Vascular Responses to Extractable Fractions of Ilex paraguariensis in Rats Fed Standard and High-Cholesterol Diets

Programa de Pós-Graduação em Ciências Fisiológicas-Fisiologia Animal Comparada, Fundação Universidade Federal do Rio Grande, Brazil.
Biological Research for Nursing (Impact Factor: 1.43). 11/2005; 7(2):146-56. DOI: 10.1177/1099800405280521
Source: PubMed


The authors investigated the vasorelaxant properties of the aqueous (Aq-EF) and acid n-butanolic (acn-BuOH) extractable fractions from Ilex paraguariensis leaves. Perfusion pressure was evaluated using isolated and perfused mesenteric arterial beds (MABs) from rats fed hypercholesterolemic and standard diets. Extract-induced vasorelaxation in the presence and absence of various inhibitors was examined following precontraction of the MABs with methoxamine (30 microM) solution. In hypercholesterolemic-diet rats, relaxation in intact MABs was significantly decreased with ac-n-BuOH-EF bolus (300, 600, 900 microg) in comparison to those in standard-diet rats. After the endothelium was stripped from the MABs, the vascular responses to ac-n-BuOH-EF and 900 microg bolus of Aq-EF were significantly changed. Treatment of the MABs with an inhibitor of nitric oxide synthase, N(G)-nitro-L-arginine methylester hydrochloride (L-NAME, 10 mM), did not change either ac-n-BuOH-EF- or Aq-EF-induced vasodilation except for the 900 microg bolus of Aq-EF. The guanilate cyclase inhibitor methylene blue (100 microM) did not affect vasodilation for either fraction in the MABs from the hypercholesterolemic-diet rats. The chronic oral administration of I. paraguariensis extract in hypercholesterolemic-diet rats resulted in a significant reduction in serum levels of cholesterol and triglycerides. These results suggest that I. paraguariensis ac-n-BuOH-EF and Aq-EF induce vasodilation in standard-diet rats in a dose-dependent manner and that the hypercholesterolemic diet substantially reduced the effect of ac-n-BuOH-EF on precontracted MABs.

