Alkaloid được phân bố rộng khắp vương quốc cây trồng và tạo thành một nhóm rất lớn của các hợp chất hóa học khác nhau với những đặc tính đa dạng dược phẩm. Alkaloids Nhiều người nổi tiếng với tính chất hướng tâm thần của họ, như các chất ma tuý và thuốc an thần rất mạnh. | 20 Spiridon E. Kintzios and Maria G. Barberaki Alkaloids are widely distributed throughout the plant kingdom and constitute a very large group of chemically different compounds with diversified pharmaceutical properties. Many alkaloids are famous for their psychotropic properties as very potent narcotics and tranquilizers. Examples are morphine cocaine reserpine and nicotine. Several alkaloids are also very toxic. Structure and properties They are principally nitrogen-containing substances with a ring structure that allows their general classification in the groups described in Table Jakubke and Jeschkeit 1975 . Most alkaloids with anticancer activity are either indole pyridine piperidine or aminoalkaloids. Table General structural classification of alkaloids Group name Base structure Pyrrolidine Pyrrolizidine Tropane Piperidine Punica Sedum and Lobelia alkaloids Quinolizidine Isoquinolizidine Indole Rutaceae alkaloids Terpene alkaloids Plants and cancer 21 Alkaloids are weak bases capable of forming salts which are commonly extracted from tissues with an acidic aqueous solvent. Alternatively free bases can be extracted with organic solvents. Distribution Quite abundant in higher plants less in gymnosperms ferns fungi and other microorganisms. Particularly rich in alkaloids are plants of the families Apocynaceae Papaveraceae and Fabaceae. Biosynthesis in plant cells Rather complicated with various amino acids phenylalanine tryptophan ornithine lysine and glutamic acid serving as precursor substances. Basis of anticancer antitumor activity Alkaloids are mainly cytotoxic against various types of cancer and leukemia. They also demonstrate antiviral properties. More rarely they demonstrate immuno-modulatory properties. Some plants containing alkaloids with anticancer properties are indicated in Table for more details on each plant please consult Chapter 3 of this book . Table Plants containing alkaloids with anticancer properties Species Target disease
