Pharmacognosy: A Comprehensive Guide to Medicinal Plants and Natural Products

Posted on May 22, 2024 in Biology

Identification Test for Alkaloids

Mayer’s reagent (Potassiomercuric iodide solution)—Take the alkaloid materials → Mix with the Mayer’s reagent → then obtained cream color ppt.
Wagner’s reagent (Solution of iodine in potassium iodide)—Take the alkaloid materials → Mix with the Wagner’s reagent → then obtained brown or reddish brown ppt.
Hager’s reagent (Saturated solution of picric acid)—Take the alkaloid materials → Mix with the Hager’s reagent → then obtained yellow color ppt.
Dragendroff’s reagent (Potassium bismuth Iodide)—Take the alkaloid materials → Mix with the Dragendroff’s reagent → then obtained reddish brown ppt.
Murexide reagent (Ammonium purpurate)— Take the alkaloid materials → Mix with the murexide reagent → then obtained purple color ppt.

Pharmacognosy

Pharmacognosy is the study of crude drugs obtained from the plant, Animals and Minerals sources. The word Pharmacognosy is derived from Greek word Pharmakon: A Drug  Gignosco : To acquire the knowledge .

History of Pharmacognosy

Egyptians wear aware of medicinal uses of several plants and animals and also about human anatomy. The Greek physician Hippocrates (460- 360 B.C) known as ‘Father of medicine’ Aristotle the renowned philosopher (384 – 322 B.C.) is well known for his studies on animal Kingdom and Theophrastus (370 – 287 B.C.) for the plants Kingdom. Pedanius Dioscorides, (040- 080 A.D.) A Greek physician in 78 A.D. described several plants of medicinal importance in “De Materia Medica”.

Scope of Pharmacognosy-

Pharmacognosy has wide and broad scope in the field of Pharmacy and its branches of them are given following:- 1) Cultivation and domestication of the medicinal plants. 2) Analysis and Phytochemical 3) Preparation of general tonic and stimulation. 4) The steroid industry 5) Herbal Preparation herbal medicine 6) Flavoring agent and perfumes. 7) Tissue Culture 8) Phytomedicine 9) Natural Products.

Omega-3 fatty acids

Biological Source:

 These are found in cold water fishes like cod, salmon, tuna, sardines blue fish, marc kevel and herring.  These are also reported in cold weather bean-oil plants like flax seed, canola, walnuts, soyabean and freshly ground wheat germ.

Pro-biotics

 These are the living microorganisms which when taken with or without food improve the intestinal microbial balance and in turn functioning of the large intestine.  These microorganisms exert their efforts by producing substances and conditions which inhibit the growth of harmful bacteria in the large intestine.  Pro-biotics include bifidobacterium and Lactobacilli species such as L. acidophillus.

Therapeutic Applications:

 It is used in diarrhoea, colon cancer, allergy and cardiovascular disease.

Prebiotics

 They are the nutraceuticals which promotes the flourishing of probiotics.  The probiotics microorganism have to survive the digestive enzymes and acids in the upper gut.  To overcome this problem nutraceuticals in the form of prebiotics are available.  Prebiotics are the food substance which reach to colon in intact from without getting depleted by gastric pH and digestive acids.  Prebiotic was described as “a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health”.

Therapeutic Applications:

 Probiotics have been shown to promote health benefits in many diseases related to an unbalanced GIT microbiota.

Tannins

— The name ‘tannin’ is derived from the French and is used for a range of natural polyphenols. Tannins are secondary metabolites complex organic, non-nitrogenous, phenolic, plant products, which generally have astringent properties.

Classification of tannin compounds

— On the basis of Goldbeater’s skin test it is divided into two major groups.

I. Pseudo tannins— Those tannins which are partly retained by the hide power and fails to give the test, are called as pseudo tannins.

II. True tannins— Those tannins which shows the maximum hide power and give the positive test are called as true tannins.

On the basis of hydrolytic reaction it is further divided into two groups: –

a. Hydrolysable/Pyrogallol tannins— These tannins are easily hydrolysable by mineral acid or enzymes. Their structure involves several molecule of polyphenolic acids are bounded through ester linkage to a central glucose molecule. On the basis of hydrolysis product it is divided into two part.

