Induction of heme oxygenase-1 by traditional Chinese medicine formulation ISF-1 and its ingredients as a cytoprotective mechanism against oxidative stress.

Traditional medicines are clinically used to treat post-stroke disorders in China. In search of alternative medicines for post-stroke rehabilitation, we recently identified the heme oxygenase-1 (HO-1) pathway as a key mechanism underlying the biological activities of the ischemic stroke formulation ISF-1. This study was designed to further investigate ISF-1 for HO-1 induction in cultured human cells and corresponding cytoprotective effects against oxidative injury. A rat stroke model induced by middle cerebral artery occlusion was employed to verify the activity of ISF-1 in vivo. It was found that HO-1 expression was induced by ISF-1 in a dose- and time-dependent manner. Four ingredients from ISF-1 were identified to be responsible for HO-1 induction. The appropriate combinations of these active ingredients or purified compounds resulted in synergistic induction of HO-1 expression. A minimal HO-1-inducing formulation was prepared and showed significant cytoprotection against H2O2-induced oxidative stress. Collectively, the herbal formulation ISF-1 was capable of inducing HO-1 expression, in vitro and in vivo, offering a potential mechanism for post-stroke rehabilitation. This study may shed light on the development of mechanism-defined therapies based on traditional herbal remedies.