Periwinkle, Vinca

Uiiergrlin, n. periwinkle, myrtle (Vinca). iniiierhm, adv. still, after all, at any rate. gunersionsflussigkeit, /. immersion liquid, miner-wahrend, p.a. everlasting, perpetual. 

Singriin, n. periwinkle, myrtle (Vinca). singular, a. singular. 

Sinngrim, n. periwinkle, myrtle (Vinca). sinn-ig, a. sensible thoughtful ingenious pretty, -lich, a. sentient, sensitive, sensuous, sensual, -los, a. senseless. 

Vinca alkaloids (vincristine, vinblastine, vindesine) are derived from the periwinkle plant (Vinca rosea), they bind to tubulin and inhibit its polymerization into microtubules and spindle formation, thus producing metaphase arrest. They are cell cycle specific and interfere also with other cellular activities that involve microtubules, such as leukocyte phagocytosis, chemotaxis, and axonal transport in neurons. Vincristine is mainly neurotoxic and mildly hematotoxic, vinblastine is myelosuppressive with veiy low neurotoxicity whereas vindesine has both, moderate myelotoxicity and neurotoxicity. 

Vinca alkaloids are derived from the Madagascar periwinkle plant, Catharanthus roseus. The main alkaloids are vincristine, vinblastine and vindesine. Vinca alkaloids are cell-cycle-specific agents and block cells in mitosis. This cellular activity is due to their ability to bind specifically to tubulin and to block the ability of the protein to polymerize into microtubules. This prevents spindle formation in mitosing cells and causes arrest at metaphase. Vinca alkaloids also inhibit other cellular activities that involve microtubules, such as leukocyte phagocytosis and chemotaxis as well as axonal transport in neurons. Side effects of the vinca alkaloids such as their neurotoxicity may be due to disruption of these functions. 

The periwinkle, or vinca plant, served as a source for the drugs vincristine and vinblastine, which are commonly referred to as the vinca alkaloids. The vinca alkaloids inhibit the assembly... 

Because of the previous inaccurate botanical determination of the Madagascan periwinkle, the alkaloids of this plant were formerly considered as Vinca alkaloids, an erroneous subclassification for alkaloids isolated from a plant belonging to the genus Catharanthus. It also should be noted that the alkaloids of C. roseus containing two different (most commonly indole and dihydroindole) alkaloid building blocks were, and sometimes still are, referred to as dimeric indole alkaloids. It is more accurate to use the term binary or bisindole alkaloids, since chemically these alkaloids are not dimers of two equal subunits, but rather comprised of two (bis) different alkaloid building blocks. 

The discovery of vinblastine and vincristine is one of the most intriguing examples of serendipity in scientihc research in recent years. In 1952, the Canadian medical researcher Robert Laing Noble (1910-90) received a package from his brother. Dr. Clark Noble, containing 25 leaves from the Madagascar periwinkle plant. Vinca rosea. Clark had received the leaves from one of his patients in Jamaica, who said that natives on the island often used the plant to control their diabetes when insulin was not available. Clark, who was retired, suggested that his brother study the plant for possible use as a drug for the treatment of diabetes. 

The contractile proteins of the spindle apparatus must draw apart the replicated chromosomes before the cell can divide. This process is prevented by the so-called spindle poisons (see also colchicine, p. 316) that arrest mitosis at metaphase by disrupting the assembly of microtubules into spindle threads. The vinca alkaloids, vincristine and vinblastine (from the periwinkle plant. Vinca rosea) exert such a cell-cycle-specific effect. Damage to the nervous system is a predicted adverse effect arising from injury to microtubule-operated axonal transport mechanisms. 

Vinblastine (4) and vincristine (5) are closely related indole-dihydroindole dimers (bisindole alkaloids), isolated from Catharanthus roseus (L.) G. Don (formerly known as Vinca rosea L.), the Madagascar periwinkle. Both of these anticancer agents, known as vinca alkaloids in the medical literature, are specific binders of tubulin, leading to tubulin depolymerization and cell cycle arrest in the metaphase stage. 

