Plant Alkaloids and Application in Modern Medicine

چکیده مقاله

The use of medicinal plants has been always an important part of the medical systems of the world. Plant secondary metabolites (SM) are a diverse group of molecules that are involved in the adaptation of plants to their environment but are not part of the primary biochemical pathways of cell growth and reproduction. Secondary metabolites are not useless waste products (as assumed earlier), but important tools against herbivores and microbes. SM are not necessarily end products and some of them, especially if they contain nitrogen, are metabolically recycled. Alkaloids form a very diverse group of organic nitrogen compounds of a basic character (with the exception of some derivatives of purine and colchicine). They have tertiary or quaternary amino groups in their molecules and only a few contain secondary amino groups. Different classes of alkaloids have been identified in plants. Extraction of alkaloids from natural products such as Hyoscyamus muticus and Datura stramonium consists of the use of a solvent extraction and sonicated solution containing a surfactant as extracting agent. The alkaloids are precipitated by Mayer reagent, dissolved in an alkaline solution, and then extracted with chloroform . Alkaloids have biological activities. For example Nicotine (Nicotiana tabacum, Solanaceae)(pyridine Alkaloid (is the stimulant alkaloidal component of tobacco and has a stimulant effect on the CNS. Ephedrine (Ephedra sinica, Ephedraceae)(Phenylalkylamine Alkaloid (possesses CNS stimulatory, vasoconstrictive and bronchodilatory properties. These effects are similar to those of the natural hormone adrenaline (epinephrine) . The drug of abuse cocaine (Erythroxylum coca) (Erythroxylaceae ( has limited use as a local anaesthetic in ear, nose and throat surgery, and in the control of severe pain for patients with terminal cancer.