NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
leaves with flowers (equivalent to 6 mg of procyanidins/kg body weight)
to anaesthetized normotensive dogs decreased norepinephrine-induced elevation
of blood pressure. The extract (equivalent to 0.03 mg procyanidins/ml)
also had β-blocking activity and inhibited epinephrine-induced
tachycardia in isolated frog hearts (69). Hyperoside, isolated from an extract
of the leaves and flowers, administered either intravenously at a dose
of 1 mg/kg body weight or by infusion at 0.1 mg/kg body weight/min for
30 min, decreased blood pressure in anaesthetized dogs (68). Intravenous
administration of an aqueous extract of the leaves (average dose 31 mg/kg
body weight) decreased the systolic, diastolic and mean blood pressure in
normotensive anaesthetized rats (66). Acute or chronic intragastric administration
of a fluidextract or a glycerol/ethanol extract reduced arterial
blood pressure in normotensive rats and in rats with desoxycorticosterone
acetate-induced hypertension (50). Intragastric administration of a standardized
extract (300 mg/kg body weight daily) decreased blood pressure
by 9 mm Hg (1.20 kPa) (67). Intravenous administration of a standardized
extract (containing 18.75% oligomeric procyanidins) to anaesthetized rats
(30 mg/kg body weight) or dogs (15 mg/kg body weight) decreased total
peripheral resistance and arterial blood pressure (54).
Anti-inflammatory effects
Both free radical production and lipid peroxidation are involved in various
pathological processes, including cardiac ischaemia. As determined
by in vitro studies, Folium cum Flore Crataegi has free radical scavenging
and antioxidant activities. A standardized extract (containing 18.75%
oligomeric procyanidins) and an oligomeric procyanidin-fraction of the
extract inhibited lipid peroxidation (IC 50
0.48 µg/ml (extract), 0.3 µg/ml
(fraction)), and the activity of human neutrophil elastase (IC 50
4.75 µg/ml
(extract), 0.84 µg/ml (fraction)) (56). A 70% methanol extract of the flower
buds inhibited lipid peroxidation in rat liver microsomes (IC 50
23 µg/l)
(70, 71). Both phenolic and flavonoid-enriched fractions of extracts of the
leaves and flowers had antioxidant activity in vitro (70–72).
Effect on signal transduction
An aqueous or methanol extract of the leaves with flowers, as well as hyperoside,
vitexin and vitexin rhamnoside, inhibited the activity of cyclic AMPdependent
phosphodiesterase isolated from guinea-pig or rat heart (73, 74).
Both luteolin 7-glucoside and rutin were also active (75). Hydroalcoholic
extracts of the flowers and flower heads inhibited the formation of thromboxane
A 2
and prostaglandin I 2
in rabbit cardiac tissues in vitro, thus indicating
an anti-inflammatory effect of the extracts (76, 77). A standardized ex-
100