Vinblastine and vincristine are alkaloids isolated from plants of the periwinkle family (Vinca rosea). These compounds cause cells to stop at metaphase and inhibit assembly of microtubules, and likewise, failure of mitotic spindle formations. They inhibit synthesis of nucleic acids and proteins. 

Vincamine, vinblastine and vincristine are very important clinic alkaloids. They are produced naturally by plants vincamine by Vinca minor, and vinblascine and vincristine by Madagascar periwinkle Catharanthus roseus). The vindoline synthesis pathway starts with strictosidine and, via dehydrogeissoschizine, preakuammicine, stemmadenine and tabersonine, is converted to vindoline and vincristine (Figure 42). Conversion from vindoline to vinblastine is based on the NADH enzyme activity. Vinblastine and vincristine are very similar alkaloids. The difference is that vincristine has CHO connected to N, whereas vinblastine in the same situation has only CO3. This synthetic structural differences influence their activity. Vinblastine is used to treat Hodgkin s disease (a form of lymphoid cancer), while vincristine is used clinically in the treatment of children s leukaemia. Vincristine is more neurotoxic than vinblastine. 

The vinca alkaloids comprise vincristine and vinblastine. These complex, heterocyclic alkaloids are derived from the periwinkle plant. Vindesine and vi-norelbine are semisynthetic analogues. These drugs are M-phase specitic. Binding specifically to tubulin they inhibit the polymerization of microtubules. The consequent ineffective chromosome segregation initiates apoptosis for both normal and malignant cells. 

Vinblastine is an alkaloid derived from the periwinkle plant Vinca rosea. Its mechanism of action involves inhibition of tubulin polymerization, which disrupts assembly of microtubules, an important part of the cytoskeleton and the mitotic spindle. This inhibitory effect results in mitotic arrest in metaphase, bringing cell division to a halt, which then leads to cell death. Vinblastine and other vinca alkaloids are metabolized by the liver P450 system, and the majority of the drug is excreted in feces via the biliary system. As such, dose modification is required in the setting of liver dysfunction. The main adverse effects are outlined in Table 54-4, and they include nausea and vomiting, bone marrow suppression, and alopecia. This agent is also a potent vesicant, and care must be taken in its administration. It has clinical activity in the treatment of Hodgkin s... 

The following plants contained substantial proportions of apiose, about the same as found in parsley Aegopodium pologaria (bishop s weed), Apium graveolens L. (celery), Conopodium majus (earthnut), Datus aucaparia (rowan), Desfontania spinosa, Ilex aquifolium (holly), Lavatera annual, Lemna wolffia (duckweed), Menyanthes trifoliata (bob bean), and Vinca minor (periwinkle). 

The Madagascar periwinkle Catharanthus roseus (= Vinca rosea) (Apocynaceae) is a small herb or shrub originating in Madagascar, but now common in the tropics and widely cultivated as an ornamental for its shiny dark green leaves and pleasant five-lobed flowers. Drug material is now cultivated in many parts of the world, including the USA, Europe, India, Australia, and South America. 

MADAGASCAR PERIWINKLE -- Catharanthus roseus, formerly Vinca rosea. Family Apocynaceae (Dogbane family). 

Vincristine [vin KRIS teen] and vinblastine [vin BLAST een] are structurally-related compounds derived from the periwinkle plant, Vinca rosea. They are therefore referred to as the vinca alkaloids. A structurally related new (and less toxic) agent, vinorelbine [vye NO rel been] shows promise in the treatment of advanced non-small cell lung cancer. 

The vinca alkaloids, vincristine and vinblastine (from the periwinkle plant, Vinca rosea), inhibit the polymerization of tubulin subunits into microtubuli. Damage to the nervous system is a predicted adverse effect arising from injury to microtubule-operated axonal transport mechanisms. 

Catharanthus roseus (Madagascar periwinkle), Rauwolfia serpentina (Indian snakeroot), R. tetraphyllo (pinque-pinque, four-leaf devil pepper), R. vomitoria (African snakeroot), Vinca minor (periwinkle) (Apocynaceae)... 

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