS

8. CLASSIFICATIONS TRUE (TYPICAL) ALKALOIDS that are derived from amino acids and have nitrogen in a heterocyclic ring eg. Atropine PROTOALKALOIDS that are derived from amino acids and do not have nitrogen in a heterocyclic ring eg. Ephrdrine PSUEDOALKALOIDS that are not derived from amino acid but have nitrogen in a heterocyclic ring eg. Caffeine 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 WAGNERS TEST : REDDISH BROWN PERCIPITATE 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

14. THANK YOU LAKSHMI MANOJ