D Pharma 1st Year || Pharmacognosy Notes || Chapter-1 || Introduction to Pharmacognosy ||

 Definition

Pharmacognosy:-  A branch of bioscience dealing with medicinal and related products of crude or primary type and obtained from plants, animals, and mineral origin. It can also be defined as the study of drugs obtained from natural origin. 

Pharmacognosy includes a broad spectrum of biological and socio-economic subjects such as botany, ethnobotany,  microbiology, herbal medicine, medical anthropology, marine biology, chemistry, biotechnology, clinical pharmacy, pharmacology, phytochemistry,  pharmaceutics, and pharmacy practice. 

The modern pharmacognosy study is divided into the following eight fields:

1. Medical Ethnobotany: 

This branch studies the traditional use of plants for medicinal use.

2. Phytotherapy: 

This branch studies the medicinal use of plant extracts.

3. Phytochemistry: 

This branch studies the chemicals obtained from plants. The branch also includes identification of new drugs of plant origin.

4. Ethnopharmacology: 

This branch studies pharmacological properties of traditional medicinal substances.

5. Zoopharmacognosy: 

This branch studies. the process by which animals self-medicate, that means  they treat and prevent diseases by using plants, soils, and insects.

6. Herbal Interactions: 

This branch studies the interactions between herbs and other drugs and body.

7. Pharmacognosy-Biotechnology:

 This branch studies the synthesis of natural bioactive molecules using biotechnology.

8. Marine Pharmacognosy:

 This branch studies the chemicals obtained from marine organisms.

 Present Status of Pharmacognosy

1) At present time, the people have realised that the use of natural occurring drugs are not only economical but even safer too.

2) Active constituents from naturally occurring drugs have lead to rapid developments in Pharmacognosy and Phytochemistry.

3) In present scenario, modern state of art facility like structure determination and pharmacological
screening are available.

4) Rapid developments in the fields of Chemistry Biochemistry and Pharmacology have further
supported advancemnents in Pharmacognosy.

5) Plants like podophyllum, liquorice, valerian, artimisia, veratrum were earlier considered to be less important but their re-evaluation has established their utility.

Scope of Pharmacognosy

In the 20h century, some important drugs (especially hormones and vitamins) were discovered from the animal kingdom. During this century, microorganisms have become an essential source of drugs. In the 21 century, chemistry and genetics were applied in plants to produce various new plant and herb varieties. 

Chromatography and many other extraction and isolation techniques were developed in this era for recognition of new medicinally useful chemical compounds (like citric acid). Scope of pharmacognosy for isolation, extraction, and development of new chemical constituents from medicinal plants was increased by the introduction of new branches of pharmacognosy.

These branches include medical ethnobotany, phytochemistry, ethnopharmacology, zoopharmacognosy, pharmacognosy-biotechnology, and marine pharmacognosy Thus, pharmacognosy made its progression steadily and formed the base and beginning of pharmacy and medicine. Pharmacognosy as an applied science has played an important role in developing different disciplines of science.

Scope of pharmacognosy is discussed below

1. Indigenous System of Medicines: Plants synthesise biologically active secondary metabolites due to which they are called a chemical laboratory. Based on the availability of medicinal plants as raw material, the WHO has emphasised the utilisation of indigenous system of medicines.

2. Synthetic Drugs and Antibiotics: The demand of pharmaceutical products of plant origin has increased due to the worldwide use of synthetic drugs and antibiotics.

3. Medicinal Plants: Medicinal plants are found distributed in almost all parts of India, thus it is the richest source of medicinal plants. Ayurvedic and Unani medicines are manufactured from the drugs supplied by the herb collectors and small traders.

4. Herbal Medicines: Since herbal medicines do not have any toxic or side effect (unlike the modern medicines), they have gained popularity in the recent years.

5. Novel Medicines: The evolution of novel medicines depends on pharmacognosy.

6. Plant Drugs and Remedies: Complex diseases like cancer and AIDS are treated by plant drugs and remedies, which are safer than the synthetic medicines.

7. Crude Drugs: Galenicals and therapeutically active substances are prepared using crude drugs, as they cannot be synthesised economically. Crude drugs obtained from medicinal plants also provide intermediates required for synthesising active compounds. Pharmacognosy provided a system in which the active principles of crude drugs can be dispensed, formulated, and manufactured in dosage forms accepted by the Allopathic medicine system.

8. Phytomedicines: The following natural plants are used as phytomedicines:

i) Artemisinin (antimalarial agent),

i) Taxol (anticancer agent),

ii) Forskolin (an antihypertensive),

iv) Rutin (used as vitamin P and a capillary

permeability factor), and

v) Piperine (enhances bioavailability).

9. Alkaloids, Gycosides, and Amtibiotics: A large number of these substances have been isolated, identified, and used as a curative agent.

10. Plant-Based Remedies: The interest in plant based remedies with a basic approach towards the nature increased in western world, when the people started becoming aware of the potency and side effects of synthetic drugs. Many drugs, e.g., balsam of Tolu, balsam of Peru. benzoin, etc. are imported to India. If these drugs are cultivated in India, foreign exchange can be significantly saved.

11. Natural Products: These have been used as drug substitute for semi-synthesis of many potent drugs.

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