Zur chemischen und sterischen Selektivität der photosensibilisierten O<sub>2</sub>‐Übertragung auf (+)‐Limonen und (+)‐Carvomenthen

Schenck, Günther O.; Gollnick, Klaus; Buchwald, Gustav; Schroeter, Siegfried H.; Ohloff, G.

doi:10.1002/jlac.19646740111

Cited by 109 publications

(27 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Since nuclear Overhauser effect (NOE) experiments did not provide conclusive stereochemical information, the stereochemistry of 3 was determined by chemical correlations. Photo-oxidation 11) C-NMR spectra of 7 were identical with those of the diol 8, which was derived from 3 by alkaline hydrolysis followed by reduction with PPh 3 . 12) This result established that the relative stereochemistry of 3 is identical with that of 7.…”

mentioning

confidence: 68%

Trypanocidal Terpenoids from Laurus nobilis L.

et al. 2002

View full text Add to dashboard Cite

Trypanosoma cruzi, a parasitic protozoan of Zoomastigophoria, is the etiologic agent of Chagas' disease which is endemic in Central and South America.1) In our screening work on medicinal plants used in Asian counties for trypanocidal activity, extracts of the dried leaves of Laurus nobilis L. (Lauraceae) showed strong trypanocidal activity against epimastigotes of T. cruzi. Leaves of L. nobilis are used as a spice known as laurel or bay leaf. They are also used as a folk medicine for rheumatism and scabies.2) Although some biological activities such as inhibition of elevation of blood ethanol level in ethanol-loaded rat, 3) inhibition of nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages, 4) induction of glutathione Stransferase activity, 5) and nematocidal activity 6) were reported for the constituents of L. nobilis, nothing has been reported on anti-protozoan constituents of this plant. Here, we report the isolation and identification of trypanocidal constituents of L. nobilis. Results and DiscussionDried leaves of Laurus nobilis were successively extracted with hexane, CHCl 3 and MeOH, and each extract was tested for anti-trypanosomal effect by the HeLa cell infection assay.7) As the CHCl 3 and MeOH extracts inhibited infection and proliferation of T. cruzi, and the MeOH extract formed the major part of the extracts, the MeOH extract was further fractionated under the guidance of in vitro trypanocidal activity against epimastigotes of T. cruzi.8) The MeOH extract was suspended in aqueous MeOH and fractionated into hexane soluble, AcOEt soluble, and water soluble fractions. Since the AcOEt soluble fraction showed the strongest activity, it was fractionated by silica gel column chromatography to give three trypanocidal compounds (1-3). These compounds were also isolated from the CHCl 3 extracts.Compounds 1 and 2 were obtained as colorless needles from hexane, mp 58-60°C, and as a colorless oil, respectively. The 1 H-and 13 C-NMR spectra indicated that both compounds were guaiane-type sesquiterpene with three exocyclic methylene moieties. Based on comparisons of the spectral data with those reported, compounds 1 and 2 were identified with dehydrocostus lactone (1) 9) and zaluzanin D (2), 10) H-detected heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) spectra (Fig. 1) revealed the structure to be 1-hydroperoxy-pmenthan-2-en-8-ol acetate. Treatment of 3 with PPh 3 gave an acetoxy alcohol 4, which showed oxygen-bearing carbons at d C 67.0 (C-1) and d C 84.4 (C-8). This confirmed that 3 had a hydroperoxy and an acetoxy group at positions 1 and 8, respectively. Since nuclear Overhauser effect (NOE) experiments did not provide conclusive stereochemical information, the stereochemistry of 3 was determined by chemical correlations. Photo C-NMR spectra of 7 were identical with those of the diol 8, which was derived from 3 by alkaline hydrolysis followed by reduction with PPh 3 . 12)This result established that the relative stereochemi...

show abstract

mentioning

confidence: 68%

Trypanocidal Terpenoids from Laurus nobilis L.

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Although the oxidation of limonene to limonene hydroperoxide was observed half a century ago (34,35), there is a limited body of literature on the biological properties of limonene hydroperoxide. A large fraction of this literature focuses on the allergenic properties of limonene, which were shown to be due to limonene hydroperoxide (25,(36)(37)(38).…”

Section: Discussionmentioning

confidence: 99%

Acute Limonene Toxicity in Escherichia coli Is Caused by Limonene Hydroperoxide and Alleviated by a Point Mutation in Alkyl Hydroperoxidase AhpC

