Introduction to Pharmacognosy and Phytochemistry
DEFINITION
• The
word Pharmacognosy is derived from the Greek "Pharmakon",
meaning a drug or poison and “gignosis" meaning to acquire knowledge
of and literally meaning “the entire knowledge of drug”.
• The
scientific study of the structural, physical, chemical and sensory
characters of crude drugs of vegetable, animal and mineral origin.
• includes
also their history, cultivation of
the medicinal plants producing them and methods involved for their collection and other particulars
related to the treatment they received during their passage from the producer
to the distributor or pharmacist and Storage
HISTORY
Contribution of the Scientists in Significant
Development of Pharmacognosy:
Hippocrates (460-370 B.C),
a Greek scientist, is known as the father of medicine. He worked on human
anatomy and Physiology, particularly circulatory system and nervous system. He
prepared famous oath for physicians, which is still taken by them.
Further Aristotle (384-322 B.C)
and Theophrastus (370-287 B.C), well known philosopher and scientist are
known for their writing animal and plant kingdom respectively. Dioscorides (1st
Century AD), a Greek Physician, published five volumes of a book, entitled “De
Materia Medica” in 78 AD, in which the described more than 600 medicinal plants
with their collection, storage and uses. Pliny de Elder (23-70 AD), a Greek
botanist, collected and described a large number of medicinal plants with their
uses
• The
practice of using herbs to cure disease is as old as human civilization but a
drastic change is observed in its practice, as compared to that era.
• It
is solely possible due to the contributions of many known and unknown
scientists.
• Plants
were used medicinally in India, China, Egypt and reporting or documenting the
proof of herbs using effectively.
Dioscorides
(40-80 AD) (600
medicinal plants) Hippocrates He was a Greek philosopher and referred to as
Father of Medicine, because he gave a structure to the medical profession,
which is being carried on till date. He relied on reasoning and logic
instead of blind faith. He brought nobility to the profession. Authors
of antiquity
“De Materia Medica”
Hippocrates (460-377 BC)
“The Father of Medicine”
Crr. A Seydler: Father of Pharmacognosy Seydler was a German scientist and he wrote a book “Analecta Pharmacognostica’’ in 1815. In that book he introduced the word Pharmacognosy. He coined this word first time by combining two Greek words “Pharmakon”: Drug “Gignosco”: To acquire knowledge of. Hence Pharmacognosy means to acquire knowledge about drugs. |
Galen change the way of utilizing herbs, when he introduced the concept of formulations for some of the drugs. He also prepared some solutions, which are referred as galenicals, after his name. He had accumulated many herbs in his apothecary for various ailments. He is known as the first Pharmacist.
He was emperor of china. He
wrote a document known as Herbals Pen T-Sao. In that he mentioned the 365 drugs
for 365 days of year. The same emperor is believed to have discovered famous
beverage like tea, accidently.
Papyrus Ebers:
Aristotle was the teacher of Alexander the Great. His work has the profound importance in the development of science, on the basis of his thinking and applied knowledge.
Charak
Charak complied a group of ten herbs that related to a
certain disease. He made 50 such groups which cover almost all the drugs
required by physicians for treatment. Then he wrote the book Charak Samhita.
Sushruta arranged a large number of drugs into distinct sets depending on their properties. He was one who introduced the practice of surgery. He arranged all his meticulous work into his book Sushruta Samhita
The history of pharmacognosy is as old as human existence. To know the future one should know the past. The word ‘drug’ is derived from Latin term Droog means dried, when dried plants were commonly used as medicine. Broadly, history of pharmacognosy can be classified into three major stages.
First stage before eighteenth century, very few documents and recorded
evidences are available showing use of natural products by human. Second stage
involves nineteenth century, which is the time when basic subject has evolved.
In this century, the name pharmacognosy came into practice.
Initially the subject was more likely to descriptive botany of medicinal
plants. But as the time progress, it changes the course and encompasses
extraction, isolation and other advances techniques. In twentieth
century, which may be considered as third stage of development, series of
discoveries resulted in complete metamorphosis of the subject. From last
two decades, pharmacognosy is studied in more systematic manner.
As herbal wave continue to sweep the world, importance of natural
product is at the pinnacle. People are expecting natural products to fit in
modern framework. As a result of this there are series of new herbal
formulations in the market.
