Journal: Journal of oleo science
Cholesterol has been suggested to play a role in stable vesicle formation by adjusting the molecular packing of the vesicular bilayer. To explore the mechanisms involved in adjusting the bilayer structure by cholesterol, the molecular packing behavior in a mimic outer layer of cationic dialkyldimethylammonium bromide (DXDAB)/cholesterol vesicular bilayer was investigated by the Langmuir monolayer approach with infrared reflection-absorption spectroscopy (IRRAS). The results indicated that the addition of cholesterol in the DXDAB Langmuir monolayers not only restrained the desorption of the DXDAB with short hydrocarbon chains, such as ditetradecyldimethylammonium bromide or dihexadecyldimethylammonium bromide, into the aqueous phase but also induced a condensing effect on the DXDAB monolayers. At a liquid-expanded (LE) state, the ordering effect of cholesterol accompanying the condensing effect occurred in the mixed DXDAB/cholesterol monolayers due to the tendency of maximizing hydrocarbon chain contact between cholesterol and the neighboring hydrocarbon chains. However, for the mixed monolayers containing the DXDAB with long hydrocarbon chains, such as dioctadecyldimethylammonium bromide (DODAB), the disordering effect of cholesterol took place at a liquid-condensed (LC) state. This was related to the molecular structure of cholesterol and hydrocarbon chain length of DODAB. The rigid sterol ring of cholesterol hindered the portion of neighboring hydrocarbon chains from motion. However, the flexible alkyl side-chain of cholesterol along with the corresponding portion of neighboring hydrocarbon chains formed a fluidic region, counteracting the enhanced conformational order induced by the sterol ring of cholesterol. Furthermore, the long hydrocarbon chains of DODAB possessed a more pronounced motion freedom, resulting in a more disordered packing of the monolayers.
Patchouli is used as an incense material and essential oil. The characteristic odor of patchouli leaves results from the drying process used in their production; however, there have to date been no reports on the changes in the odor of patchouli leaves during the drying process. We investigated the aroma profile of dried patchouli leaves using the hexane extracts of fresh and dried patchouli leaves. We focused on the presence or absence of the constituents of the fresh and dried extracts, and the differences in the content of the common constituents. Fourteen constituents were identified as characteristic of dried patchouli extract odor by gas chromatography-olfactometry analysis. The structures of seven of the 14 constituents were determined by gas chromatography-mass spectrometry (α-patchoulene, seychellene, humulene, α-bulnesene, isoaromadendrene epoxide, caryophyllene oxide, and patchouli alcohol). The aroma profile of the essential oil obtained from the dried patchouli leaves was clearly different from that of dried patchouli. The aroma profile of the essential oil was investigated by a similar method. We identified 12 compounds as important odor constituents. The structures of nine of the 12 constituents were determined by gas chromatographymass spectrometry (cis-thujopsene, caryophyllene, α-guaiene, α-patchoulene, seychellene, α-bulnesene, isoaromadendrene epoxide, patchouli alcohol, and corymbolone). Comparing the odors and constituents demonstrated that the aroma profile of patchouli depends on the manufacturing process.
This work was aimed to study the solvent fraction of coconut oil (CNO). The fatty acid and triacylglycerol compositions, solid fat content (SFC) and the crystallization properties of CNO and its solid and liquid fractions obtained from fractionation at different conditions were investigated using various techniques. CNO was dissolved in acetone (1:1 w/v) and left to crystallize isothermally at 10℃ for 0.5, 1 and 2 h and at 12°C for 2, 3 and 6 h. The solid fractions contained significantly lower contents of saturated fatty acids of ≤ 10 carbon atoms but considerably higher contents of saturated fatty acids with > 12 carbon atoms with respect to those of CNO and the liquid fractions. They also contained higher contents of high-melting triacylglycerol species with carbon number ≥ 38. Because of this, the DSC crystallization onset temperatures and the crystallization peak temperatures of the solid fractions were higher than CNO and the liquid fractions. The SFC values of the solid fractions were significantly higher than CNO at all measuring temperatures before reaching 0% just below the body temperature with the fraction obtained at 12°C for 2 h exhibiting the highest SFC. On the contrary, the SFC values of the liquid fractions were lower than CNO. The crystallization duration exhibited strong influence on the solid fractions. There was no effect on the crystal polymorphic structure possibly because CNO has β'-2 as a stable polymorph. The enhanced SFC of the solid fractions would allow them to find use in food applications where a specific melting temperature is desired such as sophisticated confectionery fats, and the decreased SFC of the liquid fractions would provide them with a higher cold stability which would be useful during extended storage time.
