Antioxidant effects of an aqueous extract of Ilex paraguariensis

In this work we investigate the antioxidant properties of an aqueous extract prepared from an infusion of Ilex paraguariensis (Aquifoliaceae) using free radical-generating systems. The extract inhibited the enzymatic and nonenzymatic lipid peroxidation in rat liver microsomes in a concentration-dependent fashion, with IC(50) values of 18 microg/ml and 28 microg/ml, respectively. The extract also inhibited the H(2)O(2)-induced peroxidation of red blood cell membranes with an IC(50) of 100 microg/ml and exhibited radical scavenging properties toward superoxide anion (IC(50) = 15 microg/ml) and 2,2-diphenyl-1-picrylhydrazyl radical. In the range of concentrations used, the extract was not a scavenger of the hydroxyl radical. Our results suggest that ingestion of extracts of Ilex paraguariensis could contribute to increase the antioxidant defense of an organism against free radicals attack.     

Yerba mate extract (Ilex paraguariensis) attenuates both central and peripheral inflammatory effects of diet-induced obesity in rats

To clarify the effects of natural dietary components on the metabolic consequences of obesity, we examined the effects of yerba mate extract Ilex paraguariensis on both central and peripheral inflammatory effects of diet-induced obesity and correlated the hypothalamic tumor necrosis factor (TNF)-α level with adipose depot weight. Wistar rats were divided into four groups: a control group (CTL) fed with chow diet, a second group fed with chow diet plus yerba mate extract (CTL+E), a third group fed with a high-fat diet rich in saturated fatty acids (HFD) and a fourth group fed with HFD plus yerba mate extract (HFD+E). Enzyme-linked immunosorbent assay, Western blotting, colorimetric method and treatment by gavage were utilized as materials and methods. The HFD groups showed a significant increase in food intake (kcal), body weight, adipose tissue and leptin level in comparison to CTL and CTL+E. HFD leads to increase of both central and peripheral inflammatory effects, and deregulation of insulin pathway. In addition, yerba mate extract intake blunted the proinflammatory effects of diet-induced obesity in rats by reducing the phosphorylation of hypothalamic IKK and NFκBp65 expression and increasing the protein levels of IκBα, the expression of adiponectin receptor-1 and consequently the amount of IRS-2. Moreover, the increase in interleukin (IL)-6 levels in the liver and muscle and of the IL-10/TNF-α ratio in groups that received yerba mate extract showed the anti-inflammatory effects of this natural substance. Taken together, our data suggest that the use of yerba mate extract may be useful for reducing low-grade obesity-associated inflammation.     

Glucosylation of ethanol in Ilex paraguariensis cell suspension cultures

To study the stress and defense response of plant cell cultures of Ilex paraguariensis St. Hil., methyl jasmonate, salicylic acid, and cellulase were added, with ethanol and water used as controls. Comparison of methanolic extracts of the treated cells showed a clear decrease in the carbohydrate content of the cells relative to the controls. One new major compound was observed, which was isolated and identified by its spectral data as 1-O-ethyl-β-glucopyranoside. This compound was found especially in the cells treated with methyl jasmonate and salicylic acid, which were both dissolved in ethanol. Addition of ethanol alone also resulted in the formation of the glucoside. Addition of methanol lead to the formation of the corresponding glucoside, while n-propanol addition resulted in only a small amount of the propyl glucoside; with n-butanol, n-octanol, and n-decanol, the corresponding glucosides could not be observed. Cell growth was severely affected by addition of the higher alcohols. From the present study, it is clear that ethanol cannot be considered as an inert solvent for these cell cultures. Received: 11 April 1997 / Revision received: 23 September 1997 / Accepted: 1 November 1997     

Ilex paraguariensis extract ameliorates obesity induced by high-fat diet: potential role of AMPK in the visceral adipose tissue

