RESUMO
Aims: To determine the effect of ethanol extract of Spondias mombin Linn on membrane potential energy, the intracellular and extracellular concentrations of Na+, K+, Ca2+ and Mg2+ in an easily accessible model cell, erythrocyte, was studied. The effect on the first approximation estimates of erythrocytic free energy changes (ΔG) was calculated. Study Design: Randomized study. Place and Duration of Study: Department of Biochemistry, Federal University of Technology, Owerri, Nigeria between January 2010 and February 2011). Methodology: Twenty-five female albino rabbits (1.47 ± 0.17 kg) of the same age set were divided into 5 groups of 5 animals. The first group served as the baseline control, the groups II and III animals were intraperitoneally administered 1ml of 750 mg/kg body weight of S. mombin extract daily for 7 and 14 days respectively, while groups IV and V animals were intraperitoneally administered 1ml of 0.14 IU/kg body weight of oxytocin drug ((Pitocin®, USA) daily for 7 and 14 days respectively. Plasma and lyzed red blood cells obtained were analyzed for extracellular and intracellular erythrocyte concentrations of sodium, potassium, calcium and magnesium using standard methods. Results: The study showed that both the extract and oxytocin administrations significantly (p<0.05) reduced intracellular [Mg2+] and extracellular [K+] and [Ca2+], with a concomitant increase in intracellular [Ca2+]. Both treatment with the extract and oxytocin, did not significantly (p>0.05) alter [Na+] and extracellular [Mg2+]. On the other hand, while the extract did not affect intracellular [K+], oxytocin significantly (p<0.05) reduced it. The results also indicated that while the extract significantly (p<0.05) increased the [K+]-based estimated ΔG, oxytocin treatment reduced it. On the other hand, both the extract and oxytocin caused a non-significant (p>0.05) drop in the Ca2+ based ΔG, with no significant (p>0.05) alteration of the [Na+] and [Mg2+] based estimated ΔG. The pole reversa observed with the study of the Ca2+-based ΔG indicates depressive effect of both the extract and oxytocin on Ca2+ ATPase pump. Conclusion: The observations above indicate that, while the use of the extract might enhance energy generation and conservation, the use of oxytocin might elicit exhaustive utilization of energy.