HABITAT: is a very common shrub in the temperate zones of the northern hemisphere, especially in uncultivated areas on the edge of forests.
USED PART: flowers and leaves.
PHARMACEUTICAL PREPARATIONS: nebulised dry extract, titrated in flavonoids calculated as hyperoside min. 0.7% (Italian Pharmacopoeia X), whose daily dose ranges from 9 to 13 mg/kg, divided into two or three administrations, preferably between meals.
CHEMICAL COMPOSITION: is a plant rich in flavonoids, which may account for about 2 per cent of the weight of the dry plant. Proanthocyanidols are also abundant, which can account for up to 3% of the weight of the dried plant. There are also triterpene aromatic amino acids and cardiotonic amines.
Cardio-protective action. In vitro and animal studies: It causes vasodilation of many arterial vessels, due to the release of muscle fibrocells in the vessel wall, with increased blood flow in these districts. Hawthorn slows the heart's beats, enhances its contractile force and slows down the conduction of electrical stimuli in the heart. In this way, it is able to hinder arrhythmias characterised by a high heart rate and to improve them when they are already present. Other studies show that hawthorn protects the heart against damage caused by cardiac ischaemia. In fact, this plant helps preserve the cell membrane of heart cells by protecting them from ischaemic damage. In addition, the flavonoids present in hawthorn cause partial inhibition of the angiotensin-converting enzyme, which is very important for the regulation of blood pressure, with possible hypotensive effects.
An evaluation of published clinical trials studied the effect of hawthorn extract in patients with moderate heart failure. Thirteen papers of good methodological quality were included. In most of these, hawthorn was used as an adjunct to normal cardiological therapy. In terms of maximum achievable cardiac work, hawthorn proved superior to placebo, as well as in terms of reducing blood pressure and heart rate. Symptoms such as dyspnoea, fatigue, paraesthesias and feeling of heart in the throat improved significantly in hawthorn-treated patients compared to those receiving placebo. Adverse events were rare and included gastrointestinal complaints, nausea and general malaise. Overall, it can be said that hawthorn extract is more effective than placebo in the treatment of moderate heart failure.
Sedative action. In vitro and animal studies: It also has a discrete central sedative action, which is especially useful in anxious patients, in whom it reduces emotionality, hypertension and improves sleep.
Sedative action. Clinical trials.
A controlled clinical trial evaluated the efficacy and tolerability of a hawthorn dry extract product in patients with moderate/moderate functional anxiety disorders. 264 patients were enrolled, taking the product or a placebo by mouth for 3 months. Efficacy was assessed by means of the Hamilton anxiety scale (a scale measuring the intensity of anxiety), the patient's opinion of the improvement of their complaints, the number of subjects who responded positively, and the evaluation of efficacy given by the investigating physicians. Any adverse events were also monitored. It was noted that in the group receiving hawthorn, the drop in the Hamilton anxiety scale score was significantly greater than that observed in subjects in the placebo group. The opinion of the patients and that of the investigating physicians was also in favour of hawthorn over placebo. 15 patients in the verum group and 13 patients in the placebo group experienced moderate adverse effects, mainly gastrointestinal.
SIDE EFFECTS: in rare cases it may cause stomach upset, particularly in patients with gastritis and/or peptic ulcer, reversible by discontinuing treatment.
DRUG INTERACTIONS: It potentiates the effect of digitalis on the heart and amplifies the heart-beat slowing action caused by beta-blockers and other drugs with this activity.
CONTRAINDICATIONS: It should be used with caution in patients with marked bradycardia, sinoatrial blocks and atrio-ventricular blocks.