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A diet of rapeseed
Natural products
494
levels than the other two groups and the highest onion and garlic eaters had decreased serum-triglyceride (P < 0.01) and P-lipoprotein levels (P < 0.05). It was concluded that the regular consumption of onion and garlic had “a protective effect on some important factors which influence atherosclerosis”. [Before garlic and onion become accepted ih a protective role, more conclusive epidemiological evidence is needed, this particular study being open to obvious criticism over group sizes. Studies relating garlic/ onion intake to actual incidences of atherosclerosis rather than to contributory factors might be more valuable.] 3210. The biochemical
basis of ackee poisoning
Tanaka, K., Kean, E. A. & Johnson, B. (1976). Jamaican vomiting sickness. Biochemical investigation of two cases. New Engl. J. Med. 295, 461. Jamaican vomiting sickness, characterized by severe vomiting, is linked with the ingestion of unripe ackee. The toxic principle in the unripe fruit is hypoglycin A, which is metabolized in rats to methylenecyclopropylacetic acid (MA); this suppresses acyl coenzyme A dehydrogenase activity and thus inhibits trans-mitochondrial transport of long-chain fatty acids, which in turn leads to the depression of gluconeogenesis (Cited in F.C.T. 1967, 5, 839; ibid 1972, 10, 277). Rats treated with hypoglycin A have been shown to excrete massive amounts of dicarboxylic acids with 5-10 carbons atoms (Tanaka, J. biol. Gem. 1972, 247, 7465), and to have high serum levels of isovaleric and a-methylbutyric acids (Tanaka et al. Science, N.Y. 1972, 175, 69). However, none of these abnormal acids has before now been identified in the body fluids of humans suffering from the disease. The paper cited above now reports that analysis of urine from two young Jamaican children who were victims of vomiting sickness revealed MA levels of 8 and 16 pg/mg creatinine, respectively, whereas none was found in the urine of five normal American children. The urine of the victims also contained high levels of adipate, glutarate, 2-ethylmalonate, suberate (octanedioate), 4-decenedioate, sebacate (decanedioate) and 2-methylsuccinate, all of which except 2-ethylmalonate had previously been detected in the urine of hypoglycin-treated rats. By contrast, in the urine of four normai children only 2-ethylmalonate and 2-methylsuccinate were present at detectable levels, and it was estimated that excretion of the dicarboxylic acids was increased by some 70-1000 times in vomiting sickness. Large amounts of P-hydroxyisovalerate, fl-hydroxyisobutyrate and n-hexanoylglycine, and smaller quantities of isovaleryl- and n-butyrylglycines, were also found in the urine of the Jamaican victims, although the acylglycines were present at much lower levels than in the urine of hypoglycin-treated rats. Excretion of both free and conjugated forms of n-hexanoic, n-butyric, isobutyric, propionic, isovaleric, crotonic and P-methylcrotonic acids (the last two perhaps derived from /3-hydroxybutyric and /3-hydroxyisovaleric acids during analysis) was increased by up to 300 times, and serum levels of these short-chain fatty acids were increased by up to 23 times. No abnormal metabolitks could be
detected in the urine of six normal Jamaican adults who had eaten ripe ackee during the previous week, or in that of five American patients with Reye’s syndrome, which has clinical manifestations similar to those of vomiting sickness. The intake of hypoglycin in the form of unripe ackee is clearly related to the origin of Jamaican vomiting sickness. The findings also indicate that the modes of action of hypoglycin A in humans and rats are identical, although the alternative metabolism of isovalerate and butyrate appeared to be different in the two species. In the human subjects. isovaleric acid seemed to be metabolized mainly to methylsuccinic and P-hydroxyisovaleric acids, and butyric acid was excreted largely as ethylmalonic acid, whereas in the rat the glycine conjugates of the parent acids were produced in large amounts. 