The aim of this research was to determine the chemical constituents and toxicities of the essential oil derived from Amomum tsaoko Crevost et Lemarie fruits against Tribolium castaneum (Herbst) and Lasioderma serricorne (Fabricius). Essential oil of A. tsaoko was obtained from hydrodistillation and was investigated by gas chromatography-mass spectrometry (GC-MS). GC-MS analysis of the essential oil resulted in the identification of 43 components, of which eucalyptol (23.87%), limonene (22.77%), 2-isopropyltoluene (6.66%) and undecane (5.74%) were the major components. With a further isolation, two active constituents were obtained from the essential oil and identified as eucalyptol and limonene. The essential oil and the two isolated compounds exhibited potential insecticidal activities against two stored-product insects. Limonene showed pronounced contact toxicity against both insect species (LD50 = 14.97 μg/adult for T. castaneum; 13.66 μg/adult for L. serricorne) and was more toxic than eucalyptol (LD50 = 18.83 μg/adult for T. castaneum; 15.58 μg/adult for L. serricorne). The essential oil acting against the two species of insects showed LD50 values of 16.52 and 6.14 μg/adult, respectively. Eucalyptol also possessed strong fumigant toxicity against both insect species (LC50 = 5.47 mg/L air for T. castaneum; 5.18 mg/L air for L. serricorne) and was more toxic than limonene (LC50 = 6.21 mg/L air for T. castaneum; 14.07 mg/L air for L. serricorne), while the crude essential oil acting against the two species of insects showed LC50 values of 5.85 and 8.70 mg/L air, respectively. These results suggested that the essential oil of A. tsaoko and the two compounds may be used in grain storage to combat insect pests.
Artemisia argyi Lévl. et Van., a perennial herb with a strong volatile odor, is widely distrbuted in the world. Essential oil obtained from Artemisia argyi was analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 32 components representing 91.74% of the total oil were identified and the main compounds in the oil were found to be eucalyptol (22.03%), β-pinene (14.53%), β-caryophyllene (9.24%) and (-)-camphor (5.45%). With a further isolation, four active constituents were obtained from the essential oil and identified as eucalyptol, β-pinene, β-caryophyllene and camphor. The essential oil and the four isolated compounds exhibited potential bioactivity against Lasioderma serricorne adults. In the progress of assay, it showed that the essential oil, camphor, eucalyptol, β-caryophyllene and β-pinene exhibited strong contact toxicity against L. serricorne adults with LD50 values of 6.42, 11.30, 15.58, 35.52, and 65.55 μg/adult, respectively. During the fumigant toxicity test, the essential oil, eucalyptol and camphor showed stronger fumigant toxicity against L. serricorne adults than β-pinene (LC50 = 29.03 mg/L air) with LC50 values of 8.04, 5.18 and 2.91 mg/L air. Moreover, the essential oil, eucalyptol, β-pinene and camphor also exhibited the strong repellency against L. serricorne adults, while, β-caryophyllene exhibited attracting activity relative to the positive control, DEET. The study revealed that the bioactivity properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components. The results indicate that the essential oil of A. argyi and the isolated compounds have potential to be developed into natural insecticides, fumigants or repellents in controlling insects in stored grains and traditional Chinese medicinal materials.
During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oils of Evodia calcicola and Evodia trichotoma leaves were found to possess strong repellency against the red flour beetle Tribolium castaneum adults, the cigarette beetle Lasioderma serricorne adults and the booklouse Liposcelis bostrychophila. The two essential oils obtained by hydrodistillation were investigated by GC-MS. The main components of E. calcicola essential oil were identified to be (-)-β-pinene (44.02%), β-phellandrene (20.93%), ocimene (16.49%), and D-limonene (9.87%). While the main components of the essential oil of E. trichotoma were D-limonene (69.55%), 1R-a-pinene (11.48%), caryophyllene (2.80%) and spathulenol (2.24%). Data showed that T. castaneum was the most sensitive than other two stored product insects. Compared with the positive control, DEET (N, N-diethyl-3-methylbenzamide), the two essential oils showed the same level repellency against the red flour beetle. However, the essential oil of E. trichotoma showed the same level repellency against the cigarette beetle, while E. calcicola essential oil possessed the less level repellency against L. serricorne, relative to the positive control, DEET. Moreover, the two crude oils also exhibited strong repellency against L. bostrychophila, but lesser level repellency than the positive control, DEET. Thus, the essential oils of E. calcicola and E. trichotoma may be potential to be developed as a new natural repellent in the control of stored product insects.
