Inhibition of carcinogenic effect of bracken fern (pteridium aquilinum) by various chemicals

Abstract

The inhibitory effect of butylated hydroxyanosole (BHA), disulfiram, calcium chloride, and polyvinylpyrrolidone (PVP) on the intestinal and urothelial carcinogenicity of bracken fern (BF) was determined in albino rats. Of 10 groups of rats, one group received a normal diet, one received a BF-containing diet (one-third of diet by weight), four received a normal diet with one of the following supplements, and four received BF-containing diet with one of the following: BHA (5 mg/g diet); disulfiram (5 mg/g diet); PVP (50 mg/g diet); or calcium chloride (20 mg/g diet). At 12 months of the experiment, the following results were noted: in the BF-treated group, 30 rats (100%) exhibited intestinal tumors and 22 of 30 (73%) urinary bladder tumors. In the BF-BHA group, 15 of 20 rats (75%) showed intestinal tumors and 12 of 20 rats (60%) urinary bladder tumors. Of the 16 rats in the BF-disulfiram group, 12 (80%) had intestinal and 10 (62.5%) had urinary bladder tumors. In the BF-calcium chloride group, intestinal tumors arose in 16 of 23 rats (70%) and urinary bladder tumors in 4 of 23 rats (17%), while in the 28 BF-PVP rats, 26 (93%) exhibited tumors of the intestine and 5 (18%) tumors of the urinary bladder. Dietary BHA, disulfiram and calcium chloride decreased the incidence of intestinal tumors by about 25--30% (p less than 0.01). Similarly, PVP and calcium chloride inhibited BF-induced urinary bladder carcinogenesis by about 80% (p less than 0.001). No tumors were detected in groups receiving either normal diet or normal diet supplemented with BHA, disulfiram, calcium chloride or PVP.

Dietary Carcinogens and Anticarcinogens

“…5) Quercetin and several similar flavonoids are mutagens in a number of short-term test systems. Flavonoids are extremely widespread (daily levels close to 1 g) in the human diet (8,16,20,21). There is evidence for the carcinogenicity of quercetin in two strains of rats (8), although it was negative in other experiments (21).…”

“…Flavonoids are extremely widespread (daily levels close to 1 g) in the human diet (8,16,20,21). There is evidence for the carcinogenicity of quercetin in two strains of rats (8), although it was negative in other experiments (21). 6) Quinones and their phenol precursors (9,14,16,23,45) are widespread in the human diet.…”

Human Carcinogenesis and Bracken Fern: A Review of the Evidence

“…They also examined the effect of this milk in the mouse and pulmonary adenomas were found in some of the mice fed bracken carcinogen-laden milk. Later experiments furnished accounts that 20 -26% of mice given such milk developed carcinomas of urinary bladder, kidney and small intestine [102] and further results led Villalobos et al [103] to conclude not only that this milk is carcinogenic but must carry other bracken metabolites with a wider range of carcinogenic activity than that of ptaquiloside alone.…”

Bracken (Pteridium aquilinum)—toxic effects and toxic constituents

“…Dietary nitrate or nitrite also increased the frequency of bracken fern induced bladder tumours (Erturk et al 1974). In contrast, dietary polyvinylpyrrolidone and calcium chloride inhibited such tumours by 80 % (Pamukcu et a[ 1977). At the time the authors considered that this was caused by insoluble complex formation but this explanation now seems less probable given the likely nature of the active substance(s).…”