In vitro inhibition of CYP2B1 monooxygenase by beta-myrcene and other monoterpenoid compounds.
ABSTRACT beta-myrcene (MYR) is an acyclic monoterpene found in the essential oils of several useful plants such as lemongrass (Cymbopogon citratus), hop, bay, verbena and others. Recently it has been reported that MYR as well as lemongrass oil blocked the metabolic activation of some promutagens (e.g., cyclophosphamide and aflatoxin B1) in in vitro genotoxicity assays. The present study was performed to evaluate the inhibitory effects of MYR and some other monoterpenoid compounds on microsomal enzymes involved in the activation of genotoxic substances. The effects of MYR and other monoterpenes on the activity of pentoxyresorufin-O-depenthylase (PROD), a selective marker for CYP2B1, was determined in a pool of liver microsomes prepared from phenobarbital-treated rats. The effect of MYR on the activity of ethoxyresorufin-O-deethylase (EROD), a marker for CYP4501A1, was investigated in liver microsomes of untreated rats. Results revealed that MYR had almost no effect on EROD (IC50 > 50 microM), but produced a concentration-dependent inhibition of PROD activity (IC50 =0.14 microM). The analysis of alterations produced by MYR on PROD kinetic parameters (Lineweaver-Burk plot) suggested that inhibition is competitive (Ki = 0.14 microM). The inhibitory effects of seven other monoterpenes on PROD activity (pentoxyresorufin 5 microM) were also studied and the IC50 were as follows: (-)-alpha-pinene, 0.087 microM; (+)-alpha-pinene, 0.089 microM; d-limonene, 0.19 microM; alpha-terpinene, 0.76 microM; citral, 1.19 microM; citronellal, 1.56 microM, and (+/-) camphor, 7.89 microM. The potent inhibitory effects on CYP4502B1 suggest that MYR, and other monoterpenes, interfere with the metabolism of xenobiotics which are substrates for this isoenzyme.
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ABSTRACT: The sweet potato whitefly, Bemisia tabaci Gennadius biotype B (Hemiptera: Aleyrodidae), causes high economic losses in vegetables, beans, soybeans, peanuts, cotton, and several ornamental plants. Repeated spray applications of synthetic pesticides has led B. tabaci to develop resistance to numerous conventional insecticides, besides polluting the environment. In this work, we investigated the bioactivity of the essential oil of Pelargonium graveolens L’Her (Geraniaceae) (PG-EO) and some related monoterpenes against the sweet potato whitefly Bemisia tabaci Gennadius biotype B (Homoptera: Aleyrodidae) in tomato. This oil significantly reduced the number of B. tabaci adults on tomato leaflets. The deterrence experiments showed similar results for PG-EO, geraniol, and citronellol; however, citronellol was more effective than PG-EO. In fumigation tests, the essential oil of P. graveolens caused 100 % mortality of adults of B. tabaci biotype B at concentrations from 0.5 μL L−1 in air. The vapor toxicity of geraniol, linalool, and citronellol, the main chemical constituents of the essential oil of P. graveolens (PG-EO), was similar to that of PG-EO. These results suggest that PG-EO and its related monoterpenes are potentially applicable to develop effective natural product-based pest-management compounds.Journal of Pest Science 03/2014; 88(1). DOI:10.1007/s10340-014-0580-8
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ABSTRACT: Les huiles essentielles (HE) extraites par entranement à la vapeur de trois plantes aromatiques de la région kabyle en Algérie (Eucalyptus globulus, Lavandula angustifolia et Satureja hortensis) ont été analysées par chromatographie en phase gazeuse couplée à la spectrométrie de masse (CG/SM). Les composants majoritaires des HE sont 1,8-cinéole (81,70 %) pour Eucalyptus globulus; 1,8-cinéole (37,80 %) et β-Caryophyllène (20,90 %) pour Lavandula angustifolia et finalement Carvacrol (46,10 %), p-cymène (12,04 %) et γ-terpinène (11,43 %) pour Satureja hortensis. Pour les tests antibactériens, les méthodes de diffusion sur gélose et celle de microdilution ont été utilisées vis-à-vis de Salmonella enterica sérotype Enteritidis CECT 4300. Les résultats ont révélé une activité antisalmonelle significative exercée par l’ensemble des HE. Des diamètres d’inhibition de 41,30 et 35,26 mm ont été rapportés respectivement pour Lavandula angustifolia et Eucalyptus globulus. Cependant, l’HE de Satureja hortensis a démontré une activité antisalmonelle supérieure par rapport aux deux autres HE (51,15 mm). Les valeurs des concentrations