3211. A diet of rapeseed Sharpe, G. L., Larsson, K. S. & Lied&, S. A. (1975). Toxicological and teratological studies of a rapeseed protein diet in rats and mice..Nutr. Metabol. 18, 24.5. Loew, F. M., Doige, C. E., Manns, J. G., Searcy, G. P., Bell, J. M. & Jones, J. D. (1976). Evaluation of dietary rapeseed protein concentrate flours in rats and dogs. Toxic. appl. Pharmac. 35, 257. Fatty deposition in the heart muscle of animals given a diet in which rapeseed oil is a ma.jor energy source has been widely attributed to the erucic acid content of the oil (Cited in F.C.T. 1977. 15, 348). while hydrolysis products of glucosinolates have been implicated in the toxic effects associated with some rapeseed products. Furthermore, rapeseed flour may contain antithyroid substances, which are widespread in plants of the Brassica genus (Golberg. J. R. Co/l. Physcns Land. 1967, 1, 385). The safe use of such products for protein supplementation depends upon eliminating or reducing the contents of these toxic principles. Pregnant rats fed rapeseed protein containing 0.2mg glucosinolates/g for the first 18 days of gestation showed no teratogenic effects, but after delivery anorexia and weight loss were apparent. In most of them the fur was stained with a reddish discharge (not blood) from the nostrils. (A similar discharge developed in control rats fasted after day 18.) The treated dams were apathetic, failed to clean their pups and instead showed an increased tendency to eat them. Administration of rapeseed protein by gavage during the anorectic period produced profound lethargy, and profuse nasal and lachrymal discharge on day 18 or later. These reactions were unaffected by vitamin supplements. When the rapeseed-protein diet was given fol; 3-6 wk before mating, no toxic effects were observed until day 18 of gestation. Rats on a casein reference diet, given glucosinolate by gavage or mixed with the diet at levels up to 0,2mg/g pure protein, showed no toxic response, possibly because this diet contained no myrosinase, on the presence of which the ultimate toxicity of glucosinolates to rats has previously been shown to depend. No ill effects were observed in the offspring of rats fed rapeseed protein, and the effects on pregnant rats suggest an
Natural products interaction with increasing endogenous levels of oestrogen and progesterone. In pregnant mice receiving the rapeseed-protein diet or a casein reference diet ad lib., no toxic signs such as anorexia, weight loss or nasal discharge were present at any time. Antithyroid activity of two protein-rich rapeseed flours with a low glucosinolate content was studied in the second paper cited above. Semi-synthetic diets providing 20 or 40% of total protein as rapeseed flour, with the remainder as casein, were fed to growing dogs and rats for 90 days. The flours contained oxazolidinethione (goitrin), which apparently retards the incorporation of iodine into thyroid hormones, but even with the higher goitrin content (0.287mg/g flour), antithyroid effects were low, uptake of iodine-131, serum-thyroxine concentration, thyroid weight and histology being within normal limits. In the rats, the activity of serum glutamic-pyruvic transaminase and the mean corpuscular haemoglobin concentration fell and the packed cell volume and red cell copnt rose in proportion to the rapeseed-protein level m the diet, but these changes did not appear in the dogs. The authors conclude that the flours used in these studies were lesstoxic than previously tested flours of this type. 3212. Soy sauce: an irritating
elixir
