Stereochemical analysis of constituents of essential oils and flavor compounds by enantioselective capillary gas chromatography

Modified cyclodextrins interact enantioselectively with a great variety of volatile chiral constituents of essential oils by forming diastereomeric inclusion complexes. Capillary gas chromatography is used for resolving the enantiomers of terpenoid hydrocarbons (camphene, α-pinene, limonene, α-phellandrene), carbonyl compounds (carvone, fenchone, menthone, isomenthone, piperitone, camphor, myrtenal), and alcohols (trifluoroacetylated β-citronellol, myrtenol, trans-pinocarveol, 1-octen-3-ol, and underivatized linalool). The enantiomeric composition of some of these compounds in a variety of essential oils is investigated.     

Chemical composition and antimicrobial activity of the essential oil of Mentha mozaffarianii Jamzad growing wild and cultivated in Iran

The aerial parts of wild and cultivated Mentha mozaffarianii Jamzad were collected at full flowering stage from two provinces (Hormozgan and Fars) of Iran. The essential oils were extracted by a Clevenger approach and analysed using GC and GC–MS. The main components in wild plants were piperitenone (33.85%), piperitone (21.18%), linalool (6.89%), pulegone (5.93%), 1, 8.cineole (5.49%), piperitenone oxide (5.17%) and menthone (4.69%) and in cultivated plants, cis-piperitone epoxide (28.89%), linalool (15.36%), piperitone (11.57%), piperitenone oxide (10.14%), piperitenone (8.42%),1,8-cineole (3.60%) were the main constituents in essential oil. The in vitro antimicrobial activity of the essential oil of M. mozaffarianii was studied against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Candida albicans. The results of the bioassays showed that the oil exhibited high antimicrobial activity against all the tested pathogens.     

Comparative analysis of some active principles of herb plants by GC/MS

A rapid extraction procedure for fingerprint chromatogram of different types of Mentha piperita L. (Labiatae family) is presented. The extracts were analysed by gas chromatography and gas chromatography-mass spectrometry (GC/MS). The main volatile compounds identified by the gas chromatography-mass spectrometric analysis of M. piperita L. were menthol, menthone, isomenthone, 1,8-cineole, menthyl acetate, limonene, beta-myrcene, carvone. M. piperita L. oil had the active principles: menthol, menthone, isomenthone, menthyl acetate, alpha-pinene, beta-pinene, champhor, limonene, linalool, piperitone. M. crispa L. showed carvone as major component.     

GC/MS combined with chemometrics methods for quality control of Schizonepeta tenuifolia Briq: Determination of essential oils

A simple and rapid gas chromatography/mass spectrometry (GC/MS) analysis method was developed for the determination of essential oils in the crude extract of Schizonepeta tenuifolia Briq (Sch.t.Briq). Five major volatiles (menthone, pulegone, 2-hydroxy-2-isopropenyl-5-methylcylohexanone, cis-pulegone oxide, and schizonal) were extracted and isolated from Sch.t.Briq as marker compounds for use in the quality control of herbal medicines. Various extraction techniques, such as solvent immersion, mechanical shaking, and sonication, were evaluated, and the greatest efficiency was observed with sonication extraction using petroleum ether. The dynamic range of the GC/MS method depended on the specific analyte; acceptable quantification was obtained between 10 and 1000 μg/mL for menthone and pulegone, and between 2.5 and 75.0 μg/mL for 2-hydroxy-2-isopropenyl-5-methylcylohexanone, cis-pulegone oxide, and schizonal. The method was deemed satisfactory by inter- and intra-day validation and exhibited both high accuracy and precision, with a relative standard deviation < 10%. Overall limits of detection were approximately 0.40–0.50 μg/mL, with a standard deviation (σ)-to-calibration slope (s) ratio (σ/s) of 3. The limit of quantitation in our experiments was approximately 2.5 μg/mL at a σ/s of 10. On the basement of method validation, 21 samples of Sch.t.Briq collected from markets in Korea were monitored for the quality control. In addition, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were performed on the analytical data of 21 different Sch.t.Briq samples in order to classify samples that were collected from different regions.     

