Metabolite catechol type

In the subsequent years, a number of other monohydroxy- A1-THC derivatives have been isolated from various metabolizing systems (Figure 2). These have been of two types hydroxyls allylic to the M-double bond and sidechain hydroxyls. No evidence for aromatic hydroxylation has thus far been reported, although these positions are chemically reactive and there is biochemical evidence for C-C glucuronide formation at the 4 -position of A6-THC. Possibly such catechol type metabolites of A1-THC are unstable and may be lost during the extraction and isolation procedures. 

The NRPS-based biosynthesis of the myxochelins - catecholate-type siderophores produced by a number of myxobacterial strains - has also been investigated. The biosynthetic pathway, the only known myxobac-terial secondary metabolite gene cluster involved in iron acquisition, has been identified in S. aurantiaca Sg al5, S. cellulosum So ce56, and M. xanthus DK1622 (unpublished data), and six genes are found to be involved... 

A relatively unique type of reactive metabolite is carbene, i.e., a divalent carbon, which is a proposed intermediate in the oxidation of methylene dioxy-containing compounds. A methylenedioxy group in aromatic compounds is subject to O-dealkylation, e.g., 3,4-methylenedioxyamphetamine, as shown in Figure 8.20. The process generates formic acid and the catechol metabolite as final products. However, in the course of the reaction, a... 

The use of HPLC to analyze biogenic amines and their acid metabolites is well documented. HPLC assays for classical biogenic amines such as norepinephrine (NE), epinephrine (E), dopamine (DA), and 5-hydroxytryptamine (5-HT, serotonin) and their acid metabolites are based on several physicochemical properties that include a catechol moiety (aryl 1,2-dihydroxy), basicity, easily oxidized nature, and/or native fluorescence characteristics (Anderson, 1985). Based on these characteristics, various types of detector systems can be employed to assay low concentrations of these analytes in various matrices such as plasma, urine, cerebrospinal fluid (CSE), tissue, and dialysate. 

Catechol-O-methyltransferase from rat liver requires S-adeno-sylmethionine as a methyl donor and can methylate catechol but not monohydroxy derivatives of phenylethylamine. In vivo, O-methylation occurs exclusively in the meta position to the carbon side chain, but with purified preparations of the enzyme in vitro methylation can lead to both meta and para methylation. The ratio of products is susceptible. to both the polarity of the substrate and the pH of the medium . In man 3-methoxy-4-hydroxy-mandelic acid (18) comprises about 40 per cent of the total urinary metabolites produced from the catecholamines whilst in other pecies 3-methoxy-4-hydroxyphenylglycol (19), isolated as a sulphate ester, is the predominant breakdown product . A typical metabolic grid which indicates the possible types of pathway leading from noradrenalin (17) to both of these metabolites is shown in Figure 4.4 analogous metabolic schemes may be drawn up for both adrenalin and dopamine. 

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