 Gallotannins composed of gallic acid.  Ellagitannins composed of hexahydrodiphenic acid.

Ayurveda

-indian system of medicine

 Ayurveda, a natural system of medicine, originated in India more than 3,000 years ago.Ayurveda is based on the hypothesis that everything in the universe is composed of five basic elements viz. Space, air, energy, liquid and solid .  They exist in human body in combined forms like VATA (space and air), PITTA (energy and liquid )  and KAPHA (liquid and solid ) .  Vitta,pitta and kapha together are called Tridosha ( three pillers of life ).  It believed that they are harmony with each other , but in every human being one of them is dominating which ,in turn is called saptadhatu viz. Rasa (lymph) ,Rakhta (blood) ,meda ( adipose tissue ) , mamsa (flesh) , majja ( nervine tissue) , shukra ( reproductive tissue ) and asti ( bones ) . .

Homoeopathic system

of medicine –

 It was developed in the late 1700s in Germany. It’s common in many European countries, but it’s not quite as popular in the United States. Homoepathy is a medical system based on the belief that the body can cure itself. Those who practice it use tiny amounts of natural substances, like plants and minerals. They believe these stimulate the healing process.  In the homoepathy system ,the drug treatment is not specified , but the choice of drug depends on symptoms and the clinical condition of the patients .this is based on the concept of proving and prover.  The drug are extracted in the form of mother tincture , which is further diluted in terms of decimal or centesimal potencies.

Unani system of medicine

–

 The roots of this system go deep to the times of the well known greek philosopher Hippocrates who is credited with it .The history of Unani medicine can be characterized by the work of its practitioners, or hakims, who relied on natural healing based on principles of harmony and balance, uniting the physical, mental, and spiritual realms. The Unani system of medicine aims at treating the cause of disease and not its symptoms. For this purpose , thorough history of the patient is recorded in addition to his pulse , urine and stool examination .

Siddha system of medicine

–

 The term “siddha” means achievement and ‘siddhars’ were saintly personalities, who attend proficiency in medicine through practice of bhakti and yoga . according to traditional belief Lord Shiva unfolded the knowledge of medicine to knowledge of medicine to his wife parvati which was then passed to Siddhars. The identification of causative factors of disease is done through pulse reading , colour of body, study of voice ,urine.

Cinchona ( Anti malarial )

Synonyms : Jesuit’s bark, Peruvian bark. Family: Rubiaceae Biological source:- It is dried bark of cultivated trees of cinchona Calisaya wedd. Chemical Constituents:- Cinchona contains alkaloids. It consists of approximately 30 types of alkaloids like:- Quinidine, Quinine, cinchonine, cinchotannic acids etc. Uses:-  It is used in stomachic and tonic.  It used in treatment of antimalaria  It is used as antiseptic  It is used to treatment dyspepsia and gastric catarrh.

Rouwolfia(Antihypertensive ) Synonyms:- Rouwolfia root, snake-root, chhotachand Family:- Apocynaceae Biological source:- It consists of dried roots of the plant known as Rouwolfia serpentinaChemical Constituents:- The chemical constituents of rauwolfia are alkaloids. Also it contain phytosterol, fatty acids, Reserpine and rescinnamine are alkaloids which have main therapeutical effect in rauwolfia. Therapeutic efficacy:  Rauwolfia has been studied for the treatment of mental diseases,  Rauwolfia treated migraine headaches effectively

(Anti-Dysenteric ) Ipecacuanha- Synonyms: Ipecac Family:- Rubiaceae Biological source : It consists of dried roots or the rhizomes of Cephaelis ipecacuanha Chemical Constituents: • It contain cephalis acuminata and cephalis ipecacuanha, alkaloids, cephalis psychotrine and ematamine. • The root also contain ipecacuanhic acid, glycoside ipecacuanhin, starch and calcium oxalate. Therapeutic efficacy: • Ipecac is emetic and used as an expectorant and diaphoretic and in the treatment of amoebic dysentery.

