Tetrahydrorhombifoline

Alkaloid profile of leaves and seeds of Lupinus hintonii C. P. Smith.[Pubmed:12064721]

Z Naturforsch C J Biosci. 2002 Mar-Apr;57(3-4):243-7.

L. hintonii C. P. Smith grows in the Central Highland forests of Mexico at altitudes between 2800 m to 3200 m above see level. Members of the genus Lupinus produce quinolizidine alkaloids as main chemical defensive compounds against herbivores. Surprisingly alkaloid profiles are rather constant within this species, while substantial variation was found when compared to morphologically closely related other taxa. As part of a phytochemical project on Mexican wild lupins, we report on the alkaloid profiles of seeds and leaves of L. hintonii. 19 alkaloids could be identified by capillary GLC-MS. Six major alkaloids occurred in leaves and seeds: 13-hydroxylupanine (28% and 45% respectively), Tetrahydrorhombifoline (31% and 23% respectively), angustifoline (2% and 4% respectively), lupanine (7% and 5% respectively), 13alpha-tigloyloxylupanine (19% and 5% respectively) and 4alpha-angeloyl-3beta-hydroxylupanine (9% and 2%). This chemical pattern resembles that of the North American lupin L. floribundus.

Biochemical and partial molecular characterization of bitter and sweet forms of Lupinus angustifolius, an experimental model for study of molecular regulation of quinolizidine alkaloid biosynthesis.[Pubmed:11045450]

Chem Pharm Bull (Tokyo). 2000 Oct;48(10):1458-61.

The bitter and sweet forms of a plant species differing with alkaloid contents may provide a model system for investigation of alkaloid biosynthesis at a molecular level. The pattern and concentration of quinolizidine alkaloids were determined by capillary GC-MS in bitter and sweet plants of Lupinus angustifolius. Bitter plant contained lupanine, 13alpha-hydroxylupanine, angustifoline, alpha-isolupanine, Tetrahydrorhombifoline, and ester-derivatives of 13alpha-hydroxylupanine. In contrast, no alkaloid was detected in sweet plant. The enzymatic activity of acyltransferase for formation of 13alpha-tigloyloxylupanine was similar or even higher in the cell-free extracts of sweet plant than that in bitter plant. These results suggest that the biosynthetic step(s) of ring closure forming the initial cyclic alkaloid, lupanine, from cadaverine is presumably blocked in sweet plant, and that the later steps for modification of the cyclized alkaloids are not altered. We hypothesized that the gene(s) encoding enzyme(s) for ring-closure step might be repressed in sweet plant, and that the expression might take place only in bitter plant. To isolate the genes specifically expressed in bitter plant, cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis was carried out. However, no bitter-specific gene was isolated, suggesting that alkaloid biosynthesis in sweet plant may be down-regulated at a post-transcriptional level.

Accumulation of quinolizidine alkaloids in plants and cell suspension cultures: genera lupinus, cytisus, baptisia, genista, laburnum, and sophora.[Pubmed:17404991]

Planta Med. 1983 Aug;48(8):253-7.

The patterns of quinolizidine alkaloids in cell cultures of 10 species of Fabaceae were analyzed by high-resolution GLC and GLC-MS and compared with the alkaloids present in the leaves of the respective plants. Lupanine was produced in all 10 cell suspension cultures as the main alkaloid. It was accompanied by sparteine, Tetrahydrorhombifoline, 17-oxosparteine, 13-hydroxylupanine, 4-hydroxylupanine, 17-oxolupanine, and 13-hydroxylupanine esters as minor alkaloids in some species. The alkaloid patterns of the plants differed markedly in that alpha-pyridone alkaloids were the major alkaloids in the genera Cytisus, Genista, Laburnum and Sophora but were not accumulated in the cell cultures. These data further support the assumption that the pathway leading to lupanine is the basic pathway of quinolizidine alkaloids biosynthesis and that the other alkaloids are derived from lupanine.