What is secondary metabolites in plants and define their classes?
Plants have ability to form a different types of organic molecules, which are divided into two categories - Primary metabolites and Secondary metabolites.br /Primary metabolites are the metabolite product which are essential for the life and it is present in living system and biosynthesized by biochemical pathway.br / strongSecondary metabolites are metabolite product which are essential for plant interaction with environment./strong Secondary metabolites are divided into four major classes:br /br /strongTerpenes/strong:- Terpenes are the natural product which made up of isoprene units. Its molecular formula(C5H8)n, here n means number of linked isoprene unit. One isoprene unit is called hemiterpenes.br /strongPhenolics/strong:- Phenolics are Chemical compound which made up of aromatic ring containing one or more hydroxyl groups. Plant phenolics work as a defense against UV radiation, herbivores, pathogens and provide mechanical support.br /strongGlycoside/strong:- Glycoside is the compound in which carbohydrate bind to non carbohydrate moiety with glycosidic bond. Glucose is the most common carbohydrate in glycoside. strongAlkaloids/strong:- Alkaloids are chemically heterogeneous in nature, containing one or more nitrogen atoms.
Plants produce thousands types of chemicals. Some of the organic compounds like carbohydrates, fats, proteins, nucleic acids, chlorophylls, hemes are required for their basic metabolic processes and found throughout the plant kingdom. These organic compounds are called primary metabolites or biomolecules. These are produced in large quantities and can easily be extracted from the plants.br /Many plants, fungi and microbes of certain genera and families synthesize a number of organic compounds which are not involved in primary metabolism (photosynthesis, respiration, and protein and lipid metabolism) and seem to have no direct function in growth and development of plants. Such compounds are called secondary metabolites (secondary plant products or natural products) These compounds are accessary rather than central to the functioning of the plants in which they are found. These compounds are produced in small quantities and their extraction from the plant is difficult and expensive.br /They accumulate in small quantities only in specific parts of plants. These are derivatives of primary metabolites. By the cultivation of plant cells in culture media, secondary metabolites can be produced on large scale.