Isothiocyanate glycosides

The activity of the ethanolic extract of both the pods and the seeds of M. oleifera is equivalent at the dose of 30 mg/kg. The ethyl acetate phase of the ethanolic extract of pods has more hypotensive potency at the same dose. The bioassay-directed fractionation ethyl acetate phase of the ethanohc extract of pods led to the isolation of thiocaibamate and isothiocyanate glycosides which are also the hypotensive compounds observed in M. oleifera leaves. Two new compounds, 0-[2 -hydroxy-3 -(2 heptei5rloxy)]-propyl undecanoate and O-ethyl-4-[(a-Z-rhamnosyloxy)-benzyl] carbamate along with methyl p-hydroxybenzoate and p-sitosterol are also isolated from the pods. The latter two compounds and /7-hydroxybenzaldehyde shows promising hypotensive activity (89). 

Nonvolatile Inhibitors. Glycosides A number of toxic constituents are known to be released by the enzymatic degradation of various glycosides. Some of the volatile components have been mentioned previously—i.e., isothiocyanates from mustard oil glycosides and hydrogen cyanide from cyanogenic glycosides. 

Synthesis of Thiourea-Bridged Glycosides from Glycosyl Isothiocyanates... 

The instability of the diazonium salts, and the lack of specificity of diazo coupling, may be overcome by converting the p-aminophenyl glycosides into isothiocyanates by treatment with thiophosgene, as shown in Scheme 3. By treating bovine serum albumin (BSA) in dilute sodium hydroxide (pH 9.0) with a 10-fold excess of isothiocyanate to... 

Black mustard is a light olive-brown powder obtained by grinding the dried ripe seeds of several varieties of plants of the Brassica genus moisture yields from this, through enzymatic hydrolysis of a contained glycoside, are about 0.6% of the volatile oil of mustard, which has as its main ingredient the irritant compound allyl isothiocyanate. Mustard is available in bulk and as the official plaster, the latter used only for the local irritant (counterirritant) properties it develops when applied to the skin after moistening with tepid water. 

The root of Raphanus sativus var. niger (black radish) contains 0.0025% of essential oil with glycosides yielding allyl isothiocyanate and butyl isothiocyanate. 

SCHEME 15.21 Preparation of p-linked aspargine glycoside 178 from glycosyl isothiocyanate 173. 

Usage For sauces and salads, in fish and meat dishes. The glycoside glucocapparin, which is degraded by the plant enzyme myrosinase to the sharp tasting methyl isothiocyanate, is the most significant constituent. 

The brassicas of importance as foods include turnips, rutabagas, mustards, and the cole crops — cabbage, broccoli, cauliflower, and brussels sprouts. The production of isothiocyanates in brassicas is via an enzymatic reaction on specific glycosides. Some of the isothiocyanates, especially allylthiocyanate, are highly pungent and are mainly responsible for the odors of brown mustard, horseradish, cabbage, and other crucifers. Any process that destroys or inactivates enzymes in these plants will cause decreases in aroma production, resulting in a less distinctive flavor. This is usually the case when brassica foodstuffs are commercially preserved. 

---