Menthol glucoside

The glucosides of menthol, citronellol, nerol, geraniol, cw-myrtenol, L-borneol, linalool and a-terpineol yielded yellow-green fluorescent chromatogram zones in long-wavelength UV light (2 = 365 nm). The same applied to arbutin (hRf 45 — 50). 

Bergmann and Wolff S reported a small yield (1 g.) of menthol a-D-glucuronide by the oxidation of 12 g. of menthol a-n-glucoside in pyridine solution with sodium hypobromite. Better yields were obtained by Smolenski, who oxidized methyl a-n-glucopyranoside with bromine and sodium carbonate a 30% yield of the methyl n-glucuronide (as the brucine salt) was reported. Jackson and Hudson obtained a 12% yield of the brucine salt of methyl a-n-mannuronide by the barium hypobromite oxidation of methyl a-n-mannopyranoside. 

A further degradation of methyl a-n-glucoside by the action of barium hypobromite was observed by Bergmann and Wolff. From 12 g. of the glycoside, 4.6 g. of glyoxylic acid benzylphenylhydrazone was obtained. The experimental conditions differed from those used in the preparation of menthol a-D-glucuronide in that about twice as much bromine was used. 

Time-course studies with 14COa showed that in a Thymus sp., y-terpinene was converted into p-cymene and thymol in sequence,916 and the appropriate y-terpinene synthetase (MW ca. 96 000) was partially purified. Tracer studies indicated that loss of a proton from C-5 of the a-terpinyl-like precursor to form the A4-un-saturation was accompanied, perhaps concertedly, by a 1,2-hydride shift from C-4 to C-8 to form y-terpinene.917 Neomenthyl-p-D-glucoside was a major metabolite of menthone in Mentha spp.,918 and a cell-free extract also acetylated menthol.919 Detailed in vivo and in vitro investigations revealed that in leaf discs the bulk of the neomenthol and menthol (produced from menthone) was converted into the gluco-... 

Related studies record the change in monoterpene corporation during maturation of Sequoia spp.949 and the similar variations of menthol and its p-glucoside in Mentha.950 Hybridization experiments have shown that the occurrence of 60—90% pulegone in certain strains of Mentha spp. resulted from the lack of the genes necessary to reduce this ketone to menthone or to oxidize it to menthofuran.951 A detailed genetic analysis of menthone-isomenthone production in Mentha spp. has also been described.952... 

Other examples are deoxycorticosterone (3-maltoside " and menthol 3-glucoside. Deoxycorticosterone glycosides show various solubilities depending on the sugar conjugate (Table 38.4). ... 

Menthol (3-glucoside is a water-soluble, non-irritating prodrug of menthol that can be used, like glucovaniUin, the 3-D-glucoside of vanillin, as a pharmaceutic flavor adjuvant. The use of sugar moieties as drug carriers has been reviewed by Chavis and Imbach. ... 

A novel in vitro glucuronidation of a phenolic substrate was carried out with rat liver microsomes [22]. The method is simple, the reagent is optically pure, only the (4- )-glucuronic acid (13) is present, and the individual enantiomers are readily recovered by a simple enzymatic hydrolysis. Glucosidation with acetobromo-a-D-glucose (14) has also been used to separate the enantiomers of menthol [23]. 

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