The study of saponins of the raspberry cake alcoholic extract by HPLC

Aim. To study saponins of the raspberry cake ethanol extract. Materials and methods. The object of the study was the extract obtained from the cake of Rubus idaeus fruit. The study of saponin compounds was carried out by HPLC. Results and discussion. The following saponins were found in the extract: euscapic acid (0.24 %), tormentic acid (0.14 %), lupeol (0.65 %). These compounds are of interest to pharmacy and medicine as substances with the oncoprotective and hepatoprotective activity. Conclusions. The qualitative and quantitative composition of saponins in the cake extract of raspberry fruits has been studied. The results indicate the prospects of creating new drugs based on biologically active substances of the raspberry fruit cake, as well as necessity of more profound study of phenolic compounds of this type of the raw material.


Ключевые слова: малина обыкновенная; ВЭЖХ; экстракт; сапонины
Raspberry is a subshrub of Rosaceae family, it has a long rhizome and erect cylindrical stem. The plant is about 50-200 cm height. In the first year of life shoots are green, tomentose, with spines. In the second year they become stiff, lose spines, blossom, fructify and dry after fruiting, and new shoots are formed from the rhizomes. Raspberry rhizomes are woody, sinuate, creep in the 10-20 centimeter layer of soil. Leaves are alternate, the lower ones are unpaired, with 5-7 leaflets on the petioles, the upper ones are ternate with broad adnate to the stem stipules. Flowers are white with a pubescent greenish-gray cup, which particles are bent downward, collected in small inflorescences, originating from the sinuses of the leaves. The petals are white, spatulate, erect.
Fruits are raspberry-red, a spherical-oval polyachenium with the length of 12-13 mm and the width of 10-14 mm, easily removed from a white cylindrical-conical receptacle; stone fruits are small (approximately 3 mm), juicy, velvety-fluffy. Raspberry fruits have long been used in various areas of the national economy: in medicine, pharmaceutical and food industries, etc. According to the literary sources raspberries have a rich chemical composition [1,2,3,4].
Despite the widespread use of this plant in medical practice, its chemical composition has been insufficiently studied. In available sources of scientific literature there is no data about the content of saponins in the raspberry fruit cake.
Saponins are polycyclic naturally occurring compounds, mainly of vegetable origin used in the light, food, cosmetic and pharmaceutical industries as natural surfaceactive substances. They have a diverse pharmacological activity, most of them increase the secretory activity of the glands, promote the absorption of other substances, cause the expectorant activity, some of them have the diuretic, antiallergic, antiviral action, regulate the watersalt metabolism. Saponins also stimulate the activity of the central nervous system, show the antihypertensive, anti-inflammatory, antimicrobial, antiallergic and corticosteroid effects [5]. In the sources of scientific literature there is also information concerning the adaptogenic, antisclerotic and hypoglycemic activity of saponins [6,7].
The aim of this work was to study saponins of the raspberry cake ethanol extract.

Materials and methods
The object of the study was the extract obtained from the cake of Rubus idaeus fruit collected in the places of its cultivation. The collection of the raw material was carried out in 2017 during the fruiting period near Ternova village, the Kharkiv region. The juice was squeezed from the fruits, the resulting cake was dried, and 80 % alcohol was added in the ratio of 1 : 5 taking into account the absorption coefficient. The extraction was carried out within 24 hours, then settled, filtered and dried to a dry extract. The HPLC studies were performed on a Shimadzu LC20 Prominence liquid chromatograph in a modular system equipped with a four-channel LC20AD pump, a thermostat of columns СТО20А, an automatic sampler SIL20A, a diode-matrix detector SPDM20A and a ChemStation LC20 under the following conditions: • X-Bridge C18 column, 150 mm * 4.6 mm in size with a grain size of 5 μm (Waters company); • column temperature -30 °С; • detection wavelength -205 nm; • flow rate of the mobile phase -1.0 ml/min; • volume of the test sample introduced -20 μl.
Elution mode: isocratic. The components were identified by the retention time and compliance of the UV spectra with standards.
The spectra of triterpene saponins have the absorption maximum at 200-210 nm; therefore, this group of compounds was detected at 205 nm.
The quantitative determination of the individual components of the extract was carried out using the working reference standards of oleanolic acid, ursolic acid and standardized extracts of the saponin-containing plant raw material -birch bark (Betulae pendulae cortex extract) and garden sage leaves (Salviae off. foliae extract). Extracts from these plants were characterized by the exact content of betulin, betulinic acid and lupeol [8,9,10].

Results and discussion
The following saponins were found in the extract: euscapic acid (0.24 %), tormentic acid (0.14 %), lupeol (0.65 %). These compounds are of interest to pharmacy The qualitative and quantitative composition of saponins in the cake extract of raspberry fruits has been studied. The content of euscapic acid was 0.24 %, tormentic acid -0.14 %, lupeol -0.65 %. The results indicate the prospects of creating new drugs based on biologically active substances of the raspberry fruit cake, as well as necessity of more profound study of phenolic compounds of this type of the raw material. The data obtained can be used for the extract standardization.
Conflict of Interests: authors have no conflict of interests to declare.