INTRODUCTION:

Plants have been used to combat disease since the dawn of civilization, and their distinguished medicine continues to play a most valuable role in the treatment of a variety of diseases.¹

Medicinal plants were considered natural resources of bioactive compounds. Secondary metabolites, flavonoids, phenols, and flavanols derived from medicinal plants have been used worldwide to treat many diseases.²

Recently, there has been increasing awareness of the importance of the high content of phenolic compounds due to their antioxidant properties, which can prevent oxidative decomposition in food and protect oils and fats.³They are able to trap free radicals and activate other antioxidants in the body,⁴ The three most famous phenolic compounds important to humans are phenolic acids, flavonoids, and polyphenols^,5

Polyphenols provide protection against ultraviolet rays and infections.⁶The antioxidant activities of flavonoids capture or neutralize free radicals that can improve the condition of damaged tissues, in other words, the inflammatory process can be inhibited.⁷

Note that polyphenols are organic compounds found in more than 8,000 species that exist today, and are found in many plant foods.⁸

Since many estimates indicate that up to 40% of the new chemical entities discovered by the pharmaceutical industry today are poorly soluble.⁹ The oral bioavailability of drugs depends on their solubility.¹⁰

Accordingly, solubility data for polyphenolic compounds are essential for the pharmaceutical, food, biological and medical industries. Therefore, choosing the appropriate solvent is very important to ensure optimal extraction rich in polyphenol compounds, and to identify the most abundant parts of these compounds in the plant, especially in light of the stability of the compounds, the selectivity of the system, the cost of the solvent, and safety.¹¹

Interest in polyphenols has increased due to their many applications, including foods, beverages, nutritional supplements and pharmaceuticals, as a result of their multiple health properties.¹²

Thus, the high efficacy of these compounds makes them usable as alternatives to conventional therapeutic drugs. The use of medicinal plants in treatments or as nutritional supplements goes back far beyond recorded history, but has increased significantly in the past decades.¹³

Plants with medicinal values are generally classified as medicinal plants such as the Solanum melongena which is used. In this study.

Although it is a culinary plant, it is also considered a medicinal plant. It has been used in the Indian medical system for centuries, and has magical uses in many countries¹⁴

It is used as a symbol of protection, good health and fertility for women.¹⁵

It is considered an important and generally beneficial food for cardiovascular patients and diabetics, and it has a major role in maintaining bone and muscle health and reducing inflammation, while providing good support for the body’s immune role. Various parts of it have been used to treat inflammatory diseases, neuralgia, nasal ulcers, cholera, bronchitis, and asthma.¹⁶

And its antioxidant activities have already been reported ^17,18 a central nervous system depressant¹⁹analgesic²⁰and hypolipidemic²¹

THE AIM OF THE STUDY:

This research aims to study the effect of solvents on the extraction of polyphenol compounds for all parts of the long black eggplant plant, which are eight parts, by extracting them with boiling under the rising cooler, and using four solvents (ethanolic, 70% ethanolic, methanolic, and aqueous) to choose the best solvent which dissolve and extract the highest quantity of polyphenols compounds and compare reults between all the parts with each to know where are the most available of these compounds.

MATERIALS AND METHODS:

Materials:

Equipment and tools used:

Boiling extraction device under the rising radiator.

Sort volumetric flasks 1000ml, 500ml, 50ml.

Sensitive electronic balance of the type AX200, Shimadzu, Japan.

Hitachi-U-1800USA spectrophotometer.

Mill. Thermometer.

Measuring 50 ml and 100 ml.

Frozen, micropipettes of different sizes.

Materials used:

The parts of the black eggplant plant Solanum melongena were collected from the local market for the same farmer, dried and kept in sealed containers, away from light and moisture (humidity less than 30%).

Distilled water.

Ethanol 99.5% from Eurolab, UK.

Methanol 99.8% from Sigma, Aldrich, USA.

(panreac spain, ) of anhydrous sodium carbonate

Standard – gallic acid, with a purity of 98% from (Titan).

(biotech, India)

Barcelons, spain from Folin ciocalteu's phenol reagent

Methods of study:

Preparation of plant samples:

The parts of the black eggplant (Solanum melongena) were removed and then dried and kept away from moisture in tightly closed containers.

They were dried in the shade in a dry, well-ventilated place at a temperature of 23-25 C for a month. Then the powder of all the parts of the black oblong eggplant was prepared by grinding it in an electric mill, and keeping the powder in tightly closed bottles, away from light and the temperature of the laboratory until it is used.

Extraction and preparation of extracts from the oblong black eggplant parts:

Four types of extracts were prepared for all parts of the plant (ethanolic, ethanolic 70%, methanolic, and aqueous).