Almond oil

Source: Almond oil is a fixed oil obtained by expression from the seeds of Prunus amygdalus. Chemical Constituents:- Bitter almond contains fixed oil (40-50 percent), Protein (20 percent), enzyme emulsin and bitter glycoside amygdalin (1-3 percent). It also contains volatile oil (0.5 percent). Amygdalin gives benzaldehyde and hydrocyanic acid upon hydrolysis. Bitter almond oil contains 80 percent benzaldehyde and 2-6 percent hydrocyanic acid. Therapeutics Use:-  Inflammation  Immune changes  Impaired wound healing

TULSI

Synonyms- Sacred basil, Holy basil. Biological Source- Tulsi consists of fresh and dried leaves of Ocimum sanctum Linn., belonging to family Labiatae. Chemical Constituents-Tulsi leaves contain bright, yellow coloured and pleas-ant volatile oil (0.1 to 0.9%). The oil content of the drug varies depending upon the type, the place of cultivation and season of its collection. The oil is collected by steam distillation method from the leaves and flowering tops. It contains approximately 70% eugenol, carvacrol (3%), and eugenol-methyl-ether (20%). It also contains caryophyl-lin. Seeds contain fixed oil with good drying properties.

Squill Synonyms: Sea onion, sqring squill, sea squill, scilla. Biological source: Squill consists of the dried slices of the bulb of white varity of Urginea maritima Linn. Chemical Constituents: Squill contains cardiac glycosides of buffadienolides types scillaren A and B and enzymes scillatenase. The other chemicals present in proscillaridin, flavonoid, mucilage, volatile substance and sinistrin. Uses:  It is used in asthama.  It is a potential substitute for foxglove in aiding a failing heart.

Pharmaceutical Aids:- The drugs and substance which have no or little pharmacological effect but they are essentially used in the preparation of pharmaceutical dosage form like tablet, injection, emulsion etc

Kaolin:- Synonyms:- China clay, kaolin umproderesum, porcelain clay. Source:- kaolin is a purified native hydrated aluminium silicate free from gritty particles. It obtained by powdering the native kaolin, elutriation and collecting the fraction which complies with the requirements of particle size. Chemical Constituents:- Silicon dioxide, Iron oxide, titanium dioxide aluminium oxide etc.Uses:-  It is treatment for enteritis

Cod liver oil:– Synonym :- Oleum morrhi Family :- Gadidae Biological Source :- Cod liver oil is processed from fresh liver oil of cod fish godus morrhua and other species of godus Chemical Constitution :-  Glycerides esters of sat.acid of linoleic acid, oleic acid, myristic acid, Palmitic acid,Vit.A,VitD Uses :-  Source of vitamin  As nutritive  Treatment of Rickets and T.B.

Uses of cinchona- It is used in stomachic and tonic.  It used in treatment of antimalaria  It is used as antiseptic

Hyoscyamus Biological source:– It consists of dried leaves and flowering tops of the plant known as Hyoscymus niger Linn. Chemical Constituents:- It constituent of Henbane leaves is the alkoloid hyoscyamine, together with smaller quantities of atropine and hyoscine also known as scoplamine.Uses-It is used as antispasmodic hypnotic and mild diuretic.  It is used for relieve pain in cystitis.

Alkaloid containing drugs– Cinchona and rauwolfia

Punarnava Biological source:- It consists of fresh as well as dried herb known as Boerhaavia diffussa.Uses: • The herb is used as Diuretic and Expectorant.

Chemical test- Tragacanth solution(boil)+ 10% aq. Ferric chloride solution gives Deep yellow ppt

Adulterants for datura– hyopscyamine, atropine oldest written document of ayurveda -The Charaka Samhita Organoleptic evaluation is done by colour , odour, taste , size , shape , texture. Uses of pale catechu – It is used as astringent. It is used in leather and fabric industry. Tolu balsam Chemical Constituents:-  It contain large amount of benzyl cinnamyl esters of benzoic and cinnamic acid.

Ashwagandha: Biological source: It consists of the dried roots and stem bases of Withinia somnifera Dunal. Chemical Constituents: Ashwagandha contain the alkaloid withanine as the main constituent and somniferine, pseudo with anine, tropine, hygrine and steroid lactones. Uses:  They are used in treatment of nervous disorders.  It used to treat intestinal infection and leprosy.

