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…
Alkaloids being chemically heterogeneous, cannot be identified in plant extracts using a single chromatographic test. However, the following general procedure may be used for the preliminary detection of alkaloids in plant tissues. The presence of alkaloids may be confirmed by measuring the UV absorbance of a sample of the alkaloid dissolved in 0.1 M sulphuric…
Alkaloids are precipitated from a neutral or slightly acid solution by a number of metallic salts. These precipitation reactions may be used for the detection of the presence of alkaloids in solution. Some of the metallic salts also give colour reactions with proteins and hence results need to be interpreted with caution. Following are some…
There are several methods reported for the extraction of alkaloids and the choice of method is dependent on the purpose of isolation and scale of operation. For small-scale isolations column chromatography will effectively separate the alkaloids from the initially prepared plant extracts. However, on a commercial scale, large volumes of aqueous extracts of plant materials…