Pharmacognosy Handouts [Tannins + Lipids + Oils + Waxes] By, Sir Tanveer Khan

Pharmacognosy By Sir Tanveer Khan

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Lecture: Tannins + Lipids + Oils + Waxes

TANNINS Introduction The term tannin was first time coined by Seguin in 1796. This term was used to denote substances present in plant extract which react with protein of animal hide, prevent their putrefaction (process of decay of organic materials) and convert hide and skin into leather.

Definition “Complex substances that usually occur as mixtures of polyphenols that are very difficult to separate since they don't crystallize, are called tannins.” OR “Tannins are polyhydroxy phenolic compounds.”

Physical Properties Color: Taste: State: Solubility:

Dark brown or reddish brown Puckering taste Non-crystalline Soluble in water, alcohol, dilute alkalis, glycerols and acetone.

Chemical properties (i) (ii) (iii) (iv) (v) (vi)

Precipitation Anti-oxidizing properties Astringent Carcinogenicity Reaction with salts Reaction with potassium ferricyanide and ammonia

(i) Precipitation: Tannins have ability to precipitate solutions of;  Gelatin.  Alkaloids.  Glycosides.  Heavy metals.  Proteins. (ii) Anti-oxidizing properties: Because of accumulation of OH group on small size nucleus, these agents have anti-oxidant nature.

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Lecture: Tannins + Lipids + Oils + Waxes (iii) Astringent:

Tannins have property to react with protein of mucous membrane and cause precipitation (iv) Carcinogenicity: Prolong use of tannin containing plant material is hazardous because it causes cancer. Habitual use of Areca catechu can cause oral and esophageal cancer. (v) Reaction with Salts:

(vi) Reaction with Potassium ferricyanide and Ammonia:

Importance of Tannins  Medicinal Uses: • • • • •

Antidote. Antiseptic. Algicidals. Astringents. Anti-carcinogenic.

 Industrial Uses: • Ink manufacture. • Vegetable tanning. • Preservatives.  Biological Activities: • • • •

Inhibition of lipid per oxidation. Decrease in blood urea nitrogen content. Inhibition of plasmin. Lipolysis in fat cells.

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Lecture: Tannins + Lipids + Oils + Waxes Chemical Classification

Based on identity of phenolic nuclei involved and on the way they are joined.

Tannins

Hydrolysable tannins

Condensed tannins

Complex tannins

(i) Hydrolysable Tannins: These tannins are hydrolyzed by enzymes or acids.  Precursors: • Phenolic acid (Gallic acid, Ellagic acid) • Glucose residue • Between phenolic acids and glucose sugar, there is ester linkage.

 Properties:

 Types: Hydrolysable tannins

Gallitannins

Ellagitannins

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Lecture: Tannins + Lipids + Oils + Waxes

Gallitannins

Ellagitannins

Occurrence

Rhubarb Clove Hamamelis

Pomegranate Eucalyptus

Hydrolysis

Upon acid hydrolysis of Gallitannins, Gallic acid is produces.

Upon acid hydrolysis of Ellagitannins, Ellagic acid is produces.

Properties

* Rapidly soluble in water. * Free Gallic acid, in plant, is converted to gluco Gallitannins.

* Slowly soluble in water. * Present in plants in open and ring forms as Hexa hydroxy diphenic acid.

(ii) Condensed Tannins These tannins are derivatives of Flavonoid, catechin, flavonol-3-4-diol.  Precursors: • Flavonoid • Catechin • Flavonol-3-4-diol

 Properties: When heated with acids, these are self condensated, polymerized and converted to insoluble red colored complexes, called Phlobaphenes.

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Lecture: Tannins + Lipids + Oils + Waxes

 Examples • Hamamelis • Cinchona • Cinnamon

(iii) Complex Tannins These tannins are mixtures of both, hydrolysable and condensed tannins  Examples: • Tea • Quercus • Castanea  Types (2nd Classification of tannins based on complexity): Tannin is a substance which is detected qualitatively by tanning test (The Gold Beater’s skin test) and quantitatively by its adsorption on standard hide powder. Depending upon this, tannins are of two types; 1) True tannins. 2) Pseudo tannins.

