Mitochondrial oxidative damage contributes to a wide range of pathologies including ischemia/reperfusion injury. Accordingly, protecting mitochondria from oxidative damage should possess therapeutic relevance. In the present study, we have designed and synthesized a series of novel indole-TEMPO conjugates that manifested good anti-inflammatory properties in a murine model of xylene-induced ear edema. We have demonstrated that these compounds can protect cells from simulated ischemia/reperfusion (s-I/R)-induced reactive oxygen species (ROS) overproduction and mitochondrial dysfunction. Furthermore, we have demonstrated that indole-TEMPO conjugates can attenuate organ damage induced in rodents via intestinal I/R injury. We therefore propose that the pharmacological profile and mechanism of action of these indole-TEMPO conjugates involve convergent roles, including the ability to decrease free radical production via lipid peroxidation which couples to an associated decrease in ROS-mediated activation of the inflammatory process. We further hypothesize that the protective effects of indole-TEMPO conjugates partially reside in maintaining optimal mitochondrial function.Download high-res image (107KB)Download full-size image

We describe several novel curcumin analogues that possess both anti-inflammatory antioxidant properties and thrombolytic activities. The therapeutic efficacy of these curcumin analogues was verified in a mouse ear edema model, a rat arterial thrombosis assay, a free radical scavenging assay performed in PC12 cells, and in both in vitro and in vivo ischemia/reperfusion models. Our findings suggest that their protective effects partially reside in maintenance of optimal mitochondrial function.

Mitochondrial oxidative stress has been implicated in aging, neurodegenerative diseases, diabetes, stroke, ischemia/reperfusion injury, age-related macular degeneration (AMD) and cancer. Recently, we developed two new mitochondria-targeting fluorescent probes, MitoProbes I/II, which specifically localize in mitochondria and employed both in vivo and in vitro for detection of mitochondrial oxidative stress. Here, we report the design and synthesis of these agents, as well as their utility for real-time imaging of mitochondrial oxidative stress in cells.

The synthesis, characteristics, and biological applications of a series of new rhodamine nitroxide fluorescent probes that enable imaging of hydroxyl radicals (•OH) in living cells are described. These probes are highly selective for •OH in aqueous solution, avoiding interference from other reactive oxygen species (ROS), and they facilitate •OH imaging in biologically active samples. The robust nature of these probes (high specificity and selectivity, and facile synthesis) offer distinct advantages over previous methods for •OH detection.

We have recently developed new Tempo-PEG-RGDs conjugates and have quantitatively examined their antithrombotic and antioxidant capabilities. These compounds were therapeutically beneficial when characterized in both in vitro platelet aggregation assays and a rat model of arterial thrombosis. Moreover, these compounds demonstrated significant protection from organ damage in a rat model of ischemia/reperfusion. Our data indicate that Tempo-PEG-RGDs represent a new class of adjuvants with therapeutic efficacy in acute and transient ischemic damage.

We synthesized and evaluated a series of acidic fluorescent pH probes exhibiting robust pH dependence, high sensitivity and photostability, and excellent cell membrane permeability. Titration analyses indicated that probe 3 could increase its fluorescence intensity 800-fold between pH 8.0 and 4.1. Additionally, its pKa value is optimal for intracellular probing of acidic organelles. Fluorescent imaging of HepG2 and Hela cells further revealed that probe 3 demonstrates outstanding capacity for monitoring of intracellular [H+] levels. The easily accessible terminal alkyne/azido function groups of these probes offer the possibility of rapidly constructing sensor molecule libraries using ‘click’ chemistry.

We have synthesized a series of new β-carboline-tripeptide conjugates, and examined their anti-inflammatory properties in a mouse model of xylene-induced ear edema. The analgesic capacity of these compounds was further evaluated in a rodent tail flick assay. Our results indicate that β-carboline conjugate 4a manifests potent anti-inflammatory and analgesic activity while exerting a protective effect against mesenteric ischemia/reperfusion (I/R) injury in the rat.Our results indicate that β-carboline conjugate 4a manifests potent anti-inflammatory and analgesic activity while exerting a protective effect against mesenteric ischemia/reperfusion (I/R) injury in the rat.Highlights►In this manuscript, we have synthesized a series of new β-carboline-tripeptide conjugates.►Their anti-inflammatory properties were examined in a mouse model of xylene-induced ear edema.►The analgesic capacity of these compounds was further evaluated in a rodent tail flick assay.►Compound 4a exerts a protective effect against mesenteric ischemia/reperfusion (I/R) injury in the rat.

We describe a novel class of β-carboline alkaloid-peptide conjugates that possess both free radical scavenging and thrombolytic activity. These conjugates demonstrate therapeutic efficacy in a rat arterial thrombosis assay, as well as free radical scavenging capacity as evaluated in a PC12 cell survival assay. Our results indicate that β-carboline alkaloid-peptide conjugate 26a exerts a significant protective effect against local and remote organ injury induced by limb I/R injury in the rat.A novel class of β-carboline alkaloid-peptide conjugates that possess both free radical scavenging and thrombolytic activity is described in this manuscript.Highlights► In this manuscript, we have developed a novel class of β-carboline alkaloid-peptide conjugates. ► These conjugates possess good free radical scavenging and thrombolytic activities. ► Compound 26a exerts a significant protective effect against limb I/R injury in the rat.

To develop more potent therapeutic agents with therapeutic efficacy for ischemia/reperfusion (I/R) injury, we linked an antiinflammatory moiety (1,3-dioxane derivative) to the key pharmacophoric moiety of melatonin. We hypothesized that the resulting new indole derivatives might induce a synergistic protection against oxidative damage associated with I/R injury. Our results indicate that one of these indole derivatives (7) manifests potent antiinflammatory antioxidant effects and exerts a protective effect against skeletal muscle injury and associated lung injury following limb I/R in rats.

Stable nitroxides are potential antioxidant drugs. In this study, we have linked nitroxide to natural amino acids with the aim to improve therapeutic activity. The radical scavenging activities of two nitronyl nitroxide–amino acid conjugates (NNR and NNK) were evaluated in PC 12 cell survival assays. The NO scavenging activities of these compounds were confirmed in the acetylcholine-induced vasorelaxation assay. In addition, the protective effect of NNR was demonstrated in an in vivo rat model of hepatic ischemia–reperfusion (I/R) induced injury and oxidative change. Because NNR reduced hepatic I/R injury by minimizing oxidative stress, it might be possible to develop it into a possible therapeutic agent for hepatic I/R injury.

In this study, a new class of phenolic tetrahydro-β-carboline RGD peptidomimetic conjugates was designed and synthesized. The radical scavenging activities of these newly synthesized compounds 12a–c were evaluated in PC12 cell survival assays. The NO scavenging activities of these compounds were confirmed in the acetylcholine-induced vasorelaxation assay. Compounds 12a–c were efficacious in a rat arterial thrombosis model, and were active in ADP- or PAF-induced in vitro platelet aggregation assays, which suggests these compounds also possess anti-thrombotic activity. The beneficial effects of dual-acting agent 12c were demonstrated on the ischemia-reperfusion induced cardiac infarct size and oxidative change in an in vivo rat model.