MacDonald, W. C. & Dueck, J. W. (1976). Long-term effect of shoyu (Japanese soy sauce) on the gastric mucosa of the rat. J. n&n. Cancer Inst. 56, 1143. Epidemiological studies have suggested that dietary factors might be responsible for the high incidence of gastritis and mortality from gastric cancer in Japan. Vegetables pickled in shoyu, a sauce that figures prominently in traditional Japaneserecipes, have previously been shown to cause reversible injury to the human gastric mucosa (MacDonald et al. Can. med. Ass. J. 1967, %. 1521). Shoyu is prepared from wheat and soya bean fermented in brine, fungi being used to start the fermentation process; it may injure the gastric mucosa because of its high salt content and may also contain unidentified mycotoxins. The longterm effects of commercial shoyu on the rat have now been reported. Two groups of 24 female rats received from the age of 4 months a standard diet or a standard diet mixed with 50ml shoyu/lOOg meal. Two further groups of 21 and 20 animals underwent fundusectomy, which has been reported to increase susceptibility to gastric cancer, and were then maintained on analogous dietary regimes. All groups were observed from month 12 to 29, after which the animals, then aged 33 months, were killed. The rats receiving a shoyu-treated diet were smaller, lived longer and were more active and apparently healthier than the control animals. Tumour incidences in the shoyu-fed rats, both fundusectomized and intact, were not statistically different from those in controls except in the case of mammary tumours, which developed in ten control rats but in none given shoyu. The frequency of mammary tumours appeared to be correlated with body weight. The consumption of shoyu-treated food over this prolonged period was associated with mucosal loss and nuclear changes in
495
the surface epithelium of the gastric mucosa in some rats and occasionally with a mild gastritis, but provided no evidence of carcinogenicity. 3213. Teratology
of zearalenone
Ruddick, J. A., Scott, P. M. & Harwig, J. (1976).Teratological evaluation of zearalenone administered orally to the rat. Bull. em. contam. & Toxicol. (U.S.) ’ 15, 678.
Zearalenone (F-2 toxin) is an oestrogenic inycotoxin produced by several species of Fusarium, a genus associated with a growing number of mycotoxins (Cited in F.C.?: 1974, 12, 287). Female rats were given 1, 5 or 10mg zearalenone/ kg/day by stomach intubation from day 6 to day 15 of gestation, and were examined on day 22. No signs of any maternal toxicity appeared, and no lesions of maternal viscerawere seen.In the highest dose group, maternal weight gain and mean foetal weight were significantly below control values, and there was a slight but not significant increase in the incidence of embryonic deaths in this group. Skeletal defects, mainly affecting the ribs, sternum and tarsal and parietal bones, occurred in 12.8% of foetuses in the 1-mg/kg group, in 26.1% in the 5-mg/kg group and in 36.8% in the lo-mg/kg group. In the high-dose group the most prominent finding was arrested parietal ossification. This osteogenic effect of zearalenone has previously been reported in connexion with the ‘splayleg’ condition found in pigs (Miller et al. Vet. Rec. 1973, 93, 555). 3214. Teratogenicity
of patulin and its cysteine adducts
Ciegler, A., Beckwith, A. C. & Jackson, L. K. (1976). Teratogenicity of patulin and patulin adducts formed with cysteine. Appl. enuir. Microbial. 31, 664. Patulin, a toxic and carcinogenic heterocyclic lactone produced by a variety of fungi liable to occur in food and feedstuffs, has been identified in rotten apples and cider products. It has been reported to inhibit lactic dehydrogenase, alcohol dehydrogenase and muscle aldolase, the inhibition of the fist and last of these enzymes being reversed or reduced by cysteine,with which patulin forms an adduct (Ashoor 8z Chu. Fd Comet. Toxicol. 1973, 11, 617 & 995). Aqueous solutions of patulin and of patulin-cysteine (1: 1 and 1: 2) adducts were injected into the air sac of fresh fertile hens’ eggs and eggs containing 4-day-old embryos. On day 20 of incubation, embryos were examined for gross teratological effects. The LD,, of patulin was 68.7pg for embryos injected before incubation and 2.35 pg for 4-day embryos, with a broad range of values. Embryos treated with 1Opg patulin before incubation or with l-2 pg at the 4-day stage showed teratogenic changes, which were more marked in the latter group and included a predominance of splayed foot and malrotated ankle. The acute toxicity of patulin was greatly reduced by reaction with cysteine, a dose of the lactone approximately 50 times the LDsO causing no deaths in 4-day embryos when it was injected as the cysteine adduct. However, 12”/, of the 4-day embryos treated
