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Introduction to Pharmacognosy

Introduction to pharmacognosy

Initially it was known as ‘ material medica ’

‘ Pharmakon ’ – ‘drug’ + ‘gignoso ‘ – to acquire knowledge of ‘= ‘pharmacognosy ‘ – knowledge or science of drugs [ latin]

‘Pharmacognosy’ coined by C.A. Seydler [ later found J.A. Schmidt used the term before ]

Definition :

Pharmacognosy is the study of medicinal uses of various naturally occurring drugs its history sources , distributions , methods of cultivation , active constituents , medicinal uses identification test preservation methods substituents and adulterants.

History

[Shang dynasty ] (1766-1122BC)

Inscription on oracle bones discovered in illness medicine and medical treatment

Earliest medical treatment existing in China – Silk banners and bamboo slips.

Most important clinical manual of traditional Chinese medicines – Shang Hang Lun ( treatment on the treatment of Acute diseases caused by cold) – written by Chang-Chug-Ching

It has a companion book ‘ Chin Kuli yao Lue’

(Prescription from the golden Chamber)

These two are the origin of the most important classical herbal formulas that are the basis of Chinese and Japanese – Chinese Herbalism.

‘Pen T‘sao Jing Ji Zhu’ (Commentaries on the herbal classic) by Tao Hong Jing

730 herbs (6 categories)

Stone (minerals)

Grass and trees

Insects and animals

Fruit and veg

Grains

Named but unused

Ancient Egypt

Ebbers papyrus (1550 BC) [800 prescription,700 drugs]

Edwin Smith Papyrus (1600 BC) [Surgical instruction and formulas for cosmetics]

Kahun medical Papyrus (1900 BC) [Health of women , birthing instruction ]

Ancient India

Med prep of plant – Rigveda and Atharvaveda (3500-1500BC) Developed Ayurveda

Ancient Greece and Rome

Hippocrates (460-370BC) – Father of medicine

Aristotle (384-322BC) – Animal kingdom

Theophrastus (370- 287 BC) – Student of Aristotle

Galen (B1 –AD200)- Method of preparation of plant and animal drug

Known as ‘ chemicals’ in his honour

Development of modern Pharmacognosy took place later during 1934-60

Development mainly due to following 4 events

Isolation of Penicillin (1928) – William Fleming

Isolation of Reserpine from rauwolfia wod road

Hypotensive and tranquillising properties

Isolation of Vinca alkaloids- Vincristine – Leukaemia- anticancer

Isolation of Steroid hormone like progesterone

Important aspect of natural products that led to the modern development of drugs and Pharmaceuticals

Isolation of phytochemicals:

Alkaloid from belladonna , ergot , morphine etc

SAR :

Hypotensive and tranquilizing actions of reserpine are attributed to trimethoxy benzoic acid moiety.

Drugs from partial synthesis of natural products:

In ergetamine , by 9:10 hydrogenation , oxytocic activity is suppressed and spasmolytic activity increased

Natural products as models for synthesis of new drugs:

Morphine for potent analgesics

Atropine for spasmelytics

Drugs of direct therapeutic uses:

Antibiotics, steroids, ergot alkaloids and certain antitumor substances.

Biosynthetic pathways:

Calvin’s cycle of photosynthesis

Shikimic acid pathway of aromatic compounds .

Pharmaceutical aids:

Acacia and tragacanth – binding and suspending agent

Sterculio and tragacanth – bulk laxative

Ishabgul and linseed – Demulcents

Saponin – detergent

Scope and development of cognosy

Pharmacognosy predominantly entails ‘ crude drugs ‘ of natural origin that are duly derived from

Plant sources

Animal sources

Minerals sources

Their active chemical constituents.

These attributes to the ‘ Core subjects matter of pharmacognosy ‘

Crude drugs – not only therapeutic utility

Used in cosmetic , textile , food and nutraceutical industries .

1800 – 1850 BC – ‘ Apothecaries ‘

Stocking crude drugs for the preparation a host of useful products such as

Herbal tea mixture

Various type of tincture

Extracts and juice invariably used for preparing

Medicinal drops

Syrups

Infusions

Ointments / liniments

1850 – 1900 BC – Growth in fields of ‘ medicinal plant ‘

Phytochemists did isolation and characterization of pure ‘ active plant constituent ‘

These active components knocked out the crude drugs by semisynthetic/ synthetic medicines

Herbal drug fate brighten gradually.

1900-2000 BC – Modern Pharnacognosist have better knowledge and understanding of

Active constituents

Prominent therapeutic efficacy on human ailments

Both scientist and researchers are broadly exploring

Clanical plant sources

Allied plant species that contains either identical or similar types of constituents.

Ongoing researches are

Marine flora and fauna

Genetic engineering aspects

Tissue culture biotech

Futuristic growth – Anti-neoplastic profile

Hypoglycemic activity

Hepatoprotective profile

Hypotensive property

Anti-fertility activity

Anti-inflammatory profile

Antipsychotics activity

General tonics ( rejuvenation phenomenon).

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