The subject of this study is to determine chemical composition, antioxidant and antimicrobial activity of essential oil obtained from chamomile flowers (Matricaria chamomilla L.). The essential oil has been obtained by hydrodistillation process on semi industrial production conditions. Qualitative and quantitative composition of the oil was determined by GC-MS and GC-FID analysis. The antioxidative and antimicrobial activity of chamomile essential oil was investigated in terms of their possible application as natural antioxidants and antimicrobial agents. The obtained results proved the presence of 52 components, wherein the highest content of β-farnesene (29.8 %), α-farnesene (9.3 %), α-bisabolol and its oxide (15.7 %), chamazulene (6.4 %), germacrene D (6.2 %) and spiroether (5.6 %) is determined. The antioxidant activity was investigated by DPPH assay. Chamomile essential oil has shown the best antioxidant properties after 90 minutes of incubation with EC₅₀ value of 2.07 mg/ml. The antimicrobial activity of chamomile essential oil was tested using the agar diffusion method wherein the essential oil has shown notably antibacterial effect with the inhibition zone in diameter from 13.33 mm (on Listeria monocytogenes) to 40.00 mm (on Staphylococcus aureus). There was no antimicrobial activity of chamomile oil on the Pseudomonas aeruginosa bacteria. Chemical composition, antioxidant and antimicrobial activity of the tested chamomile essential oil, obtained from plant material from the northwestern Republic of Srpska, indicate a significant phytomedical potential.

Essential oils, as sources of natural products, represent an alternative to synthetic antioxidants and antimicrobial agents in food and pharmaceutical industry, alternative medicine and natural therapy. Basil (Ocimum basilicum L.) belongs to the Lamiaceae family of herbs, which in addition to being used as a spice, is also medicinally known as a powerful antibacterial, antimutagenic and chemopreventive agent. The aim of the present study was to determine chemical composition, antioxidant and antimicrobial activity of essential oil obtained from basil aerial parts (grown in the northwestern Republic of Srpska) by hydrodistillation on semi-industrial level of production. Qualitative and quantitative composition of the oil was determined by GC-MS and GC-FID spectrometry. The antioxidant activity of essential oil was investigated spectrophotometrically by DPPH assay and antimicrobial activity using the agar diffusion method on the following microorganisms: Escherichia coli, Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Providencia stuartii, coagulase-positive Staphylococcus, Streptococcus group D, Salmonella spp. and Candida albicans. The results obtained proved the presence of 65 components, with the highest content of linalool (31.6%) and methyl chavicol (23.8%). Essential oil has shown the best antioxidant properties after 90 minutes of incubation with EC₅₀ value of 2.38mg/ml. The oil has shown the best antimicrobial activity on coagulase-positive Staphylococcus. Chemical composition, antioxidant and antimicrobial activity of the investigated basil essential oil indicate a significant phytomedical potential.

In the present work, essential oil has been obtained by Clevenger-type hydrodestillation from grounded curcuma rhizome (Rhizoma Curcumae) (Turkey) with hydromodulus 1:5 m/V during 180 minutes. The qualitative and quantitative composition of the oil was determined by GC-MS and GC-FID spectrometry. The antioxidant activity of the obtained oil was determined using DPPH assay just after adding DPPH radical and after 20 min, 30 min and 45 min incubation with radical. The antimicrobial activity was determined using a discdiffusion method. The yield of the essential oil was 0.3 cm3/ 100 g plant material. Eight compounds were identified. The major ones were ar-turmerone (22.7%), turmerone (26%) and curlone (16.8%). The best antioxidant activity showed the oil incubated for 45 minutes with DPPH radical. EC50 values for the obtained oil were 1.784 mg/cm3 (without incubation), 0.098 mg/cm3 (after 20 minutes), 0.072 mg/cm3 (after 30 minutes) and 0.045 mg/cm3 (after 45 minutes incubation with radical). The oil showed the best antimicrobial activity against Candida albicans. The results indicate that turmeric essential oil is an extremely strong antioxidant and antimicrobial (antifungal) agent with potential application in the food and pharmaceutical industries as a safer alternative to the synthetic antioxidants and antimicrobial agents.