Coconut oil has recently attracted considerable attention as a potential Alzheimer’s disease therapy because it contains large amounts of medium-chain fatty acids (MCFAs) and its consumption is thought to stimulate hepatic ketogenesis, supplying an alternative energy source for brains with impaired glucose metabolism. In this study, we first reevaluated the responses of plasma ketone bodies to oral administration of coconut oil to rats. We found that the coconut oil-induced increase in plasma ketone body concentration was negligible and did not significantly differ from that observed after high-oleic sunflower oil administration. In contrast, the administration of coconut oil substantially increased the plasma free fatty acid concentration and lauric acid content, which is the major MCFA in coconut oil. Next, to elucidate whether lauric acid can activate ketogenesis in astrocytes with the capacity to generate ketone bodies from fatty acids, we treated the KT-5 astrocyte cell line with 50 and 100 μM lauric acid for 4 h. The lauric acid treatments increased the total ketone body concentration in the cell culture supernatant to a greater extent than oleic acid, suggesting that lauric acid can directly and potently activate ketogenesis in KT-5 astrocytes. These results suggest that coconut oil intake may improve brain health by directly activating ketogenesis in astrocytes and thereby by providing fuel to neighboring neurons.
Inhibition of β-secretase (BACE1) is currently regarded as the leading treatment strategy for Alzheimer’s disease. In the present study, we aimed to screen the in vitro inhibitory activity of 80 types of aroma compounds (monoterpenes, sesquiterpenes, and C13 norisoprenoids), including plant-based types, at a 200-μM concentration against a recombinant human BACE1. The results showed that the most potent inhibitor of BACE1 was geranyl acetone followed by (+)-camphor, (-)-fenchone, (+)-fenchone, and (-)-camphor with the half-maximal inhibitory concentration (IC50) values of 51.9 ± 3.9, 95.9 ± 11.0, 106.3 ± 14.9, 117.0 ± 18.6, and 134.1 ± 16.4 μM, respectively. Furthermore, the mechanism of inhibition of BACE1 by geranyl acetone was analyzed using Dixon kinetics plus Cornish-Bowden plots, which revealed mixedtype mode. Therefore aroma compounds may be used as potential lead molecules for designing anti-BACE1 agents.
Rosa acicularis seed oil was extracted from Rosa acicularis seeds by the ultrasonic-assisted aqueous enzymatic method using cellulase and protease. Based on a single experiment, Plackett-Burman design was applied to ultrasonic-assisted aqueous enzymatic extraction of wild rose seed oil. The effects of enzyme amount, hydrolysis temperature and initial pH on total extraction rate of wild rose seed oil was studied by using Box-Behnken optimize methodology. Chemical characteristics of a sample of Rosa acicularis seeds and Rosa acicularis seed oil were characterized in this work. The tocopherol content was 200.6±0.3 mg/100 g oil. The Rosa acicularis seed oil was rich in linoleic acid (56.5%) and oleic acid (34.2%). The saturated fatty acids included palmitic acid (4%) and stearic acid (2.9%). The major fatty acids in the sn-2 position of triacylglycerol in Rosa acicularis oil were linoleic acid (60.6%), oleic acid (33.6%) and linolenic acid (3.2%). According to the 1,3-random-2-random hypothesis, the dominant triacylglycerols were LLL (18%), LLnL (1%), LLP (2%), LOL (10%), LLSt (1.2%), PLP (0.2%), LLnP (0.1%), LLnO (0.6%) and LOP (1.1%). This work could be useful for developing applications for Rosa acicularis seed oil.
The synthesis of phytosteryl ester via the lipase-catalyzed esterification of phytosterol with fatty acid from echium oil was performed in a recirculating packed bed reactor. A commercial lipase from Candida rugosa was immobilized and then used to optimize the reaction conditions for the synthesis of the phytosteryl ester. The parameters investigated were temperature, molar ratio of phytosterol to fatty acid, retention time, and amount of solvent. The optimum conditions were determined as the temperature of 40°C, the molar ratio of 1:3 (phytosterol to fatty acid), the retention time of 3 min, and the solvent amount of 40 mL. The maximum conversion of phytosteryl ester was ca. 90 mol% under the optimum conditions. The major fatty acid in phytosteryl ester synthesized was α-linolenic acid (ca. 38 mol%).