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    • "YMT has been reported to have various biological activities, which have been related to its high content of polyphenols. Some of the pharmacological properties attributed to YMT include antioxidant capacity [2] [3], vasodilatation [4], anti-inflammation [5– 7], anti-microbial [7], inhibition of glycation and atherosclerosis [8], modulation of lipid metabolism [9] [10], antiobesity effects [11], and beneficial effects on glucose absorption and metabolism [12]. Previous in vitro and in vivo studies on the antitumor effect of YMT showed that extracts induced cytotoxicity in human squamous carcinoma cell line SCC-61 [13], in premalignant human skin keratinocytes cell line HaCaT and in human hepatoma cell line HepG2 with inhibition of topoisomerase II activity [14], as well as in human colorectal adenocarcinoma cells CaCo-2 and HT-29 [15]. "
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    ABSTRACT: Yerba mate tea (YMT) has a chemopreventive role in a variety of inflammatory diseases. The objective was to determine the capability of YMT and mate saponins to prevent azoxymethane (AOM)-induced colonic inflammation in rats. YMT (2% dry leaves, w/v, as a source of drinking fluid) (n = 15) and mate saponins (0.01% in the diet, at a concentration present in one cup of YMT) (n = 15) were given ad libitum to rats 2 weeks prior to AOM-injection until the end of the study; while control rats (n = 15) received a basal diet and drinking water. After 8-weeks of study, total colonic mucosa was scraped (n = 3 rats/group) and the remaining colons (n =12 rats/group) were cut into three equal sections and aberrant crypt foci (ACF) were analyzed. YMT reduced ACF formation from 113 (control group) to 89 (P < 0.05). YMT and mate saponins reduced the expression of proinflammatory molecules COX-2 and iNOS with concomitant reduction in p-p65 (P < 0.05). Immunohistochemical analysis of the formalin-fixed middle colons showed that YMT and mate saponins reduced the expression of p-p65(ser311) by 45.7% and 43.1%, respectively, in comparison to the control (P < 0.05). In addition, the expression of molecules upstream of NF-κB such as p-IκB-α and p-GSK-3β(Y216) was downregulated by YMT 24.7% and 24.4%, respectively (P < 0.05). Results suggest the mechanism involved in the chemopreventive effect of YMT and mate saponin consumption in AOM induced-colonic inflammation in rats is through inhibition of NF-κB. © 2013 BioFactors, 2013.
    Full-text · Article · Jul 2013 · BioFactors
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    • "), lipolytic, hypolipidemic (Kim et al., 2012; Martins et al., 2009; Paganini Stein et al., 2005; Pang et al., 2008), prevention of lipoprotein oxidation (Bracesco et al., 2011), and thermogenic (Martinet et al., 1999) activities. Weight reduction induced by mate had been associated with these activities, but other factors may be involved, such as cholesterol binding by saponins in intestinal lumen (Francis et al., 2002), appetite suppression (Andersen and Fogh, 2001; Pang et al., 2008), and pancreatic lipase inhibition (Kim et al., 2009; Martins et al., 2009; Sugimoto et al., 2009). "
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    ABSTRACT: Ethnopharmacological relevance: Ilex paraguariensis A. St. Hilaire (mate) has traditionally been used in several South American countries to prepare tea-like beverages having stimulant effects on the CNS and appetite. In recent years, however, mate preparations have been recommended putatively as an appetite suppressant and slimming remedy. Moreover, studies carried out on either normal or diet-induced obese rats treated with mate extracts revealed anti-obesity and satiety effects, thus refuting ethnopharmacological data. In this work, the effect of mate on the intra-abdominal and epididymal fat, and glucose oxidation levels after oral administration in male Wistar rats, was studied using crude extract from leaves, unripe fruits, and a chemically well-defined purified saponin fraction (MSF). Material and methods: Saponin, polyphenol and methylxanthine contents in MSF were analyzed by HPLC-PDA and UPLC/Q-TOF-MS. Crude extracts from mate leaves (LAE) and unripe fruits (FHE) were assayed for comparison purposes. Male Wistar rats fed with standard diet and water ad libitum were used as the control group. Results: The fat weight and both liver and adipose glucose oxidation were reduced significantly by MSF (35, 90 and 60%, respectively), while LAE and FHE were less active. Also, a significant lowering of the blood triglycerides level was observed in rats treated with MSF and LAE. All creatinine, urea, and transaminase plasma levels remained unaffected no matter what mate preparation was considered. It is also worth pointing out that the glucose blood level was increased after treatment with FHE. This finding did not correlate either with the content of methylxanthines, polyphenols or saponins. Conclusion: A reduction in both visceral fat weight and glucose oxidation of hepatic and adipose tissue in healthy rats fed with a standard diet could be ascribed to a purified mate saponin fraction from unripe fruits. These findings agree with former studies carried out with crude mate extracts and also suggest their potential use as an anti-obesity preparation. Nonetheless, further in vivo experiments are still required to corroborate its effect on human beings.
    Full-text · Article · Oct 2012 · Journal of ethnopharmacology
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    • "c o m Nutrition 28 (2012) 1157–1164 potential benefits of I. paraguariensis to human health, particularly in the prevention of cardiovascular diseases [5]. Studies on in vitro systems and in vivo models have shown that yerba mate possesses vasorelaxation [6] [7] [8], anti-inflammatory [9] [10], anti-atherosclerotic [11], hypocholesterolemic [4] [7] [12], and antioxidant [1–3,13] properties. Recently, our research group demonstrated that the ingestion of green or roasted yerba mate infusions decreased low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol levels in healthy subjects, particularly in hypercholesterolemic individuals on statin therapy [4], and in prediabetic or type 2 diabetic subjects [14]. "
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    ABSTRACT: Paraoxonase-2 (PON-2) is an intracellular antioxidant enzyme that can be modulated by polyphenols. The aim of this study was to verify whether yerba mate (Ilex paraguariensis), a plant species rich in phenolic compounds, modulates gene expression and the activity of PON-2 in macrophages in vitro and in monocytes from peripheral blood and monocyte-derived macrophages obtained after the ingestion of green or roasted yerba mate infusions by healthy subjects. THP-1 macrophages were incubated with increasing amounts of yerba mate extracts or chlorogenic and caffeic acids (1-10 μmol/L). The in vivo effects of yerba mate or water (control) intakes were evaluated acutely (2 h after ingestion) and in the short term (after daily ingestion for 7 d) in 20 healthy women. In general, there was no difference between the two kinds of yerba mate studied. Yerba mate extracts or chlorogenic acid at 1 and 3 μmol/L increased PON-2 relative gene expression in THP-1 macrophages (P < 0.05), whereas higher concentrations (5 and 10 μmol/L) increased the activity only. Caffeic acid induced PON-2 activity only. The acute ingestion of yerba mate infusions increased relative gene expression and PON-2 activity in monocytes (P < 0.05), whereas the consumption of yerba mate for 7 d increased PON-2 relative gene expression (P < 0.05) and had a tendency to increase PON-2 activity in monocytes and monocyte-derived macrophages. It is suggested that green or roasted yerba mate modulates positively the mRNA relative expression and activity of the PON-2 enzyme in monocytes and macrophages, which may prevent cellular oxidative stress.
    Full-text · Article · Sep 2012 · Nutrition
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