Therapeutic Composition Containing Alpha-Linolenic Acid and a Compound Capable of Promoting the Passage of the Acid Through the Cell Membrane, Plant Extract Comprising the Acid and the Compound, and Process for the Preparation of the Extract

The invention concerns the field of drugs, especially antiinflammatories.

It relates to a therapeutic composition which contains, as the active principle, at least .alpha.-linolenic acid and at least one compound capable of promoting the passage of the acid through the cell membrane, in association with a physiologically acceptable excipient.

It further relates to the plant extracts containing the active principle.

.alpha.-Linolenic acid by itself has no therapeutic activity.

According to the present invention, it has been found that the active principle described above has totally unexpected therapeutic properties, especially antiinflammatory properties. Alcohols of vegetable origin, such as tocopherols (.alpha., .beta., .gamma. and .delta.) or sitosterols like .beta.-sitosterol, may be mentioned among the compounds which are capable of promoting the passage of .alpha.-linolenic acid through the cell membrane. Apart from these two types of product, the active principle can contain other compounds, especially C.sub.16 and C.sub.18 fatty acids such as palmitic acid, stearic acid, oleic acid and linoleic acid. Moreover, the presence of these other compounds often results from the process for the preparation of the active principle, as will be understood below.

Thus, preferably, the active principle will have the following composition in percentages by weight:

The active principle is preferably an aqueous or organic extract of plants which contain .alpha.-linolenic acid and a compound capable of promoting the passage of the acid through the cell membrane.

The expression "aqueous or organic extract" refers to the product which results from the action of an aqueous or organic solvent on ground plants, i.e. the process involves extracting the products which are soluble or miscible in these solvents.

Among the plants which are suitable for the present invention, preference will be given to those belonging to the Resedaceae family, such as Reseda lutea, Reseda luteola, Reseda glauca L., Reseda suffruticosa, Reseda alba, Reseda jacquini Rehb, Reseda odorata, Reseda complicata, Reseda bory, and Reseda phyteuma.

It is possible to use the whole plants harvested when flowering or fruiting, or seeds. They are then dried in the absence of light under a stream of air.

The aqueous extract advantageously results from extraction of ground plants or seeds with water, followed by recovery of the dry solute by an appropriate means.

Appropriate means which may be used are lyophilization or nebulization (after the addition, in the latter case, of an agent for imparting viscosity or an adsorbent, such as hydroxypropyl methyl cellulose (HPMC) or silicic acid).

It is also possible to extract the resulting aqueous solution with an organic solvent and then to concentrate the organic phase and finish, if appropriate, with a chromatographic fractionation of the concentrate. Advantageously, the fractionation will be such as to enable the fractions containing the fatty acids to be recovered. Preferably, the aqueous extract will result from a solid-liquid chromatographic fractionation, the eluent being a 50/50 benzene/methanol mixture, the support being silica and elution being carried out in 10 ml fractions, and from recovery of the fractions between forty-three and sixty.

The organic extract results from extraction of ground plant or seeds with an organic solvent such as ether, hexane or methanol, or with liquid CO.sub.2 in the supercritical phase, followed by recovery of the dry solute by evaporation. However, preferred solvents will be ether, hexane or petroleum ether and especially methyl tert-butyl ether, or liquid CO.sub.2 in the supercritical phase, either in the pure state or, if appropriate, with traces of water, ethanol or the like (to extract the compounds of greater or lesser polarity).

It must be emphasized that all the plant extracts are novel and the applicant is claiming them as novel products characterized by the process for their preparation, as follows from the foregoing description.

The therapeutic compositions according to the invention have proved useful as antiinflammatories, antihistamines, agents for inhibiting hemorrhoids, agents for inhibiting varicose veins, anticoagulants, vasoconstrictors or agents for inhibiting psoriasis.

The concentration of the extract in the finished product is advantageously between 10 and 25% by weight in the case of the aqueous extract and 2 to 12% in the case of the organic extract.

The product can be administered locally (ointment, cream, spray, lotion, gel), intradermally (ampoules or with the aid of conventional excipients) or by the general oral or parenteral route (capsules, drops to be taken orally, etc.).

The invention is now illustrated by particular non-limiting Examples.

The plant is pulverized with a roller mill until a fairly coarse powder is obtained. The resulting powder is extracted with 8 times its weight of distilled water at a temperature of 70.degree. C. for 8 h, with mechanical agitation.

The extract obtained after filtration and expression of the pulp is dried by nebulization or lyophilization.

Nebulization is carried out after the addition of hydroxypropyl methyl cellulose (HPMC).

The aqueous extract of Example 1 is precipitated with 95.degree. ethanol to give a mixture of fatty substances.

Starting from the aqueous phase obtained according to Example 1, and instead of lyophilization or nebulization, the solute is extracted with ether in a separating funnel. The ether phase is concentrated under reduced pressure until a green oil is obtained. This extract is then fractionated on a silica column using a 50/50 benzene/methanol mixture as the eluent. 10 ml fractions are collected. As from fraction 45, the solution only contains fatty acids up to fraction sixty. Fractions 45 to 60 are combined.

The operation was carried out on the whole plant or on the seeds.

1 kg of plant is extracted by maceration with 6 1 of organic solvent (ether, petroleum ether and especially hexane) for 48 h at room temperature, with mechanical agitation.

After filtration on paper, the resulting solution is concentrated under reduced pressure until an oily extract is obtained, which is dried under a stream of nitrogen.

The ether extract has the following chemical composition (in percentages by weight) with a 10% margin of error:

The operation is carried out under the same conditions as for Example 4, except that methanol is taken as the solvent.

The antiinflammatory activity of the extracts of Reseda Phyteuma obtained according to Example 1 to 5 was evaluated by general administration, in comparison with a reference in Wistar rats and with the powerful antiinflammatory indomethacin, as the percentage reduction in the swelling of the back paw caused by the phlogogenic agent carrageenin. The results are collated in Table I on the following page.

A. Acute toxicity

This was determined on male rats of the Wistar strain and male mice of the Swiss strain using two modes of administration: oral and intraperitoneal.

LD.sub.50 rat

oral: LD.sub.50 greater than 5 g/kg

intraperitoneal: LD.sub.50 greater than 2 g/kg

LD.sub.50 mouse

oral: LD.sub.50 greater than 5 g/kg

intraperitoneal: LD.sub.50 greater than 2 g/kg

B. Local tolerance of the nebulizate and of the ether extract in the form of a 10% cream

The local tolerance of the cream was assessed on Fauve de Bourgogne rabbits by the repeat cutaneous application of 2 g/kg of cream for 4 weeks to the animal's side, which had been shaved beforehand over an area of 80 cm.

The treatment did not influence the change in weight of our animals. The consumption of food and drinking water was identical in the control animals and treated animals.

The fur grew again normally.

Examination of the integuments showed a smooth and extremely supple skin.

In autopsy, examination and weighing of the following organs: liver, spleen, kidneys, testicles, adrenal glands, heart, thyroid and pituitary gland, showed no signs of toxicity. There was no apparent difference between control animals and treated animals.

Meticulous examination of the gastric and duodenal mucosa showed no anomalies.

The tests were performed with the extract of Reseda Phyteuma of Example 1 in the form of a cream containing 10% by weight of organic extract.

The results collated in Table II on the following pages, which were recorded by doctors, are very satisfactory for external or internal hemorrhoids, whether or not accompanied by pruritus or slight fissures, for varicose veins and for insect bites.

The product is also an excellent emollient.