Papaya – Chemical constituents- The enzymes, papain, papayaproteinase, and chymopapain, have been isolated in crystalline form from the latex. Papain is atypical protein digesting enzyme with isoelectric point. It contains 15.5% nitrogen and 1.2% sulphur

Adulterations

Adulterations are defined as admixture of genuine articles with spurious or harmful substances.Example:-  Mixture of Papaya seed with black pepper.  Mixture of power of brick into red chili powder.

Methods of adulterating the drugs

Following are the various methods used for drugs adulteration. A. Substitution with manufactured materials B. Substitution with Inferior material C. Substitution with Exhausted material. D. Substitution with cheap natural substance. E. Adulteration with non- plant material. F. Excessive adventitious matter. A. Substitution with manufactured materials:- This is done with artificially manufactured material which resembles various drugs in form and appearance. Example: – Paraffin wax has been colored yellow to substitute bee wax. B. Substitution with Inferior material:- Drug are sometimes adulterated and substituted with standard commercial material. The common example of substitution is adulteration of cloves by mother cloves. Saffron is adulterated with dried flowers of Carthamus tinctorius (Safflower).C. Substitution with Exhausted material. Exhausted material the vegetable residues which remain after the original material has been use for drug preparation. Example  The substitution of Alexandrian Senna with Arabian Senna.  Used of exhausted Clove and ginger for adulteration. D. Substitution with cheap natural substance. Sometimes drugs are adulterated with cheaper natural substance which has no relation to the genuine article. Example: – Japan wax for bees wax and sterculia gum for Tragacanth. E. Adulteration with non- plant material. Plant materials are sometime adulteration with worthless non-plant materials

Ergot Synonyms:- Ergot of rye Ergota Family : Hypocreaceae Biological Source: Ergot is the dried scleratium of a fungus Claviceps purpurea Chemical constituents:  It contain Potent indole alkaloids.  Ergometrine and ergometrinine are both water soluble chemical constituents of ergot.  Ergotamine,ergotaminine, ergosinine and ergosine are water insoluble chemical constituents of ergot. Uses:  Ergot is used in labour to assist delivery.  It used in the treatment of migraine.  Ergometrine is also known as Ergonovine.

Volatile oils are the odorous chemical substances which are easily evaporate when exposed to air at ordinary temperature. These represent essence of active constituents of the plants and hence also known as essential oil.

Classification of the volatile oils— On the basis of chemical nature it is divided into many partsi. Hydrocarbons— Example- Turpentine oil. ii. Alcohols— Example- Sandal wood oil, Peppermint oil. iii. Ketone— Example- Caraway, dill, fennel, camphor. iv. Aldehyde— Example- Lemon grass oil, Cinnamon oil, Saffron. v. Phenols— Example- Clove, Ajowan, Tulsi. vi. Phenolic ethers— Example- Nutmeg, calamus. vii. Oxides— Example- Cardamom, Eucalyptus, Chenopodium oil. viii. Esters— Example- Rosemary oil, Garlic, Gaultheria oil. Volatile are chemically derived from terpenes (mainly mono and sesqui terpenes) and their oxygenated derivatives .

Surgical dressing– The word surgical dressing is used to include all the materials either used alone or in combination to cover the wound.

Sutures– These are the sterile threads, strings or strands specially prepared for use in surgery meant for sewing tissue together. SUTURES must possess the following properties. A. A-They must be sterile and should cause no irritation. B. B- They are intended to be used for one occasion only. C. C- If absorbable, their time of absorbation must be known.

Surgical Catgut -Catgut is a type of string or cord that is prepared by the natural fibers, present in the cattle intestine. First time it is prepared by the sheep intestine fibres. It is also prepared by the many cattles intestine like goat, horses, donkey, etc. Catgut sutures finally treated with the chromium salt solutions to resists body enzymes and slow down their absorbation process, this sutures are widely used in surgical procedure and it is known as chromic catgut sutures.

Ideal Characteristics of Sutures- Eaisly degraded by the proteolytic enzyme.  Eaisly absorbable by the body.  Do not cause any irritation and allergic reaction. Uses/Applications  Catgut sutures are used in the surgical process at any accidental/trauma condition for blocking the excessive bleeding.  Also used in other surgical process like- tissue replacement, during delivery of baby, Cancer surgery, for wound healing.