Natural products 2930. Mustard oil capers
Mitchell, J. C. (1974). Contact dermatitis from plants of the caper family, Capparidaceae. Effects on the skin of some plants which yield isothiocyanates. Br. J. Derm. 91, 13. Plants of the caper family (Capparidaceae) are the tropical relatives of the Cruciferae of temperate regions. They contain isothiocyanates, or glycosides that are converted to isothiocyanates by the action of the enzyme myrosinase. One such glycoside is glucocapparin, which gives rise to methyl isothiocyanate. The same enzyme converts siningrin, the glycoside of seeds of mustard (Brassica nigra), to allyl isothiocyanate. Isothiocyanates may be primary irritants, inducing a chemical dermatiti.s, and in some individuals they may provoke allergic contact dermatitis into the bargain. The plant genera that possess irritant or sensitizing properties include Capparis, Cleome, Courbonia, Crateva and Gynandropsis. Some of these, especially species of Cleome (spider-flowers), are cultivated as ornamental plants and may prove troublesome to gardeners. Although the glycosides that give rise to the irritant isothiocyanates are mainly present in the seeds, they occur also in the green parts of some species. It appears that a 'substantial number' of garden plants and vegetables may be potential irritants if not potential sensitizers, and the author makes the point that, in view of the wide confusion that exists in connexion with the common names given to capparidaceous plants, it is important that in records of episodes of dermatitis the accurate botanical nomenclature be used.
similar to those in animals treated intragastrically and examined after 6 and 15 min, and were less severe than those seen after 30 min. The villi were oedematous, showing capillary congestion in the lamina propria and some lymphocyte infiltration, particularly after 15min, when some epithelium had separated from the basement membrane around the tips of the villi. Villous-tip cells showed an increase in numbers of pyknotic nuclei. Similar but more pronounced changes appeared after 30min while after 45 and 60min many areas of the duodenal mucosa were denuded of epithelium and the remaining epithelial cells showed acidophilic cytoplasm and irregular small nuclei with distinct nuclear membranes. Ultrastructural changes revealed mitochondrial swelling 2 min after intraduodenal instillation, together with a rarefied matrix and disorganized cristae. The numbers of free ribosomes and lysosomes increased, the endoplasmic reticulum was slightly extended and Golgi complexes were swollen. Nuclei showed some shrinking, and chromatin was clumped and concentrated at the inner periphery of the nuclear envelope. Less severe changes followed intragastric instillation of capsaicin for 6min, but at 15 min the changes were similar in degree to those after intraduodenal instillation for 2 min. The severity of the changes was increased at 30 min and became maximal at 45 and 60 min. The findings of this study indicate clearly that capsaicin, whether natural or synthetic, has a direct toxic effect on the duodenal cells of rats. The physiological consequences, which are of prime importance in man, require further investigation. 2932. Tannic acid in the enema
2931. Pepper and the duodenum
Nopanitaya, W. & Nye, S. W. (1974). Duodenal mucosal response to the pungent principle of hot pepper (capsaicin) in the rat: Light and electron microscopic study. Toxic. appl. Pharmac. 30, 149. Hot green and red peppers are commonly used as food spices. Hot red peppers contain 0'1-1.0% of the pungent principle, capsaicin, which is unaffected by drying and is readily soluble in hot water. Investigations into the potential hepatocarcinogenicity of red peppers in man have given inconclusive results (Cited in F.C.T. 1970, 8, 84). The study cited above describes changes induced in the duodenal lining of rats by contact with 10% capsicum in normal saline or a roughly equivalent solution of 0.014% synthetic capsaicin for various periods. These solutions, in a volume of 0"8 ml, were instilled into the ligated upper duodenum of anaesthetized rats and retained therein for 2 min. Other lightly anaesthetized rats were given 2 ml of one or other solution by gastric intubation and were killed for examination after intervals of 6-60 min. This treatment provided a dose of 1 mg capsaicin/kg. All control animals received an appropriate volume of normal saline. Throughout the study, there was virtually no difference between the morphological changes induced by 10% capsicum or 0.014% capsaicin solution when the duration of exposure and route of administration were the same. Microscopic findings in the duodenal villi of animals in the 2-min test were
Eshchar, J. & Friedman, G. (1974). Acute hepatotoxicity of tannic acid added to barium enemas. Am. J. dig. Dis. 19, 825. Much discussion and debate on the possible hepatotoxicity of tannic acid in barium sulphate enemas has led to the tentative conclusion that, if unduly long retention is avoided and patients with extensive colonic lesions are not submitted to such treatment, the hazard of absorption can be kept within reasonable limits (Cited in F.C.T. 1967, 5, 244). Similar conclusions were reached in the recent study cited above. In 50 patients who had shown no prior indications of liver damage and in 11 known to have some liver damage, liver-function tests were performed before and after the administration of a 1500ml enema of barium sulphate to which 1% tannic acid had been added to improve colonic visualization. Three patients in the first group showed minor rises in the serum activity of glutamic-oxalacetic and glutamicpyruvic transaminases after the enema; in one the change was attributed to coronary ischaemia, in the second to retention of the enema for longer than 30 min, and in the third to childhood susceptibility. Four patients in the second group showed some deterioration in liver function after the enema, as demonstrated by the bromsulphthalein retention test (three patients) or by determination of alkaline phosphatase (one patient). There is thus no evidence from this'study that the addition of 1% tannic acid to a barium enema is likely