RESUMEN
BACKGROUND: Mitochondrial membrane permeability transition (MMPT) pore ha s emerged as a promisingtarget for various pharmacological interventions because of the consequent release of cytochrome c upon the opening of the pore which is the point of no return for apoptosis, a form of programed cell death that is down regulated in cancercells. AIM: To evaluate the modulatory effects of fractions (Chloroform fraction of calliandra portoricensis( CFCP), Aqueous fraction of calliandra portoricensis (AFCP), and Ethylacetate fraction of Calliandra portoricensis (EFCP) of methanol extracts of the root bark of Calliandra portoricensis (MECP), a medicinal plant used in the traditional treatment of prostate tumour, on mitochondrial membrane permeability transition (MMPT) pore. METHODOLOGY: Opening of the pore was assessed as mitochondrial swelling and was monitored spectrophotometrically as changes in absorbance at 540nm. RESULTS: Varying concentrations of MECP (10microg/ml, 20microg/ml, 40microg/ml, and 60microg/ml) induced opening of the pore, in the absence of calcium, by 1.1, 2.8, 4.5, 13.8 folds, respectively while spermine reversed this inductive effect. Interestingly, unlike MECP, EFCP and AFCP did not have any effect at lower concentrations (<40microg/ml) but induced pore opening at 60microg/ml, 80microg/ ml, 100microg/ml and 120microg/ml by 1.6, 3.1, 12.7, 16.7folds, respectively for EFCP and 1.4, 5.4, 7 and 10 folds respectively, for AFCP. In the presence ofcalcium, the pore was slightly further opened by MECP, EFCP andAFCP. The CFCP however did not have any significant effect on the pore either in the presence or absence of calcium. CONCLUSION: These findings suggest that the bioactive agents that induced the opening of the pore are present in the most potent ethylacetate fraction of the root bark of C. portoricensis. This fraction will therefore be useful for the structural elucidation of the bioactive principle in the plant and for further studies in diseases that require increased apoptosis such as cancer.