The development of modern Pharmacognosy began during
the period of 1930-1960 by the application of a broad spectrum of biological
and socio-scientific subjects, including botany, ethno botany, medical
anthropology, marine biology, microbiology, herbal medicine, chemistry,
biotechnology, phytochemistry, pharmacology, pharmaceutics, clinical pharmacy and
pharmacy practice along with modern analytical techniques like paper and thin
layer chromatography (TLC), gas chromatography (GC), High performance liquid chromatography
(HPLC), Extreme and ultra-pressure liquid chromatography (XLC, UPLC), high
pressure thin layer chromatography (HPTLC), Mass spectroscopy, Liquid
chromatography combined with mass spectroscopy (LC/ MS), High Resolution Mass
Spectroscopy (HRMS) etc. During this period isolation, structure elucidation
and various pharmacological activity of different phytoconstituents were
studied. Examples like isolation of penicillin in 1928 by Alexander Fleming
from microorganisms and later on commercial production of the same in 1941 by
Florey and Chain.
SCOPE
OF PHARMACOGNOSY
Pharmacognosy is critical in development of different disciplines of
science. A pharmacognosist should possess a sound knowledge of the terms used
to describe the vegetable and animal drugs as covered under botany and zoology,
respectively. The knowledge of plant taxonomy, plant breeding, and plant
pathology and plant genetics is helpful in the development of cultivation
technology for medicinal and aromatic plants. Plant - chemistry
(phytochemistry) has undergone significant development in recent years as a
distinct discipline. It is concerned with the enormous variety of substances
that are synthesized and accumulated by plants and the structural elucidation
of these substances. Extraction, isolation, purification and characterization
of phytochemicals from natural sources are important for advancement of
medicine system. The knowledge of chemotaxonomy, biogenetic pathways for
formation of medicinally active primary and secondary metabolites, plant tissue
culture and other related fields is essential for complete understanding of
Pharmacognosy. One should have the basic knowledge of biochemistry and chemical
engineering is essential for development of collection, processing and storage
technology of crude drugs.
• About
80% of world population directly or indirectly depends on herbs for relieving
the disease and keeping them healthy.
• Many
of drugs today are being derived from herbs molecules.
• Many
new molecules every year are being introduced through this field alone, so it
is great source of lead molecules.
• Marine
sources possess about 5 Lakh species with lots of possibilities of developing
medical purpose.
• Source
of natural drug improves the importance of plants and animals.
• Beneficial
against allopathic medicine because of less chances of toxicity issue to human
being
• These
are less cost effective formulations.
•
DEVELOPMENT
OF PHARMACOGNOSY
ü Modern
Pharmacognosy occurred during 1934 - 1960.
This
development was mainly due to some events like
ü Discovery
of Penicillin in 1928 by Alexander Fleming
ü Isolation
of Resperine 1952
ü Anticancer
properties of Vinca rosea
ü Discovery
of Dioscorea was utilized to prepare semisynthetic
ü Steroidal
hormones.
ü Pharmacognosy
as an applied science.
ü It
played a crucial role in the development of different disciplines of science.
ü Some
isolated components from plants were made into different formulations and used
as drugs
APPLICATIONS
OF PHARMACOGNOSY
1. Plant Bioactive extraction and isolation:
The extraction of plant material and isolation of plant constituents typically
require tedious protocols that are essential for isolating biologically active
compounds and understanding their role in disease prevention and treatment.
Bioactives isolated from leaf, stem, root, bark, flower, fruit, seed or other
plant materials are often identified using a Bioassay-Guided approach. This
type of approach is useful for the investigation of alkaloids, antioxidants,
bioflavonoids, terpenoids and other compounds as promising therapeutics from an
immense pool of plant biodiversity.
2. Development of plant biomarkers:
DNA fingerprinting is the technique based on the use of polymerase chain
reaction (PCR), to reveal the specific DNA profile of a particular organism
which is as unique as a fingerprint. DNA fingerprinting can distinguish plants
from different families, genera, species, cultivars and even sibling plants.
Chromatographic techniques such as High Performance Thin-Layer Chromatography
and High Performance Liquid Chromatography give the profiling of various secondary
metabolites of a plant. Combining the use of DNA fingerprinting and chemical
fingerprinting will be an effective tool in authentication and quality control
of herbs. Some examples of biomarkers are:
(a) Curcumin isolated from Curcuma longa rhizome which
is recently under clinical trial for curing head and neck squamous cell
carcinoma.
(b) Withanolide-D isolated from Withania somnifera
roots, the recent clinical trial projected that it induces apoptosis in
leukemia.
3. Development of nano fertilizers and nano medicines:
Nanotechnology in drug delivery is exemplified by nanocrystals, liposomes,
nanoparticle-protein conjugates, magnetic nanoparticles, nanogels and
biodegradable nanoparticles. Fertilizer particles can be coated with nano
membranes that facilitate slow and steady release of nutrients thereby reducing
loss of nutrients and enhancing its use efficiency of medicinal plants
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