STUDY OF THE AMINO ACID COMPOSITION OF Phlomis solificolia Regel GROWING IN THE REPUBLIC OF UZBEKISTAN

ABSTRACT

In this scientific study, Phlomis solificolia Regel — a plant species distributed in the mountainous regions of the Kashkadarya and Tashkent provinces of the Republic of Uzbekistan — was selected as the research object. The flowering aerial parts of the plant were collected in June from areas of the Angren district of the Tashkent region, located at an altitude of 850 meters above sea level. The amino acids present in the plant extract were identified using the High-Performance Liquid Chromatography (HPLC) method. It was determined that the content of glutamic acid predominated in the Tashkent climatic sample, while proline amino acid was dominant in the Kashkadarya climatic sample. The total protein content in the samples was determined by the Kjeldahl method.

АННОТАЦИЯ

В данном научном исследовании объектом изучения был выбран Phlomis solificolia Regel — вид растения, распространенный в горных районах Кашкадарьинской и Ташкентской областей Республики Узбекистан. Цветущие надземные части растения были собраны в июне в районах Ангренского округа Ташкентской области на высоте 850 метров над уровнем моря. Аминокислоты, присутствующие в экстракте растения, были идентифицированы с помощью метода высокоэффективной жидкостной хроматографии (ВЭЖХ). Было установлено, что в пробе из Ташкентского региона преобладает глутаминовая кислота, тогда как в пробе из Кашкадарьинского региона доминирует аминокислота пролин. Общий белковый состав проб определялся методом Кельдаля.

Keywords: HPLC, antioxidant, antimicrobial, antidiabetic, allergy, cancer, hemorrhoids, Agilent Technologies, centrifuge, phenylthiocyanate.

Ключевые слова: ВЭЖХ, антиоксидант, антимикробное, антидиабетическое, аллергия, рак, геморрой, Agilent Technologies, центрифуга, фенилтиоцианат.

Introduction

According to literature data, Phlomis solificolia Regel is an endemic plant belonging to the family Lamiaceae. The genus Phlomis includes more than 100 species distributed across Turkey, North Africa, Europe, and Asia [1]. Within the territory of the Republic of Uzbekistan, 15 species of the Phlomis genus have been identified [2]. Numerous scientific studies have been conducted on species such as Phlomis tuberosa, Phlomis fruticosa, Phlomis nissolii, Phlomis samia, and Phlomis sieheana. In particular, the biological activity of Phlomis nissolii, Phlomis samia, and Phlomis sieheana species was investigated in 2021 by Nuraniye Eruygur, Damla Kirci, Fatma Ayaz, and others. The genus is also widely distributed in Iran as an endemic group of plants. In traditional medicine, members of this genus are used as analgesics for the treatment of stomach pain and colds. Plants belonging to this genus possess valuable biological properties such as antioxidant, antimicrobial, antidiabetic, cardioprotective, anti-inflammatory, antiallergic, anticancer, antihemorrhoidal, and analgesic activities. In traditional medicine, Phlomis grandiflora is also used in the treatment of hemorrhoids [3].

Experimental Part

The amino acids present in the vegetative organs of Phlomis solificolia Regel were analyzed using the High-Performance Liquid Chromatography (HPLC) method. The precipitation of proteins and peptides in the aqueous extract was carried out in centrifuge tubes. For this purpose, 1 mL of a 20% trichloroacetic acid (TCA) solution was added to 1 mL of the sample under study. After 10 minutes, the precipitate was centrifuged at 8000 rpm for 15 minutes. From the upper layer, 0.1 mL of the supernatant was separated and lyophilized. The hydrolysate was evaporated, and the dry residue was dissolved in a triethylamine–acetonitrile–water mixture and dried again. This operation was repeated twice to neutralize the acid. According to the method of Steven A. and Cohen Daniel, phenylthiocarbamyl (PTC) derivatives of amino acids were obtained by reacting them with phenyl isothiocyanate.

HPLC conditions: Instrument – Agilent Technologies 1200, DAD detector; Column – Discovery HS C18, 75×4.6 mm; Solvent A – 0.14 M CH₃COONa + 0.05% TEA, pH 6.4; Solvent B – CH₃CN; Flow rate – 1.2 mL/min; Detection wavelength – 269 nm; Gradient program (%B/min): 1–6% / 0–2.5 min; 6–30% / 2.51–40 min; 30–60% / 40.1–45 min; 60–60% / 45.1–50 min; 60–0% / 50.1–55 min.

Analysis of the Obtained Results

In this study, the amino acid composition, and their quantitative content in the leaves of Phlomis solificolia Regel were determined using the High-Performance Liquid Chromatography (HPLC) method, and conclusions were drawn based on the obtained results.

Figure 1. Chromatogram of the sample from the Kashkadarya climate

Figure 2. Chromatogram of the sample from the Tashkent climate

According to the chromatogram results, the amino acid composition of the samples collected from the two regions was summarized in a table based on their quantitative and qualitative characteristics.

Table 1.

Amino acid composition and content of Phlomis solificolia Regel distributed in the Tashkent and Kashkadarya regions

Conclusion. The quantity and quality of amino acids present in Phlomis solificolia Regel were comparatively studied in samples collected from the mountainous regions of Tashkent and Kashkadarya provinces. In the Tashkent sample, the total amino acid content was approximately 75.3 mg/g, with glutamic acid—a dicarboxylic amino acid—being the most abundant. In the Kashkadarya sample, the total amino acid content was approximately 84.3 mg/g, with proline—an aliphatic amino acid without a side-chain carboxyl group—being the most abundant. In both regions, aromatic amino acids were found to be present in the lowest amounts.

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