(+)-Pulegone is a central intermediate in the biosynthesis of (-)-menthol, the most significant component of peppermint essential oil. Depending on environmental conditions, this branch point metabolite may be reduced to (-)-menthone en route to menthol, by pulegone reductase (PR), or oxidized to (+)-menthofuran, by menthofuran synthase (MFS). To elucidate regulation of pulegone metabolism, we ...

Interactions between herbivorous insects and plants storing terpenoids are poorly understood. This study describes the ability of Chrysolina herbacea to use volatiles emitted by undamaged Mentha aquatica plants as attractants and the plant's response to herbivory, which involves the production of deterrent molecules. Emitted plant volatiles were analyzed by GC-MS. The insect's response to plant...

peppermint has considerable commercial value and widely cultivated for essential oil production, especially menthol. the aim of this study was to determine the quantitative expression of pulegone reductase (pr), menthofuran synthase (mfs) and limonene synthase (ls) genes in menthol biosynthesis pathway in mentha x piperita , using semiquantitative rt-pcr analysis and evaluating menthol producti...

Menthofuran rich eight half-sib seed progeny of Mentha piperita (MPS-36) were studied for various genetic parameters, namely, coefficient of variation, heritability, genetic advance, correlation, and path of various plant and oil attributes, namely, plant height, L:S ratio, herb yield, β -myrcene, limonene, 1,8-cineole, menthone, menthofuran, neomenthone, pulegone, and menthol. Maximum genotypi...

Peppermint has considerable commercial value and widely cultivated for essential oil production, especially menthol. The aim of this study was to determine the quantitative expression of pulegone reductase (pr), menthofuran synthase (mfs) and limonene synthase (ls) genes in menthol biosynthesis pathway in Mentha x piperita , using semiquantitative RT-PCR analysis and evaluating menthol producti...

Peppermint (Mentha x piperita L.) was independently transformed with a homologous sense version of the 1-deoxy-d-xylulose-5-phosphate reductoisomerase cDNA and with a homologous antisense version of the menthofuran synthase cDNA, both driven by the CaMV 35S promoter. Two groups of transgenic plants were regenerated in the reductoisomerase experiments, one of which remained normal in appearance ...

(R)-(+)-Menthofuran is a metabolite of (R)-(+)-pulegone, the chief constituent of pennyroyal oil. Menthofuran has been shown to account for a significant percentage of pulegone toxicity through further metabolism to a reactive intermediate, an enonal (2-Z-(2'-keto-4'-methylcyclohexylidene)propanal). Hydration of the enonal followed by a 1,4-dehydration and rearrangement gives rise to diastereom...

Peppermint (Mentha × piperita L.) was transformed with various gene constructs to evaluate the utility of metabolic engineering for improving essential oil yield and composition. Oil yield increases were achieved by overexpressing genes involved in the supply of precursors through the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway. Two-gene combinations to enhance both oil yield and compositi...

(R)-(1)-Menthofuran is a potent, mechanism-based inactivator of human liver cytochrome P450 (CYP or P450) 2A6. Menthofuran caused a timeand concentration-dependent loss of CYP2A6 activity. The inactivation of CYP2A6 was characterized by a Ki of 2.5 mM and a kinact of 0.22 min 21 for human liver microsomes and a Ki of 0.84 mM and a kinact of 0.25 min 21 for purified expressed CYP2A6. Addition of...

(R)-(+)-Pulegone, a monoterpene constituent of pennyroyal oil, is a hepatotoxin that has been used in folklore medicine as an abortifacient despite its potential lethal effects. Pulegone is metabolized by human liver cytochrome P-450s to menthofuran, a proximate hepatotoxic metabolite of pulegone. Expressed human liver cytochrome (CYP) P-450s (1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4) were tested...