Alkaloidal components in the poisonous plant, Ipomoea carnea (Convolvulaceae).
Natural intoxication of livestock by the ingestion of Ipomoea carnea (Convolvulaceae) sometimes occurs in tropical regions of the world. Polyhydroxylated alkaloids were isolated from the leaves, flowers, and seeds of the poisonous plant and characterized. Chromatographic separation of the leaf extract resulted in the isolation of swainsonine (1), 2-epi-lentiginosine (2), calystegines B(1) (3), B(2) (4), B(3) (5), and C(1) (6), and N-methyl-trans-4-hydroxy-l-proline (7). The contents of 1 in the fresh leaves and flowers were 0.0029 and 0.0028%, respectively, whereas the contents of 1, 3, and 4 in the seeds were approximately 10 times higher than those in the leaves and flowers. Alkaloids 3, 4, and 6 showed a potent inhibitory activity toward rat lysosomal beta-glucosidase, with IC(50) values of 2.1, 0.75, and 0.84 microM, respectively, and alkaloid 5 was a moderate inhibitor of alpha- and beta-mannosidases. Although alkaloid 1 is known as a powerful inhibitor of lysosomal alpha-mannosidase (IC(50) = 0.02 microM), alkaloid 2, which has been thought to be an intermediate in the biosynthesis of 1, was also a potent inhibitor of alpha-mannosidase with an IC(50) value of 4.6 microM.
Haraguchi
Mitsue
M
Animal Health Center, Biological Institute of São Paulo, São Paulo, Brazil.
Gorniak
Silvana L
SL
Ikeda
Kyoko
K
Minami
Yasuhiro
Y
Kato
Atsushi
A
Watson
Alison A
AA
Nash
Robert J
RJ
Molyneux
Russell J
RJ
Asano
Naoki
N
D000470:Alkaloids / Q000032:analysis* / Q000633:toxicity; D000818:Animals; D004791:Enzyme Inhibitors / Q000633:toxicity; D035264:Flowers / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006900:Hydroxylation; D027741:Ipomoea / Q000737:chemistry*; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D008361:Mannosidases / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D012639:Seeds / Q000737:chemistry; D043323:alpha-Mannosidase; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors; D044902:beta-Mannosidase
D000470:Alkaloids; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D008361:Mannosidases; D001617:beta-Glucosidase; D043323:alpha-Mannosidase; D044902:beta-Mannosidase