Tannins

True tannins

Pseudo tannins

Difference: True tannins

Pseudo tannins

Polyhydroxy phenolic compounds which convert animal hide to leather by precipitating proteins and give positive Gold beater’s skin test, are called true tannins.

Phenolic compounds of plant origin that don't convert animal hide to leather but do give positive Gold beater’s skin test, are called pseudo tannins.

Molecular weight is 1000-5000

Molecular weight is less than true tannins.

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Lecture: Tannins + Lipids + Oils + Waxes

Identification Tests (for Tannins) 1. Color reaction: Tannins give color reaction with iron.

2. Matchstick test: • Dip matchstick in plant extract. • Dry it. • Moisten it with hydrochloric acid. And warm near flame. • Wood will turn pink or red in color due to phloroglucinol. 3. Gelatin test: Solution of tannin (0.5%-1%) precipitates 1% solution of gelatin containing 10% sodium chloride. 4. Phenazone test: • Take 5ml of aqueous extract of drug. • Add 0.5grams of sodium acid phosphate. • Warm it and cool. • Filter solution. • To the filtrate, add 2%solution of Phenazone. • Tannins will be precipitated. • Precipitates will be bulky and colored. 5. Gold beater’s skin test: Gold beater’s skin is a membrane prepared from intestine of Ox and behaves similarly to un tanned skin. • Soak a small piece of Gold beater’s skin in 2% hydrochloric acid. • Rinse it with distilled water. • Place it in solution to be tested for 5 minutes. • Wash in water and transfer to 1% solution of ferrous sulphate. • Black or brown color of skin indicates presence of tannins. *** It is a quantitative test and +ive only for true tannins.

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Lecture: Tannins + Lipids + Oils + Waxes

6. Catechin test: Catechin when heated with acid produce phloroglucinol. Phloroglucinol can be detected with matchstick test. 7. Test for chlorogenic acid: Treat extract containing chlorogenic acid with aqueous ammonia and expose it to air. Green color will appear gradually.

Plants, Containing Tannins a) Hamamelis Botanical origin: Family: Part used:

Hamamelis virginiana. Hamamelidaceae. Dried leaves.

 Collection: Leaves are collected throughout summers. Drying is done in open air, preferably under shade to preserve green color.  Constituents: • Gallitannins • Ellagitannins • Free gallic acid • Pro-anthocyanadins • Hamamelase  Uses: • Astringent • Anti-hemorrhagic • Anti-inflammatory • Anti-carcinogenic

b) Catechu Botanical origin: Family: Part used:

Uncaria gambir Rubiaceae Dried aqueous extract from leaves and young twigs.

 Collection: Boil leaves and twigs in water. Evaporate to a pasty consistency. Paste is put in cubes and dried in sun.

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Lecture: Tannins + Lipids + Oils + Waxes  Constituents: • Catechin • Catechutannic acid • Catechu red • Quercitin • Gambir flourescin  Uses: • Astringent • Dying • Tanning industry

c) Nutt gall Botanical origin: Family: Part used:

Quercus infectoria. Fagaceae. Galls obtained from twigs.

 Formation of galls: Galls are pathological outgrowth formed on twigs of tree. Galls arise due to deposition of eggs by small insect Adleria galactinctoria. Steps are; • Early summers, insects lay eggs on twigs • Larvae come out from eggs and enter soft epidermis. • Larvae secretes enzyme that stimulates abnormal growth around larvae. • Starch in the tissue gets converted to sugars and stimulate cell division. • Disappearance of starch causes cell shrinkage. • Central cavity is formed in which larvae and pupae grows. • Larvae remains in gall for 5-6months. • Mature insect bores the covering of gall and escapes away. • Galls are collected before escaping of insect.  Constituents: • Tannic acid • Gallic acid • Ellagic acid • Roburic acid • Syringic acid • Calcium oxalate crystals  Uses: • Haemostatic • Antidote for alkaloidal poisoning • Astringent

