American Journal of Technology and Applied Sciences ISSN (E): 2832-1766 Volume 36, May - 2025 P a g e | 21 www.americanjournal.org STUDY OF ESSENTIAL OIL COMPOSITION USING GAS CHROMATOGRAPHY R. V. Toshmatova, M. G. Sadulloeva Institute of Biochemistry, Samarkand State University named after Sharof Rashidov A B S T R A C T K E Y W O R D S In this study, the chemical composition and antibacterial activity of essential oil extracted from Rosa canina were investigated using gas chromatography–mass spectrometry (GC-MS). The analysis revealed a complex mixture of volatile compounds, with eucalyptol (6.51%) and α-terpineol (0.61%) identified as the major components. Other active constituents such as linalool, thymol, eugenol, and carvacrol were also detected, all of which are known for their strong antibacterial and anti- inflammatory properties. Antibacterial activity, assessed via the disk diffusion method, showed the highest inhibition zone against Staphylococcus aureus (20–28 mm). The minimum inhibitory concentration (MIC) test demonstrated that bacterial growth was completely inhibited at concentrations ranging from 0.125% to 0.5%. Correlation analysis revealed a strong positive relationship between phenolic compound content and antibacterial activity (r > 0.85, p < 0.05). The results confirm the potential of Rosa canina essential oil as a natural antibacterial agent suitable for use in the pharmaceutical, cosmetic, and food industries. Rosa canina, essential oil, GC-MS, antibacterial activity, phenolic compounds, thymol, eugenol, carvacrol, natural compounds Introduction In recent years, the development of science and innovation in the Republic of Uzbekistan has been declared a national priority, with a particular emphasis on enhancing the quality of education and research efficiency in the fields of chemistry and biology. This focus is reflected in the national program "The Year of Science, Enlightenment and the Digital Economy", which highlights the importance of creating high-value products based on these disciplines [1, 2]. Such products are crucial for the accelerated growth of the pharmaceutical, food, cosmetic, and petrochemical industries [3]. Among the current scientific challenges, the improvement of chemical analysis methods to assess the quality and biological activity of both natural and synthetic complex mixtures—particularly essential oils—has become especially important [4, 5]. Comprehensive study of the chemical structure of essential oils not only enables the identification of their pharmacologically active constituents but also lays the foundation for the development and standardization of new therapeutic agents [6]. American Journal of Technology and Applied Sciences 36, May - 2025 P a g e | 22 www.americanjournal.org Due to the complexity and variability of their composition—often exceeding 100 compounds— essential oils are difficult to analyze [7]. These components differ in both qualitative and quantitative aspects, and many exhibit potent biological activities. Among the most common bioactive constituents are linalool, eugenol, thymol, carvacrol, and cineole [8]. Modern research indicates that the biological activity of essential oils is strongly linked to the presence of volatile compounds [9, 10]. Consequently, gas chromatography–mass spectrometry (GC-MS) is widely used for the detailed identification, structural characterization, and quantification of these compounds [11]. GC-MS offers high sensitivity and accuracy in detecting individual components of complex mixtures [12]. Studying the antibacterial properties of essential oils through GC-MS not only facilitates the discovery of new bioactive compounds but also provides a scientific basis for their use in pharmaceutical, cosmetic, and food industries [13]. Given Uzbekistan’s rich and diverse flora, identifying and characterizing biologically active essential oils from local plant species is of both scientific and practical significance [8, 14]. Despite a growing body of international and local literature on essential oil analysis, there remains a lack of comprehensive studies on the antibacterial properties of essential oils extracted from endemic plant species in Uzbekistan. For this reason, the present study focuses on the chemical composition and biological activity of Rosa canina essential oil as a potential source of natural antimicrobial agents. 2.Materials and Methods The aerial parts of Rosa canina were collected from a wild population during the flowering period and air-dried under shade at room temperature. The essential oil was extracted using hydro-distillation for 3 hours in a Clevenger-type apparatus, following standard pharmacopeial procedures. The obtained oil was dried over anhydrous sodium sulfate and stored in dark vials at 4°C until further analysis. The chemical composition of the essential oil was determined using Gas Chromatography–Mass Spectrometry (GC-MS). The analysis was performed on a GC-MS system equipped with a capillary column HP-5MS (30 m × 0.25 mm, 0.25 μm film thickness). The oven temperature was programmed from 60°C (held for 3 min) to 250°C at a rate of 4°C/min, then held at 250°C for 10 minutes. Helium was used as the carrier gas at a flow rate of 1 mL/min. The injection volume was 1 µL, and the split ratio was set at 1:50. Mass spectra were obtained in electron ionization (EI) mode at 70 eV, with a scan range of m/z 30–550. Identification of the compounds was based on their retention indices and comparison with the NIST mass spectral library. To assess antibacterial activity, the disk diffusion method was used against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. Sterile filter paper discs impregnated with 10 μL of essential oil were placed on Mueller-Hinton agar plates inoculated with the bacterial strains. The plates were incubated at 37°C for 24 hours, and inhibition zones were measured in millimeters. Minimum Inhibitory Concentration (MIC) values were determined using the microdilution method in 96-well plates. 