Isolation,Identification and High-Throughput Screening of Neutral Lipid Producing Indigenous Microalgae from South African Aquatic Habitats

Exploring indigenous microalgae capable of producing significant amounts of neutral lipids through high-throughput screening is crucial for sustainable biodiesel production. In this study, 31 indigenous microalgal strains were isolated from diverse aquatic habitats in KwaZulu-Natal, South Africa. Eight superior lipid-producing strains were selected for further analysis, based on Nile red fluorescence microscopy screening. The microalgal isolates were identified to belong to the genera Chlorella, Neochloris and Chlamydomonas via morpho-taxonomic and molecular approach by 18S rRNA gene sequencing. Chlorella vulgaris PH2 had the highest specific growth rate (μ) and lowest doubling time of 0.24 day⁻¹ and 2.89 ± 0.05 day⁻¹, respectively. Chlorella vulgaris T4 had the highest biomass productivity of 35.71 ± 0.03 mg L⁻¹day⁻¹. Chlorella vulgaris PH2 had the highest lipid content of 34.28 ± 0.47 and 38 ± 9.2% (dcw) as determined by gravimetric analysis and the sulfo-phospho-vanillin (SPV) method, respectively. Chlorella vulgaris PH2 exhibited a high content of saturated fatty acids, while Chlorella sp. T4 exhibited a high total content of saturated and monounsaturated fatty acids with a low content of polyunsaturated fatty acids. The preponderance of neutral lipids suggests that Chlorella sp. T4 is a suitable candidate for biomass feedstock for biodiesel production.

     

Disruption of <Emphasis Type="BoldItalic">Chlorella vulgaris</Emphasis> Cells for the Release of Biodiesel-Producing Lipids: A Comparison of Grinding,Ultrasonication, Bead Milling,Enzymatic Lysis,and Microwaves

A comparative evaluation of different cell disruption methods for the release of lipids from marine Chlorella vulgaris cells was investigated. The cell growth of C. vulgaris was observed. Lipid concentrations from different disruption methods were determined, and the fatty acid composition of the extracted lipids was analyzed. The results showed that average productivity of C. vulgaris biomass was 208 mg L⁻¹ day⁻¹. The lipid concentrations of C. vulgaris were 5%, 6%, 29%, 15%, 10%, 7%, 22%, 24%, and 18% when using grinding with quartz sand under wet condition, grinding with quartz sand under dehydrated condition, grinding in liquid nitrogen, ultrasonication, bead milling, enzymatic lysis by snailase, enzymatic lysis by lysozyme, enzymatic lysis by cellulose, and microwaves, respectively. The shortest disruption time was 2 min by grinding in liquid nitrogen. The unsaturated and saturated fatty acid contents of C. vulgaris were 71.76% and 28.24%, respectively. The extracted lipids displayed a suitable fatty acid profile for biodiesel [C16:0 (~23%), C16:1 (~23%), and C18:1 (~45%)]. Overall, grinding in liquid nitrogen was identified as the most effective method in terms of disruption efficiency and time.     

Chemical diversity of Ziziphora clinopodioides: composition of the essential oil of Z. clinopodioides from Tajikistan

The chemical composition of the essential oils of Ziziphora clinopodioides Lam. from the aerial flowering parts, collected during two different years, were obtained by hydrodistillation and analyzed by gas chromatography - mass spectrometry. Forty-five components representing 100% and 94.7% of the total oil were identified. The main constituents of the essential oils were pulegone (72.8 and 35.0%), neomenthol (6.5 and 23.1%), menthone (6.2 and 13.3%), p-menth-3-en-8-ol (1.7 and 3.5%), piperitenone (2.6 and 1.1%) and piperitone (0.7 and 1.2%). A cluster analysis was carried out on the essential oil compositions of Z. clinopodioides.     

Supercritical carbon dioxide extraction of Mentha pulegium L. essential oil

The dependence of Mentha pulegium L. (pennyroyal) essential oil composition, obtained by supercritical carbon dioxide (SC-CO₂), with the following parameters: pressure, temperature, extraction time (dynamic), and modifier (methanol) was studied. The results were also compared with those obtained by conventional hydrodistillation method in laboratory conditions. Regarding the percentages of menthone (30.3%) and pulegone (52.0%), the optimum SFE results were obtained at the following experimental conditions: pressure=100 atm, T=35 °C, dynamic time=10 min, and V_modifier=0 μl. The results of hydrodistillation showed that the major components of M. pulegium L. were pulegone (37.8%), menthone (20.3%), and piperitenone (6.8%). The evaluation of the composition of each extract was performed by gas chromatography-mass spectrometry.     

