Medicinal plants economic botany: Importance, Classification, Primary and Secondary metabolites II Free studymaterial II Economic botany notes

 MEDICINAL PLANTS AND THEIR IMPORTANCE

Medicinal plants are important because they confer Medicinal activities due to presence of Phytochemicals. Plant phytochemicals has been broadly classified into

Primary constituents which include the common sugars, amino acids, chlorophylls, proteins, purines and pyrimidines of nucleic acids etc.

Secondary constituents are the remaining plant chemicals such as alkaloids, terpenes, flavonoids, lignans, plant steroids, curcumines, saponins, phenolics, flavonoids and glucosides. The activity of the phytochemicals depends on their structures.

Central Drug Research Institute of India (CDRI):

This is located in Lucknow. Here extensive research is done on the drugs their sources, extraction and effects. Regular attempts are made to find out new medicines from herbs for treating various diseases.

What are Secondary Metabolites?

Compounds that do not have direct physiological role in plants are secondary in function and are characterized as Secondary Metabolites. 

Plants synthesize secondary metabolites (small organic molecules) that are not required for their normal growth or development but are essentially required for reproduction and defense mechanism against bacteria, fungus, virus, vertebrates, etc. These products have a great potential to act as drugs.

What does Secondary Metabolites do?

   Disruption of cell membrane functions and structure of microbes.

      Interference with intermediary metabolism 

      Interruption of DNA/RNA synthesis and function

v  Interruption of normal cell communication (quorum sensing)

v  Induction of coagulation of cytoplasmic constituents

v  Medicinal plants have shown promising antimicrobial activities, anti-helminthic, anticancer, antidiarrheal and antiviral activities.

Some important secondary metabolites

Plant derived drug	Plant
Papaver somniferum	Codeine, Papaverine
Catharanthus roseus	Vinblastine and vincristine
Atropa belladonna	Tiotropium bromide

Why medicinal plants?

Used in drug development and drug synthesis.

Some birds selected nested material rich in antimicrobial activity for protection of their young ones.

Phytomedicine preparation: According to the World Health Organization (WHO, 2001), phytomedicine is defined as herbal preparations produced by subjecting plant materials to extraction, fractionation, purification, concentration or other physical or biological processes.

Classification: They are classified according to the part used, habit, habitat, therapeutic value etc,

Classification	Example
Based on the part used	Leaf(Indigofera tinctoria, Aloe vera), Flower (Biophytum sensityvum), Fruit (Solanum species) and Seed (Datura stramonium). Root (Raulfia serpentina)
Based on the Habit	Herbs (Vernonia cineria), Shrubs (Solanum species), Climbers (Asparagus racemosus) and Trees (Azadirachta indica)
Based on the Ayurvedic formulation	The three fruits of the Triphala (Thriphalam) Phyllanthus emblica (Nellikka/Amla), Terminalia bellerica (Thannikka/Bahera) and Terminalia chebula (Kadukka/Harar)