minimales inhibitrices (CMI) rapportées dans cette étude sont comprises entre 1–8 μl/ml. Lavandula angustifolia fut l’HE dont la valeur CMI était la plus basse (1 μl/ml). De plus, l’activité antisalmonelle des HE additionnées à différentes concentrations dans les oeufs entiers liquides a été évaluée. Les résultats ont montré que l’effet antibactérien est proportionnel à la quantité d’HE additionnée au produit. Les résultats obtenus permettent de dire que les HE testées possèdent une activité antisalmonelle et par conséquent constituent une alternative naturelle prometteuse pour être utilisées dans la préservation des oeufs entiers liquides. Essential oils (EO) extracted by steam distillation of three aromatic plants of Kabyle region in Algeria (Eucalyptus globulus, Lavandula angustifolia and Satureja hortensis) were analyzed by gas chromatography coupled with mass spectrometry (GC/MS). The main components of the EOs are 1.8 cineole (81.70 %) for Eucalyptus globulus; 1.8 cineole (37.80%) and β-Caryophyllene (20.90 %) for Lavandula angustifolia and finally Carvacrol (46.10%), p-cymene (12.04%) and γ-terpinene (11.43%) for Satureja hortensis. For antibacterial testing, the agar diffusion and the microdilution methods have been used against Salmonella enterica serovar Enteritidis CECT 4300. The results showed a significant antisalmonelle activity exerted by all HEs. The diameters inhibition of 41.30 and 35.26 mm were reported respectively for Lavandula angustifolia and Eucalyptus globulus. However, the Satureja hortensis EO demonstrated an antisalmonelle activity superior to the other EO (51.15 mm). The values of minimum inhibitory concentrations (MIC) reported in this study were between 1–8 μl/ml. Lavandula angustifolia was the EO whose MIC value was the lowest (1 μl/ml). In addition, the activity antisalmonelle of the EO added at different concentrations in liquid whole egg was also evaluated. The results showed that the antibacterial effect is proportional to the amount of EO added to the product. The antisalmonelle activity and therefore constitute a promising natural alternative for use in the preservation of liquid whole egg. Mots clésHuiles essentielles– Eucalyptus globulus – Lavandula angustifolia – Satureja hortensis –CG/SM–Composition chimique–Activité antibactérienne in vitro–OEufs entiers liquides– Salmonella enteritidis KeywordsEssential oils– Eucalyptus globulus – Lavandula angustifolia – Satureja hortensis –Chemical composition–GC/MS–In vitro antibacterial activity–Liquid whole egg– Salmonella enteritidisPhytotherapie 12/2011; 9(6):343-353. DOI:10.1007/s10298-011-0664-z
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ABSTRACT: Essential oils from three species of Chrysanthemum growing in Tunisia (C. coronarium, C. fuscatum, and C. grandiflorum) were first analyzed by gas chromatography (GC) and GC/mass spectrometry (MS) and then evaluated for toxicity and antifeeding action against Tribolium confusum. The essential oils obtained from leaves and flowers shared a similar qualitative composition, but the relative proportions of the constituents were quite different. The essential oil of C. grandiflorum was rich in sesquiterpenoids, while those of C. fuscatum and C. coronarium were rich in monoterpenoids. The main common constituents of all the essential oils were α-pinene, myrcene, α-humulene, β-caryophylene, spathulenol, and caryophyllene oxide. The most effective essential oil was obtained from the leaves of C. grandiflorum, that inhibited the relative growth rate (−0.03 mg/mg/d), efficiency of conversion of ingested food (−50.69%), relative consumption rate, caused an antifeeding effect (66.43%) and a high mortality (80%) of T. confusum larvae. Topical application C. grandiflorum essential oil caused a significant insect mortality that attends 27% after 7 days of treatment. While essential oil from C. coronarium flowers has contact and fumigant toxicity with a mortality of 9 and 13%, respectively. Results analysis highlights a relationship between essential oils composition and insecticidal activity against T. confusum. The study showed that each essential oil has specific chemical composition and act differently according to the nature of attributed test. The use of essential oils from different Chrysanthemum species with different methods helps poor farmers who store small amounts of grains to preserve it against pest infestation.Journal of Pest Science 09/2012; 85(3). DOI:10.1007/s10340-012-0420-7