Catalytic asymmetric syntheses. : Part III. Asymmetric hydrogenation of piperitenone catalysed by chiral ruthenium hydrides : An example of a catalytic kinetic resolution1

Piperitenone has been hydrogenated in the presence of chiral ruthenium catalysts to give piperitone, menthone and isomenthone. Starting from piperitone (42 % e.e.) excellent selectivity (⋍80 % e.e.) was obtained with menthone. The mechanism of the reaction, a double asymmetric synthesis, is discussed with respect to kinetic resolution of piperitone as well as the effect of the chiral center in the substrate on the catalytic asymmetric induction.     

The association mode of arsenic accumulated in the freshwater alga Chlorella vulgaris

Arsenic accumulated in living Chlorella vulgaris cells was solvent-fractionated with chloroform/methanol (2:1), and the fractions were analyzed for arsenic. A large part of the accumulated arsenic was localized in the extract residues. The extract residue from the same extraction of C. vulgaris, which had been, however, cultured in any arsenic-free Detmer medium (MD), adsorbed arsenic physico-chemically at a concentration of 1.1 mg As g^?1 dry weight. Arsenic was found to be combined with protein with molecular weight around 3000 in the arsenicaccumulated living cells. The arsenic-bound protein was analyzed for amino acids. The experimental results showed that no metallothionein-like protein was inductively biosynthesized in C. vulgaris on the exposure to arsenic.     

C3 and C6 Modification-Specific OYE Biotransformations of Synthetic Carvones and Sequential BVMO Chemoenzymatic Synthesis of Chiral Caprolactones

The scope for biocatalytic modification of non-native carvone derivatives for speciality intermediates has hitherto been limited. Additionally, caprolactones are important feedstocks with diverse applications in the polymer industry and new non-native terpenone-derived biocatalytic caprolactone syntheses are thus of potential value for industrial biocatalytic materials applications. Biocatalytic reduction of synthetic analogues of R-(−)-carvone with additional substituents at C3 or C6, or both C3 and C6, using three types of OYEs (OYE2, PETNR and OYE3) shows significant impact of both regio-substitution and the substrate diastereomer. Bioreduction of (−)-carvone derivatives substituted with a Me and/or OH group at C6 is highly dependent on the diastereomer of the substrate. Derivatives bearing C6 substituents larger than methyl moieties are not substrates. Computer docking studies of PETNR with both (6S)-Me and (6R)-Me substituted (−)-carvone provides a model consistent with the outcomes of bioconversion. The products of bioreduction were efficiently biotransformed by the Baeyer–Villiger monooxygenase (BVase) CHMO_Phi1 to afford novel trisubstituted lactones with complete regioselectivity to provide a new biocatalytic entry to these chiral caprolactones. This provides both new non-native polymerization feedstock chemicals, but also with enhanced efficiency and selectivity over native (+)-dihydrocarvone Baeyer–Villigerase expansion. Optimum enzymatic reactions were scaled up to 60–100 mg, demonstrating the utility for preparative biocatalytic synthesis of both new synthetic scaffold-modified dihydrocarvones and efficient biocatalytic entry to new chiral caprolactones, which are potential single-isomer chiral polymer feedstocks.     

β-Cyclodextrin and its derivatives mediate selectivity in reduction of (R)-(+)-pulegone with sodium dithionite

Pulegone is reduced in two stages by sodium dithionite—first to menthone and later to epimeric methols. The presence of-cyclodextrin (BCD) and its derivatives resulted in more of the alcohols being formed. While the double bond was reduced predominantly in water, the ketone moiety was also reduced in a water-DMF mixture. A small percentage of menthone remained relatively unaffected in water-DMF even in the presence of BCD and its derivatives. Although no unreacted pulegone could be detected, exclusive alcohol formation was also not observed. Reduction of the double bond was found to be faster than that of the ketone.     

