Effect of the vehicle polyvinylpyrolidone and the Methanolic Fraction of Ligaria cuneifolia (Argentine Mistletoe) extract on hemorheological properties and biliary secretion in rats.

Ligaria cuneifolia (R et P) Tiegh. (Loranthaceae) (Lc) aqueous extract-treated rats by via intraperitoneal (i.p.) show increased blood viscosity and decreased plasma cholesterol (Chol) levels. In this work, we analize the effect of the vehicle polyvinylpyrrolidone (PVP) and that of the Methanolic Fraction of the extract of Lc (MFLc) on hemorrheological properties in vivo and in vitro and on biliary excretion. For in vivo conditions, adult male Wistar rats were divided in five experimental groups (n=5 each one) which were injected, every 24 hr during 3 days by via i.p., with: (1) saline solution (Control); (2) PVP 0.47 mg/100 g bw; (3) MFLc 0.95 mg/100 g bw plus PVP 0.47 mg/100 g bw; (4) PVP 12.5 mg/100 g bw; and (5) MFLc 23.0 mg/100 g bw plus PVP 12.5 mg/100 g bw. Intended for in vitro conditions, blood samples obtained by heart puncture were divided into three fractions, which were incubated with: saline solution (Control), PVP 12.5 mg%, and MFLc 25 mg% plus PVP 12.5 mg%. We demonstrated a direct effect of PVP alone and of MFLc "per se" on the erythrocyte membrane resulting in a cell shape change from dyscocyte to spherostomatocyte (MI more negative) as well as a decrease in erythrocyte deformability (increased RI). These changes induce an increase in blood viscosity. Decreased plasma Chol is a consequence of an increased bile salts biliary excretion.

The Enriched Proanthocyanidin Extract of Ligaria cuneifolia Shows a Marked Hypocholesterolemic Effect in Rats Fed with Cholesterol-Enriched Diet.

BACKGROUND: Ligaria cuneifolia (Lc) (R. et P.) Tiegh. (Loranthaceae) (Argentine mistletoe) is usually used in local folk medicine. OBJECTIVE: We studied the effect of treatment with the Lc proanthocyanidin-enriched fraction (PLc) in rats fed with Cho-enriched diet on plasma lipids levels, the hemorheological parameters, and biliary secretion. METHOD: Adult male Wistar rats were fed ad libitum with a Cho-enriched diet (Cho (97% purity) 8 g/kg of diet and corn oil 280 g/kg of diet) during 28 days. Then, were separated in six experimental groups (n=5 each one), which were injected ip every 24 h with: 1) saline solution (control group, C) and 2) PLc, 3 mg/100 g body weight (treated group, C+PLc), during 3, 7 and 10 days. Group C presented an increase in plasma levels of Cho and Triglycerides (TG), and also, accumulation of hepatic lipid droplets. Also, cell shape and their corresponding morphological index (MI) were altered too. RESULTS: The treatment with PLc at 3, 7 and 10 days produces a diminution in the plasma Cho, LDL-Cho and serum TG levels, accompanied by a diminution of the lipid accumulation in the liver. The rates of bile acid output in bile can explain the diminution of plasma Cho, evidencing that some of the enzymes involved in the cholesterol conversion into bile acids could be up regulated by the treatment with PLc, leading to the observed increase bile flow. PLc treatment leads to a diminution of plasma levels of Cho and TG. CONCLUSION: Essentially, the treatment with PLc, despite the duration produces a modification in hemorheological parameters approaching the values of the experimental group with standard diet. Plasma levels of Cho, LDL-Cho and TG represent selected markers to evaluate the effect of enriched extract from Ligaria cuneifolia. Further work is necessary to better evaluate the mechanisms by which PLc induces modifications in the lipids metabolism.

Effects of proanthocyanidin enriched extract from Ligaria cuneifolia on plasma cholesterol and hemorheological parameters. In vivo and In vitro studies.

