Fruit proteins, seed proteins and capsaicinoids fractions were isolated from red pepper of Capsicum annum L. plants family and their effects on mitochondrial permeability transition pore (MPTP) and lipid peroxidation of rat liver were studied in vitro. Seed proteins did not influence to MPTP; however fruit proteins caused MPTP to open and led to mitochondrial membrane permeabilization. Opening of the MPTP causes massive swelling of mitochondria; capsaicinoids fractions inhibited the swelling process of mitochondria and caused the closed state of the MPTP. Fruits and seeds protein fractions from red pepper did not reduce the effect of Fe2+/ascorbate-induced mitochondrial swelling and had no effect on the accumulation of malondialdehyde (MDA) in the membranes of mitochondria. Capsaicinoid fraction had a concentration-dependent inhibitory effect on the Fe2+/ascorbate-dependent swelling of mitochondria and of lipid peroxidation. Half-maximal inhibitory concentration (IC50) on the swelling of mitochondria fraction was 2 µg/ml. Сapsaicinoids fraction prevented the effect of Fe2+/ascorbate on mitochondria and reduced the accumulation of MDA in membrane. Complete inhibition of lipid peroxidation was shown at a 50 µg/ml capsaicinoids concentration. Capsaicinoids, reducing the membrane destructive effects of Fe2+/ascorbate, had antioxidant properties and a protective effect on mitochondria. The obtained results showed the presence of different compounds in red pepper differently affecting MPTP and lipid peroxidation.
Red pepper, proteins, capsaicinoid, mitochondria, MPTP, lipid peroxidation