Mentha spicata, 443 products

The main renewable resource for L-carvone is spearmint oil (Mentha spicata), which contains up to 75% of this flavour chemical. There also exists a synthetic process for the manufacturing of L-carvone, which is based on (-t)-limonene, which is available as a by-product of the citrus juice industry as a major component of orange peel oil (Scheme 13.4). The synthesis was developed in the nineteenth century and starts with the reaction of (-t)-limonene and nitrosyl chloride, which ensures the asymmetry of the ring. Treatment with base of the nitrosyl chloride adduct results in elimination of hydrogen chloride and rearrangement of the nitrosyl function to an oxime. Acid treatment of the oxime finally results in l-carvone. 

Different plants including spearmint (Mentha spicata L ), rosemary (Rosmarinus officinalis L.), dill (Anethum graveolens L.), clary sage (Salvia sclarea L.) and chamomile (Matricaria chamomilla L.) were extracted with CO2 in a high pressure apparatus with 5 L extractor vessel volume. Fractionation of extracts was carried out by releasing the separation pressure at two stages. The extracts were separated into essential oil rich oil and fatty/waxy products. The extracts were collected as separate samples successively in time. The extraction with carbon dioxide was compared to conventional steam distillation (essential oils) and to Soxhlet extraction with hexane (fatty oils). 

Production By steam distillation from the flowering shrub of the crisped or curled mint species Mentha spicata ( native spearmint ) and Mentha cardiaca ( Scotch spearmint ). The main areas of cultivation are the American states of Idaho, Oregon, and Washington as well as Indiana, Michigan, and Wisconsin ( Middle West ) oil production in 1992 was ca. 32001. It is also cultivated in smaller amounts in China and India production in 1992 ca. 500 t. 

The biosynthetic route to menthol, starts from isopentenyl- and dimethylallyl diphosphate, which in the case of mint derive from the triose-pyruvate pathway, and consists of eight discrete steps (see also section 7.1.2). This route was established by feeding experiments with radio-lahelled intermediates and cell-free enzyme studies. [110] Condensation of isopentenyl- and dimethylallyl diphosphate gives geranyl diphosphate, which is cyclised to (-)-limonene. Both steps are Mg +-dependent. By-products of the cyclisation are around 2 % of myrcene and both, a- and y -pinene. The limonene synthases in Mentha piperita and Mentha spicata are identical, which shows how closely related to each other the species are. 

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