Irreversible degradation of quercetin and rutin, dissolved in methanol and water, induced by continuous UV-irradiation from two different sub-ranges (UV-B and UV-C) has been studied in this work. The degradation of both flavonoids is related to formation of UV-induced degradation products: both processes follow first-order kinetics. The degradation and products formation rate constants are both dependent on the involved UV-photons energy input in both solvents.

The present study focuses on the yield, chemical composition, and antioxidant activity of essential oils from different parts (flowers or leaves/stems) of cultivated plants grown under pearl shade nets with a 40% shaded index or in nonshaded plants and wild-grown oregano. The chemical composition of isolated essential oils was determined by GC/MS and GC/FID. Antioxidant activity was determined using the DPPH assay. The highest yield of oregano essential oils (OEOs) was obtained in cultivated shaded plants (flowers) at 0.35 mL/100 g p.m., in contrast to nonshaded plants (flowers), where the yield of OEOs was low (0.21 mL/100 g p.m.). Qualitative and quantitative analyses of the OEOs identified 16–52 constituents that varied with origin and plant organs. The oxygenated sesquiterpene caryophylleneoxide (7.4–49.9%) was predominant in all the essential oil samples. Other major constituents were sesquiterpene hydrocarbon-germacrene D (8.4–22.5%) and (E)-caryophyllene (8.5–10.8%), monoterpene hydrocarbon-sabinene (1.6–7.7%), and oxygen-containing monoterpenes-terpinen-4-ol (1.5–7.0%). The plant part has a significant effect on the antioxidant activity of OEOs, while the influenceof modified light under the shade nets is significantly lower. The OEOs from wild flowers showed the highest antioxidant activity, with an EC₅₀ value of 4.78 mg/mL. OEOs from cultivated nonshaded plants (flowers) recorded the lowest antioxidant activity with an EC₅₀ value of 24.63 mg/mL. The results suggest that the yield and quality of OEOs can be scaled-up by optimizing plant production in comparison with wild-growing plants. The content and quality of OEO can be increased by optimizing its production compared to plants from the spontaneous flora. Adequate cultivation techniques, such as shading, can achieve high-quality oregano yields and better quality parameters in terms of specific OEO components and meet the different requirements of the market and industrial sectors.

This study determined the content and composition of dill seed (Anethum graveolens L.) essential oil under varying light conditions: non-shaded plants in open fields and plants covered with pearl shade nets (40% shade index). Essential oil was extracted using Clevenger hydrodistillation. The essential oil content was 4.63% for non-shaded plants and 4.81% for shaded plants. GC/MS analysis revealed twenty-one and twenty-two components in dill seed from non-shaded and shaded plants, respectively. The terpenic fraction of essential oil from non-shaded plants consisted mainly of oxygen-containing monoterpene derivatives (53.6%), with carvone (46.1%) as the primary component, followed by monoterpene hydrocarbons (46.4%), predominantly limonene (43.8%). Essential oil from shaded plants contained a higher content of carvone (49.8%) and a lower content of limonene (37.8%) compared to essential oil from non-shaded plants. Non-shaded plant essential oil exhibited stronger antioxidant activity (EC₅₀ value: 26.04 mg mL⁻¹) than shaded plant essential oil (54.23 mg mL⁻¹). Dill seed essential oil showed the most potent antimicrobial activity (disc diffusion method) against Escherichia coli (inhibition zone: 15–18 mm). Shaded plants demonstrated a positive influence of essential oil against Klebsiella pneumoniae. Carvone and its derivatives, as the main components, hold significant potential in the food industry and alternative medicines. A practical implication of this study could be higher plant densities or intercropping of dill, as it thrives with minimal light.