Crinine-type alkaloids from Hippeastrum aulicum and H. calyptratum

Abstract

An ongoing search for alkaloids in the Amaryllidaceae species using GC-MS resulted in the identification of two crinine-type alkaloids, aulicine (1) and 3-O-methyl-epimacowine, (2) from the indigenous Brazilian species Hippeastrum aulicum and Hippeastrum calyptratum, respectively. In addition, two alkaloids, 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, we provide here complete NMR spectroscopic data for the homolycorine analogues nerinine (5) and albomaculine (6). The absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was determined by circular dichroism and X-ray crystallographic analysis, thus presenting the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum.

Identification of Alkaloids from Hippeastrum aulicum (Ker Gawl.) Herb. (Amaryllidaceae) Using CGC-MS and Ambient Ionization Mass Spectrometry (PS‑MS and LS-MS)

“…This library has been regularly updated with alkaloids isolated and unequivocally identified via physical and spectroscopic methods. 18 NMR data for the known alkaloids described herein closely matched those reported elsewhere. [18][19][20][21][22][23][24][25][26] Mass spectra were deconvoluted using AMDIS 2.64 software (NIST) (WA, USA) and RIs recorded using a standard n-hydrocarbon calibration mixture (C9-C36).…”

“…Thirteen alkaloids are reported here for the first time in H. aulicum, although some chemical similarities with previous studies have also been found. 18,30 The H. aulicum studied here, from Biritiba-Mirim City (São Paulo, Brazil), displayed aulicine (15), haemanthamine (16), and lycorine (25) as the main compounds, as does H. aulicum from Cunha City (São Paulo, Brazil). 18 Both Brazilian cities are relatively close, which may explain the presence of the same major components.…”

“…18,30 The H. aulicum studied here, from Biritiba-Mirim City (São Paulo, Brazil), displayed aulicine (15), haemanthamine (16), and lycorine (25) as the main compounds, as does H. aulicum from Cunha City (São Paulo, Brazil). 18 Both Brazilian cities are relatively close, which may explain the presence of the same major components. Lycorine (25) was found to be one of the main alkaloids (see Experimental section) even though its low solubility in MeOH 31 covered the correct relative quantification by CGC-MS (Table 2).…”

“…Soc. 826 a l b o m a c u l i n e ( 2 9 ) , 1 8 h a e m a n t h i d i n e ( 2 2 ) , 6 -e p i h a e m a n t h i d i n e ( 2 3 ) , 1 9 7 -m e t h o x y -Omethyllycorenine (12), 18 aulicine (15), 18 lycorine (25), 22,23 trisphaeridine (3), 21,24 galanthine (21), 20 and norpluviine (14), 25 were isolated and identified by comparison of their spectroscopic data with those previously reported. The phytochemical procedure was assisted by CGC-MS and the new compound haemanthamine N-oxide (1) was purified from a natural source for the first time.…”

Amaryllidaceae alkaloids: Absolute configuration and biological activity

“…In total, 23 Amaryllidaceae alkaloids were isolated. Lycorine ( 1 ) was the main constituent of both Hippeastrum species, while haemanthamine ( 15 ) was abundant only in H. aulicum . The structures of the four new alkaloids were determined by spectroscopic investigation.…”