Effect of crataemon on the respiration of isolated mitochondria.

Crataemon is a drug containing the total mixture of flavonoids isolated from the leaves of Crataegus minogina. Crataemon causes activation and inhibition of the respiration of isolated liver and heart mitochondria, with different time and dose dependence and with different sensitivity to EDTA. The activating effect develops immediately, it is caused by small doses of crataemon, it is lacking in uncoupled mitochondria and completely abolished by EDTA. The inhibitory effect develops immediately or after the activation phase, it is caused by higher doses and the degree and the latency period depend on the dose. This effect is due to the action of crataemon on the flavoprotein-cytochrome c section of the electron transport chain. The inhibitory effect is partly abolished by EDTA. These effects are explained by the presence of at least two crataemon components: EDTA-sensitive and EDTA-insensitive. The EDTA-sensitive component is determined as a zinc-flavonoid complex. In small doses it uncouples oxidative phosphorylation, while large doses inhibit the electron transport between flavoprotein and cytochrome c. The EDTA-insensitive component causes only inhibition of the electron transport in the same part of the chain and manifests its effect in the higher doses.