Dactylorhin B reduces toxic effects of beta-amyloid fragment (25-35) on neuron cells and isolated rat brain mitochondria.

beta-amyloid is strongly implicated in Alzheimer's pathology, and mitochondria play an important role in neurodegenerative disorders. Dactylorhin B [short for bis(4-beta-D-glucopyranosyloxybenzyl)-2-beta-D-glucopyranosyl-2-isobutyltartrate (DHB)] is an active compound isolated from Coeloglossum viride. (L.) Hartm. var. bracteatum (Willd.) and may have neuroprotective effects. In the present study, we investigated the damage of rat brain mitochondrial function induced by beta-amyloid and the protective effect of DHB. Isolated rat brain mitochondria were incubated with amyloid-beta peptide (Abeta)(25-35) alone or together with DHB. reactive oxygen species production, pyruvate dehydrogenase complex activity, alpha-ketoglutarate dehydrogenase complex activity, cytochrome c oxidase activity, mitochondrial swelling, mitochondrial membrane potential and the release of cytochrome c from mitochondria were measured. Data showed that Abeta(25-35) directly disrupted mitochondrial function, inhibited the key enzymes and contributed to apoptosis and the deficiency of energy metabolism. Co-incubation of DHB attenuated Abeta(25-35)-induced pathological changes. The significance of DHB in the management of mitochondria-related disorders is discussed.