Bioaccumulation of Antimony by Chlorella vulgaris and the Association Mode of Antimony in the Cell

The bioaccumulation and excretion of antimony by the freshwater alga Chlorella vulgaris , which had been isolated from an arsenic-polluted environment, are described. When this alga was cultured in a medium containing 50 μg cm⁻³ of antimony(III) for 14 days, it was found that Chlorella vulgaris bioaccumulated antimony at concentrations up to 12 000 μg Sb g⁻¹ dry wt after six days' incubation. The antimony concentration in Chlorella vulgaris decreased from 2570 to 1610 μg Sb g⁻¹ dry wt after the cells were transferred to an antimony-free medium. We found that the excreted antimony consists of 40% antimony(V) and 60% antimony(III). This means that the highly toxic antimony(III) was converted to the less toxic antimony (V) by the living organism. Antimony accumulated in living Chlorella vulgaris cells was solvent-fractionated with chloroform/methanol (2:1), and the extract residue was fractionated with 1% sodium dodecyl sulfate (SDS). Gel-filtration chromatography of the solubilized part showed that antimony was combined with proteins whose molecular weight was around 4×10⁴ in the antimony-accumulated living cells. © 1997 by John Wiley & Sons, Ltd.     

Biomethylation of arsenic and its excretion by the alga Chlorella vulgaris

Experimental results in this paper lead to the following conclusions. (1) Cell homogenates of Chlorella vulgaris adsorbed the inorganic arsenic compound Na₂HAsO₄ but no methylation of the arsenic occurred in vitro. (2) A small part of the arsenic bioaccumulated by C. vulgaris was methylated in vivo. The quantity of arsenic methylated in the cell increased with an increase of arsenic concentration in the medium. (3) When the arsenic-accumulating cells were transferred into arsenic-free media, the arsenic was excreted and the relative quantity of the methylated arsenic in the excrement was larger than that in the cell. (4) In the growth phase of C. vulgaris, a small fraction of the arsenic accumulated in the cell was first transformed to monomethyl and dimethyl-arsenic compounds during the early exponential phase, and after a short time a fraction was transformed to trimethylarsenic species.     

Effect of pulegone and pulegone oxide on the corrosion of steel in 1 <Emphasis Type="Italic">M</Emphasis> HCl

The inhibitive action of pulegone and pulegone oxide toward acid corrosion of steel in molar hydrochloric acid was studied by weight loss measurements, potentiodynamic polarization, and impedance spectroscopy (EIS) methods. The pulegone is extracted starting from oil of Pennyroyal Mint (Mentha pulegium). The natural compound was found to delay the corrosion rate. The pulegone oxide is prepared by oxidation of pulegone. The inhibition efficiency was found to increase with the inhibitor content to attain 81 and 75% at 5 g dm⁻³ for pulegone and pulegone oxide. The increase in temperature leads to an increase in the inhibition efficiency of the natural compared. Correspondence: Belkheir Hammouti, Laboratoire de chimie Appliquée & Environnement, Faculté des Sciences, B.P. 717, 60000 Oujda, Morocco.     

Removal of uranyl ions from UO2(NO3)2 solution by means of Chlorella vulgaris and Dunaliella salina algae

This paper deals with a study of the biosorption of UO₂ ²⁺ ions on two green algae: Chlorella vulgaris and Dunaliella salina. By investigating the retention degree versus contact time from Langmuir and Freundlich biosorption isotherms, kinetic investigations and FTIR spectra it was found that the biosorption process was greater for Chlorella vulgaris than for Dunaliella salina. A new kinetics method is proposed to establish the reaction order concerning the biosorption process of uranyl ions on these biomasses.      

