A number of phytochemicals have been established as potent inducers of the mitochondrial membrane permeability transition (MMPT) pore, a transient structure formed in the inner mitochondrial membrane (IMM). There is however no information on the effect of Ficus exasperata (F. exasperata) a popular medicinal plant, on this pore, necessitating this investigation. The in vitro effects of varying concentrations (200, 400, 600, 800 and 1000µg/ml) of the methanol, n-hexane and ethylacetate fractions of leaf and stem of F. exasperata on MMPT pore opening in experimental rat liver were assessed. Opening of MMPT pore was spectrophotometrically assayed under succinate-energized condition using a modified method of Lapidus and Sokolove, 1993<sup>[34]</sup>. The results obtained for the Stem Methanol Fraction (SMF) and Leaf Methanol Fraction (LMF) show significant (P< 0.05) increases in the extents to which MMPT pore opening was induced at all concentrations compared with the control group, with the highest induction observed at 400µg/ml and the least seen at 1000µg/ml. The inductive effects of Leaf n-hexane Fraction (LHF) and Stem n-hexane Fraction (SHF) increased as concentration increased such that the highest induction observed in LHF and SHF were 2.80 and 2.28 fold increases respectively. Leaf Ethylacetate Fraction (LEF) and Stem Ethylacetate Fraction (SEF) of F. exasperata also show a concentration-dependent effect such that the inductive effect decreased as concentration increased i.e. at 200µg/ml of LEF and SEF, 3.97 and 4.25-fold increases were achieved respectively while the least folds in induction were observed at 1000µg/ml for both at 2.0-fold and 1.97-fold respectively. Taken together, all tested fractions of F. exasperata have significant P < 0.05 inductive effect on the MMPT pore opening at all tested concentrations, the most potent fraction being the SEF. We thus conclude that F. exasperata is an effective inducer of the MMPT pore, albeit, different fractions derived from different parts vary in their potency. Also, F. exasperata could find a great use in the treatment of ailments dependent on the induction of the mitochondrial membrane permeability transition pore opening.
Mitochondrial toxicity of organic arsenicals: membrane permeability transition pore opening and respiratory dysfunction
