Doris M. Hilker

ANTITHIAMINS OF PLANT ORIGIN: THEIR CHEMICAL NATURE AND MODE OF ACTION

The existence of non-enzymatic thiamin inactivating factors in plant material was first observed by Weswig et al. in 1946’ roughly ten years after the structure of this vitamin was established. This short note stated that rats fed bracken fern as 40% of the diet lost weight and developed symptoms suggestive of thiamin deficiency. The term “antithiamine activity” was used in describing this action and the possible relation to “fern poisoning” i n cattle was discussed. Three years later, Evans and Evans2 confirmed these findings using rats fed a standard diet plus bracken leaves. Subsequently, Kundig and Somogyi’ analyzed a number of fruit and vegetables for antithiamin activity (ATA) and found highest activity in blueberries, red chicory, black currants, red beetroot, brussel sprouts, and red cabbage. The activity appeared to be associated with colored plants. Plant antithiamin activity was also studied by Japanese workers: Thai: and Indian investigators.6 The next investigations concerned the chemical nature of the antithiamin substances in plants. It was soon concluded that the activity was connected with phenolic compounds. Matsukawa and Kawakami’ determined the ATA of a number of phenols, quinones, catechol, and tannic acid: the optimal conditions for activity; as well as products of thiamin decomposition. They noted that (a) the ATA in plants was associated with phenol compounds having two OH groups, (b) the optimal pH was above 7.0 (c) the optimal temperature was above 5OoC, (d) the reaction required oxygen, (e) the reaction was inhibited by cysteine, and (f) thiochrome and thiamin disulfide appeared as reaction products of thiamin decomposition. After analyzing over 30 phenolic compounds for ATA, Somogyi and Bonicke’ postulated that the number and position of OH groups is of primary importance for antithiamin activity. Compounds having only one OH group had no activity, those with ortho OH groups had the highest activity, those with para OH groups had medium activity, and those having the OH in the meta position had no activity. Caffeic acid (3,4-dihydroxycinnamic acid) was isolated from fern’ and blueberries’” as one the the antithiamin factors in these plants. Sarkar and Chaudhuri” isolated and characterized an antithiamin factor from cotton seed as 3,5-dimethoxy salicylic acid. A more complex substance containing glucose and an ortho-hydroxy phenol group with CH3 and COOH radicals has been partially characterized from rice bran.” Williams in 1927 described experiments in which pigeons were fed rice mill by-products and developed 137

Experimental dietary production of aortic atherosclerosis in Japanese quail

Abstract Japanese quail ( Coturnix coturnix japonica ) were evaluated as laboratory animals for use in atherosclerosis research by measuring plasma cholesterol along with macroscopic examination of the large arteries for atheromatous lesions. Eighteen-day old quail chicks were placed on a series of 11 varied diets to elicit response to sugar, fats and cholesterol. Birds were sacrificed at the end of 3, 6 and 9 months. Atheromas were found in birds given diets with high saturated fat and added cholesterol. Well defined indications of early stage arterial damage was observed in quail on several of the diets containing cholesterol, high sucrose and high saturated fatty acids (SAFA).

Carcinogens occurring naturally in food.

Carcinogens naturally occurring in food include metabolites of microorganisms which infect plants during harvesting and storage; products of the normal metabolism of plants and products of chemical changes occurring during processing, preservation, preparation or which are picked up from the environment, including contaminated water or soil. Some examples of these types of carcinogens are: fungal metabolites such as aflatoxins in peanuts stored under improper conditions; safrol from the oil of various plants; tannin in tea, grain and grapes; and polycyclic hydrocarbons including benzo (a) pyrene formed by smoking meat and fish. Epidemiological studies indicate that there is a high incidence of gastric cancer in the areas of the world where smoked fish are common in diets. Vitamin A may play a role in preventing the carcinogenic action of polycyclic hydrocarbons.Abstract Carcinogens naturally occurring in food Include metabolites of microorganisms which infect plants during harvesting and storage; products of the normal metabolism of plants and products of chemical changes occurring during processing, preservation, preparation or which are picked up from the environment, including contaminated water or soil. Some examples of these types of carcinogens are: fungal metabolites such as aflatoxins in peanuts stored under improper conditions; safrol from the oil of various plants; tannin in tea, grain and grapes; and polycyclic hydrocarbons including benzo (a) pyrene formed by smoking meat and fish. Epidemiological studies indicate that there is a high incidence of gastric cancer in the areas of the world where smoked fish are common in diets. Vitamin A may play a role in preventing the carcinogenic action of polycyclic hydrocarbons.

Diet and carcinogenesis

Carcinogens naturally occurring in food include metabolites of microorganisms which infect plants during harvesting and storage; products of the normal metabolism of plants and products of chemical changes occurring during processing, preservation, preparation or which are picked up from the environment, including contaminated water or soil. Some examples of these types of carcinogens are: fungal metabolites such as aflatoxins in peanuts stored under improper conditions; safrol from the oil of various plants; tannin in tea, grain and grapes; and polycyclic hydrocarbons including benzo (a) pyrene formed by smoking meat and fish. Epidemiological studies indicate that there is a high incidence of gastric cancer in the areas of the world where smoked fish are common in diets. Vitamin A may play a role in preventing the carcinogenic action of polycyclic hydrocarbons.Abstract Carcinogens naturally occurring in food Include metabolites of microorganisms which infect plants during harvesting and storage; products of the normal metabolism of plants and products of chemical changes occurring during processing, preservation, preparation or which are picked up from the environment, including contaminated water or soil. Some examples of these types of carcinogens are: fungal metabolites such as aflatoxins in peanuts stored under improper conditions; safrol from the oil of various plants; tannin in tea, grain and grapes; and polycyclic hydrocarbons including benzo (a) pyrene formed by smoking meat and fish. Epidemiological studies indicate that there is a high incidence of gastric cancer in the areas of the world where smoked fish are common in diets. Vitamin A may play a role in preventing the carcinogenic action of polycyclic hydrocarbons.