Examination of the enantiomeric distribution of certain monoterpene hydrocarbons in selected essential oils by automated solid-phase microextraction-chiral gas chromatography-mass selective detection.
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A viable approach for the determination of sources of essential oils based on automatic injection solid-phase microextraction-chiral-gas chromatography-mass selective detection is demonstrated. With no sample preparation, it is shown that the source of essential oils such as peppermint, spearmint, and rosemary can be easily distinguished. Short fiber exposure times of approximately 6 s to the headspace above submicroliter quantities of the selected oils are all that is required to obtain both the required sensitivity and resolution to afford analyses with excellent reproducibilities (relative standard deviation values consistently less than 5.0%). (+info)
Subcellular compartmentation of the diterpene carnosic acid and its derivatives in the leaves of rosemary.
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The potent antioxidant properties of rosemary (Rosmarinus officinalis) extracts have been attributed to its major diterpene, carnosic acid. Carnosic acid has received considerable attention in food science and biomedicine, but little is known about its function in the plant in vivo. We recently found that highly oxidized diterpenes increase in rosemary plants exposed to drought and high light stress as a result of the antioxidant activity of carnosic acid (S. Munne-Bosch, K. Schwarz, L. Alegre [1999] Plant Physiol 121: 1047-1052). To elucidate the significance of the antioxidant function of carnosic acid in vivo we measured the relative amounts of carnosic acid and its metabolites in different compartments of rosemary leaves. Subcellular localization studies show that carnosic acid protects chloroplasts from oxidative stress in vivo by following a highly regulated compartmentation of oxidation products. Carnosic acid scavenges free radicals within the chloroplasts, giving rise to diterpene alcohols, mainly isorosmanol. This oxidation product is O-methylated within the chloroplasts, and the resulting form, 11,12-di-O-methylisorosmanol, is transferred to the plasma membrane. This appears to represent a mechanism of a way out for free radicals from chloroplasts. Carnosic acid also undergoes direct O-methylation within the chloroplasts, and its derived product, 12-O-methylcarnosic acid, accumulates in the plasma membrane. O-methylated diterpenes do not display antioxidant activity, but they may influence the stability of the plasma membrane. This study shows the relevance of the compartmentation of carnosic acid metabolism to the protection of rosemary plants from oxidative stress in vivo. (+info)
Antioxidant properties of phenolic diterpenes from Rosmarinus officinalis.
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AIM: To investigate the inhibition capacities of carnosol, rosmanol, and epirosmanol, which are phenolic diterpenes from Rosmarinus officinalis, to oxidized low-density lipoprotein (LDL) formation in human blood and detect their scavenging activities to lipid free radical and superoxide anion in vitro. METHODS: The antioxidant activities which were expressed with the inhibilities to lipid free radicals in the membrane lipid of cell and oxidized LDL formation were evaluated by TBARS assay and ESR method. The inhibition on the Cu2+-mediated oxidization of apo B formation in LDL was investigated by fluorescence spectroscopy. RESULTS: Carnosol, rosmanol, and epirosmanol had an inhibitory activity to lipid peroxidation and oxidized apo B formation in human bloods LDL. The IC50 were 7-10 micromol/L. The antioxidant mechanism was related to the scavenging activities to lipid free radical. CONCLUSION: carnosol, rosmanol, and epirosmanol showed the activity in inhibiting LDL oxidation. (+info)
Ursolic acid as a trypanocidal constituent in rosemary.
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The MeOH extract of the leaves of rosemary (Rosmarinus officinalis L.) completely inhibited the motility of cultured epimastigotes of Trypanosoma cruzi at the concentration of 2 mg/ml after 2 h of incubation. Activity-guided fractionation of the MeOH extract has resulted in the isolation of three triterpene acids, betulinic, oleanolic and ursolic acids. Ursolic acid stopped the movement of all T. cruzi epimastigotes at the minimum concentration (MC(100)) of 40 micro g/ml (88 micro M) after 48 h of incubation. Oleanolic acid was less active (MC(100): 250 micro g/ml, 550 micro M) and betulinic acid was practically inactive. (+info)
Biotransformation of (-)-verbenone by human liver microsomes.
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The biotransformation of (-)-verbenone was investigated with human liver microsomes by using GC-MS. Regioselective biotransformation was observed when (-)-verbenone was incubated with the liver microsomes. (-)-10-Hydroxyverbenone was formed from (-)-verbenone of kinetic analysis showed that the Km and Vmax values for the hydroxylation of (-)-verbenone by liver microsomes from three human samples, HG-70, HG-56 and HG-23, were 1.1 mM and 4.8 nmol/min/nmol P450, 0.6 mM and 2.1 nmol/min/nmol P450, and 2.8 mM and 4.6 nmol/min/nmol P450, respectively. (+info)
Essential oil formulations useful as a new tool for insect pest control.
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This study investigated the effects of some essential oils on Limantria dispar (Lepidoptera: Lymantridae, gypsy moth) larvae, one of the most serious pests of cork oak forests. The essential oils were first formulated as oil in water (o/w) emulsions and used in laboratory bioassays to assess their lethal concentration (LC50). Microcapsules containing the most promising oils (Rosmarinus officinalis and Thymus herba-barona) were then prepared by a phase separation process, followed by freeze-drying. The formulations thus obtained, characterized in terms of essential oil content and composition, morphology, storage stability, and release profile, were tested on gypsy moth larvae. The results showed that the tested oils possess interesting larvicidal effects that make them suitable for application in integrated control strategies. The microencapsulation process gave high encapsulation yields (over 98%) with both essential oils, which have different chemical compositions. The microcapsules had toxic effects at a concentration similar to that usually employed for localized treatments with microgranular synthetic pesticides. Toxicity appeared to be maximized when the microparticles adhered to the typical hair structures of several defoliator families. These formulations seem to be able to protect the core material against environmental agents and could be considered for use in controlled drug release systems. The natural active principles they contain could provide an alternative system in insect pest control. (+info)
Carnosic acid, a component of rosemary (Rosmarinus officinalis L.), promotes synthesis of nerve growth factor in T98G human glioblastoma cells.
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Nerve growth factor (NGF) is a factor vital for the growth and functional maintenance of nerve tissue. The authors found that a rosemary (Rosmarinus officinalis L.) extract enhanced the production of NGF in T98G human glioblastoma cells. Furthermore, the results indicated that carnosic acid and carnosol, which are major components of the rosemary extract, were able to promote markedly enhanced synthesis of NGF. (+info)
Effects of a novel gaseous antioxidative system containing a rosemary extract on the oxidation induced by nitrogen dioxide and ultraviolet radiation.
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Rosemary is commonly used as a spice and a flavoring agent in food processing. Although the antioxidative properties of its extracts have been investigated, there have been few reports on the volatile components of rosemary. We designed a novel antioxidative system which can generate the volatile constituents in the gaseous phase from a rosemary extract and evaluated the gaseous antioxidative activities against both lipid peroxidation and cell death induced by nitrogen dioxide and ultraviolet radiation. The antioxidative effects of the major volatile components on the oxidation of linoleic acid induced by azo compounds were also investigated in a solution. The volatile components in the novel antioxidative system suppressed the Jurkat cell death induced by nitrogen dioxide and the intracellular formation of reactive oxygen species in fibroblast cells induced by ultraviolet radiation. 1,8-Cineole among the volatile components exerted an antioxidative effect against the oxidation of linoleic acid in a solution induced by azo compounds and ultraviolet radiation. These data suggest that the volatile constituents of a rosemary extract had antioxidative properties and that gaseous exposure antioxidant is a promising method for promoting health. (+info)