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Lecture: Tannins + Lipids + Oils + Waxes

LIPIDS INTRODUCTION Lipids constitute a broad group of naturally occurring molecules which include waxes, fats, sterols, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids and others. FIXED OILS Fixed oils are esters of fatty acid with glycerol. PROPERTIES        

Non-irritant Odorless Tasteless Non-volatile Insoluble in water and soluble in organic solvents Produce greasy mark on paper Upon heating strongly, undergo decomposition Upon hydrolysis, yield glycerol and fatty acid

CHEMISTRY Fixed oils are esters of fatty acid with glycerol. These may be;  Monoglycerides  Diglycerides  Triglycerides CLASSIFICATION On the basis of their ability to absorb Oxygen from air; these are classified as: a) Drying oil b) Non-drying oil c) Semi-drying oil a) Drying oil when exposed to air, undergo oxidation and form tough and hard film. These are usually used in paints and varnishes. For example; Linseed oil

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Lecture: Tannins + Lipids + Oils + Waxes

b) Non-Drying oil These oils neither undergo oxidation nor form tough and hard film. For example; Olive oil c) Semi-Drying oil When exposed to air, undergo little bit oxidation and form tough and thin film. For example; Cotton seed oil METHODS OF OBTAINING FIXED OILS  Direct expression  Solvent extraction  Steam treatment + extraction

COTTON SEED OIL Botanical origin:

Gossypium herbaceum

Family:

Malvaceae

Part used:

Seeds

Collection:

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Lecture: Tannins + Lipids + Oils + Waxes Constituents: Glycerides of;

Uses:  Food



Linoleic acid

 Emollient



Oleic acid

 Vehicle for injections



Palmitic acid



Stearic acid



Arachidic acid



Myristic acid

 Preparation of hydrogenated vegetable oils  Soap manufacture

Toxicity: Occur due to intravenous administration of Cottonseed oil emulsion. Acute toxicity includes following symptoms;       

Fever Pain in back or chest Nausea Vomiting Headache Tachycardia Dizziness

Chronic toxicity includes following symptoms;  GIT bleeding  Mild anemia  Defects in blood clotting Treatment of toxicity:  IV hydrocortisone sodium succinate 50grams  Promethazine 50mg  Heparin (to aid clearance of fat from circulation)

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Lecture: Tannins + Lipids + Oils + Waxes

CASTER OIL Botanical origin:

Ricinus communis

Family:

Euphorbeaceae

Part used:

seeds

Collection:

Constituents: Glycerides of;  Ricinoleic acid  Oleic acid  Linoleic acid  Stearic acid Toxicity: Excessive oral administration in larger doses Results in toxicity Symptoms include;     

Nausea Colic Vomiting severe purgation Electrolyte imbalance

Uses:  Purgative  Emollient  Preparation of zinc and castor oil ointment  Sterilized castor oil as soothing agent in eye  Oily vehicle for eye drops 12

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Lecture: Tannins + Lipids + Oils + Waxes

LINSEED OIL Botanical origin:

Linum usitatissimum

Family:

Linaceae

Part used:

Seeds

Constituents: Glycerides of; 

Isolinoleic acid



Linoleic acid



Stearic acid



Myristic acid



Palmitic acid

Uses:  In veterinary medicine as Purgative

OLIVE OIL Botanical origin:

Olea europaea

Family:

Oleaceae

Part used:

Ripe fruit

Constituents: Glycerides of;     

Uses:

Oleic acid Linoleic acid Stearic acid Arachidic acid Palmitic acid

   

Laxative Nutrient Emollient Demulcent

PEANUT OIL Botanical origin:

Arachis hypogaea

Family:

Leguminosae

Part used:

Seeds

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Lecture: Tannins + Lipids + Oils + Waxes Constituents: Glycerides of;       

Oleic acid Linoleic acid Stearic acid Arachidic acid Behenic acid Lignoceric acid Palmitic acid

Uses:

 Vehicles in emulsions, liniments, plasters, soap  Ink manufacture  Preparation of hydrogenated vegetable oil

CORN OIL Botanical origin:

Zea mays

Family:

Gramineae

Part used:

Embryo

Constituents: Glycerides of; 1. 2. 3. 4. 5. 6. 7.

