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).