Influence of pH shift and salting on the energetics of microalgae <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> and <Emphasis Type="Italic">Dunaliella maritima</Emphasis>

The influence of pH shift and NaCl salting on the heat production, oxygen adsorption, and oxygen evolution rates of the unicellular green halotolerant microalga Dunaliella maritima and the freshwater microalga Chlorella vulgaris were investigated. In the growth process of both microalgae the alkalization of their culture medium was observed. And simultaneously it was shown that at increasing NaCl salting of cultural medium its acidification occurs. At alkalization and acidification of Chlorella medium the increase of heat production and respiration rates were observed. At alkalization and acidification of Dunaliella culture the adverse effect of decreasing heat production rate was observed. Acidification of culture medium of both algae led to short-term and sharp increase of photosynthesis measured by polarography and photomicrocalorimeter.     

超临界CO2流体萃取法与水蒸气蒸馏法提取荆芥穗挥发油化学成分的研究

采用超临界CO2萃取法(SFE)与水蒸气蒸馏法(SD)从荆芥穗中提取挥发油。采用SE-54毛细管柱进行分析,用气相色谱-质谱法对挥发油中各种化学成分进行鉴定,用归一化法测定各组分的含量。色谱条件:SE-54毛细管柱 (30 m×0.25 mm i.d.,0.25 μm),柱温50 ℃(3 min)5 ℃/min180 ℃(2 min)10 ℃/min260 ℃(50 min);分流进样,分流比1∶50;进样口温度280 ℃。在采用超临界CO2萃取法提取的挥发油中共鉴定出54种成分,其主要成分为长叶薄荷酮、薄荷酮、亚油酸氯化物等;在水蒸气蒸馏法提取的挥发油中共鉴定出39种成分,其主要成分为长叶薄荷酮、薄荷酮、柠檬烯等。超临界法较水蒸气法更加稳定可靠,重现性好,适用于中药挥发油的化学成分分析。     

Gibberellin Promotes Cell Growth and Induces Changes in Fatty Acid Biosynthesis and Upregulates Fatty Acid Biosynthetic Genes in Chlorella vulgaris UMT-M1

Microalgae lipids and oils are potential candidates for renewable biofuels and nutritional inventions. Recent studies from our lab have shown that two plant hormones, auxin and jasmonic acid, influence microalgae growth and fatty acid accumulation. Therefore, in this study, a high oil-producing strain Chlorella vulgaris UMT-M1 was selected for hormonal study using gibberellin (GA). Exogenous GA₃ was applied to early stationary culture of C. vulgaris UMT-M1. Results showed that GA₃ gradually increases the cell density of C. vulgaris to up to 42% on days after treatment (DAT)-8 and also capable of delaying the algal senescence. However, the increment in cell density did not enhance the total oil production albeit transient modification of fatty acid compositions was observed for saturated (SFA) and polyunsaturated (PUFA) fatty acids. This illustrates that GA₃ only promotes cell division and growth but not the oil accumulation. In addition, application of GA₃ in culture medium was shown to promote transient increment of palmitic (C16:0) and stearic (C18:0) acids from DAT-4 to DAT-6 and these changes are correlated with the expression of β-ketoacyl ACP synthase I (KAS I) gene.

     

Assessment of Antioxidant and Anticancer Activities of Microgreen Alga Chlorella vulgaris and Its Blend with Different Vitamins

There is a very vital antioxidant extracted from microgreen alga. Chlorella vulgaris has major advantages and requires high yield worldwide. Some microalgae require vitamins for their growth promotion. This study was held to determine the impact of different vitamins including Thiamine (B1), Riboflavin (B2), Pyridoxine (B6), and Ascorbic acid (c) at concentrations of 0.02, 0.04, 0.06, and 0.08 mg/L of each. Each vitamin was added to the BG11 growth medium to determine the effect on growth, total carbohydrate, total protein, pigments content, antioxidant activities of Chlorella vulgaris. Moreover, antitumor effects of methanol extract of C. vulgaris without and with the supplement of thiamine against Human prostate cancer (PC-3), Hepatocellular carcinoma (HEPG-2), Colorectal carcinoma (HCT-116) and Epitheliod Carcinoma (Hela) was estimated in vitro. C. vulgaris supplemented with various vitamins showed a significant increase in biomass, pigment content, total protein, and total carbohydrates in comparison to the control. Thiamine was the best vitamin influencing as an antioxidant. C. vulgaris supplemented with thiamine had high antitumor effects in vitro. So, it’s necessary to add vitamins to BG11 media for enhancement of the growth and metabolites.