DETERMINATION OF THE AMOUNT OF CHEMICAL COMPOUNDS IN Hypericum scabrum AND Calendula officinalis PLANTS GROWING IN THE CONDITIONS OF UZBEKISTAN

ABSTRACT

This article preents the results of determining the content of macro- and microelements in a 3:1 mixture prepared from Hypericum scabrum and Calendula officinalis, which grow in the conditions of Uzbekistan, using the inductively coupled plasma optical emission spectrometry (ICP-OES) method. In addition, the physiological roles and therapeutic applications of the identified macro- and microelements in the fielda of medicine and pharmaceuticals are also thoroughly discussed.

АННОТАЦИЯ

В данной статье представлены результаты определения содержания макро- и микроэлементов в смеси 3:1, приготовленной из Hypericum scabrum и Calendula officinalis, произрастающих в условиях Узбекистана, методом оптической эмиссионной спектрометрии с индуктивно связанной плазмой (ICP-OES). Кроме того, подробно обсуждаются физиологические роли и терапевтическое применение выявленных макро- и микроэлементов в области медицины и фармацевтики.

Keywords: standart solutions, inductively coupled plasma optical emission spectrometry (ICP-OES), working solutions, ultrapure water.

Ключевые слова: стандартные растворы, оптическая эмиссионная спектрометрия с индуктивно связанной плазмой (ICP-OES), рабочие растворы, сверхчистая вода.

1. Introduction

Medicinal plants have long been used as natural sources for maintaining and restoring human health. In recent years, scientific research on the application of biologically active plant-derived compounds in the development of pharmaceutical and medical products has gained increasing attention. Medicinal plants such as Hypericum scabrum and Calendula officinalis are recognized for their rich content of flavonoids, phenolic compounds, terpenoids, carotenoids, tannins, essential oils, and various macro- and microelements. These constituents are considered the primary components responsible for the pharmacological activity of these plants. [1,2,3,4].

These plants are distinguished by their anti-inflammatory, antiseptic, antioxidant, and regenerative properties. In particular, the biologically active elements found in their composition—such as zinc (Zn), iron (Fe), copper (Cu), boron (B), and silicon (Si)—play a crucial role in various physiological processes, including cell regeneration, immune system function, hematopoiesis, and the maintenance of hormonal balance. [5,6,7] .

Iranian researchers H. Rafiee, A. Mehrafarin, and their colleagues analyzed the chemical composition of Calendula officinalis using high-performance liquid chromatography (HPLC), and investigated its mineral content through atomic absorption spectrometry (AAS), determining the concentrations of several specific elements [8,9].

In this study, the chemical elements present in a 3:1 mixture of Hypericum scabrum and Calendula officinalis plant extracts were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES), and their potential applications in medicine and pharmaceuticals were investigated.

II. Experimental Section

II.1. Preparation of the Working Sample Solution

A pre-dried and finely ground plant sample was weighed with an accuracy of 0.001 g using an analytical balance (Navigatortm, OHAUS®, USA), placed into a porcelain crucible, and incinerated in a muffle furnace (Nabertherm, Germany). The heating was performed in stages as follows: 95°C for 30 minutes, 120°C for 60 minutes, 300°C for 120 minutes, and 550°C for 60 minutes. The sample was then maintained isothermally at 550°C for 5 hours.

To the resulting ash, 6 mL of 70% HNO₃ (Sigma Aldrich, USA) and 2 mL of 60% H₂O₂ solution were added and the mixture was heated on a hot plate until white fumes completely disappeared. The cooled solution was transferred to a 100 mL polypropylene volumetric flask, diluted to volume with ultrapure water, filtered through a 0.45 µm membrane filter, and submitted for analysis.

II.2. Preparation of Standard Solutions

For ICP–OES analysis, the following certified standard solutions were used in a 2% HNO₃ matrix:

- A 68-element standard solution (10 mg/L) (High-Purity Standards, USA)

- A mercury (Hg) standard solution (1000 mg/L in 2 mol/L HNO₃) (Sigma Aldrich, Germany)

- A 25-element standard solution (10 mg/L) (Aristar, USA)

- 70% HNO₃ (Sigma Aldrich, USA)

Based on these, a main working standard solution covering 69 elements was prepared, from which a series of dilutions at various concentrations was made. A 2% HNO₃ solution was used as the blank. Calibration curves were constructed for each element, with the correlation coefficients (R²) of all calibration lines being no less than 0.995.

II.3. Experimental Procedure

Elemental analyses were performed using an iCAP PRO X Duo ICP-OES instrument (Thermo Fisher Scientific, USA). Measurements and data processing were carried out using the QTegra ISDS software. The operating parameters are presented in Table 1.

Table 1.

Operating Parameters of the iCAP PRO X Duo ICP-OES Instrument

III. Results

Within the scope of this study, the concentrations of chemical elements in the extracts of Hypericum scabrum and Calendula officinalis were determined using inductively coupled plasma optical emission spectrometry (ICP-OES), and the results are presented in Table 2. The data are expressed in mg per 100 units and serve for the quantitative assessment of the elemental composition in the samples.

Table 2.

Results of Chemical Element Determination in the Sample by ICP-OES Method, mg/100 g

Note: <LOD – result is below the limit of detection

IV. Analysis of the Results

According to the analysis results, among the 69 chemical elements quantified in the sample, elements essential for physiological functions such as K, Ca, Mg, Na, P, and Al were detected in high concentrations. Elements playing crucial roles in metabolic processes, enzymatic activity, and cellular balance, including Fe, Zn, Mn, Cu, B, Mo, Cr, Ni, and Li, were found in adequate amounts. Toxic and heavy metals such as Pb, Cd, Hg, As, Sb, Sn, Al, and others were present at low concentrations or below the permissible limits. Undetected elements (below the detection limit) include Se, Co, Bi, Ga, Nb, Ge, Er, Ag, Pd, Rh, Ho, Dy, Ce, Eu, Pr, Yb, Gd, Y, among others. Their concentrations being <LOD enhances the safety profile of the sample.

Table 3.

Macroelements and Beneficial Microelements

Table 4.

Heavy Metals and Potentially Toxic Elements

Table 5.

Elements Detected in Trace Amounts

IV. Conclusion

The analysis results demonstrate that the quantitative composition of 69 chemical elements in the sample includes high concentrations of essential macroelements such as K, Ca, Mg, Na, P, and Al, which are vital for the body. Microelements crucial for regulating metabolic processes, enzymatic activity, and maintaining cellular balance—namely Fe, Zn, Mn, Cu, B, Mo, Cr, Ni, and Li—were confirmed to be present in adequate amounts. Additionally, the concentrations of toxic and heavy metals (Pb, Cd, Hg, As, Sb, Sn, Al, and others) were found to be below the permissible safety limits, indicating the extract’s safety. Based on these findings, the rich composition of the extract suggests potential anti-inflammatory, regenerative, and immunomodulatory properties. Therefore, this extract may be effectively used in phytotherapy and pharmaceutical applications, particularly for the treatment of gynecological disorders. Moreover, the employed ICP-OES method demonstrated high sensitivity and reliability, enabling the detection of a wide spectrum of elements, thus confirming its importance as a precise and trustworthy analytical tool for assessing the mineral content of plant extracts.

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