The aim of present study was to investigate the anti-obesity effect of Ilex paraguariensis extract and its molecular mechanism in rats rendered obese by a high-fat diet (HFD). I. paraguariensis extract supplementation significantly lowered body weight, visceral fat-pad weights, blood and hepatic lipid, glucose, insulin, and leptin levels of rats administered HFD. Feeding I. paraguariensis extract reversed the HFD-induced downregulation of the epididymal adipose tissue genes implicated in adipogenesis or thermogenesis, such as peroxisome proliferators’ activated receptor γ2, adipocyte fatty acid binding protein, sterol-regulatory-element-binding protein-1c, fatty acid synthase, HMG-CoA reductase, uncoupling protein 2, and uncoupling protein 3. Dietary supplementation with I. paraguariensis extract protected rats from the HFD-induced decreases in the phospho-AMP-activated protein kinase (AMPK)/AMPK and phospho-acetyl-CoA carboxylase (ACC)/ACC protein ratio related to fatty acid oxidation in the edipidymal adipose tissue. The present study reports that the I. paraguariensis extract can have a protective effect against a HFD-induced obesity in rats through an enhanced expression of uncoupling proteins and elevated AMPK phosphorylation in the visceral adipose tissue.     

G-CSF prevents the progression of atherosclerosis and neointimal formation in rabbits

Granulocyte colony-stimulating factor (G-CSF) prevents left ventricular remodeling after myocardial infarction, but its effect on atherosclerosis is unknown. We examined two kinds of rabbit atherosclerosis models. Myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHL-MI) rabbits were treated with G-CSF or saline for 7 days from 14 months old. The vascular injury models were created by inflating angioplasty balloon in the iliac artery of rabbits and were divided into G-CSF and saline group. G-CSF significantly reduced the stenosis score of coronary artery and lipid plaque area of thoracic aorta in WHHL-MI rabbits at 4 weeks after the treatment. In the vascular injury model, G-CSF significantly prevented an increase in neointima/media ratio at 4 weeks after the treatment. G-CSF accelerated the reendothelialization of denuded arteries, and the pretreatment with nitric oxide synthase inhibitor significantly inhibited it. These results suggest that G-CSF has a therapeutic potential for the progression of atherosclerosis.     

Trehalose administration attenuates atherosclerosis in rabbits fed a high-fat diet

Disruption of macrophage autophagy is a major contributor to macrophage dysfunction and subsequent inflammation leading to atherosclerosis. Trehalose is a natural disaccharide that is able to induce macrophage autophagy-lysosomal biogenesis and reduce inflammation. Here, we studied the efficacy of intravenous trehalose administration in reducing atherosclerotic plaque burden in high-cholesterol-fed rabbits. Adult male New Zealand white Rabbits were fed with a high-fat diet containing 1% cholesterol for 8 weeks followed by a cholesterol-free diet for the next 4 weeks. In the latter 4-week phase of the cholesterol-free diet, one group received intravenous trehalose solution at a dose of 350 mg/kg, three times per week. In the control group, an equivalent volume of PBS (3 mL) was administered with the same protocol. At the end of the 12th week of the study, all rabbits were anesthetized and aortic arch sections were collected followed by hematoxylin and eosin staining and assessment of plaque grading. Fasting serum lipids were also measured using routine enzymatic methods. At the end of the 12th week, there were no significant differences in the body weight and blood lipids between the control- and trehalose-treated groups. Intravenous trehalose administration significantly attenuated atherosclerotic plaque development as revealed by reduced plaque grading ( P = 0.048) and intima/media thickness ratio ( P = 0.017). Intimal thickening was also found to be reduced in the trehalose versus control group, though this reduction did not reach statistical significance. The present study provided evidence as to the efficacy of short-term intravenous trehalose administration in regressing atherosclerotic plaque in high-fat-fed rabbits.     

