Biomedical subjects

A G Ravelo

Publications and source records attributed to A G Ravelo.

25 records · Page 2Linked to original sources

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↗

PubMed1995

Bioactive anthraquinone glycosides from Picramnia antidesma spp. fessonia.

A bioactivity guided fractionation, using KB cells and brine shrimp assays, of the methanolic extract from the leaves of Picramnia antidesma yielded two known anthraquinones, aloe-emodin and aloe-emodin anthrone, and three new aloe-emodin C-glycosides, named picramnioside A, picramnioside B and picramnioside C. Structures were established by spectroscopic methods (UV, IR, mass spectrometry, 1H and 13C and 2D NMR including COSY 45, HMQC, HMBC and ROESY). CD was used to establish the absolute configuration of the picramniosides.

Animals↗

PubMed1995

Xanthine oxidase inhibitory activity of some Panamanian plants from Celastraceae and Lamiaceae.

Thirty four crude extracts of Panamanian plants, from nine species of Celastraceae and Lamiaceae, were assayed for xanthine oxidase (XO) inhibitory activity. The enzymatic activity was estimated by measuring the increase in absorbance at 290 nm due to uric acid formation. Eighty five percent of the crude extracts were found to possess XO inhibitory activity at 50 micrograms/ml and all the extracts of the species from Lamiaceae were active even at 1 micrograms/ml. The ethanol extracts of Hyptis obtusiflora Presl ex Benth. (Lamiaceae) and H. lantanaefolia Poit. (Lamiaceae) exhibited the highest activity with an inhibition of approximately 40% at 1 micrograms/ml.

Ethanol↗

PubMed1994

Antibiotic activity and absolute configuation of 8S-heptadeca-2(Z),9(Z)-diene-4,6-diyne-1,8-diol from Bupleurum salicifolium.

A polyacetylene has been isolated from Bupleurum salicifolium. Its structure and absolute configuration were determined to be 8S-heptadeca-2(Z),9(Z)-diene-4,6-diyne-1,8-diol [1] by means of 1H- and 13C-nmr spectroscopic studies, including 1H-13C heteronuclear correlation (HMQC) and long-range correlation spectra with inverse detection (HMBC). Its absolute configuration was determined by application of the Horeau method. This compound exhibited significant antibiotic activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis. Also isolated during this investigation were the known compounds; betulin, herniarin, 6,7,8-trimethoxycoumarin, p-hydroxyphenethyl alcohol, pluviatolide, guamaroline, bursehernin, guayadequiol, kaerophyllin, and matairesinol dimethyl ether.

Alkynes↗

PubMed1991

Mode of action of netzahualcoyone.

The activity of netzahualcoyone on Bacillus subtilis and Escherichia coli was studied. The product inhibited the respiration of intact cells of B. subtilis but had no effect on the respiration of E. coli. However, when preparations of sonically disrupted cells were examined, inhibitory activity on both bacteria was observed.

Anti-Bacterial Agents↗

PubMed1988

Biological study of triterpenequinones from celastraceae.

The cytostatic activity of several triterpenequinone methides isolated from Rzedowskia tolantonguensis and Maytenus horrida (Celastraceae) was evaluated against HeLa cell cultures. Their ID50 were determined and compared with those of other related compounds. A preliminary study of the antibacterial activity of the above triterpenequinone methides was also carried out.

Antineoplastic Agents, Phytogenic↗

PubMedDate not supplied

Minor sesquiterpenes from Maytenus chubutensis.

Four new minor dihydro-beta-agarofuran-skeleton sesquiterpenes, 9 beta-benzoyloxy-1 alpha,2 alpha,6 beta-triacetoxy-15-hydroxydihydro-beta- agarofuran [1], 9 beta-benzoyloxy-1 alpha,2 alpha,6 beta,15-tetracetoxydihydro-beta-agarofuran [6], 9 alpha-benzoyloxy-1 alpha,2 alpha,6 beta-triacetoxy- 8 alpha,15-dihydroxydihydro-beta-agarofuran [7], and 9 alpha-benzoyloxy-1 alpha,2 alpha,6 beta,8 alpha-tetracetoxy-15- hydroxydihydro-beta-agarofuran [8] were isolated from the aerial parts of Maytenus chubutensis and identified by spectroscopy and chemical reactions.

Chemical Phenomena↗