Inhibitory effect of cyanide on G-6-PD activity of erythrocytes in Calabar, Nigeria

Screening test for G-6-PD was carried out on 100 subjects in Calabar using the methaemoglobin reduction test of Brewar et al, [1978]. Twenty percent of the subjects were deficient for G-6-PD, while 80% were normal. Of the 27 female subjects screened, none was deficient for the enzyme. Out of the 73 males, 53 were normal, while 20 were deficient. The difference between deficient male subjects and female was statistically significant [P<0.05]. Different concentrations of potassium cyanide [KCN] were incubated with the 80 blood samples that were normal for G-6-PD for 30 min at 37°C and G-6-PD screening was reported. It was observed that 0.15 mml/L KCN had a significant inhibitory effect on erythrocyte G-6-PD activity in vitro with apparent inhibitory affect of the cyanide indicated at other concentrations of the salt. The inhibition effect of cyanide seen in vitro may inversely represent an in vivo inhibitory effect, therefore there is need to modify the processing method of one of our regular food stuffs like cassava, bean and corn to completely remove cyanide and thereby to prevent possible inhibition of G-6-PD activity. Further direct study on the in vivo effect of the cyanide on G-6-PD activity is proposed

Hypoglycemic effects of Coccinia indica: inhibition of key gluconeogenic enzyme, glucose-6-phosphatase.

Coccinia indica (Family: Cucurbitaceae, locally known as telakucha) leaves were extracted with 95% ethanol. Following evaporation of the solvents, the residue was suspended in distilled water. When this suspension was fed orally to male normal-fed and 48-hr starved rats, the blood glucose was lowered 21% (P less than 0.01) in normal-fed and 24% (P less than 0.001) in 48-hr starved animals respectively. Starvation had induced a 3-fold increase in the activity of glucose-6-phosphatase and this activity was depressed 19% (P less than 0.05) by extract feeding while basal activity of the enzyme in normal-fed rats remained unaffected. Consistent with the depression of glucose-6-phosphatase, urea cycle enzyme arginase was also depressed 21% (P less than 0.001) and 12% (P less than 0.01) in the liver of 48 hr-starved and normal-fed animals respectively. Unlike glucose-6-phosphatase, starvation induced levels of gluconeogenic enzymes alanine aminotransferase and aspartate aminotransferase were not affected by Coccinia extract. These results suggest that the hypoglycemic effect of C. indica is partly due to the repression of the key gluconeogenic enzyme glucose-6-phosphatase.