Tanus Jorge Nagem

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.

Antimicrobial activity of Rheedia brasiliensis and 7-epiclusianone against Streptococcus mutans

This in vitro study evaluated the antimicrobial activity of extracts obtained from Rheedia brasiliensis fruit (bacupari) and its bioactive compound against Streptococcus mutans. Hexane, ethyl-acetate and ethanolic extracts obtained (concentrations ranging from 6.25 to 800 microg/ml) were tested against S. mutans UA159 through MIC/MBC assays. S. mutans 5-days-old biofilms were treated with the active extracts (100 x MIC) for 0, 1, 2, 3 and 4h (time-kill) and plated for colony counting (CFU/ml). Active extracts were submitted to exploratory chemical analyses so as to isolate and identify the bioactive compound using spectroscopic methods. The bioactive compound (concentrations ranging from 0.625 to 80 microg/ml) was then tested through MIC/MBC assays. Peel and seed hexane extracts showed antimicrobial activity against planktonic cells at low concentrations and were thus selected for the time kill test. These hexane extracts reduced S. mutans biofilm viability after 4h, certifying of the bioactive compound presence. The bioactive compound identified was the polyprenylated benzophenone 7-epiclusianone, which showed a good antimicrobial activity at low concentrations (MIC: 1.25-2.5 microg/ml; MBC: 10-20 microg/ml). The results indicated that 7-epiclusianone may be used as a new agent to control S. mutans biofilms; however, more studies are needed to further elucidate the mechanisms of action and the anticariogenic potential of such compound found in R. brasiliensis.

7-Epiclusianona, a nova benzofenona tetraprenilada e outros constituintes químicos dos frutos de Rheedia gardneriana

Phytochemical investigation of the fruits of Rheedia gardneriana led to the isolation of sesquiterpenes mixture, methyl esters of fatty acids (palmitate, estearate, oleate, linoleate, linolenate), sugars (galactose, glucose, fructose), triterpene (oleanolic acid), steroids mixture (stigmasterol and sitosterol) and the new tetraprenylated benzophenone 7-epiclusianone.

Xanthones and other constituents of vismia parviflora

The stems and fruits of Vismia parviflora have been shown to contain sitosterol, betulinic acid, lupeol, friedelin, β-friedelinol, shikimic acid, 3,4-dihydroxybenzoic acid, quercetin, 1,7-dihydroxyxanthone, 1,5-dihydroxy-8-methoxyxanthone, madagascine, chrysophanic acid, vismiaquinone-A and its isomer vismiaquinone-C. The structures of these compounds have been elucidated by using spectroscopic data as MS, UV, IR, one- and two-dimensional NMR.

Inhibitory effects of 7-epiclusianone on glucan synthesis, acidogenicity and biofilm formation by Streptococcus mutans.

The aim of this study was to examine the effects of 7-epiclusianone, a new prenylated benzophenone isolated from the plant Rheedia gardneriana, on some of the virulence properties of Streptococcus mutans associated with biofilm development and acidogenicity. The synthesis of glucans by glucosyltransferases B (GTF B) and C (GTF C) was markedly reduced by 7-epiclusianone showing more than 80% inhibition of enzymatic activity at a concentration of 100 microg mL(-1). Double-reciprocal analysis (Lineweaver-Burk plots) revealed that the inhibition of GTF B activity was noncompetitive (mixed) while GTF C was inhibited uncompetitively. The glycolytic pH drop by S. mutans cells was also disrupted by 7-epiclusianone without affecting the bacterial viability, an effect that can be attributed, in part, to inhibition of F-ATPase activity (61.1+/-3.0% inhibition at 100 microg mL(-1)). Furthermore, topical applications (1-min exposure, twice daily) of 7-epiclusianone (at 250 microg mL(-1)) disrupted biofilm formation and physiology. The biomass (dry-weight), extracellular insoluble polysaccharide concentration and acidogenicity of the biofilms were significantly reduced by the test agent (P<0.05). The data show that 7-epiclusianone disrupts the extracellular and intracellular sugar metabolism of S. mutans, and holds promise as a novel, naturally occurring compound to prevent biofilm-related oral diseases.

Experimental atherosclerosis in rabbits

Many researches have been conducted in experimental models in order to study the development of atherosclerosis from hyperlipidemia-inducing diets. Since rabbits are very sensitive to cholesterol-rich diets and accumulate large amounts of cholesterol in their plasma, their use as experimental models to evaluate the development of atherosclerosis is highly relevant and brings information on factors that contribute to the progression and regression of this condition that can be applied to humans. As such, this review includes studies on the atherogenic function of cholesterol based on rabbits as the experimental model, since they have become the most largely used experimental model of atherosclerosis.

