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DOI: 10.1055/s-0035-1565417
New pyrrolizidine alkaloid from Heliotropium digynum
The phytochemical study of the ethanol extract of aerial parts of Heliotropium digynum Forssk family Boraginaceae growing in Egypt resulted in the isolation and identification of seven pyrrolizidine alkaloids: heliotrine (1), heliotrine N-oxide (2), 7-angeloyl heliotrine (3), 7-angeloyl heliotrine N-oxide (4), lasiocarpine (5), europine (6) and europine N-oxide (7). Compound 4 was isolated for the first time from natural source and its structure was determined using 1D and 2D NMR spectroscopic analysis. Although compounds 2 and 7 are known alkaloids but were isolated for the first time from this species. The ethanol extract at concentration 25 µg/mL showed a very comparable inhibition of nitric oxide generation (40%) to reference drug dexamethasone at concentration 0.05 µg/mL (46%). It is also notable that the ethanol extract inhibits tumor necrosis factor alpha (TNFα) secretion by 66% in comparison to positive control lipopolysaccharide (LPS), in LPS stimulated RAW 264.7 murine macrophage.
R1 |
R2 |
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1 |
H |
OH |
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2 |
N-Oxide of |
1 |
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3 |
H |
angeloyl |
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4 |
N-Oxide of |
3 |
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5 |
OH |
angeloyl |
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6 |
OH |
OH |
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7 |
N-Oxide of |
6 |