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Analysis of the gut contents of rats killed at intervals after dosage with methyl cinnamate or cinnamic acid suggested that both ester and acid were rapidly absorbed; at no time was more than 5% of the dose detected in the lower part of the gut. Not more than 9% of the administered methyl cinnamate was detected in the stomach as cinnamic acid whereas at least 40% of the small amounts of the dosed ester detected in the lower part of the gut was present as cinnamic acid. No ester was detected in the peripheral blood of dosed rabbits or rats and only traces were detected in portal and heart blood samples taken from dosed rats. Cinnamic acid and methanol were readily detected in the blood of rabbits and rats which had been dosed with methyl cinnamate. No qualitative or significant quantitative difference was detected in the metabolism of the ester as compared with the parent acid. In addition to the metabolites of cinnamic acid described in the literature p-hydroxyhippuric acid was excreted as a minor metabolite of both cinnamic acid and methyl cinnamate.
The interaction of trans-cinnamic acid with the cytochrome P-450 of microsomes derived from washed potato slices has been studied. The washing process increased the specific content of microsomal electron transport components and hence provided a useful material in which to study the interaction. Evidence is presented that the trans-cinnamic acid interacts with the cytochrome P-450, and that this interaction is analogous to "type 1" interactions of other cytochrome P-450 systems. This evidence includes the formation of a "type 1" substrate binding spectrum, an increased rate of reduction of cytochrome P-450 by NADPH in the presence of trans-cinnamic acid, an increased oxygen uptake and NADPH oxidation when trans-cinnamic acid is added to the microsomes in the presence of NADPH, and a close correlation between biophysical parameters of electron transport in the cytochrome P-450 system and enzymological parameters of the trans-cinnamic acid 4-hydroxulation reaction. The investigation has been extended to cytochrome P-450 systems of other tissues and it has been found that the trans-cinnamic acid 4-hydroxylation reaction cannot account for the presence of most of th cytochrome P-450 in several tissues. This suggests that other functions of higher plant cytochrome P-450 chains exist, and that the substrate specificityof the hemoprotein may vary in different plant tissues.
In the presence of activated factor XIII, 2-diethylbenzyl-aminoethylthiol-14C-transcinnamate bromide completely inhibited the crosslinking of fibrin. However, all three fibrin chains bound the cinnamic acid, and, in the alpha- and gamma-chains, the binding of label was not restricted to the crosslinking donor sites as might be expected. Furthermore, even in the absence of activated factor XIII, fibrinogen and fibrin incorporated cinnamic acid. Thus, as well as reacting with the functional thiol group of factor XIII, the thiocholine ester of cinnamic acid is incorporated non-specifically throughout the fibrinogen and fibrin subunit chains. The thiocholine ester used differs in this respect from dansyl cadaverine which is incorporated enzymatically and exclusively to the (acceptor) sites involved in crosslinking. Thiocholine ester of cinnamic acid cannot be used as a label for localization of specific crosslinking donor sites.
A non-dialysable inhibitor of phenylalanine ammonia-lyase (L-phenylalanine ammonia-lyase, EC 4.3.1.5) has been partially purified from dark-grown gherkin hypocotyls. On extraction of tissue it is found both in the soluble (106 000 X g supernatant) and microsomal (106 000 X g pellet) fractions and can be extracted from the microsomal membranes with 10 mM sodium cholate and 1 M KCl. The soluble and microsomal fractions have similar properties, suggesting the presence of the same active component. The inhibitor is small (Mr less than 20 000), thermolabile, sensitive to proteolytic digestion, and apparently hydrophobic. Purification of the inhibitor was achieved by chromatography on DEAE-cellulose by gel filtration on Sephadex G-50. The inhibitor preparations inhibit phenylalanine ammonia-lyase isolated from a number of plant tissues and also cinnamic acid-4-hydroxylase (trans-cinnamate, NADPH:oxygen oxidoreductase (4-hydroxylating), EC 1.14.13.11) from gherkins and peas, but not a wide range of other enzymes. The evidence suggests that inhibition of the two enzymes is due to the same substance, but this has not yet been confirmed. Kinetic experiments show that the inhibitor is competitive with phenylalanine for the lyase and that its association with the lyase is reversible. Further, a mixture of inhibitor and lyase can be separated on non-denaturing polyacrylamide gels without loss of lyase activity. The activities of phenylalanine ammonia-lyase and cinnamic acid 4-hydroxylase are often concurrently regulated and both have regulatory roles in phenol metabolism; it is suggested that the inhibitor may be specifically involved in controlling their activities in vivo.
