兰香草挥发油化学成分的研究

采用常压水蒸气蒸馏法提取了兰香草挥发油,得油率为 0.35 ~ 0.52%。其相对密度(20℃/4℃)0.9980 ~0.9900,折射率(20℃)1.4608,比旋光度+0.51°;酸值1.5。并用毛细管气相色谱、红外光谱、核磁共振谱和色-质联机等对该挥发油进行了系统的成分分析。在分出的112个色谱峰中,共鉴定出 71 个化合物,占挥发油总量的 94.6%。其主要成分为芳樟醇、紫苏醇、香芹酮、荠苎烯、4-甲基-6-庚烯-3-酮、葎草烯、马鞭草烯酮、左旋松香芹酮、2-壬烯-4-炔等。     

从香紫苏油中分离提纯芳樟醇和乙酸芳樟酯工艺的研究

采用真空间歇精馏技术,通过变换操作工艺条件,对香紫苏油进行分离得到芳樟醇和乙酸芳樟酯产品.考虑原料的热敏性制定出适宜的分离方案:首先在操作压力为1.5kPa条件下对原料进行初步分离,得到富含芳樟醇的轻馏分和富含乙酸芳樟酯的重馏分两个原料;再分别对轻馏分和重馏分进行不同条件下的真空间歇精馏,可以使芳樟醇的含量达到90.6%,乙酸芳樟酯的含量达到96.6%,满足两产品的不同需求.在提纯轻馏分中芳樟醇时,操作压力为5kPa,塔釜温度小于105℃;在提纯重馏分中乙酸芳樟酯时,操作系统压力为1.33kPa,塔釜温度低于110℃.此分离操作工艺,缩短了乙酸芳樟酯的受热时间、降低了分离温度以及乙酸芳樟酯因受热而异构化的趋势,降低了能耗.     

Chemical investigation and antimicrobial properties of mastic water and its major constituents

Mastic water is a commercial flavouring obtained during the steam distillation of mastic resin (the resin of Pistacia lentiscus var. chia) for the production of mastic oil. The mastic water extracts were analysed by GC−MS. The major compounds identified were verbenone, α-terpineol, linalool and trans-pinocarveol. Overall the composition was found to be very different from that of mastic oil. Additional GC−MS revealed the enantiomeric ratio of the chiral constituents of mastic water. The antimicrobial activity of mastic water extract, as well as that of its major constituents, was examined against Escherichia coli, Staphylococcus aureus and Candida spp. including ATCC wild clinical and food-borne strains. Linalool and α-terpineol were found to be the most potent antimicrobial constituents. Finally the stability of mastic water at different temperatures was studied, showing no change in the GC−MS profile of the organic extract for a period of 4 months at storage temperatures up to 4 °C.     

Optimization of Supercritical Extraction of Linalyl Acetate from Lavender via Box‐Behnken Design

Essential oil was extracted from lavender using supercritical carbon dioxide by means of a newly developed periodic static‐dynamic (PSD) procedure and the conventional semicontinuous (SC) technique. Applying GC‐FID analysis in conjunction with Box‐Behnken design, an optimum overall extraction yield (94.4 %) was obtained via PSD in contrast to 90 % for the SC method. The results indicate that supercritical fluid extraction is a viable technique for separation of constituents such as linalyl acetate, linalool, fenchone, and camphor for pharmaceutical and medicinal applications. Furthermore, a substantial reduction of energy consumption and solvent consumption is achieved with the developed PSD process compared to the conventional SC method.     

Putative Mode of Action of the Monoterpenoids Linalool,Methyl Eugenol,Estragole, and Citronellal on Ligand-Gated Ion Channels

Essential oil has been used as sedatives, anticonvulsants, and local anesthetics in traditional medical remedies; as preservatives for food, fruit, vegetable, and grain storage; and as bio-pesticides for food production. Linalool (LL), along with a few other major components such as methyl eugenol (ME), estragole (EG), and citronellal, are the active chemicals in many essential oils such as basil oil. Basil oil and the aforementioned monoterpenoids are potent against insect pests. However, the molecular mechanism of action of these chemical constituents is not well understood. It is well-known that the γ-aminobutyric acid type A receptors (GABA_ARs) and nicotinic acetylcholine receptor (nAChR) are primary molecular targets of the synthetic insecticides used in the market today. Furthermore, the GABA_AR-targeted therapeutics have been used in clinics for many decades, including barbiturates and benzodiazepines, to name just a few. In this research, we studied the electrophysiological effects of LL, ME, EG, and citronellal on GABA_AR and nAChR to further understand their versatility as therapeutic agents in traditional remedies and as insecticides. Our results revealed that LL inhibits both GABA_AR and nAChR, which may explain its insecticidal activity. LL is a concentration-dependent, non-competitive inhibitor on GABA_AR, as the half-maximal effective concentration (EC₅₀) values of γ-aminobutyric acid (GABA) for the rat α1β3γ2L GABA_AR were not affected by LL: (36.2 ± 7.9) μmol·L⁻¹ and (36.1 ± 23.8) μmol·L⁻¹ in the absence and presence of 5 mmol·L⁻¹ LL, respectively. The half-maximal inhibitory concentration (IC₅₀) of LL on GABA_AR was approximately 3.2 mmol·L⁻¹. Considering that multiple monoterpenoids are found within the same essential oil, it is likely that LL has a synergistic effect with ME, which has been previously characterized as both a GABA_AR agonist and a positive allosteric modulator, and with other monoterpenoids, which offers a possible explanation for the sedative and anticonvulsant effects and the insecticidal activities of LL.     

