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…
Global market for medicinal plants is growing exponentially as plant materials are being increasingly used both in developing countries and in the industrialized world. Today there is a substantial market for herbal drugs both as traditional medicines and in modern medicine. Their widespread availability and lack of effective machinery to regulate manufacturing practices and quality…
Chromatography is the science which studies the separation of molecules based on differences in their structure and/or composition. In general it involves moving (in a mobile phase) preparation of materials to be separated over a stationary support. Based on their differential affinity between the mobile and stationary phase, molecules in the preparation get separated between…
To ensure quality of herbal drugs, it is necessary not only to establish the identity, but also to ensure batch-to-batch reproducibility. Apart from macroscopic and microscopic evaluation, tests to identify principal chemical groups are the next priority. These cover identification and characterization of the crude drug with respect to phytochemical constituents. Several analytical techniques are…
Parasites, microbial contaminants, mycotoxins and endotoxins are the classes of biological contaminants likely to be found in herbal materials. A large number of bacteria and moulds often originating in soil or derived from manure are found in herbal materials. Some of them form the naturally occurring microflora of medicinal plants of which aerobic spore-forming bacteria…
Herbs and herbal products ideally need to be free of pesticides, fumigants and other hazardous contaminants. At best they may be controlled for the absence of unsafe levels. Herbal drugs are prone to pesticide residues, which accumulate from agricultural practices, such as spraying, treatment of soils during cultivation and administration of fumigants during storage. Presence…
Crude drugs may be processed to separate crude fibre, which is a means of concentrating the more resistant cellular material of drugs for microscopic examination. This is especially applicable when the amount of foreign matter in a powder is small. Preparing a crude fibre concentrates the resistant parts of adulterants in a small amount of…