Chemical composition,antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations

Chemical composition, antioxidant and antimicrobial activities of the essential oils from aerial parts of basil (Ocimum basilicum L.) as affected by four seasonal, namely summer, autumn, winter and spring growing variation were investigated. The hydro-distilled essential oils content ranged from 0.5% to 0.8%, the maximum amounts were observed in winter while minimum in summer. The essential oils consisted of linalool as the most abundant component (56.7–60.6%), followed by epi-α-cadinol (8.6–11.4%), α-bergamotene (7.4–9.2%) and γ-cadinene (3.2–5.4%). Samples collected in winter were found to be richer in oxygenated monoterpenes (68.9%), while those of summer were higher in sesquiterpene hydrocarbons (24.3%). The contents of most of the chemical constituents varied significantly (p < 0.05) with different seasons. The essential oils investigated, exhibited good antioxidant activity as measurements by DPPH free radical-scavenging ability, bleaching β-carotene in linoleic acid system and inhibition of linoleic acid oxidation. Evaluation of antimicrobial activity of the essential oils and linalool, the most abundant component, against bacterial strains: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pasteurella multocida and pathogenic fungi Aspergillus niger, Mucor mucedo, Fusarium solani, Botryodiplodia theobromae, Rhizopus solani was assessed by disc diffusion method and measurement of determination of minimum inhibitory concentration. The results of antimicrobial assays indicated that all the tested microorganisms were affected. Both the antioxidant and antimicrobial activities of the oils varied significantly (p < 0.05), as seasons changed.     

藤椒挥发油的成分分析

实验采用水蒸气蒸馏仪对藤椒进行挥发油的提取,测出藤椒在实验条件下挥发油含量为8．4649mL／100g,用GC-MS法对挥发油组分进行分离、鉴定,并通过峰面积归一法确定其相对含量。结果表明,藤椒挥发油的主要化学成分中,芳樟醇52．17％、柠檬烯18．87％、桧烯11．88％、月桂烯3．88％、大根香叶烯1．26％和伊石竹烯1．17％的含量较高。     

硫代香叶醇的制备

讨论了以芳樟醇Linalool为原料,对甲基苯磺酸为催化剂,合成硫代香叶醇.并对合成硫代香叶醇的工艺条件进行优化.使硫代香叶醇的收率达到56%.     

Bioactivity of five monoterpenoid vapours to Tribolium confusum (du Val) (Coleoptera: Tenebrionidae)

Five monoterpenoids (terpinen-4-ol, 1,8-cineole, linalool, R-(+)-limonene and geraniol) were tested in vapour form against different stages of Tribolium confusum. Terpinen-4-ol (with LC₅₀ values ranging between 1.1 and 109.4 μl/l air), (R)-(+)-limonene (with LC₅₀ values ranging between 4 and 278 μl/l air) and 1,8-cineole (with LC₅₀ values ranging between 3.5 and 466 μl/l air) were the most toxic to all stages tested, followed by linalool (with LC₅₀ values ranging between 8.6 and 183.5 μl/l air) while the least toxic monoterpenoid tested was geraniol with LC₅₀ values ranging between 607 and 1627 μl/l air. In all cases, except for geraniol, third-instar larvae were the most susceptible stage and 3-day-old eggs most tolerant. Apart from the observed direct toxicity, exposure of females to the vapours led in some cases to lower fecundity and egg hatchability. All monoterpenoids tested revealed insect growth regulator (IGR)-like properties when applied to 3-day-old pupae, producing adultoids and deformed adults.     

Variability of<Emphasis Type="Italic"> Satureja cuneifolia</Emphasis> Ten. essential oils and their antimicrobial activity depending on the stage of development

The essential oils obtained from Satureja cuneifolia Ten. harvested in the central part of Dalmatia at three ontogenetic stages were evaluated for their chemical composition and antimicrobial activity against food pathogens. The GC/MS analyses allowed 32 compounds to be determined; the main constituents of the essential oils were linalool (18.2–17.2%), carvacrol (16.0–5.0%), p-cymene (14.8–4.0%), -pinene (12.0–5.8%) and limonene (11.0–1.8%). The compounds linalool and borneol appeared to be relatively constant but carvacrol, limonene and -pinene showed variability during the growth cycles. The oils had a broad-spectrum antimicrobial activity against food pathogens in broth microdilution bioassays. Maximum activity was observed against the yeast Candida albicans, the Gram-negative bacteria Escherichia coli, Salmonella typhimurium and Proteus mirabilis and the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus. The essential oils showed good antibacterial effects against E. coli with a minimum inhibitory concentration of 0.06% and a minimum bactericidal concentration of 0.12% during the flowering stage. These inhibitory effects are interesting in relation to the prevention of microbial contamination in many foods and, therefore, essential oils of S. cuneifolia could be used as substitutes for synthetic antimicrobial compounds.     

