Effect of short term ingestion ofTelfaria occidentalis (fluted pumpkin) on the liver

Four groups of female mice (18–22g) were fed for at least 10 days on a control diet or diets with addedTelfaria occidentalis (10% w/w) vegetables. Group 1 were the control animals. Group 2 were fed the vegetable diet alone. Group 3 were fed the control diet and injected with aflatoxin B₁(AFB₁, 0.35 mg/kg/day) in the last 3 days. Group 4 were fed with the vegetable diet and similarly treated for 3 days with AFB₁. No effects attributable to treatment were encountered in body weight, food intake, water intake and relative liver weight (g/100 g body weight). Decreases (17–40%) in PB sleeping time in the vegetable fed animals were not significant (P>0.05) in comparison to the control. Microsomal proteins increased by 2 fold in group 2 but were apparently normal in groups 3 and 4. In group 2 the activities of liver microsomal glucose-6-phosphatase and NADH-cytochrome c reductase increased but those of NADPH-cytochrome c reductase and aniline hydroxylase decreased. Increases were observed in the activities of all of these enzymes in groups 3 and 4. The highest increases were observed in glucose-6-phosphatase activity in mice fed the vegetables and also injected with AFB₁.     

Inhibition of hepatic microsomal NADPH-cytochrome C (P-450) reductase activity in gari-fed rats

NADPH-cytochrome c (P-450) reductase activities were measured in liver microsomes prepared from male albino rats (110–150 g) fed control and (35% w/w) gari (a dried cassava product) based diets for 8 weeks and sacrificed at intervals of 1, 3, 5, and 8 weeks. After an initial increase (2-fold) in NADPH oxidation in the first week, the gari diet consistently produced marked decreases in theK _m andV _max values for NADPH oxidation and cytochrome C reduction. Inhibition of cytochrome C reduction was consistently greater than that of NADPH oxidation. Inhibition was generally not dependent on duration of gari feeding. The site of inhibition of electron-transfer was probably between the reduced prosthetic groups (FAD and FMN) and cytochrome C (P-450).     

Comparative effects of scopoletin and cyanide on rat brain, 1: Histopathology

Four week old male Wistar rats were used to study the effects of scopoletin and cyanide on the histopathology of rat brain. The rats were divided into a control and three experimental groups (2–4) and fed rations containing 0.07 g scopoletin/100 g, 0.07g scopoletin + 1.8 mg cyanide/100 g and 1.8 mg cyanide/100 g, respectively. These levels of scopoletin and cyanide corresponded to levels found in a processed cassava diet. The first group was fed the same ration as the others but without scopoletin and cyanide. The rats were fed these rations for twelve months. Rats from each group were sacrificed at the third, sixth, ninth and twelfth months; the relative brain weight of the rats (% of body weight) and histology of their brains were studied. The lipid peroxide levels of the rat brains were also studied at the twelfth month. The results showed that the relative brain weights of the rats fed scopoletin + cyanide were significantly (p<0.05) less than that of the control from the third month. There were no significant changes in the lipid peroxide levels of the rat brains in the various groups. Histological examination of the brains of the rats sugested that scopoletin is involved in the pathogenesis of the neuropathy seen in cassava consuming populations.     

Effect of prolonged consumption of gari (Cassava,Manihot Utilisima) on rat hepatic energy metabolism

Rats were fed high (35%, w/w) gari (Cassava,Manihot utilisima) — based diets for a prolonged period and sacrificed after 22/23 days, 30/31 days, 45/46 days and 59/60 days. Hepatic mitochondrial respiratory control for succinate oxidation was evaluated by four criteria (a) osmotic swelling/contraction cycle, (b) oxygen uptake, (c) ATPase activity and (d) Ca²⁺ uptake. A decrease (28–51% in respiratory control ratio (RCR)) in the degree of oxidative phosphorylation coupling, ATPase activity (19–24%) and increased swelling/contraction (30–75%) with no apparent effect on Ca²⁺ uptake were suggestive of moderate alterations in mitochondrial energy metabolism caused by the ingestion of garri based diet. The possible in vivo significance of these observations are discussed.     

Coumarin compounds in cassava diets: 2 health implications of scopoletin in gari

Scopoletin has been isolated and identified in gari, a cassava food consumed in Nigeria (West Africa). Its levels in gari and cassava flour is not altered by post processing treatments such as sundrying, refrigeration and storage. Scopoletin has also been identified as an active principle in the traditional herbal infusion of the fruit ofTetrapleura tetraptera TAUB used in the ethnopharmacology of West Africa. It is a potent hypotensive and non-specific spasmolytic agent. These pharmacological effects of Scopoletin are probably the underlying factors in the slowly developing tropical neuropathy characterised by optic atrophy, nerve deafness and ataxia endemic among populations subsisting on cassava diets such as gari. Hitherto, these toxicities were attributed to cyanogenic glucosides (cyanide) present in cassava.     

Effect of high and prolonged gari diets on some microsomal enzymes activities of rat liver

Male wister albino rats (90–130 g) were fed control and gari (56% w/w) (a dried cassava product) containing diets for 9 wks and sacrificed at intervals (1, 3, 6 and 9 wks). Liver microsomal fractions were assayed for glucose-6-phosphatase, NADPH-cytochrome c (P-450) reductase, NADPH-dichlorophenolindophenol reductase, cytochrome P-450 peroxidase and aniline hydroxylase activities. Whereas changes were observed in the activity rates of all enzymes, significant changes were observed in the NADPH-cytochrome c reductase activity (43% inhibited,P<0.001) and glucose-6-phosphatase (19% inhibited,P<0.05) at 9 wk. The results are discussed in terms of the hepatotoxicity of gari.