494
levels than the other two groups and the highest onion and garlic eaters had decreased serum-triglyceride (P < 0.01) and P-lipoprotein levels (P < 0.05). It was concluded that the regular consumption of onion and garlic had “a protective effect on some important factors which influence atherosclerosis”. [Before garlic and onion become accepted ih a protective role, more conclusive epidemiological evidence is needed, this particular study being open to obvious criticism over group sizes. Studies relating garlic/ onion intake to actual incidences of atherosclerosis rather than to contributory factors might be more valuable.] 3210. The biochemical
basis of ackee poisoning
Tanaka, K., Kean, E. A. & Johnson, B. (1976). Jamaican vomiting sickness. Biochemical investigation of two cases. New Engl. J. Med. 295, 461. Jamaican vomiting sickness, characterized by severe vomiting, is linked with the ingestion of unripe ackee. The toxic principle in the unripe fruit is hypoglycin A, which is metabolized in rats to methylenecyclopropylacetic acid (MA); this suppresses acyl coenzyme A dehydrogenase activity and thus inhibits trans-mitochondrial transport of long-chain fatty acids, which in turn leads to the depression of gluconeogenesis (Cited in F.C.T. 1967, 5, 839; ibid 1972, 10, 277). Rats treated with hypoglycin A have been shown to excrete massive amounts of dicarboxylic acids with 5-10 carbons atoms (Tanaka, J. biol. Gem. 1972, 247, 7465), and to have high serum levels of isovaleric and a-methylbutyric acids (Tanaka et al. Science, N.Y. 1972, 175, 69). However, none of these abnormal acids has before now been identified in the body fluids of humans suffering from the disease. The paper cited above now reports that analysis of urine from two young Jamaican children who were victims of vomiting sickness revealed MA levels of 8 and 16 pg/mg creatinine, respectively, whereas none was found in the urine of five normal American children. The urine of the victims also contained high levels of adipate, glutarate, 2-ethylmalonate, suberate (octanedioate), 4-decenedioate, sebacate (decanedioate) and 2-methylsuccinate, all of which except 2-ethylmalonate had previously been detected in the urine of hypoglycin-treated rats. By contrast, in the urine of four normai children only 2-ethylmalonate and 2-methylsuccinate were present at detectable levels, and it was estimated that excretion of the dicarboxylic acids was increased by some 70-1000 times in vomiting sickness. Large amounts of P-hydroxyisovalerate, fl-hydroxyisobutyrate and n-hexanoylglycine, and smaller quantities of isovaleryl- and n-butyrylglycines, were also found in the urine of the Jamaican victims, although the acylglycines were present at much lower levels than in the urine of hypoglycin-treated rats. Excretion of both free and conjugated forms of n-hexanoic, n-butyric, isobutyric, propionic, isovaleric, crotonic and P-methylcrotonic acids (the last two perhaps derived from /3-hydroxybutyric and /3-hydroxyisovaleric acids during analysis) was increased by up to 300 times, and serum levels of these short-chain fatty acids were increased by up to 23 times. No abnormal metabolitks could be
detected in the urine of six normal Jamaican adults who had eaten ripe ackee during the previous week, or in that of five American patients with Reye’s syndrome, which has clinical manifestations similar to those of vomiting sickness. The intake of hypoglycin in the form of unripe ackee is clearly related to the origin of Jamaican vomiting sickness. The findings also indicate that the modes of action of hypoglycin A in humans and rats are identical, although the alternative metabolism of isovalerate and butyrate appeared to be different in the two species. In the human subjects. isovaleric acid seemed to be metabolized mainly to methylsuccinic and P-hydroxyisovaleric acids, and butyric acid was excreted largely as ethylmalonic acid, whereas in the rat the glycine conjugates of the parent acids were produced in large amounts. 