Chemical Composition and Bioactivity of Dill Seed (Anethum graveolens L.) Essential Oil from Plants Grown under Shading

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.

Antifungal Activity and Type of Interaction of Melissa officinalis Essential Oil with Antimycotics against Biofilms of Multidrug-Resistant Candida Isolates from Vulvovaginal Mucosa

(1) Background: Vulvovaginal candidosis (VVC) is a major therapy issue due to its high resistance rate and virulence factors such as the ability to form biofilms. The possibility of combining commonly used antifungals with natural products might greatly improve therapeutic success. (2) Methods: A total of 49 vulvovaginal isolates, causative agents of recurrent VVC, were tested for their susceptibility to fluconazole, nystatin, and Melissa officinalis essential oil (MOEO). This examination included testing the antibiofilm potential of antifungals and MOEO and the determination of their types of interaction with mature biofilms. (3) Results: Antimicrobial testing showed that 94.4% of the Candida albicans isolates and all the Candida krusei isolates were resistant to fluconazole, while all strains showed resistance to nystatin. The same strains were susceptible to MOEO in 0.156-2.5 mg/mL concentrations. Additionally, the results revealed very limited action of fluconazole, while nystatin and MOEO reduced the amount of biofilm formed by as much as 17.7% and 4.6%, respectively. Testing of the combined effect showed strain-specific synergistic action. Furthermore, the lower concentrations exhibited antagonistic effects even in cases where synergism was detected. (4) Conclusions: This study showed that MOEO had a very good antibiofilm effect. However, combining MOEO with antimycotics demonstrated that the type of action depended on the choice of antifungal drugs as well as the applied concentration.

Osage orange (Maclura pomifera (Raf.) Schneid) fruit extracts: UHPLC-DAD-ESI-MS/MS analysis, antioxidant activity and in vivo skin tests

This work aimed to evaluate chemical profile, antioxidant activity and topical application safety of the raw Osage orange (Maclura pomifera (Raf.) Schneid) fruit extracts obtained by maceration using ethanol and acetone. Out of eighteen different compounds registered in the extracts, fifteen were identified by ultra-high-performance liquid chromatography-tandem mass spectrometry. Pomiferin and osajin were characteristic and representative compounds in both ethanolic and acetone extracts of the Osage orange fruit. Both extracts showed good antioxidant activity (EC₅₀ = 0.03 mg/cm³) after 20 min of incubation. The topical administration safety of the extracts was evaluated in vivo by measuring skin biophysical parameters: electrical capacitance and erythema index, as indicators of stratum corneum hydration and irritation, respectively. Based on the results of the in vivo skin tests, it can be concluded that both of the Osage orange fruit extracts are safe for topical administration - they increased skin hydration and reduced skin irritation under the occlusion.

Comparative analysis of chemical composition and antioxidant activity of essential oil and hydrolate from black pepper fruit (Piper nigrum L.)

The objective of this study was to analyze the chemical composition of the essential oil (EO) and hydrolate of black pepper fruit, as well as their antioxidant activity. The EO was obtained by Clevenger-type hydrodistillation with hydromodule 1:10 m/v for 240 minutes, and the hydrolate was collected after the hydrodistillation process. The qualitative composition of EO was determined by GC/MS and quantitative by GC/FID method, while the qualitative composition of a hydrolate was determined by HS-SPME-GC/MS and quantitative composition by HS-SPME-GC/FID method. The antioxidant activity was investigated by DPPH assay. Fifty-five compounds were identified from black pepper EO, where the most abundant compounds were (E)-caryophyllene (41.6 %), limonene (9.7 %), and sabinene (8.6 %). Twelve compounds were identified from black pepper hydrolate, where the most abundant compounds were α-terpineol (34.7 %), borneol (17.3 %), and terpinen-4-ol (13.9 %). The hydrolate showed higher antioxidant activity after 20 minutes of incubation with an EC50 value of 0.993 ± 0.011 mg/cm3 compared to the EO with an EC50 value of 67.72 ± 1.871 mg/cm3. According to the results obtained in this study, both the EO and hydrolate are good sources of natural antioxidants with potential uses in the food, organic agriculture, pharmaceutical, and cosmetic industries as a safer alternative to synthetic additives. Furthermore, the possibility of wider uses of the hydrolate should be investigated in more detail. Although researchers interested in hydrolate investigation focus mostly on their antioxidant activity, these "aromatic wastes" could also present promising cosmetic activities.

