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…
Despite their great diversity, alkaloids have many common physical and chemical properties. In general, alkaloids are colourless, crystalline (a few are amorphous) with an intensely bitter taste, and have sharp melting points. Alkaloids like nicotine and coniine are liquids and berberine and sanguinarine are coloured. Presence of nitrogen in their structure confers basic properties and…
Alkaloids Alkaloids constitute the single largest class of plant secondary metabolites. Around 10,000 of them are reported and many more newer ones are being identified. They are generally referred to as organic nitrogenous bases of plant origin that are pharmacologically active. All alkaloids cannot be described by a clear-cut definition because not all are basic,…
Most of the underlying principles of phytochemical operations are traceable to the early nineteenth-century methods of plant drug isolations. Comprehensive knowledge of the physicochemical nature of targeted constituent is an essential prerequisite before its isolation may be attempted. Extraction refers to the physical separation of soluble active metabolite from the insoluble, inactive/inert plant cellular matrix.…
Recent global acceptance and renewed interest toward plant-derived drugs, nutraceuticals, and other natural products, has generated a lot of commercial as well as research activity in phytochemistry. Earliest drug discoveries made possible by random sampling of higher plants, used simpler operations for the separation, purification, and identification of phytoconstituents. Further, research developments with the introduction…