纯种芳樟及其组培苗叶油的分析报告

本文介绍了“纯种芳樟”的寻找与发现过程 ,利用组织培养育苗后叶油化学成份变化规律 ,为芳樟的组织培养育苗、栽种提供了令人信服的理论依据     

Efficacy of polyethylene-based antimicrobial films containing principal constituents of basil

The feasibility of low-density polyethylene (LDPE)-based films containing linalool or methylchavicol as antimicrobial (AM) packages to retard microbial growth on food surfaces was investigated. The AM LDPE-based films were tested for inhibition against selected microorganisms. Both compounds retained their AM activity, after an extrusion film-blowing process, against Escherichia coli in solid medium. Cheddar cheese was wrapped with the AM films and the packaged cheese samples were stored at 4 °C. The changes in the mesophilic aerobic bacteria and coliform, as well as yeast and mould counts were monitored. In addition, cheese samples inoculated with E. coli or Listeria innocua were wrapped with the AM films, stored at refrigerated (4 °C) or at abuse (12 °C) temperatures and the count of these microorganisms was monitored as a function of time. The results showed an inhibitory effect of these AM films against microbial growth in naturally contaminated cheese and in inoculated samples. The effect on suppression of E. coli and L. innocua growth was more pronounced at the abuse temperature. Methylchavicol-LDPE-based film exhibited a higher efficacy of inhibition than that of linalool-LDPE-based film. In addition, a sensory evaluation was performed with regards to possible taint in the flavour of the cheese. Taint in flavour as affected by linalool or methylchavicol was not significantly detectable by the panelists at the end of the storage period of 6 weeks. This study shows the potential use of polymeric films containing the principal constituents of basil as the AM components for enhancing quality and safety of cheeses.     

Antifungal activity of Michelia alba oil in the vapor phase and the synergistic effect of major essential oil components against Aspergillus flavus on brown rice

The objectives of this study were to investigate the effect of essential oil (Michelia alba) vapor on the spore germination and mycelium growth of Aspergillus flavus on brown rice and to perceive the shelf life of the brown rice could be extended to a longer storage time. Different volumes (150, 300, 450 μl) of M. alba and a 300 μl linalool/caryophyllene combination at ratios of 10:1, 1:1, and 1:10 were first absorbed into plant absorbent material (Φ∼20 mm) before being put into a closed glass box (1L) containing A. flavus spore and the mycelium (Φ∼5 mm) in a Malt Extract Agar (uncovered plate). Mold testing was also carried out on brown rice with A. flavus spore suspension before being incubated at 25° C and 100% RH for 16 weeks. Quality tests e.g. texture, a sensorial evaluation (hedonic scale) of brown rice were also conducted. Results indicated that the vapor phase of M. alba at ≥ 300 μl L⁻¹ air could inhibit both spore germination and A. flavus mycelium. Antifungal activity of M. alba in air was strongly correlated with the linalool/caryophyllene combination at the ratio of 10:1 in 300 μl L⁻¹ air. In addition, M. alba vapor at 300 μl L⁻¹ air was found to extend the shelf-life of the brown rice by four times (16 weeks) in comparison with the control treated without essential oil (4 weeks). After being cooked, the hardness of brown rice with volatile essential oil was found to be reduced by one third (compared to the control brown rice). The hedonic value (overall liking) of cooked brown rice packed with M. alba vapor at 300 μl for 1 week and then stored for 16 weeks was a 7, rated as “like moderately”. Therefore, this study has demonstrated the good potential of M. alba vapor to control mold growth on the surface of brown rice.     

Feasibility of 1,3-butanediol as solvent for limonene and linalool separation

Liquid–liquid equilibrium of the system limonene + linalool + 1,3-butanediol has been studied at two different temperatures. The obtained data were satisfactorily correlated with the NRTL activity coefficient model, in order to obtain the binary interaction parameters of the mixture. Later on, an extraction column was simulated with ASPEN PLUS^® software, to ascertain the feasibility of 1,3-butanediol as solvent for limonene and linalool separation and to determine the advantages of this solvent over the employed previous ones in this process. The influence of the number of theoretical stages and the solvent/feed ratio over the amount and purity of the recovered limonene and linalool were also studied.     

Composition and antioxidant and antimicrobial activity of the essential oil and extracts of Stachys inflata Benth from Iran

Composition and antioxidant and antimicrobial activities of essential oil and methanol extract polar and nonpolar subfractions of Stachys inflata were determined. GC and GC/MS analyse of the essential oil showed 45 constituents representing 95.46% of the oil, the major components linalool (28.55%), α-terpineol (9.45%), spathulenol (8.37%) and (2E)-hexenal (4.62%) constituted 50.99% of it. Essential oil and extracts were also tested for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid assays. In the DPPH test, IC₅₀ value for the polar subfraction was 89.50 μg/ml, indicating an antioxidant potency of about 22% of that of butylated hydroxytoluene (IC₅₀ = 19.72 μg/ml) for this extract. In β-carotene/linoleic acid assay, the best inhibition belonged to the nonpolar subfraction (77.08%). Total phenolic content of the polar and nonpolar extract subfractions was 5.4 and 2.8% (w/w), respectively. The plant also showed a week antimicrobial activity against three strains of tested microorganisms. Linalool and α-terpineol were also tested as major components of the oil and showed no antioxidant but considerable antimicrobial activities.