Synthesis and characterization of functional copolymer of Linalool and vinyl acetate: A kinetic study

Linalool (LIN) and vinyl acetate (VA) were copolymerized by benzoyl peroxide (BPO) in p‐xylene at 60°C for 90 min. The system follows nonideal kinetics: R_pα[I]^0.6[LIN]^1.2[VA]^1.1. It results in the formation of alternating copolymer as evidenced from reactivity ratios as r₁ (VA) = 0.01, r₂ (LIN) = 0.0015, which have been calculated by Kelen–Tudos method. The overall activation energy is 82 kJ/mol. The FTIR spectrum of the copolymer shows the presence of the band at 3425 cm^?1 due to alcoholic group of LIN and at 1641 cm^?1 due to >C?O group of VA. The ¹H‐NMR spectrum shows peaks at 7.0–7.7 δ due to hydroxy proton of LIN and at 1.0–1.4 δ due to acetoxy protons of VA. ¹³C‐NMR spectrum of copolymer shows peaks at 167 ppm due to acetoxy group and at 75–77 ppm due to C? OH group. The Alfrey–Price Q–e parameters for LIN has been calculated as Q₂ = 1.24 and e₂ = 3.11. The copolymer is highly thermally stable and has a glass transition temperature (T_g) of 85°C, evaluated from DSC studies. The mechanism of copolymerization has been elucidated. This article also reports measurement of Mark–Houwink constants in THF at 25°C by means of GPC as α = 0.8 and K = 3.0 × 10^?4 dl/g. The thermal decompositions of copolymer are established with the help of TGA technique. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1134–1143, 2004     

The effects of tangerine peel (Citri reticulatae pericarpium) essential oils as glazing layer on freshness preservation of bream (Megalobrama amblycephala) during superchilling storage

This work was aim to the application of tangerine peel essential oils (TPEOs) as glazing layer on fish preservation. In this paper, essential oils were respectively extracted from the peel of ponkan, bitter orange and sweet orange. Their compositions were analyzed using GC–MS method. Fresh sample of bream was immersed into different TPEO for the formation of glazing layers on the surface and stored at −1 ±0.2 °C for 25-days storage. A thorough study of freshness evaluation was carried out and statistics analysis was performed to analyze the effect of TPEO. The result showed that the glazing layers of TPEO can effectively slow down the degradation process of fish samples and the resulting variations in electrical, moisture, chemical, microbial, sensory and textural characteristics. Additionally, statistical analysis showed that there are significant (most of p is less than 0.05) difference between control and treated sample, but insignificant (most of p is more than 0.05) differences among the samples with glazing layer of different TPEOs.The work indicated TPEOs had remarkable effect in the storage of aquatic products.     

Antioxidant properties of coriander essential oil and linalool and their potential to control Campylobacter spp.

Foodborne diseases remain common around the world with Campylobacteriosis being the most commonly reported zoonosis in the European Union in 2013. Campylobacter jejuni and Campylobacter coli are the main species associated with human illness. Furthermore, Campylobacter can develop biofilms which is becoming a major problem within the food industry. In addition to foodborne pathogens, oxidation is a non-microbial cause of deterioration of food causing loss of quality and safety. Thus, there is an urgent need in the food industry for new and effective strategies that can help prevent food contamination, spoilage and consequently, foodborne illnesses. Essential oils are known for their antimicrobial and antioxidant properties and are already widely used in the food industry. So, the aim of this work was to study the antimicrobial and anti-biofilm activity of coriander essential oil and its major compound linalool against C. jejuni and C. coli strains, as well as their effect in the quorum sensing (QS) system and their potential as antioxidants. Our results, demonstrated that both compounds have anti-Campylobacter activity, inhibited in vitro biofilm formation and promoted biofilm dispersion even at sub-MIC concentrations and interfered with the QS system through the inhibition of violacein production. Moreover, the essential oil and linalool were shown to have radical scavenging properties and lipid peroxidation inhibition ability which could make them potential alternatives to synthetic antioxidants. In sum, our results demonstrated the antibacterial, anti-biofilm, anti-QS and antioxidant potentials of the coriander essential oil and its major compound, linalool, suggesting that they could be used in the food industry to enhance shelf life of food products and increase food safety without requiring chemical additives or preservatives.