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. A. Dominighini et al. / Effect of Ligaria cuneifolia catechin-and quercetin-enriched fractions

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.

Ligaria cuneifolia (Lc) (R. et P.) Tiegh. (Loranthaceae), popularmente conocida como “muérdago criollo”, “liga” o “liguilla”, es una especie hemiparásita, que se encuentra en el centro y norte de Argentina. En medicina tradicional es utilizada para disminuir la presión arterial y el colesterol. Basándonos en las observaciones empíricas, planteamos como objetivo demostrar científicamente que Ligaria cuneifolia tiene propiedades hipotensoras e hipocolesterolémicas. En ratas Wistar machos adultas alimentadas con dieta normal, enriquecida en colesterol y en hiperlipémicas (alimentadas con High Fat Diet), demostramos que el tratamiento por vía intraperitoneal con una fracción enriquecida en Proantocianidinas extraídas de Lc (PLc) produce disminución del 40% del colesterol plasmático (Co) debido al aumento de la velocidad de excreción biliar de sales biliares, así como disminución de triglicéridos y LDLCo, sin producir cambios en la fluidez de la sangre. Evaluamos el efecto vasoactivo de PLc in vitro en anillos de aorta aislada de ratas determinando su tensión isométrica, presentando efecto vasodilatador dependiente de endotelio, ya que la remoción mecánica del mismo anula completamente la relajación. El tratamiento con infusión de extracto liofilizado de hojas y tallos de Lc ingerida tres veces por semana durante dos meses por pacientes hipercolesterolémicos de ambos sexos (edad: 50 ± 15 años), permitió observar descenso en los niveles Co y LDLCo, sin mostrar alteraciones en la fluidez de la sangre ni en la funcion hepático. Conclusión: Ligaria cuneifolia sería una potencial herramienta en la prevención de enfermedades cardiovasculares, por disminuir el Colesterol plasmático y presentar un marcado efecto hipotensor.