Oleic acid Linoleic acid Stearic acid Arachidic acid Palmitic acid Myristic acid Lignoceric acid

Uses: 1. 2. 3.

Vehicles in pharmaceutical and cosmetic preparation Solvent for injections Nutrient

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Lecture: Tannins + Lipids + Oils + Waxes

SWEET ALMOND OIL Botanical origin:

Prunus amygdalus

Family:

Rosaceae

Part used:

Seeds

Constituents: Glycerides of; 1. 2. 3. 4.

Oleic acid Linoleic acid Palmitic acid Myristic acid Uses:

5. 6. 7. 8.

Nutrient Demulcent Emollient Preparation of cold creams, hair lotions and toilet articles

COCONUT OIL Botanical origin:

Cocos nucifera

Family:

Palmae

Part used:

Dried solid part of endosperm

Constituents: Glycerides of; 1. Lauric acid 2. Myristic acid 3. Capric acid 4. Caprylied acid 5. Caproic acid 6. Oleic acid 7. Palmitic acid 8. Stearic acid

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Lecture: Tannins + Lipids + Oils + Waxes Uses:    

Nutrient Confectionaries Cosmetics Ointment base MUSTARD OIL

Botanical origin:

Brassica juncea

Family:

Cruciferae

Part used:

Seeds

Constituents: Glycerides of;    Uses:    

Linoleic acid Oleic acid Erucic acid

Nutrient Rubefacient In preparation of liniments In massages SESAME OIL

Botanical origin:

Sesamum indicum

Family:

Pedaliaceae

Part used:

Seeds

Constituents: Glycerides of;  

Linoleic acid Oleic acid

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Lecture: Tannins + Lipids + Oils + Waxes   

Stearic acid Palmitic acid Arachidic acid

And other components include;  

Sesamin sesamolin

SAFFLOWER OIL Botanical origin:

Carthamus tinctorius

Family:

Compositae

Part used:

Seeds

Constituents: Glycerides of;      

Palmitic acid Stearic acid Arachidic acid Oleic acid Linoleic acid Linolenic acid

Uses: 

Nutritive

SUNFLOWER OIL Botanical origin:

Helianthus annus

Family:

Compositae

Part used:

Seeds

Constituents:

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Lecture: Tannins + Lipids + Oils + Waxes Glycerides of;      

Palmitic acid Stearic acid Arachidic acid Oleic acid Linoleic acid Behenic acid

Uses:  Nutritive  Preparation of hydrogenated products  Preparation of paints, varnishes and soap

THEOBROMA OIL Botanical origin:

Theobroma cacao

Family:

Sterculiaceae

Part used:

Seeds

Constituents:   

2% Theobromine 40-60% solid fat Mucilage

Uses:    

Ingredient in cosmetic ointment in pharmacy for coating pills Preparation of suppositories Diuretic

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Lecture: Tannins + Lipids + Oils + Waxes

LENOLIN Lanolin is also called wool wax or wool grease. It is a yellow waxy substance secreted by the sebaceous glands of wool bearing animals. Most lanolin used by humans comes from domestic sheep.

Constituents: A typical high purity grade of lanolin is composed predominantly of;  long

chain waxy esters

 lanolin alcohols  lanolin acids  lanolin hydrocarbons It has been estimated that there may be between 8,000 and 20,000 different types of lanolin ester present in lanolin. Production: Lanolin is extracted by washing the wool in hot water with a special wool scouring detergent to remove dirt, wool grease (crude lanolin), suint (sweat salts), and anything else stuck to the wool. The wool grease is continuously removed during this washing process by centrifugal separators, which concentrate the wool grease into a wax-like substance melting at approximately 38 °C (100 °F). Applications:  Lanolin and its many derivatives are used extensively in high value cosmetics, facial cosmetics, lip products etc  Lanolin is used commercially in many industrial products ranging from rust-proof coatings to lubricants.  Lanolin is often used as a raw material for producing cholecalciferol (vitamin D3).  Anhydrous lanolin is also used as a lubricant for brass instrument tuning slides.  Lanolin can also be restored to woolen garments to make them water and dirt repellent.