UNLABELLED: It was demonstrated that Ligaria cuneifolia (Lc) crude extract increased blood viscosity and decreased plasma cholesterol in rats. In the present study, we analyzed the Lc proanthocyanidin enriched fraction (PLc) to determine if it is capable of altering the hemorheological parameters while diminishing the plasma cholesterol. In vivo studies in adult male Wistar rats, randomized in three groups (n = 6 each one) were performed: 1. CONTROL: saline intraperitoneal (i.p.); 2. PLc 0.6 mg/100 g body weight (b.w.) i.p. and 3. PLc 3 mg/100 g b.w. i.p., every 24 hours during 3 days. IN VITRO STUDIES: with blood obtained by cardiac puncture, separated in aliquots and incubated with: 1. Saline solution (Control); 2. PLc 0.1 mg/mL, and 3. PLc 1.0 mg/mL, equivalent to doses in vivo experiments. The results demonstrated that in vivo PLc 0.6 and PLc 3 reduced plasma cholesterol (Cho) and LDL-Cho. Neither blood nor plasma viscosity was altered. Decrease of plasma cholesterol could be due to an increase of cholesterol and bile salts excretion leading to an increase of bile flow. In vitro experiments showed a direct interaction of PLc, at high concentration, with the erythrocyte membrane, inducing a switch from discocyte to stomatocyte. Only, PLc without hepatic metabolism produces hemorheological changes. Thus, PLc in vivo might be a pharmacological agent capable of decreasing plasma cholesterol.

Hemorrheologic changes induced by aqueous extract of Ligaria cuneifolia: treatment by two different administration routes.

Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae) (Argentine mistletoe) is usually used in local folk medicine. This work focuses on the hemorrheologic parameters in the treatment with an aqueous extract of Ligaria cuneifolia (Lc) by two different administration routes: intraperitoneal (i.p.) and intravenous (i.v.). Adult male Wistar rats were injected by via i.p. or by via i.v. with: saline solution; 2.5 mg/100 g body weight of Lc and 5.5 mg/100 g body weight of Lc. The relative viscosity of blood (eta r)(45/Hct) was measured showing that Lc-treatment by via i.p. produced an increase of about 69% while Lc by via i.v. enhanced the parameter about 47%. All of Lc-treated animals showed a significant increase in the rigidity index (RI). The mean corpuscular hemoglobin concentration (MCHC) exhibited an increase of about 15% in all the treated groups. Lc-treatment by via i.p. produced a diminution of plasma cholesterol level associated with RI augmentation which induced an increase of (eta r)(45/Hct). By via i.v. Lc produces both RI and (eta r)(45/Hct) augmentation by increasing MCHC but without modifying plasma cholesterol level, indicating a direct Lc-action on the internal viscosity of the erythrocyte.

Effect of Ligaria cuneifolia catechin- and quercetin-enriched fractions on hemorheology and plasma cholesterol.

UNLABELLED: We tested the in vivo and the in vitro effects of both Ligaria cuneifolia catechin- and quercetin-enriched fractions on erythrocyte shape and deformability, and on plasma cholesterol level. For in vivo studies, adult male Wistar rats were randomized in three experimental groups which received intraperitoneally, once a day, 3 days: CONTROL: saline solution (C; n = 6); catechin from L. cuneifolia, 0.60 mg/100 g body weight (CLc; n = 6), or quercetin from L. cuneifolia, 2.3 mg/100 g body weight (QLc; n = 6). For in vitro studies, blood samples obtained from male Wistar rats were divided into three fractions, which were incubated with saline solution (C), catechin (CLc; n = 5) and quercetin (QLc; n = 5), in a concentration equivalent to 0.60 mg/100 g body weight, and 2.3 mg/100 g body weight, respectively. CLc significantly reduced the rigidity index due to a diminished mean concentration volume. QLc induced erythrocyte rigidization (less deformability), thus increasing blood viscosity. Neither of the two treatments produced any changes in plasmatic or biliary excretion of cholesterol. Opposite results were observed in rigidity index with CLc and QLc. In vitro studies showed an interaction of both CLc and QLc with the erythrocyte membrane, which induced changes in the erythrocyte shape from discocyte to stomatocyte.