Modification of light intensity influence essential oils content, composition and antioxidant activity of thyme, marjoram and oregano

Thymus vulgaris L. (thyme), Origanum majorana L. (marjoram), and Origanum vulgare L. (oregano) were used to determine whether light modification (plants grown under nets with 40% shaded index or in un-shaded open field) could improve the quantity and quality of essential oils (EOs) and antioxidant activity. The yield of EOs of thyme, marjoram, and oregano obtained after 120 min of hydrodistillation was 2.32, 1.51, and 0.27 mL/100 g of plant material, respectively. At the same time under shading conditions plants synthetized more EOs (2.57, 1.68, and 0.32 mL/100 g of plant material). GC/MS and GC/FID analyses were applied for essential oils determinations. The main components of the thyme essential oil are thymol (8.05-9.35%); γ-terpinene (3.49-4.04%); p-cymene (2.80-3.60%) and caryophyllene oxide (1.54-2.15%). Marjoram main components were terpinene 4-ol (7.44-7.63%), γ-terpinene (2.82-2.86%) and linalool (2.04-2.65%) while oregano essential oil consisted of the following components: caryophyllene oxide (3.1-1.93%); germacrene D (1.17-2.0%) and (E)-caryophyllene (1.48-1.1%). The essential oil from thyme grown under shading (EC₅₀ value after 20 min of incubation) have shown the highest antioxidant activity - 0.85 mg mL^-1 in comparison to marjoram and oregano (shaded plants EC₅₀ 19.97 mg mL^-1 and 7.02 mg mL^-1 and unshaded, control plants EC₅₀ 54.01 mg mL^-1 and 7.45 mg mL^-1, respectively). The medicinal plants are a good source of natural antioxidants with potential application in the food and pharmaceutical industries. For production practice, it can be recommended to grow medicinal plants in shading conditions to achieve optimal quality parameters.

Effect of shading and grafting on yield and quality of tomato

BACKGROUND

The need to increase marketable tomato yields and decrease losses due to sunburn and disease during the summer motivates farmers to adopt additional cultural practices such as shading and grafting. To investigate complex interactions among grafting, shading, and tomato cultivar, grafted and ungrafted tomatoes (cv. 'Optima' F₁ and cv. 'Big Beef' F₁ ) were grown in the soil under net-house cover, using pearl and red nets, and in unshaded conditions (open fields). Tomato fruit at the red stage of maturity were used for the analysis of quality traits, and total and marketable yields were recorded during the whole production season.

RESULTS

Grafting and shading in tomato production might be considered as cultivation practices to increase the marketable tomato yield. A decrease in sugar content increased the uptake of some micro elements (Fe and Zn) and macro elements (Ca). In some cases, firmer and less elastic skin may be expected due to grafting. Shading with pearl net might result in fruit with lower firmness and higher total, and particularly malic, acid content.

CONCLUSION

Shading with colored nets and grafting provide alternative strategies for achieving higher fruit yields and avoiding or reducing a decrease in tomato quality caused by environmental stresses such as excessive radiation and temperature in the summer cropping season. © 2019 Society of Chemical Industry.

Transformation of synthetic allicin: the influence of ultrasound, microwaves, different solvents and temperatures, and the products isolation

The transformation of the synthesized allicin, using conventional method, the influence of ultrasound and microwaves, in different organic solvents (acetonitrile, acetone, methanol, and chloroform), at various temperatures (room temperature, 45 °C, and 55 °C) was investigated. Allicin degradation kinetic was monitored by HPLC. Allicin transformation under the effect of microwaves is faster than transformations performed under the influence of ultrasound or by conventional method. Increase of the temperature accelerates allicin transformation. Pharmacologically active compounds of (E)-ajoene, (Z)-ajoene, 3-vinyl-4H-1,2-dithiin, 2-vinyl-4H-1,3-dithiin, and diallyl disulfide were isolated from the mixture of transformation products of allicin under the influence of microwaves in methanol at 55 °C, which is according to kinetic parameters (highest values of the order of reaction and the lowest activation energy) the optimal method.

Antioxidant Activity and Total Phenolic and Flavonoid Contents of Hieracium pilosella L. Extracts

The antioxidant activity of water, ethanol and methanol Hieracium pilosella L. extracts is reported. The antioxidative activity was tested by spectrophotometrically measuring their ability to scavenge a stable DPPH(•) free radical and a reactive hydroxyl radical trapped by DMPO during the Fenton reaction, using the ESR spectroscopy. Total phenolic content and total flavonoid content were evaluated according to the Folin-Ciocalteu procedure, and a colorimetric method, respectively. A HPLC method was used for identification of some phenolic compounds (chlorogenic acid, apigenin-7-O-glucoside and umbelliferone). The antioxidant activity of the investigated extracts slightly differs depending on the solvent used. The concentration of 0.30 mg/mL of water, ethanol and methanol extract is less effective in scavenging hydroxyl radicals (56.35, 58.73 and 54.35%, respectively) in comparison with the DPPH(•) radical scavenging activity (around 95% for all extracts). The high contents of total phenolic compounds (239.59-244.16 mg GAE/g of dry extract) and total flavonoids (79.13-82.18 mg RE/g of dry extract) indicated that these compounds contribute to the antioxidative activity.