In vitro plant regeneration of Ilex paraguariensis (aquifoliaceae)

Summary Nodal segments as well as shoot tips and apical meristems of 2-yr-old “maté” plants (Ilex paraguariensis St. Hil.) were cultured in vitro to establish micropropagation systems. Maximum shoot regeneration was achieved when nodal segments were cultured with 1/4 Murashige and Skoog (MS) medium with 3% sucrose. We induced roots to differentiate by transferring the regenerated shoots onto the same medium, solidified with 2.5 g Phytagel per 1 and supplemented with indole-3-butyric acid (7.4 μM) and finally transferring shoots to 1/4 MS medium with 3% sucrose and lacking growth regulators. Plants were successfully established in soil.     

Influence of the traditional Brazilian drink Ilex paraguariensis tea on glucose homeostasis

In this study we examined the acute in vivo effect and short- and long-term in vitro effects of samples from native and commercial Ilex paraguariensis on glucose homeostasis. Also, the potential effect of I. paraguariensis on serum insulin secretion was investigated. The chemical identification and quantification of methyl xanthines and polyphenols in CH(2)Cl(2), EtOAc and n-BuOH fractions of native I. paraguariensis as well as infusions of green and roasted I. paraguariensis from a commercial source was verified by high-performance liquid chromatography. The results for the serum glucose-lowering indicated that both fractions and both infusions were able to improve significantly the oral glucose tolerance curve. Additionally, both the EtOAc and n-BuOH fractions induced-insulin secretion, but EtOAc induced an early (at 15min) and late (at 60min) biphasic peak of insulin secretion similar to glipizide stimulatory effect. Both fractions increased liver glycogen content compared with fasted normal rats. Also, EtOAc and n-BuOH fractions inhibited in vitro disaccharidases activities after an acute treatment. The maximum inhibitory effect of the EtOAc and n-BuOH fractions on maltase activity (at 5min) was around 35%. The evident reduction of protein glycation by glucose or fructose with EtOAc and n-BuOH fractions increased from 7 to 28 days of in vitro incubation. Inhibition of bovine serum albumin glycation by glucose and fructose, by around 50% and 90%, respectively, was observed. Additionally, the green and roasted mate infusions reduced the formation of AGEs in a characteristic long-term effect. In conclusion, this study shows that I. paraguariensis has an anti-hyperglycemic potential role able to improve the diabetic status and is probably a source of multiple hypoglycemic compounds.     

Constituents of antibacterial extract of Caesalpinia paraguariensis Burk

The Argentinean legume Caesalpinia paraguariensis Burk. (Fabaceae) was selected for further fractionation work based on the strong antimicrobial activity of its CH2Cl2-MeOH (1:1 v/v) extract against a host of clinically significant microorganisms, including antibiotic resistant strains. 1D and 2D NMR enabled the identification of the novel benzoxecin derivative caesalpinol along with the known compounds bilobetin, stigma-5-en-3-O-beta-6'-stearoylglucopyranoside, stigma-5-en-3-beta-6'-palmitoylglucopyranoside, stigma-5-en-3-beta-glucopyranoside, oleanolic acid, 3-O-(E)-hydroxycinnamoyl oleanolic acid, betulinic acid, 3-O-(E)-hydroxycinnamoyl betulinic acid, and lupeol from the active fractions. Oleanolic acid was found active against Bacillus subtilis and both methicillin-sensitive and -resistant Staphylococcus aureus with MICs of 8 (17.5 microM), 8 and 64 (140 microM) microg/ml, respectively. The rest of the compounds, however, did not show activity.     

