Flavonoids are a large group of naturally occurring plant polyphenolic compounds based on the C6-C3-C6 carbon skeleton. These non-nitrogen plant pigments are responsible for flower coloration and are involved in UV filtration, symbiotic nitrogen fixation, metabolic oxidation-reduction processes and play an important role in reproductive physiological processes in higher plants. These ubiquitous compounds of large variety…
Glycosides on account of their varied nature are first analyzed for the nature of the sugar and then tested according to the characteristic of the aglycone. Many glycosides are coloured, fluorescent, or chromogenic and are therefore tested accordingly. Different chemical tests specific for the aglycone are used to detect them after hydrolysis. I. Some of…
Inactivation of enzymes that may be present in plant tissues is an important first step before isolation of glycosides is attempted. This is especially so when fresh plant material is being processed. Dried material does not require such precaution as these enzymes are active only in fresh tissues. Due to the wide range of physical…
The basic physical and chemical properties of glycosides are dependent on the nature of the aglycone and sugar–nonsugar linkage. Some general properties are:
Glycosides are a large and varied group of plant metabolites found universally distributed in higher plants and also in some lower plants. They are defined by the common property of yielding sugars among the products of their hydrolysis. Chemically they are considered sugar ethers as they are formed by the condensation of the –OH group…
Plant lipids may be conveniently identified by chromatographic techniques. For a preliminary analysis and to identify lipid fractions or products of saponification, TLC is best suited. Isolated lipid components or products of hydrolysis can be derivatized into methyl esters and analyzed directly by GLC.
Due to their special solubility properties, lipids may be extracted from plant tissues with alcohol or ether. Such an extraction removes other classes of lipids like leaf alkanes and steroids. The actual method of isolation of lipids from natural sources is largely dependent on the nature of the lipid and its source. Conventional vegetable oils…
The properties associated with lipids are dependent on the nature and extent of its fatty acid composition. Lipids are in general defined by their solubility properties. They are soluble in organic solvents (ether, petroleum ether, benzene, chloroform, alcohol, etc.) and sparingly soluble in water. Greasy in nature, they yield a permanent translucent stain when applied…
Oils and fats, the principal plant lipids, are esters of long-chain fatty acids and alcohol or of closely related derivatives. Chemically fixed oils and fats are composed predominantly of triacyl glycerols having identical or different fatty acids esterified to the three hydroxyl positions on the glycerol molecule. Numerous fatty acids are now known in plants,…
Lipids are a heterogenous group of compounds widely distributed throughout the plant kingdom. In plants they occur in the seeds, nuts, and fruits; in animals they are stored in adipose tissues, bone marrows, and nervous tissues. They are found in all organisms as structural components of the cell membrane. Based on the chemical composition, lipids…