Positive patch test reactions to 2% cinnamic aldehyde were obtained from 2.8% of 34 males and 9.1% of 55 females. The 9.1% female reactivity may be traceable to perfumed cosmetics. Simultaneous Jasmin allergy is documented as is the occurrence of alpha-amyl cinnamic aldehyde in synthetic Jasmin. The relevance of these reactions is discussed. In two of the patients a proper diagnosis was not made from the original contact history. Only after a screening tray demonstration of cinnamic aldehyde allergy could a relevant history be taken from these patients.
The authors carried out further studies to assess the significance of the findings of patients sensitive to cinnamic aldehyde in a toothpaste. Selected groups of patients in whom sensitivity to this might have been overlooked were patch-tested. With the exception of three patients, two with cosmetic sensitivity and one with hand eczema, the results were negative. The frequency of use of the original toothpaste was assessed among patients attending the clinic and this was followed by a circular letter to general practitioners and dentists inviting referral of patients with oral symptoms. As a result, five further cases, four of whom gave positive patch test reactions to cinnamic aldehyde, were discovered. The authors emphasize the importance of attempting to obtain accurate information as quickly as possible when 'new' or hitherto unsuspected allergens are implicated.
Using some 14C-labelled derivatives of cinnamic acid which are of interest as metabolites of chlorogenic acid we studied their pharmacokinetic behaviour in rats. The absorption rate constant from intestinal was 2--10 times greater than the elimination rate constant. After i.v. application the half life of elimination from the blood was between 13 and 37 minutes. When greater amounts (50 mg/kg) were given by i.d. application, absorption and elimation were delayed. The tested compounds were excreted mainly by the kidneys and most of the given dosis could be found in urine within 2 hours. The biliary excretion differed widely among the tested compounds: only up to 3% were excreted in the bile in the case of m-cumaric acid, p-cumaric acid and caffeic acid, whereas up to 30% were found when ferulic acid or trimethoxycinnamic acid were given. From these results a greater ole of caffeic acid in the enterohepatic circulation is not to be expected.
1. There is an increase in the extractable acitivity of phenylalanine ammonia-lyase following excision of hypocotyl segments of dark-grown gherkin seedlings This increase is prevented by the reaction product, cinnamin acid. 2. Density-labelling experiments show that cinnamic acid affects the rate of enzyme synthesis. By contrast the regulation of phenylalanine ammonia-lyase activity by light has previously been shown to involve activation of existing inactive enzyme. 3. It is proposed that regulation of synthesis by reaction products represents a mechanism for controlling the size of the pool of phenylalanine ammonia-lyase, and that the activity of this pool is regulated by light.
Bibliographic sources for the complex subject of aroma chemicals are reviewed. The references are not comprehensive but are those which we found to be of value in finding out some of the opportunities for contact with a sensitizing chemical compound, cinnamic aldehyde.
Tobacco leaves of Nicotiana tabacum L., variety Samsun NN, show a low cinnamic acid-4-hydroxylase activity and a rather high O-methyltransferase activity. Caffeic acid, the substrate of the latter enzyme, is methylated specifically in the meta position. In TMV-infected leaves a strong increase in the activities of phenylalanine ammonia-lyase and of these two enzymes occurs at the time of appearance and development of the necrotic reaction.
A patient had acute stomatitis and dermatitis due to a popular toothpaste containing cinnamon oil flavor. Cinnamon cassia oil is known as a topical sensitizer and was demonstrated to be the offending allergen. Cinnamic aldehyde and related chemicals are used widely, so that patients having cinnamon allergy may be exposed to many sources. There is difficulty in diagnosing allergic contact stomatitis.
Although cinnamon is known to cause dermatitis in bakers and confectioners, it has only rarely been reported as causing trouble in food or cosmetics. A newly-formulated 'spicy' toothpaste containing cinnamon as a flavouring agent was the cause of oral symptoms in eight patients referred to clinics in Buckinghamshire and in Malmö and in a further eight patients discovered subsequently. Similar symptoms and patch test results were observed independently at both centres. Positive reactions were obtained with 1% cinnamic aldehyde in 15 out of 16 patients tested. Only one patient reacted to a standard sample of balsam of Peru (25% in petrolatum).
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