Mast cell deficiency attenuates progression of atherosclerosis and hepatic steatosis in apolipoprotein E-null mice

Mast cells are important cells of the immune system and are recognized as participants in the pathogenesis of atherosclerosis. In this study, we evaluated the role of mast cells on the progression of atherosclerosis and hepatic steatosis using the apolipoprotein E-deficient (ApoE(-/-)) and ApoE(-/-)/mast cell-deficient (Kit(W-sh/W-sh)) mouse models maintained on a high-fat diet. The en face analyses of aortas showed a marked reduction in plaque coverage in ApoE(-/-)/Kit(W-sh/W-sh) compared with ApoE(-/-) after a 6-mo regimen with no significant change noted after 3 mo. Quantification of intima/media thickness on hematoxylin and eosin-stained histological cross sections of the aortic arch revealed no significant difference between ApoE(-/-) and ApoE(-/-)/Kit(W-sh/W-sh) mice. The high-fat regimen did not induce atherosclerosis in either Kit(W-sh/W-sh) or wild-type mice. Mast cells with indications of degranulation were seen only in the aortic walls and heart of ApoE(-/-) mice. Compared with ApoE(-/-) mice, the serum levels of total cholesterol, low-density lipoprotein and high-density lipoprotein were decreased by 50% in ApoE(-/-)/Kit(W-sh/W-sh) mice, whereas no appreciable differences were noted in serum levels of triglycerides or very low density lipoprotein. ApoE(-/-)/Kit(W-sh/W-sh) mice developed significantly less hepatic steatosis than ApoE(-/-) mice after the 3-mo regimen. The analysis of Th1/Th2/Th17 cytokine profile in the sera revealed significant reduction of interleukin (IL)-6 and IL-10 in ApoE(-/-)/Kit(W-sh/W-sh) mice compared with ApoE(-/-) mice. The assessment of systemic generation of thromboxane A(2) (TXA(2)) and prostaglandin I(2) (PGI(2)) revealed significant decrease in the production of PGI(2) in ApoE(-/-)/Kit(W-sh/W-sh) mice with no change in TXA(2). The decrease in PGI(2) production was found to be associated with reduced levels of cyclooxygenase-2 mRNA in the aortic tissues. A significant reduction in T-lymphocytes and macrophages was noted in the atheromas of the ApoE(-/-)/Kit(W-sh/W-sh) mice. These results demonstrate the direct involvement of mast cells in the progression of atherosclerosis and hepatic steatosis.     

Caffeine and theobromine in epicuticular wax of Ilex paraguariensis A. St.-Hil

Caffeine and theobromine were identified and quantified in leaf epicuticular waxes of Ilex paraguariensis A. St.-Hil. (Aquifoliaceae). The total epicuticular leaf wax content was ca. 0.5% on average of dry leaf weight. Epicuticular caffeine and theobromine contents varied from 0.16 to 127.6 microg/mg and from 0 to 9.5 microg/mg of wax, respectively. For some selected samples, the intracellular methylxanthine concentration was also determined. A positive correlation was found between inner and epicuticular caffeine contents.     

Pollenkitt formation in Ilex paraguariensis A.St.Hil. (Aquifoliaceae)

 We investigated the cellular and organelle transformations during the formation of the pollenkitt in the secretory tapetum of Ilex paraguariensis. After the dissolution of the callose surrounding the young microspores, the elaioplasts of the tapetum produce many globules of saturated and unsaturated lipids (plastoglobules). Further on, oleosomes with unsaturated lipids, synthesized in the endoplasmic reticulum, accumulate in the tapetal cytoplasm. In contrast to other species, the plastoglobule production seems to precede the oleosome synthesis. The tapetum shows signs of cellular maturation in the late vacuolated microspore stage, when the plastoglobules and oleosomes coalesce and form the pollenkitt mass. In mature stages of the tapetum the pollenkitt is released into the loculus. Finally, it is mainly deposited on the exine, according to the entomophilous character of this species. The mode of pollenkitt formation in Ilex para guariensis and its transfer to the pollen surface is slightly dissimilar to other Angiosperms. Received October 24, 2002; accepted December 2, 2002 Published online: March 20, 2003     

Change of hematocrit and blood viscosity in cholesterol-fed rabbits

In the cholesterol-fed rabbits, we observed that the whole blood viscosity was maintained at the normal level in spite of the decrease in hematocrit. This phenomenon suggests that there exists some visco-regulatory mechanism, and we could simulate it by a simple integration type model.