Phospholipid complexes of proanthocyanidin A2 as antiatherosclerotic agents

The present invention relates to complexes of proanthocyanidin A2 and one or more phospholipids, pharmaceutical compositions containing the complex of proanthocyanidin A2 and one or more phospholipids, and methods of treating or preventing atherosclerosis and myocardial and cerebral infarction in a patient by administering the complex of proanthocyanidin A2 and one or more phospholipids, as well as methods of forming such complexes

TECHNICAL FIELD

The present invention relates to phospholipid complexes of proanthocyanidin A2 or of extracts enriched in proanthocyanidin A2 and the use thereof for the preparation of medicaments for the prophylaxis and the therapy of atherosclerosis, and myocardial and cerebral infarction.

BACKGROUND OF THE INVENTION

SUMMARY OF THE INVENTION

It has now surprisingly been found that the phospholipid complexes of proanthocyanidin A2 exert a marked antiatherosclerotic activity both in animals and in humans when administered systemically, preferably through the oral route.

The complexes of the invention can consist of natural or synthetic phospholipids, such as lecithins, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine. The ratio of proanthocyanidin A2 to phospholipids ranges from 2:1 to 1:2, and preferably is about 1:1.5 w/w. A particularly preferred complex is that with soy phosphatidylcholine.

The complexes of the invention are prepared by reacting a solution of the phospholipid with a solution of proanchocyanidin A2 in suitable solvents, such as acetone, ethyl acetate, ethanol, then concentrating the reaction mixture under reduced pressure, to obtain a thick residue which can be ground.

The complexes of the invention dose-dependently prevent or reduce the formation of, atherosclerotic plaques. The activity was evidenced in rabbits fed with a hypercholesterolemic diet so as to induce atherosclerotic lesions similar to the human ones at the vasal level, particularly at the aortal arch, ventral aorta, carotids and cerebral vessels. In said model, the above mentioned phospholipid complexes change the macro- and microscopical vascular condition reducing, compared with untreated animals, both the number and the severity of the atheromatous plagues, with surprising vascular-tissutal benefit. In another atherosclerosis model, with the purpose of cerebral protection, wherein the vasal lumen of rabbit internal carotid had been surgically reduced while administering a hypercholesterolemic diet rich in saturated fats, a decrease in carotid obstruction, a reduction of vasal walls thickness and increased survival of the animals were observed. Atherosclerotic patients showed, after six month-treatment, a reduction of carotid obstruction due to atheromatous plaques and an improved carotid flow, evaluated by Doppler ultrasonography.

The phospholipid complexes of proanthocyanidin A2 can be used in suitable administration forms for the oral route such as tablets, soft- or hard-gelatin capsules, at dosages ranging from 50 to 500 mg two-three times a day, depending on the severity of the disease. The preparation of the pharmaceutical formulations can be carried out according to conventional techniques and excipients.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples illustrate the invention in greater detail.

Preparation of the Complex of Proanthocyanidin A2 with Phosphatidylcholine

A solution of 1577 g of phosphatidylcholine in 5 liters of ethyl acetate, kept at 70 C., was added with a solution of 1 kg of proanthocyanidin A2 in 5 liters of acetone.

The mixture was refluxed under stirring and evaporated to dryness under vacuum. The residue was dried under vacuum at 50 C. for 24 h, then ground to the desired particle size.

32 New Zealand rabbits were divided in 4 groups of 8 animals each, and treated as follows:

Group 1): Control, normal diet

Group 4): Hypercholesterolemic diet proanthocyanidin A2 extract (0.2% cholesterol amount of proanthocyanidin A2 equivalent to that present in 2% w/w of the complex of Example 1). After 8 week-treatment, during which cholesterol, LDL/VLDL, HDL and triglycerids levels were measured, the animals were killed.

The number, size and distribution of the atherosclerotic lesions on thoracic and abdominal aorta were evaluated.

Aorta strips were fixed and stained with Sudan IV to visualize the lesions and to evaluate the vasal cholesterol and the content in oxidized cholesterol by gaschromatography.

The results reported in the following table prove that the treatment with phospholipid complexes of Proanthocyanidin A2 decreases in a statistically significant way the atherosclerotic lesions induced by hypercholesterolemic diet.

TABLE Treatment area percent of the lesion Group 1 0.5% Group 2 34% Group 3 7.5%* Group 4 30% *p < 0.01 compared with group 2. EXAMPLE 3

Capsules Containing 500 mg of Phospholipid Complex of Proanthocyanidin A2

Complex of Proanthocyanidin A2 150 mg with soy phosphatidylcholine Lactose 57 mg Modified starch 40 mg Magnesium stearate 3.0 mg EXAMPLE 4

Gastro-resistant tablets Complex of Proanthocyanidin A2 200 mg with soy phosphatidylcholine Microcrystalline cellulose 118 mg Precipitated silica 3 mg Magnesium stearate 4 mg Methacrylic acid anionic 12 mg polymer and esters thereof Talc 8 mg Magnesium carbonate 8 mg Maize starch 5 mg Gum arabic 159 mg EXAMPLE 5

Soft-gelatin capsules Complex of Proanthocyanidin A2 216 mg with soy phosphatidylcholine Peanut oil 209 mg Partially hydrogenated vegetable oils 100 mg Soy lecithin 5 mg