Chubukov

Mingardon

Schackwitz

et al. 2015

Appl Environ Microbiol

View full text Add to dashboard Cite

f Limonene, a major component of citrus peel oil, has a number of applications related to microbiology. The antimicrobial properties of limonene make it a popular disinfectant and food preservative, while its potential as a biofuel component has made it the target of renewable production efforts through microbial metabolic engineering. For both applications, an understanding of microbial sensitivity or tolerance to limonene is crucial, but the mechanism of limonene toxicity remains enigmatic. In this study, we characterized a limonene-tolerant strain of Escherichia coli and found a mutation in ahpC, encoding alkyl hydroperoxidase, which alleviated limonene toxicity. We show that the acute toxicity previously attributed to limonene is largely due to the common oxidation product limonene hydroperoxide, which forms spontaneously in aerobic environments. The mutant AhpC protein with an L-to-Q change at position 177 (AhpC L177Q ) was able to alleviate this toxicity by reducing the hydroperoxide to a more benign compound. We show that the degree of limonene toxicity is a function of its oxidation level and that nonoxidized limonene has relatively little toxicity to wild-type E. coli cells. Our results have implications for both the renewable production of limonene and the applications of limonene as an antimicrobial. L imonene, the major component of citrus peel oil, has a variety of industrial and microbiological applications. Its antimicrobial properties make it a popular component of disinfectants and food preservatives and an environmentally friendly solvent used at the industrial scale (1-4). More recently, limonene or its hydrogenated forms have been identified to be potential jet fuel components (5-7). As such, the anticipation of a greater global demand for limonene has provided significant motivation for the renewable production of this compound from plant biomass through a microbial process (8-10), and recent efforts to optimize production have resulted in titers of over 400 mg/liter at the bench scale (11). In this context, the toxicity of limonene to the microbial host presents a major challenge, as the accumulation of toxic products limits growth and metabolic activity.Curiously, the toxicity of limonene has been reported to be significantly higher than that of other monoterpenes or solvents with similar hydrophobicities (12, 13), suggesting that this acute toxicity is due to something other than its solvent-like properties. However, molecular-level studies of limonene toxicity in microbes are limited. While several studies in Escherichia coli have noted an impact of limonene on lipid composition (14) and suggested a role for reactive oxygen species (ROS) (15), no specific hypothesis for how limonene causes these cellular perturbations has been proposed.In this work, we investigated the basis of limonene toxicity in the model Gram-negative bacterium E. coli. We identified a mutant with significantly enhanced tolerance to limonene and show that the majority of the toxicity in wild-type (WT) cells is due no...

show abstract

“…The reaction of singlet oxygen with limonene (112), a typical monoterpene, gives a mixture of the 6 isomeric allylic hydroperoxides 113a-113c (Scheme 28) 129,130 . The overall syn/anti selectivity observed is quite low (60/40), in contrast to the relatively higher syn/anti preference which was found for 113a.…”

Section: Monocyclic Hydrocarbonsmentioning

confidence: 99%

Selective Formation of Allylic HydroperoxidesviaSinglet OxygeneneReaction

Orfanopoulos

Vougioukalakis

Stratakis

2009

Patai's Chemistry of Functional Groups

View full text Add to dashboard Cite

Introduction Regioselective Formation of Allylic Hydroperoxides Diastereoselective Formation of Allylic Hydroperoxides Selective Formation of Allylic Hydroperoxides by Dye‐Sensitized Intrazeolite Photooxygenation Synthetic Applications Perspectives Acknowledgements

show abstract

Zur chemischen und sterischen Selektivität der photosensibilisierten O₂‐Übertragung auf (+)‐Limonen und (+)‐Carvomenthen

Cited by 109 publications

References 25 publications

Trypanocidal Terpenoids from Laurus nobilis L.

Trypanocidal Terpenoids from Laurus nobilis L.

Acute Limonene Toxicity in Escherichia coli Is Caused by Limonene Hydroperoxide and Alleviated by a Point Mutation in Alkyl Hydroperoxidase AhpC

Selective Formation of Allylic HydroperoxidesviaSinglet OxygeneneReaction

Contact Info

Product

Resources

About

Zur chemischen und sterischen Selektivität der photosensibilisierten O2‐Übertragung auf (+)‐Limonen und (+)‐Carvomenthen

Cited by 109 publications

References 25 publications

Trypanocidal Terpenoids from Laurus nobilis L.

Trypanocidal Terpenoids from Laurus nobilis L.

Acute Limonene Toxicity in Escherichia coli Is Caused by Limonene Hydroperoxide and Alleviated by a Point Mutation in Alkyl Hydroperoxidase AhpC

Selective Formation of Allylic HydroperoxidesviaSinglet OxygeneneReaction

Contact Info

Product

Resources

About

Zur chemischen und sterischen Selektivität der photosensibilisierten O₂‐Übertragung auf (+)‐Limonen und (+)‐Carvomenthen