Mitochondria, the power house of cell plays a central role in cell life and cell death. Its membrane permeability transition pore which is normally closed, opens when stimulated by mitochondrial matrix Ca2+ accumulation, adenine nucleotide depletion, increased phosphate concentration or oxidative stress and sustained mitochondrial matrix Ca2+ overload triggers prolonged high-conductance MPTP opening, leading to mitochondrial dysfunction and cell death (Apoptosis). Thus, maintenance of mitochondrial Ca2+ homeostasis is of critical importance. Some plants such as Ficus exasperata vahl commonly known as sandpaper plant possesses phytochemicals which have been detailed to have the capacity to induce the opening of MPTP.
Thus, this study was designed to investigate the effect of fractions derived from Ficus exasperata on the mitochondria permeability transition pore. Fractions (n-hexane, and ethylacetate) were obtained at varying concentrations (200µg/ml, 400µg/ml, 600µg/ml, 800µg/ml, 1000µg/ml).
This experimental study shows that leaf n-hexane and stem ethylacetate stem of Ficus exaspearata have triggering effects on the Mitochondria Membrane Permebility Transition Pore (MMPTP) in a concentration-dependent manner as compared with the control (without Ca2+ or triggering agent). The induction effect of the leaf n-hexane fraction increases whereas the stem ethylacetate fraction induction effect decreases as concentration increases as measured by a 752N UV-VIS spectrophotometer. The results obtained for stem ethylacetate fraction is as follow: at 200µg/ml, ∆540nm = – 0.121which translates to 92.06% induction and 1.92-fold increase, a significant induction at P < 0.05. For 400µg/ml, a similar trend of induction was observed i.e. ∆540nm = –0.086 which translates to 36.5% induction and 1.37-fold increase being significant at P < 0.05. Compared with the control, the next three tests show no significant induction on MMPTP at P < 0.05. At 600µg/ml, ∆540nm = – 0.068 which translates to 7.94% induction and 1.03-fold, same at 800µg/ml, ∆540nm = – 0.057 which translates to – 9.52% induction and 0.91-fold and lastly at 1000µg/ml, ∆540nm = – 0.053 which translates to – 15.87% induction and 0.08-fold increase. For leaf n-hexane fraction, the results obtained were as follow: at 200µg/ml, ∆540nm = – 0.063 which translates to 0% induction and 1-fold an insignificant induction at P < 0.05. In the same vein, ∆540nm = –0.067 at 400µg/ml, a result which translates to 6.35% induction and 1.06-fold an insignificant induction at P < 0.05. The result obtained at 600µg/ml also shows an insignificant induction at P < 0.05 such that ∆540nm = – 0.072 which translates to 14.29% induction and 1.14-fold increase. However, the two significant induction at P < 0.05 are observed at 800µg/ml and 1000µg/ml. A ∆540nm of 0.089 which translates to 41.27% induction and 1.41-fold increase and ∆540nm of – 0.094 which translates to 49.21% induction and 1.49-fold increase was obtained at 800µg/ml and 1000µg/ml respectively.
Conclusively, stem ethylacetate fraction causes significant induction at lower concentration (200µg/ml and 400µg/ml) while leaf n-hexane fraction of the extract causes significant opening at higher concentrations (800µg/ml and 1000µg/ml).