New skeletons and new concepts in Amaryllidaceae alkaloids

Abstract

The Amaryllidaceae alkaloids, represent a group of isoquinoline alkaloids, which are produced almost solely by members of the Amaryllidaceae family. The alkaloids of this family have attracted considerable amount of interest due to some important pharmacological activities they were shown to possess. In the last decade, our phytochemical studies on four Galanthus (Amaryllidaceae) species of Turkish origin have yielded quite a number of new alkaloids with diverse structures. Among these alkaloids, gracilines and plicamines constitute two new subgroups for the Amaryllidaceae alkaloids. The gracilines contain an incorporated 10b,4a-ethanoiminodibenzo[b,d]pyrane skeleton. The plicamines are dinitrogenous compounds, where the oxygen atom in position 7 of a tazettine skeleton is replaced by a nitrogen atom substituted by a pendant 4-hydroxyphenethyl moiety. One of the new alkaloids, galanthindole, which possesses a nonfused indole ring, unlike the already known subgroups of Amaryllidaceae alkaloids, may be considered as the prototype of a third new subgroup of the Amaryllidaceae alkaloids. Additionally, two known isoquinoline alkaloids which do not possess one of the established skeletons of the Amaryllidaceae alkaloids, namely ( -)-capnoidine and (+)-bulbocapnine, have been isolated from a Turkish Galanthus species. Totally, 21 new, 20 known alkaloids and 2 known lignans have been characterized. In this review, the isolation and structure elucidation of these compounds with interesting chemical structures are described.

Application of HPLC-DAD for the quantification of Lycorine in Galanthus elwesii Hook

“…Plants of the Amaryllidaceae are known to produce alkaloids with a wide range of pharmacological activities (Unver, 2007;Hoshino, 1998). Among the Amaryllidaceae alkaloids, galanthamine, is used for the treatment of mild and moderate cases of Alzheimer's disease (AD) (Howes, Perry, 2011).…”

Recycling and Catalytic Approaches for the Development of a Rare-Metal-Free Synthetic Method Using Hypervalent Iodine Reagent

“…2, we applied the method mainly to obtain the key synthetic intermediates of the Amaryllidaceae alkaloid families, such as galanthamine and other crinine-type alkaloids, that are useful in the treatment of Alzheimer's disease [43][44][45] and we achieved their total syntheses. [4][5][6] At this point, the formation of the desired spirocyclic product 8g as a major product demonstrated the applicability of the method even in highly functionalized substrates with complex molecular structures.…”

The Genus Galanthus: A Source of Bioactive Compounds

“…silicicus (Baker) Gottlieb-Tannenhain). Two new alkaloids, the N-oxides of 9-Omethyldihydrosternbergine (62) and 11-hydroxyvittatine (29), were also isolated, along with several known alkaloids 2, 5, 10, 24, 28, 29, 31-33, 54, 62 and 63 (Kaya et al, 2004b;Ünver 2007). Compounds 84-90 are benzyltetrahydroisoquinoline-, aporphine-and phthalide-type isoquinolines, found in dicotyledonous plants of the Fumariaceae and Papaveraceae families (Kametani and Honda 1985;MacLean, 1985).…”