RESUMO
Background: Gomphrena perennis L. is a native plant of South America whose pharmacological properties have not been studied yet. Aim: To evaluate the cardiovascular and intestinal pharmacological effects of Gomphrena perennis L. leaves tincture (GphT) and the mechanisms involved. Experimental procedure: The chromatographic profile of GphT was done. Its ex vivo effects were evaluated by contractile concentration-response curves (CRCs) obtained from the agonist carbachol or calcium found in isolated rat small intestine, as well as in the relaxant CRCs. Cardiac effects were evaluated on isolated rat hearts exposed to ischemia/reperfusion (I/R). Experiments in vivo were performed to evaluate the diuretic activity in conscious rats and the hypotensive effect in anaesthetised rats. Results: Fifteen flavonoids were identified in GphT by HPLC-UV, including diosmin. GphT induced a non-competitive inhibition in both carbachol and calcium CRCs on rat small intestine. The first was not affected by indomethacin. Moreover, GphT, unlike diosmin, relaxed the contracture produced by a high-potassium solution in a dose-dependently way. Neither propranolol nor l-NAME changed it. GphT did not show diuretic activity but induced hypotension insensitive to l-NAME. While GphT perfusion of isolated hearts increased injury consequent to I/R, oral administration was cardioprotective and reversed by l-NAME. However, diosmin did not improve the post-ischemic recovery. Conclusions: This study supports the use of Gomphrena perennis L. tincture as an antispasmodic and hypotensive agent. Moreover, it has been demonstrated to be preventive of post-ischemic cardiac dysfunction. However, diosmin would not be responsible for these effects.
RESUMO
BACKGROUND AND AIM: Phytoestrogens are traditionally used for cardiovascular risks but direct effects on the ischemic heart remain unclear. Plants with phytoestrogens are used for reducing menopausic symptoms and they could also be cardioprotectives. Here we investigated whether maca (Lepidium meyenii) contains isoflavones and prevents cardiac stunning, in comparison to soy isoflavones. EXPERIMENTAL PROCEDURE: Both products were orally and daily administered to rats during 1 week before exposing isolated hearts to ischemia/reperfusion (I/R). Young male (YM), female (YF) and aged female (AgF) rats treated with maca (MACA, 1 g/kg/day) or soy isoflavones (ISOF, 100 mg/kg/day) were compared to acute daidzein (DAZ, 5 mg/kg i.p.) and non-treated rat groups. Isolated ventricles were perfused inside a calorimeter to simultaneously measure contractile and calorimetrical signals before and during I/R. RESULTS AND CONCLUSIONS: Maca has genistein and daidzein. MACA and ISOF improved the post-ischemic contractile recovery (PICR) and muscle economy (P/Ht) in YM and YF hearts, but not in AgF hearts. DAZ improved PICR and P/Ht more in YM than in YF. The mKATP channels blockade reduced both PICR and P/Ht in DAZ-treated YM hearts, without affecting them in ISOF or MACA-treated YM hearts. In MACA treated YF hearts, the simultaneous blockade of NOS and mKATP channels, or the mNCX blockade reduced cardioprotection. Results show that subacute oral treatment with maca or with soy isoflavones was strongly preventive of cardiac ischemic dysfunction, more than the acute administration of a pure isoflavone (daidzein, genistein). Maca induced synergistic and complex mechanisms which prevented mitochondrial calcium overload.