Effect of flavonoids morin: quercetin and nicotinic acid on lipid metabolism of rats experimentally fed with triton

Atherosclerosis is a coronary disease where deposition of lipids in the arteries leads to problems of blood circulation. The present work evaluates the action of the flavonoids morin, quercetin and nicotinic acid isolated in association on lipid metabolism in hyperlipidemi c rats. Blood serum levels cholesterol, cholesterol-HDL, and triacylglycerids have been analysed following the intraperitoneal administration of the flavonoid compounds dissolved in propyleneglyc ol by in doses of 5mg/kg body weight. Quercetin presented the largest percentual reduction of cholesterol. The best results for cholesterol-HDL have been obtained with-nicotinic acid alone while morin-nicotinic acid combination showed the best triacylglycerols results. Results showed that flavonoids could be beneficious in the treatment of coronary diseases.

Bixina, Norbixina e Quercetina e seus efeitos no metabolismo lipídico de coelhos

Flavonoids have been isolated with several biological activities and there are correlations among the consumption of rich foods in flavonoids and heart diseases. The 7-glucosyl-apigenin, 7- bisulfate-apigenin, 7-glucosyl-luteolin, 7-bisulfate-luteolin flavonoids and bixin and norbixin were isolated from urucu seeds. The aim of this study was to test the bixin and norbixin dyes and quercetin flavonoid from urucu and bixin with quercetin association to obtain its hypolipidemic effects in rabbits. Induction of hyperlipidaemia was performed with 1% cholesterol + 0,1% colic acid during 28 days. The substances were applied through the oral route, in capsule, in the doses of 0,01 mol/kg body weight. Total cholesterol, HDL-cholesterol and triacylglycerols have quantified from serum, after 28 days, and showed in mg/dL The best results for total cholesterol reduction and the HDL-cholesterol elevated levels maintenance was obtained with bixin. On the other hand, the best results for triacylglycerols reduction have been obtained with quercetin. The bixin and quercetin association showed efficacy to HDL-cholesterol and triacylglycerols and norbixin to total cholesterol and HDL-cholesterol. These results stimulate further research on the use of these substances as pharmacs in the heart diseases treatment and/or prevention.

Epiclusianone: a New Natural Product Derivative of Bicyclo[3.3.1]nonane-2,4,9-trione

Epiclusianone [3-benzoyl-4-hydroxy-6,6-dimethyl-1,5,7-tris(3-methyl-2-butenyl)bicyclo[3.3.1]non-3-ene-2,9-dione] is a new isomeric form of the C 33 H 42 O 4 compound identified by X-ray diffraction analysis. Structure comparison with the known clusianone evidences a case of epimerism in one of the chiral C atoms. A comparison of the melting point and the optical activity of the two isomers shows them to have different values.

Antiproliferative effect of benzophenones and their influence on cathepsin activity.

The antiproliferative activity of two prenylated benzophenones isolated from Rheedia brasiliensis, the triprenylated garciniaphenone and the tetraprenylated benzophenone 7‐epiclusianone, was investigated against human cancer cell lines. The antiproliferative activity on melanoma (UACC‐62), breast (MCF‐7), drug‐resistant breast (NCI‐ADR), lung/non‐small cells (NCI460), ovarian (OVCAR 03), prostate (PC03), kidney (786‐0), lung (NCI‐460) and tongue (CRL‐1624 and CRL‐1623) cancer cells was determined using spectrophotometric quantification of the cellular protein content. The effect of these benzophenones on the activity of cathepsins B and G was also investigated. Garciniaphenone displayed cytostatic activity in all cell lines, whereas 7‐epiclusianone showed a dose‐dependent cytotoxic effect. The IC50 values for cell proliferation revealed that 7‐epiclusianone is more active than garciniaphenone against most of the cell lines. Furthermore, the antiproliferative effects demonstrated by garciniaphenone and 7‐epiclusianone were related to their cathepsin inhibiting properties. In conclusion, 7‐epiclusianone is a promising naturally occurring agent which displays multiple inhibitory effects which may be working in concert to inhibit cancer cell proliferation in vitro. The putative pathway by which 7‐epiclusianone affects cancer cell development may involve cathepsin inhibition. Copyright