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Lecture: Tannins + Lipids + Oils + Waxes

BEES WAX Zoological origin:

Apis mellifera/ Apis dosarta/ Apis cerana/ Apis indica/ Apis florea

Family:

Apidae

Source:

Bee hives

Production: Worker bees have eight wax-producing mirror glands. The size of these wax glands depends on the age of the worker and after daily flights begin these glands gradually atrophies. The new wax scales are initially glass-clear and colorless becoming opaque afterwards. The wax of honeycomb is nearly white, but becomes progressively more yellow or brown by incorporation of pollen oils and propels.Honey bees use the beeswax to build honeycomb cells. In which their young are raised and honey and pollen are stored. For the wax-making bees to secrete wax, the ambient temperature in the hive has to be 33 to 36°C (91 to 97 °F).To produce their wax, bees must consume about eight times as much honey by mass. When beekeeper extracts the honey, they cut off the wax caps from each honeycomb cell with an uncapping knife or machine. The wax may further be clarified by heating in water. Constituents: Beeswax is a tough wax formed from a mixture of several compounds. Its main components are;     

Palmitate Palmitoleate Hydroxypalmitate oleate esters of long-chain (30-32 carbons) Aliphatic alcohols with the ratio of triacontanyl Palmitate to cerotic acid, the two principal components, being 6:1.

Applications:  Making of honeycomb foundation  Beeswax is an ingredient in surgical bone wax  Purified and bleached beeswax is used as:  Coating for cheese  Protectant of the food as it ages  Food additive  As a component of shoe polish, furniture polish

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Lecture: Tannins + Lipids + Oils + Waxes

 As a component of modelling waxes

JOJOBA OIL Botanical origin:

Simmondsia chinensis

Family:

Simmondsiaceae

Part used:

seeds

Constituents: This oil is rare in that it is an extremely long (C36-C46) straight-chain wax ester Uses:  In cosmetics as a moisturizer  As a carrier oil for specialty fragrances  Bio-diesel fuel for cars and trucks  Biodegradable lubricant.

SPERMACETI Source: Spermaceti is a wax present in the head cavities of the whale i.e. Physeter macrocephalus. Extraction: Spermaceti is extracted from oil by Crystallization at 6 °C. When treated by pressure and a chemical solution of caustic alkali, spermaceti forms brilliant white crystals that are hard but oily to the touch, and are devoid of taste or smell.

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Lecture: Tannins + Lipids + Oils + Waxes Uses:      

Ingredient in cosmetics Leather working Lubricants Making of candles Dressing of fabrics Pharmaceutical excipient (in ointments) CARNAUBA WAX

Botanical origin:

Copernicia cerifera/ Copernicia prunifera

Family:

Arecaceae

Part used:

Leaves

Constituents: Carnauba consists mostly of;     

Aliphatic esters Diesters of 4-hydroxycinnamic acid ω-hydroxycarboxylic acids Fatty acid alcohols Methoxy cinnamic acid

Uses:       

Automobile waxes Shoe polishes Dental floss Food products such as sweets, Floor and furniture waxes and polishes Use for paper coatings Emollient

FATS VS FIXED OILS Fats

Fixed oils

 Solid at room temperature

 Liquid at room temperature

 Contain saturated glycerides e.g. glyceryl stearate

 Contain unsaturated glycerides e.g. glyceryl oleate

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Lecture: Tannins + Lipids + Oils + Waxes VOLATILE OILS VS FIXED OILS Volatile oils

Fixed oils



Volatilize at room temperature



Don't get volatiles at room temperature



Obtained by distillation



Obtained by extraction



Leave no spot after evaporation



After evaporation, do leave spot



Cannot be saponified



Can be saponified



Mixtures of oleoptenes and stereoptenes



Esters of fatty acid with glycerol



High refractive index



Low refractive index

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