A- Boiling method under the rising radiator:

1- The ethanolic extract: The ethanolic extract was prepared with an ascending cooler device, where 30g of powdered leaves and peels of the oblong black eggplant were separately extracted by 300 ml of 90% ethanol for two hours, after that the resulting extracts were collected and dried using a rotary evaporator.²²

- Ethanolic extract 70%: The ethanolic extract was prepared in the ascending cooler device by adding ethanol 70%+30% distilled water, where 30g of powdered leaves and peels of the oblong black eggplant were separately extracted by 300ml of ethanol 70% for two hours, after that The resulting extracts were collected and dried using a rotary evaporator^22.

2- The methanolic extract: The methanolic extract was prepared with an ascending cooler device, where 30g of the plant sample was extracted by 250ml of methanol 99% for two hours, after that the resulting extract was collected and dried using a rotary evaporator^22.

3- The aqueous extract: 30g of powdered leaves and peels of the oblong black eggplant are placed separately in an extraction flask with 200ml of distilled water, and heated under an ascending cooler for an hour and a half, then the resulting extract is filtered, and evaporated using a rotary evaporator until dryness²³.

Determination of the total phenolic content of the total TPC:

The Folin–Ciocalteu method is used to determine Tpc, where the phenols are reduced in tungsten phosphomolybdate acid in an alkaline medium, resulting in a blue solution. Absorption is measured at a wavelength of 765nm, where a series of reduction reactions occur by transferring one or two electrons from the phenols leading to the formation of blue complexes²⁴.

Preparation of the calibration series: 0.5grams of gallic acid is dissolved in 10ml of ethanol → supplemented with water up to 100ml in a calibration balloon, and it can be opened daily, but for storage it is preferable to keep it closed in the refrigerator for up to two weeks.

To set up the calibration curve:

Add 5/4/3/2/1/0 and 10ml of the above phenol solution to a 100ml calibration balloon and complete the volume with distilled water.

Then we extend the volume with water.

We will have the following concentrations of phenol:

Gallic acid 0/50/150/250/150/500 mg/L Gallic acid, put 20 microliters in separate cuvettes, add 1.58ml of distilled water +100 microliters of Folin reagent, mix well, then leave for 8 minutes and 30 seconds, then add 300 microliters of sodium carbonate, mix well, and leave the mixture for two hours At twenty degrees Celsius.

The absorbance is measured at a wavelength of 760nm against pure (distilled water instead of the sample)²⁵.

Prepare the sodium carbonate solution:

Sodium carbonate solution 20% 200g of anhydrous sodium carbonate is dissolved in 800ml of distilled water, boiled and then cooled, and after 24hours it is filtered and the volume is completed to -1 liter²³.

RESULTS AND DISCUSSION:

A table showing the results of titration of phenols in parts of the oblong black eggplant plant

Type of botanical extract				vegetable part
Aqueous	methanolic	% 70 ethanolic	ethanol
The gram equivalent of gallic acid is mg/100g dry
1010	1199	1257	1182	flowers
1218	1099	1371	899	pulp
585	1046	774	905	the roots
313	1038	491	524	Seeds
1185	1149	1580	1380	leaves
938	916	1082	591	calyx
1346	1288	1205	730	peel
785	1080	1116	568	stem

The results of this study showed that the best extract to obtain the highest yield of polyphenol compounds was the ethanolic (70%) extract of five parts of the black oblong eggplant plant (flowers, pulp, leaves, cones, and stem), while the methanolic extract was the best for extracting seeds and roots, and the aqueous extract remained, It retained the highest yield among the four extracts of plant peels, and the yield of this extract remained the highest among the aqueous extracts of the rest of the other parts.

The highest yield of polyphenol compounds was in the leaves in the ethanolic extract 70% with a value of 1580mg/100g dry powder, and the lowest yield of polyphenol compounds was in the seeds in the aqueous extract with a value of1038mg/100g dry powder

The edible parts of the plant were characterized by very high values of polyphenol compounds, especially in the aqueous extract (peel and pulp), and this gives us an idea of the importance of the ingredients that we get from eating this plant cooked because the cooking method is very close to the method of extraction by boiling under the rising cooler, that is, By feeding on this plant, we obtain important and very beneficial active compounds and components for human body that are usually used in the medical field as anti-cancer, anti-inflammatory, anti-viral, anti-bacterial, anti-allergic, antioxidant, and anti-atherosclerosis.

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Received on 07.11.2023 Modified on 01.01.2024

Research J. Pharm. and Tech 2024; 17(7):3115-3118.

DOI: 10.52711/0974-360X.2024.00487