Menthae

Artificial materials include aUphatic, aromatic, and terpene compounds that are made synthetically as opposed to those isolated from natural sources. As an example, ben2aldehyde may be made synthetically or obtained from oil of bitter almond (51) and t-menthol may be made synthetically or isolated from oil of Mentha arvensis var. to give Bra2iUan mint oil or com mint oil. 

Many cycHc ketones occur in natural oils. Jasmone [488-10-8] (3-meth5l-2-(2-pentyl)-2-cyclopenten-l-one) (4) is an odoriferous component of the oil obtained from jasmine flowers. /-Menthone [14073-97-3] (5) is the most frequently occurring of four optically active isomers, and is a colorless Hquid with a minty odor obtained from Mentha species of plants. Muscone [541-91-3] (6) and civetone [542-46-1] (7) are expensive animal products. 

Menthol Manufacture. Of the menthol isomers, only (-)-menthol [2216-51 -5] and (+)-menthol [15356-70-4] are of commercial importance. The most important natural sources of (—)-menthol are the oUs of Mentha arvensis (75—90%) and Mentha piperita (50—65%). The main suppUers ate Japan, China, BrazU, and Taiwan for the former and the United States, CIS, Bulgaria, and Italy for the latter. (—)-Menthol is known for its refreshing, diffusive odor characteristic of peppermint. It also is known for its strong physiological cooling effect, which is useful in cigarettes, dentifrices, cosmetics, and pharmaceuticals. 

Natural menthol is obtained by freezing the essential oU, eg, Mentha arvensis and the menthol crystals ate separated by centrifuging the supernatant hquid away from the crystals. The supernatant oU is then caUed dementholized cornmint oU. Impurities in the crystals come from the essential oU and usuaUy give a slight peppermint aroma to the crystallized menthol. The cornmint oU, rich in (—)-menthone (- 28%) and (—)-menthol (- 32%), can be further processed to give additional natural menthol. 

Chemical Designations - Synonyms Limonene para-Mentha-1,8-diene Phellandrene Terpinene delta-1,8-Terpodiene Chemcal Formula CjoH]j. 

The separation capacity of a TLC method can be easily improved by use of a two-dimensional high performance TLC technique (2D HPTLC). Various plant essential oils (menthae, thymi, anisi, lavandulae, etc.) have been analysed by 2D TLC with florisil (magnesium silicate) as the adsorbent, using dichloromethane/ -heptane (4 6) in the first direction and ethyl acetate/n-heptane (1 9) in the second direction (69). 

A small quantity of peppermint oil is distilled in the neighbourhood of Hong-Kong, from a plant which is, in all probahility, Mentha, cand-dettsis, var. glabrata. This oil has been examined by the Imperial Institate, by Schinimel i Co..- and hv Shino Saki. The three samplea had the following characters —... 

Erauseminze, /. curled mint (Mentha criapa) spearmint (Mentha apicata). 

This example involves a smdy of free flavonoids (aglycones) present on the leaf surface of Mentha suaveolens Ehrh. (Lamiaceae) growing in Spain and in Algeria... 

Zaidi, F., Voirin, B., Jay, M. and Viricel, M. R. 1998. Free flavonoid aglycones from leaves of Mentha pulegium and Mentha suavolens (Labiatae) Phytochemistry 48 991-994. 

Both the (+)- and (-)- enantiomers of limonene were transformed by larvae of the cutworm Spodop-tera litura (Miyazawa et al. 1998). For both of them the reactions involved are (a) dihydroxylation between C-8 and C-9 and (b) oxidation of the C-1 methyl group to carboxyl. These transformations were not dependent on the intestinal microflora in contrast to the transformation of a-terpinene to p-mentha-l,3-dien-7-ol and p-cymene whose formation could be attributed to the intestinal flora. 

Recently the most employed method for the production of A9-THC on industrial scale is the condensation of (+)-p-mentha-2,8-dien-l-ol (5.1 in... 

At the first sign of a cold, it can be mixed with hyssop (Hyssopus officinalis), peppermint (Mentha piperita) and yarrow (.Achillea millefolium). 

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