Three New Tazettine-Type Alkaloids from Galanthus gracilis and Galanthus plicatus Subsp. byzantinus

Abstract

Three new tazettine-type alkaloids were isolated from two different GALANTHUS species of Turkish origin. (+)-Isotazettinol and (+)-3- O-demethylmacronine are obtained from G. GRACILIS, while (+)-3- O-demethyl-3-epimacronine is found in G. PLICATUS subsp. BYZANTINUS. The known base, trispheridine, is reported for the first time in GALANTHUS genus.

Biosynthesis and Biological Activities of Newly Discovered Amaryllidaceae Alkaloids

“…Some AAs with ring types different than those of group I to IX were classified in group X (or other-types) because they follow distinct biogenetic pathway, or because we cannot clearly indicate their biosynthetic origin (Table 1). Galanthindole contains a non-fused indole ring and might represent an artifact of homolycorine-or of pretazettine-type derivatives [27]. Ismine is considered to be a catabolic product from the haemanthamine-type skeleton, thus not a specific type of AA [28].…”

“…Several of these novel AAs belong to known structural types, while others harbor new structures. The 91 AAs were classified in this manuscript as I) norbelladine-type (1-6), II) cherylline-type (7, 8), III) galantamine-type (9-16), IV) lycorine-type (17-25), V) homolycorine-type (26)(27)(28)(29)(30), VI) crinine-type (31-50), VII) narciclasine-type (51), VIII) pretazettine-type (52-54), IX) montanine-type (55), and X) other types including AAs related to plicamine (56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67), seco-plicamine (68-70), cripowellin (71)(72)(73)(74)(75)(76), mesembrine (77,78), and various others AAs (79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89)(90)(91). Structures of novel AAs belonging to the I to III scaffold types (norbelladine-, cherylline-, and galantamine-type) are depicted in Figure 3, whereas types IV and V (lycorine-and homolycorine-type) are represented in Figure 4.…”

“…Their structural elucidation was performed by spectroscopic methods, such as 1D and 2D ( 1 H-1 H, COrrelation SpectroscopY (COSY), Heteronuclear Multiple Quantum Coherence (HMQC), and Heteronuclear Multiple Bond Correlation (HMBC)) Nuclear Magnetic Resonance (NMR) spectroscopy, in addition to high resolution mass spectrometry [67]. From the bulb of L. radiata, were also isolated four new AAs, lycoranines C-F (9, 27, 28, 80), respectively belonging to galantamine-(9), homolycorine- (27,28) and other-types (80), with known alkaloids homolycorine, haemanthidine, haemanthamine, α-dihydrolycorine, galanthine, lycorine, and pseudolycorine. Their structure was determined using extensively NMR and high-resolution electrospray ionization mass spectrometry (HR-ESIMS) data.…”

“…Chemical structure of new alkaloids of the lycorine-(17-25) and homolycorine-type(26)(27)(28)(29)(30). Numbers in bold refer to the compounds depicted in…”

New skeletons and new concepts in Amaryllidaceae alkaloids

“…G. plicatus subsp. byzantinus afforded the known alkaloids 9-O-demethylhomolycorine (1), 5,6-dihydrobicolorine, trisphaeridine (Unver 1999;Unver et al 1999b), (+)-tazettine (20), 3-epimacronine (23), ismine (26), (Akıneri and Gü nes 1998;Linden et al 1998), (+)-11-hydroxyvittatine and hordenine (Unver et al 2003). Of these compounds, (+)-3-epimacronine (23), 5,6-dihydrobicolorine and trisphaeridine are reported for the first time in the genus Galanthus.…”