NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
generally attributed to the flavonoid and procyanidin constituents of the
leaves with flowers (3, 36–38). A hydroalcoholic extract of the flowers
with leaves, flavonoid and procyanidin fractions of the extract, and isolated
constituents (e.g. biogenic amines, crataegolic acid, epi-catechin, hyperoside,
luteolin 7-glucoside, rutin and vitexin) all have positive inotropic
effects, and prolong the refractory period in cardiac myocytes,
isolated papillary muscles and isolated guinea-pig hearts (36–48). In isolated
guinea-pig hearts perfused at constant pressure, 3 µg/ml of a standardized
extract increased the contractility of the heart by 9.5% (40). In
isolated, electrically stimulated strips of failing human left ventricular
myocardium, a standardized extract (18.75% oligomeric procyanidins)
increased the force of contraction at concentrations higher than 10 µg/ml;
a 100 µg/ml extract improved the force–frequency relationship (39). A
standardized extract of the leaves and flowers increased the contractility
of myocardial cells by 153%, at a concentration of 120 µg/ml (44). An
aqueous extract of the leaves with flowers, two proanthocyanidin fractions
and two flavonoid fractions of the extract dilated coronary blood
vessels, and had positive inotropic effects on isolated guinea-pig hearts
(extract or fraction: 0.05 mg/ml) (41).
Chronotropic effects
Intragastric administration of a macerate or fluidextract of the shoots,
flowers or leaves to rats (12.5–25.0 mg/kg body weight) significantly inhibited
arrhythmias induced by aconitine, calcium chloride or chloroform/epinephrine
(P < 0.05) (49, 50). The extracts also reduced blood pressure
in rats at the same dosage (49, 50). Aconitine-induced arrythmias
were also inhibited after intravenous administration of a 95% ethanol extract
of the bark and leaves (50 mg/kg body weight) to rabbits (51). Intravenous
administration of a flavonoid-enriched extract of the leaves and
flowers to rabbits (20 mg/kg body weight) or rats (2 mg/kg body weight)
inhibited barium chloride-induced arrhythmias (52, 53). Intravenous administration
of a standardized extract (containing 18.75% oligomeric procyanidins)
to anaesthetized dogs (7.5–30.0 mg/kg body weight) increased
maximum left ventricular contraction velocity by 16.8–31.1% (54).
An aqueous extract improved cardiac performance during reperfusion,
reduced lactate levels and accelerated energy metabolism in reperfused
ischaemic rat heart. No increase in coronary blood flow was observed
(55). Intragastric administration of single doses of a standardized extract
(containing 18.75% oligomeric procyanidins) of the leaves with flowers
(100 mg/kg body weight) or an oligomeric procyanidin-enriched fraction
(20 mg/kg body weight) daily to rats protected against perfusion-induced
98