Biomedical subjects

A Estévez-Braun

Publications and source records attributed to A Estévez-Braun.

6 recordsLinked to original sources

PubMed2003

Acetylenic acids from the aerial parts of Nanodea muscosa.

The aerial parts of Nanodea muscosa, collected in Chile, yielded two new acetylenic acids. Their structures were elucidated by spectroscopic analyses, including 2D NMR techniques, as (13E)-octadec-13-en-11-ynoic acid (1) and (2E)-octadec-2-en-4-ynedioic acid (2). Compound 2 constitutes the first example of a conjugated ene-yne fatty diacid isolated from a natural source. Compounds 1 and 2 did not exhibit toxicity toward a panel of DNA damage checkpoint defective yeast mutants or show affinity for the 5-HT(1A), 5-HT(2A), D(2), and H(1) receptors.

Alkynes↗

PubMed2000

Macrocarpins A-D, new cytotoxic nor-triterpenes from Maytenus macrocarpa.

Macrocarpins A (1), B (2), C (3) and D (4), four new nor-triterpenes, have been isolated from the roots of Maytenus macrocarpa. The structures were established by spectroscopic examinations. Natural compounds 1, 2, 4 and the acetyl derivative 1a are cytotoxic against four tumoral cell lines with IC50 values ranging between 0.4 and 5.2 microM.

Molecular Structure↗

PubMed1999

New phenolic and quinone-methide triterpenes from Maytenus amazonica.

The new nortriterpene methylene quinones amazoquinone (1) and (7S, 8S)-7-hydroxy-7,8-dihydro-tingenone (2), and the new norphenolic triterpenes 7,8-dihydro-6-oxo-tingenol (3), 23-nor-6-oxo-tingenol (4), and 23-oxo-iso-tingenone (5) were isolated from Maytenus amazonica. Their structures were elucidated by spectroscopic methods. Compounds 1, 2, 3, and 5 showed low antitumor activity against four cancer cell lines.

Aldehyde Reductase↗

PubMed1998

Friedelane triterpenoids from Maytenus macrocarpa.

A set of friedelane triterpenoids has been isolated from the stem bark exudates of Maytenus macrocarpa. It includes a new friedelan triterpene (1), together with the known compounds friedelin, 3-oxo-29-hydroxyfriedelane, 3-oxofriedelan-25-al, and canophyllol. The structures of these compounds were elucidated by spectroscopic and chemical evidence. Complete 1H and 13C assignments were achieved by 2D NMR spectroscopy. The new compound showed weak activity against aldose reductase. It did not display antitumor activity against P-388 lymphoid neoplasm, A-549 human lung carcinoma, HT-29 human colon carcinoma, or MEL-28 human melanoma cell lines.

Aldehyde Reductase↗

PubMed1997

Coumarins.

Explore the source record for details and available documents.

Coumarins↗

PubMed1995

Biological activity of secondary metabolites from Bupleurum salicifolium (Umbelliferae).

Secondary metabolites from Bupleurum salicifolium were tested against viruses, Gram-positive and Gram-negative bacteria, the yeast Candida albicans, the nematodes Globodera pallida and G. rostochiensis, the insect Spodoptera littoralis and the crustacean Artemia salina. These compounds were also tested against tumoral and non-tumoral cell lines. The polyacetylene 8S-heptadeca-2(Z)-9(Z)-diene-4,6-diyne-1,8-diol exhibited toxicity for A. salina and specific antibiotic activity against Gram-positive bacteria. Nine of the lignans and one coumarin showed toxicity for A. salina, and the lignans bursehernin and matairesinol inhibited the hatching of the two nematode species. These are the first lignans that have been reported as affecting phytoparasitic nematodes, and the first natural products known to have an effect on the hatching of G. pallida. Lignans may play a role in the defence mechanisms of potato plants, as allelopathic substances acting against cyst-forming nematodes.

Animals↗