3211. A diet of rapeseed Sharpe, G. L., Larsson, K. S. & Lied&, S. A. (1975). Toxicological and teratological studies of a rapeseed protein diet in rats and mice..Nutr. Metabol. 18, 24.5. Loew, F. M., Doige, C. E., Manns, J. G., Searcy, G. P., Bell, J. M. & Jones, J. D. (1976). Evaluation of dietary rapeseed protein concentrate flours in rats and dogs. Toxic. appl. Pharmac. 35, 257. Fatty deposition in the heart muscle of animals given a diet in which rapeseed oil is a ma.jor energy source has been widely attributed to the erucic acid content of the oil (Cited in F.C.T. 1977. 15, 348). while hydrolysis products of glucosinolates have been implicated in the toxic effects associated with some rapeseed products. Furthermore, rapeseed flour may contain antithyroid substances, which are widespread in plants of the Brassica genus (Golberg. J. R. Co/l. Physcns Land. 1967, 1, 385). The safe use of such products for protein supplementation depends upon eliminating or reducing the contents of these toxic principles. Pregnant rats fed rapeseed protein containing 0.2mg glucosinolates/g for the first 18 days of gestation showed no teratogenic effects, but after delivery anorexia and weight loss were apparent. In most of them the fur was stained with a reddish discharge (not blood) from the nostrils. (A similar discharge developed in control rats fasted after day 18.) The treated dams were apathetic, failed to clean their pups and instead showed an increased tendency to eat them. Administration of rapeseed protein by gavage during the anorectic period produced profound lethargy, and profuse nasal and lachrymal discharge on day 18 or later. These reactions were unaffected by vitamin supplements. When the rapeseed-protein diet was given fol; 3-6 wk before mating, no toxic effects were observed until day 18 of gestation. Rats on a casein reference diet, given glucosinolate by gavage or mixed with the diet at levels up to 0,2mg/g pure protein, showed no toxic response, possibly because this diet contained no myrosinase, on the presence of which the ultimate toxicity of glucosinolates to rats has previously been shown to depend. No ill effects were observed in the offspring of rats fed rapeseed protein, and the effects on pregnant rats suggest an
Natural products interaction with increasing endogenous levels of oestrogen and progesterone. In pregnant mice receiving the rapeseed-protein diet or a casein reference diet ad lib., no toxic signs such as anorexia, weight loss or nasal discharge were present at any time. Antithyroid activity of two protein-rich rapeseed flours with a low glucosinolate content was studied in the second paper cited above. Semi-synthetic diets providing 20 or 40% of total protein as rapeseed flour, with the remainder as casein, were fed to growing dogs and rats for 90 days. The flours contained oxazolidinethione (goitrin), which apparently retards the incorporation of iodine into thyroid hormones, but even with the higher goitrin content (0.287mg/g flour), antithyroid effects were low, uptake of iodine-131, serum-thyroxine concentration, thyroid weight and histology being within normal limits. In the rats, the activity of serum glutamic-pyruvic transaminase and the mean corpuscular haemoglobin concentration fell and the packed cell volume and red cell copnt rose in proportion to the rapeseed-protein level m the diet, but these changes did not appear in the dogs. The authors conclude that the flours used in these studies were lesstoxic than previously tested flours of this type. 3212. Soy sauce: an irritating
elixir
MacDonald, W. C. & Dueck, J. W. (1976). Long-term effect of shoyu (Japanese soy sauce) on the gastric mucosa of the rat. J. n&n. Cancer Inst. 56, 1143. Epidemiological studies have suggested that dietary factors might be responsible for the high incidence of gastritis and mortality from gastric cancer in Japan. Vegetables pickled in shoyu, a sauce that figures prominently in traditional Japaneserecipes, have previously been shown to cause reversible injury to the human gastric mucosa (MacDonald et al. Can. med. Ass. J. 1967, %. 