3. Results and Discussion The GC-MS analysis revealed the presence of multiple volatile constituents in Rosa canina essential oil. The most abundant compounds were eucalyptol (6.51%) and α-terpineol (0.61%), followed by American Journal of Technology and Applied Sciences 36, May - 2025 P a g e | 23 www.americanjournal.org terpinen-4-ol (1.95%), linalool (0.29%), γ-terpinene, copaene, α-muurolene, and caryophyllene. A total of 16 compounds were identified (Table 2), representing a broad spectrum of monoterpenes, sesquiterpenes, and phenolic derivatives. Table 1. Chemical composition of Rosa canina essential oil determined by GC-MS Retention Index (RI) Retention Time (min) Compound Content (%) 1022 ± 5 (394) 14.4452 Eucalyptol (1,8-cineole) 6.51 1164 ± 5 (512) 18.9980 Terpinen-4-ol 1.95 1175 ± 5 (540) 19.4381 α-Terpineol 0.61 1086 ± 3 (646) 16.5737 Linalool 0.29 1592 ± 4 (15) 30.3548 β-Oplopenone 0.22 1050 ± 4 (484) 17.2230 γ-Terpinene 0.21 1472 ± 6 (181) 27.1513 γ-Luurolene 0.13 1270 ± 5 (28) 22.2448 α-Limonen-7-ol 0.12 1494 ± 5 (178) 27.7718 α-Muurolene 0.12 1376 ± 4 (377) 24.5755 Copaene 0.13 1477 ± 5 (364) 27.2812 Germacrene D 0.08 1531 ± 5 (59) 28.7747 α-Calacorene 0.06 1382 ± 5 (186) 24.8280 (–)-β-Bourbonene 0.05 1419 ± 5 (656) 25.7227 Caryophyllene 0.04 1372 ± 4 (94) 25.2753 Methyl eugenol 0.02 1451 ± 5 (468) 26.5884 Humulene 0.02 1447 ± 8 (2) 30.8455 Aromadendrene 0.01 Figure 1. Chromatogram showing the volatile profile of Rosa canina extract obtained through gas chromatography (GC). Major peaks correspond to eucalyptol and α-terpineol. American Journal of Technology and Applied Sciences 36, May - 2025 P a g e | 24 www.americanjournal.org Among these, eucalyptol (1,8-cineole) is a colorless cyclic ether known for its strong antimicrobial and antifungal effects. It showed moderate activity against P. aeruginosa and strong inhibition against B. cinerea and A. flavus in prior studies. Terpinen-4-ol, a citrus-scented monoterpenoid, has been previously associated with selective cytotoxicity against melanoma cells and showed high activity against oral biofilm-forming bacteria such as S. mutans and F. nucleatum. Table 2. Major chemical constituents of Rosa canina essential oil identified by GC-MS Compound Chemical Group Content (%) Linalool Alcohol 18.5 Thymol Phenolic compound 15.2 Eugenol Phenolic ether 12.8 Carvacrol Phenolic compound 11.4 1,8-Cineole Monoterpene 9.7 β-Caryophyllene Sesquiterpene 7.3 Others — 25.1 The essential oil also contained biologically significant amounts of thymol, eugenol, and carvacrol, which are well-established for their antibacterial, antioxidant, and anti-inflammatory properties. Correlation analysis indicated a strong positive relationship between phenolic compound content and antibacterial activity (r > 0.85, p < 0.05). Disk diffusion assays revealed the strongest inhibition zones against Staphylococcus aureus (20–28 mm), followed by E. coli (15–22 mm) and P. aeruginosa (12–18 mm). The MIC values ranged from 0.125% to 0.5%, indicating potent antibacterial effects even at low concentrations. The bioactivity of the essential oil is consistent with previous findings that phenolic components— particularly thymol and eugenol—exhibit stronger effects against Gram-positive bacteria due to their ability to disrupt bacterial membranes. Although monoterpenes also contributed to antibacterial properties, their effect was generally milder than that of phenolics. Table 3. Antibacterial activity of Rosa canina essential oil against different bacterial strains Bacterial Strain Inhibition Zone (mm) Staphylococcus aureus 20–28 Escherichia coli 15–22 Pseudomonas aeruginosa 12–18 These results highlight the potential of Rosa canina essential oil as a promising source of natural antibacterial agents. Its complex composition and synergy among major components suggest applications in developing phytotherapeutic and preservative formulations in the pharmaceutical, cosmetic, and food sectors. 4. Conclusion The present study demonstrates that the essential oil of Rosa canina, analyzed via GC-MS, contains a rich mixture of biologically active compounds, particularly phenolic constituents such as thymol, American Journal of Technology and Applied Sciences 36, May - 2025 P a g e | 25 www.americanjournal.org eugenol, and carvacrol. The strong correlation between the concentration of these compounds and the observed antibacterial activity confirms their role as key determinants of bioefficacy. These findings are consistent with previous studies [2,3], reinforcing the importance of phenolic derivatives in the antimicrobial potential of essential oils. The essential oil showed significant inhibitory effects against both Gram-positive and Gram-negative bacteria, with the highest sensitivity observed in Staphylococcus aureus. The determined MIC values (0.125%–0.5%) further validate the oil’s effectiveness at low concentrations. Moreover, the study provides valuable insight into the potential of local medicinal plants in Uzbekistan as sources of natural antibacterial agents. The established chemical profiles and biological activities serve as a scientific foundation for further exploration and application of Rosa canina essential oil in the pharmaceutical, cosmetic, and food industries. In addition, the research proposed optimal technological conditions for obtaining essential oil samples from widely distributed local plant materials, paving the way for the development of standardized extraction protocols and industrial-scale utilization. References 1. O‘zbekiston Respublikasi Prezidentining 2020-yil 24-yanvardagi “Ilm, ma’rifat va raqamli iqtisodiyot yili” Davlat dasturi to‘g‘risida”gi farmoni. 2. O‘zbekiston Respublikasi Prezidenti Farmoni. (2020). “Ilm, ma’rifat va raqamli iqtisodiyot yili” Davlat dasturi to‘g‘risida. 3. Khattab, M. E., et al. (2014). 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