Biomedical subjects

T J Nagem

Publications and source records attributed to T J Nagem.

8 recordsLinked to original sources

PubMed2005

Vascular effects of 7-epiclusianone, a prenylated benzophenone from Rheedia gardneriana, on the rat aorta.

The vascular effects of 7-epiclusianone on the rat aorta were investigated. In the rat aortic rings with functional endothelia, 7-epiclusianone up to 10microM induced a concentration-dependent vasodilatation of the sustained contractions induced by phenylephrine (0.3microM). At concentrations higher than 10microM, 7-epiclusianone induced a concentration-dependent contraction in the aortic rings. The vasodilator effect of 7-epiclusianone was drastically decreased with L-NAME (100microM) as well as in endothelium-denuded aortic rings. Moreover, indomethacin (10microM) induced a significant shift to the left in the vasodilator but did not modify the vasoconstrictor effect of 7-epiclusianone. In arteries without pre-contraction, 7-epiclusianone (3-100microM) induced concentration-dependent contraction only in endothelium-intact and in the presence of L-NAME (100microM). This effect was inhibited by indomethacin (10microM) and ZM230487 (1microM), selective inhibitors of cyclooxygenase and of 5-lipoxygenase, respectively. We can conclude that at low concentrations 7-epiclusianone induces an endothelium-dependent vasodilator effect in rat aortic rings. At higher concentrations and in conditions where NO synthase was inhibited, 7-epiclusianone induces a vasocontractile effect. Nitric oxide seems to participate in the vasodilatation, while endothelial cyclooxygenase- and 5-lipoxygenase-derived products play a role in the vasoconstrictor effect.

Animals↗

PubMed2001

6-Deoxyjacareubin.

The natural compound 5,10-dihydroxy-2,2-dimethylpyrano[3,2-b]xanthen-6(2H)-one (6-deoxyjacareubin), C(18)H(14)O(5), was isolated from leaves of Vismia latifolia (Guttiferae family). The compound has four six-membered rings. The molecule has two planar benzenoid and one planar pyranoid ring, plus a pyranoid ring in a distorted chair conformation. The crystal is stabilized by one intra- and one intermolecular hydrogen bond.

Crystallography, X-Ray↗

PubMed2001

[Hypocholesterolemic effect of naringin and rutin flavonoids].

Flavonoids are pigments fenolics of plants that possess several biological activities, and many of these are associated with prevention of chronic diseases as cancer and hyperlipidemia. This work had as objective evaluates the effect of the flavonoids naringin and rutin on the metabolism lipidic of chicks hypercholesterolemic. In agreement with the results it can be observed that naringin and rutin reduced the levels of total cholesterol significantly, cholesterol-LDL, cholesterol-VLDL and triglycerols, not presenting, however, reductions in the levels of cholesterol-HDL.

Animals↗

PubMed2000

Tetraoxygenated naturally occurring xanthones.

This review, with 350 references, gives information on the chemical study of 234 naturally occurring tetraoxygenated xanthones in 12 families, 53 genus and 182 species of higher plants, and two which are described as fungal and lichen metabolites. The value of these groups of substances in connection with pharmacological activity and therapeutic use of some species is described. The structural formulas of 135 isolated compounds, and their distribution, are also given.

Molecular Structure↗

PubMed1999

Hypolipidaemic effects of naringenin, rutin, nicotinic acid and their associations.

Atherosclerosis can be defined as being a disease of coronary circulation. The present work evaluates the action of the naringenin, rutin, nicotinic acid, isolated and in association, on the metabolism of lipids. Cholesterol, cholesterol HDL, and triacylglycerols have been dosed after retreat of blood, following the administration of the compounds dissolved in propylene glycol by intraperitoneal route in doses of 5 mg kg-1 body wt. Results evidence that naringenin and nicotinic acid, isolated as well as their association with naringenin and nicotinic acid-rutin, present the largest percentual reduction of cholesterol. On the other hand, the best results for cholesterol-HDL have been obtained with naringenin, while rutin has shown the best triacylglycerols levels.

Animals↗

PubMed1999

Biological activities of 7-epiclusianone.

7-Epiclusianone, isolated from Rheedia gardneriana, was tested in several biological assays. It was active in vitro against trypomastigotes of Trypanosoma cruzi but inactive in vivo in experimentally infected mice. It was also active against Artemia salina, but inactive against the fungus Cladosporium sphaerospermum and the snail Biomphalaria glabrata.

Animals↗

PubMed1997

Antiplasmodial triterpene from Vernonia brasiliana.

The hexane extract from leaves of Vernonia brasiliana (L.) Druce (Compositae) was active in vitro against Plasmodium falciparum and in vivo in mice infected with Plasmodium berghei. This extract was subjected to a bioassay-guided fractionation protocol based on the in vitro model. Lupeol was identified as a compound responsible for the activity, inhibiting the P.falciparum growth by 45% when tested at 25 micrograms/ml. However, this triterpene was inactive in vivo when 15 mg/kg were administered per os during four consecutive days to mice infected with P.berghei. beta-Amyrin and germanicol, isolated from the same fraction that yielded lupeol, were inactive in the in vitro assay.

Animals↗

PubMed1995

A diterpene from Mikania obtusata active on Trypanosoma cruzi.

The diterpene ent-kaur-16-en-19-oic acid (1) was identified as the trypanocidal component of the ethanolic extract from Mikania obtusata D. C. (Asteraceae). This compound presents an IC50 of 0.5 mg/ml (1.66 mM) against the trypomastigote blood form of the Trypanosoma cruzi, the causative agent of Chagas' disease (American trypanosomiasis).

Animals↗