The aim of this work was to compare the chemical composition and antioxidant activity of the essential oils from two plant parts (leaves and stems) of fennel, wild-grown in the Montenegro seaside. The chemical composition of the isolated essential oils was determined by gas chromatography with mass spectrometry (GC/MS) and flame ionization detection (GC/FID). The yield of the fennel essential oils (FEOs) from leaves (0.83%) was four times higher than that from the fennel stems (0.21%). Forty-six compounds were identified from leaves’ FEOs and were mainly aromatic compounds (68.5%), monoterpenes (17.8%), and others, where the most abundant compounds were (E)-anethole (51.4%) and methyl chavicol (9.3%). Forty-seven compounds were identified in the FEOs from stems, which were mainly aromatic compounds (69.7%), oxygen-containing monoterpenes (14.9%), where the most abundant compounds were also (E)-anethole (55.7%) and methyl chavicol (7.8%). The FEOs from stems showed higher antioxidant activity, with an EC₅₀ value of 2.58 mg/mL, than in the fennel leaves, which had an EC₅₀ value of 6.91 mg/mL. The FEOs show superior antimicrobial activity against Candida albicans (45.3 mm) and Bacillus subtilis (24.0 mm). Isolated essential oils could be used as a safer alternative to synthetic additives in the food industry.

Thyme, mint, and lemon balm were used to determine whether shading conditions could improve the yield, composition, antioxidant, and antimicrobial activity in plant essential oils (EOs) in comparison with non-shaded plants from an open field. The yield of the EOs of non-shaded thyme, mint, and lemon balm, was 3.44, 3.96, and 0.21 mL/100 g, respectively. Plants covered by nets produced different levels of EOs (3.46, 2.20, and 0.45 mL/100 g) after 120 min of hydrodistillation. The main components of the thyme essential oil are thymol (44.2–43.9%), γ-terpinene (18.3–16.8%), and p-cymene (16.5–17.4%). The predominant components of mint essential oil are piperitenone oxide (52.6–64.8%) and 1,8 cineole (25.9–16.3%), while lemon balm essential oil consists of the following main components: geranial (34.0–32.8%); neral (21.3–24.9%); and piperitenone oxide (17.2–16.7%). The EOs from non-shaded thyme and mint plants have the highest antioxidant activity (EC₅₀ value 0.54 mg/mL and 3.03 mg/mL). However, shaded lemon balm showed a stronger antioxidant activity (EC₅₀ 3.43 mg/mL) than non-shaded plants (12.85 mg/mL) after 60 min of incubation. The EOs from all plants showed significant effects against Escherichia coli, Proteus vulgaris, Bacillus subtilis, Staphylococcus aureus, and Candida albicans. The most active EOs against most of the isolates originated from Thymus vulgaris L., plants. Adequate cultivation techniques, such as shading for Lamiaceae plants, has positive effects, especially in Melissa officinalis L. Shading can achieve a higher content and components in terms of the specific biological activity (antioxidant and microbial) of EOs.

The manipulation of light intensity by shade nets can lead to exchanges in the phytochemical quality and antioxidants ofsome herbs. This study aimed to determine whether shading by pearl nets (50% shade index) could improve the bioactive compounds in several medicinal herbs such as thyme (Thymus vulgaris L.), marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), lemon balm (Melissa officinalis L.), and peppermint (Mentha piperita L.), and their correspondingherbal extracts during a four-week maceration process in ethanol. Oregano and thyme provided the highest yield of total extractive substances (TES) from both shaded and non-shaded plants. Among all studied herbs, the highest level of antioxidants, expressed as total phenolic content (TPC) was found in extracts from shaded plants of lemon balm. Herbal extracts produced from non-shaded thyme and marjoram had higher flavonoid contents compared to herbal extracts from shaded plants. Accumulation of the investigated secondary metabolites depends more on the specificity of a plant species rather than light intensity. This study was an initial step in the production of medicinal plants with an increased quantity of antioxidant and other bioactive compounds during the maceration process in extracts, aimed to be used as natural alcoholic productwith added value.

The purpose of this study was to determine essential oil yield, composition, and antioxidant activity during two different maturation stages of umbels with seeds(I stage: premature–waxy; and II stage: mature–fully ripening) of wild carrot (Daucus carrota var. carota) from the Montenegrin coast. A higher yield of carrot essential oil (CEO) was determined in mature, fully ripening umbels (1.96 mL/100 g p.m) than in premature umbels at the waxy stage (mL/100 g p.m). Thirty-three components were identified in premature umbels, with β-bisabolene (32.3%), 11-α-(H)-himachal-4-en-1-β-ol (27.9%), elemicin (10.1%), and α-longipipene (7.7%) being the main components. They were followed by α-pinene (3.7%), (E)-asarone (3.4%), (E)-anethole (3.2%), and β-himachalene (2.0%). Thirty-two components were identified in CEO from mature umbels, with β-bisabolene (41.0%), 11-α-(H)-himachal-4-en-1-β-ol(21.1%), elemicin (14.8%), andα-longipipene (5.7%) being the most abundant. These components were followed by (E)-asarone (3.9%), cis-α-bisabolene (2.4%), and β-himachalene (2.0%). The CEO isolated from mature umbelsshowed better antioxidant activity (EC₅₀ value of 31.80 mg/mL) in comparison to the CEO isolated from premature umbels (EC₅₀ value of 49.18 mg/mL) during the incubation time of 60 min. The degree of DPPH radical neutralization increased as the incubation time increased from 20 to 60 min. Therefore, our findings recommend that wild carrot could be harvested in the fully ripening stage when the umbel improves CEO yield and antioxidant activity, without the risk of seed shedding from the umbel and seed losses.

This study was conducted to determine the sea fennel essential oil (SFEO) yield, composition, and antioxidant activity of leaves, stem, inflorescences, and umbels from seeds of wild sea fennel (SF) (Crithmum maritimum L.) from the Montenegro coast. The chemical composition of isolated essential oil was determined by GC/MS and GC/FID analyses. The antioxidant activity was determined using the DPPH assay. The maximum SFEO yield was found in umbels with seeds (4.77 mL/100 g p.m.). The leaves contained less EO (0.52 mL/100 g p.m.) than immature inflorescence (0.83 mL/100 g p.m.) The minimum EO content was found in the stem (0.08%). Twenty components were isolated from SFEO leaves, twenty-four from inflorescence, thirty-four components from the stem, and twenty-one components from umbels with seeds. Limonene (62.4–72.0%), γ-terpinene (9.5–14.0%), α-pinene (1.4–5.8%), and sabinene (1–6.5%) were found to be the main components of the SFEO from monoterpene hydrocarbons as dominant grouped components (86% to 98.1%). SF plant parts showed differences in chemical profiles, especially in specific and low-represented ingredients. (E)-anethole (4.4%), fenchone (0.5%), and trans-carveol (0.2%) were present only in umbel with seeds, while the β-longipipene (0.5%), (E)-caryophyllene (0.5%), and (2E)-decenal (0.2%) were found only in the stems. The degree of DPPH radical neutralization increased with incubation time. The SFEO isolated from the stems showed stronger antioxidant activity during the incubation times of 20 and 40 min (EC₅₀ value of 5.30 mg/mL and 5.04 mg/mL, respectively) in comparison to the SFEO isolated from the other plant parts. The lowest antioxidant activity was obtained with the SFEO leaves (155.25 mg/mL and 58.30 mg/mL, respectively). This study indicates that SFEO possesses significant antioxidant activities and is animportant component in the food and pharmaceutical industries. It is important to preserve the existing gene pool and biodiversity with rational use SF for the extraction of high-quality essential oils.