1521). Shoyu is prepared from wheat and soya bean fermented in brine, fungi being used to start the fermentation process; it may injure the gastric mucosa because of its high salt content and may also contain unidentified mycotoxins. The longterm effects of commercial shoyu on the rat have now been reported. Two groups of 24 female rats received from the age of 4 months a standard diet or a standard diet mixed with 50ml shoyu/lOOg meal. Two further groups of 21 and 20 animals underwent fundusectomy, which has been reported to increase susceptibility to gastric cancer, and were then maintained on analogous dietary regimes. All groups were observed from month 12 to 29, after which the animals, then aged 33 months, were killed. The rats receiving a shoyu-treated diet were smaller, lived longer and were more active and apparently healthier than the control animals. Tumour incidences in the shoyu-fed rats, both fundusectomized and intact, were not statistically different from those in controls except in the case of mammary tumours, which developed in ten control rats but in none given shoyu. The frequency of mammary tumours appeared to be correlated with body weight. The consumption of shoyu-treated food over this prolonged period was associated with mucosal loss and nuclear changes in
495
the surface epithelium of the gastric mucosa in some rats and occasionally with a mild gastritis, but provided no evidence of carcinogenicity. 3213. Teratology
of zearalenone
Ruddick, J. A., Scott, P. M. & Harwig, J. (1976).Teratological evaluation of zearalenone administered orally to the rat. Bull. em. contam. & Toxicol. (U.S.) ’ 15, 678.
Zearalenone (F-2 toxin) is an oestrogenic inycotoxin produced by several species of Fusarium, a genus associated with a growing number of mycotoxins (Cited in F.C.?: 1974, 12, 287). Female rats were given 1, 5 or 10mg zearalenone/ kg/day by stomach intubation from day 6 to day 15 of gestation, and were examined on day 22. No signs of any maternal toxicity appeared, and no lesions of maternal viscerawere seen.In the highest dose group, maternal weight gain and mean foetal weight were significantly below control values, and there was a slight but not significant increase in the incidence of embryonic deaths in this group. Skeletal defects, mainly affecting the ribs, sternum and tarsal and parietal bones, occurred in 12.8% of foetuses in the 1-mg/kg group, in 26.1% in the 5-mg/kg group and in 36.8% in the lo-mg/kg group. In the high-dose group the most prominent finding was arrested parietal ossification. This osteogenic effect of zearalenone has previously been reported in connexion with the ‘splayleg’ condition found in pigs (Miller et al. Vet. Rec. 1973, 93, 555). 3214. Teratogenicity
of patulin and its cysteine adducts
Ciegler, A., Beckwith, A. C. & Jackson, L. K. (1976). Teratogenicity of patulin and patulin adducts formed with cysteine. Appl. enuir. Microbial. 31, 664. Patulin, a toxic and carcinogenic heterocyclic lactone produced by a variety of fungi liable to occur in food and feedstuffs, has been identified in rotten apples and cider products. It has been reported to inhibit lactic dehydrogenase, alcohol dehydrogenase and muscle aldolase, the inhibition of the fist and last of these enzymes being reversed or reduced by cysteine,with which patulin forms an adduct (Ashoor 8z Chu. Fd Comet. Toxicol. 1973, 11, 617 & 995). Aqueous solutions of patulin and of patulin-cysteine (1: 1 and 1: 2) adducts were injected into the air sac of fresh fertile hens’ eggs and eggs containing 4-day-old embryos. On day 20 of incubation, embryos were examined for gross teratological effects. The LD,, of patulin was 68.7pg for embryos injected before incubation and 2.35 pg for 4-day embryos, with a broad range of values. Embryos treated with 1Opg patulin before incubation or with l-2 pg at the 4-day stage showed teratogenic changes, which were more marked in the latter group and included a predominance of splayed foot and malrotated ankle. The acute toxicity of patulin was greatly reduced by reaction with cysteine, a dose of the lactone approximately 50 times the LDsO causing no deaths in 4-day embryos when it was injected as the cysteine adduct. However, 12”/, of the 4-day embryos treated