In vitro and in vivo antioxidative and hepatoprotective activity of aqueous extract of Cortex Dictamni.

AIM: To investigate the antioxidant and hepatoprotective effects of Cortex Dictamni aqueous extract (CDAE) in carbon tetrachloride (CCl4)-induced liver damage in rats. METHODS: The in vitro antioxidant effect of CDAE was investigated using α,α-diphenyl-ß-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ß-carotene bleaching, reducing power, and thiobarbituric acid reactive substance assays. A linoleic acid system, including ferric thiocyanate (FTC) and thiobarbituric acid (TBA) assays, was used to evaluate the inhibition of lipid peroxidation. The in vivo hepatoprotective and antioxidant effects of CDAE against CCl4-induced liver damage were evaluated in Sprague-Dawley rats. Silymarin was used as a positive control. Liver damage was assessed by determining hepatic histopathology and liver marker enzymes in serum. Enzyme and non-enzyme antioxidant levels and lipid peroxide content were measured in the liver. Cytochrome P450 2E1 (CYP2E1) protein expression was measured via immunohistochemical staining. Nuclear factor E2-related factor (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H quinine oxidoreductase 1 (NQO1), and γ-glutamylcysteine synthetase catalytic subunit (γ-GCSc) protein expression was measured by Western blot. RESULTS: Our results showed that CDAE exhibited a strong antioxidant activity in vitro. CDAE scavenged DPPH and ABTS radicals in a dose-dependent manner. CDAE inhibited lipid peroxidation with a lipid peroxide inhibition rate of 40.6% ± 5.2%. In the FTC and TBA assays, CDAE significantly inhibited lipid peroxidation (P < 0.01). In vivo histopathological studies indicated that CCl4-induced liver injury was alleviated following CDAE treatment in rats of both sexes. CDAE (160 and 320 mg/kg) significantly prevented CCl4-induced elevations of alkaline phosphatase, glutamate pyruvate transaminase, aspartate aminotransferase, and total bilirubin levels in rats of both sexes (P < 0.05, 0.01, or 0.001). Moreover, CDAE restored the decreased activities of hepatic antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, as well as non-enzyme antioxidant glutathione, which were induced by CCl4 treatment. CDAE significantly suppressed the up-regulation of CYP2E1 and promoted Nrf2, HO-1, NQO1, and γ-GCSc protein expression. CONCLUSION: CDAE exhibits good antioxidant performance in vitro, with marked radical-scavenging and anti-lipid peroxidation activities. CDAE is effective in preventing CCl4-induced hepatic damage in rats of both sexes. The hepatoprotective activity of CDAE may be attributable to its antioxidant activity, which may involve Keap1-Nrf2-mediated antioxidant regulation.

Aqueous extract of Cortex Dictamni protects H9c2 cardiomyocytes from hypoxia/reoxygenation-induced oxidative stress and apoptosis by PI3K/Akt signaling pathway.

Ischemia-reperfusion injury is the major manifestation of ischemic heart disease, which facilitates cardiac arrhythmias, heart failure and death. Oxidative stress and apoptosis have been involved in the pathogenesis of myocardial ischemia-reperfusion injury. Modern pharmacological studies have indicated that the extracts and active compounds of Cortex Dictamni exhibit antioxidative and cardiovascular protective activities. This study was designed to investigate the protective effect of aqueous extract of Cortex Dictamni (CDAE) on regulating hypoxia/reoxygenation (H/R)-induced cardiomyocytes oxidative stress and apoptosis. H9c2 cardiomyocytes pretreatmented with CDAE for 24h were exposed to hypoxia/reoxygenation. Cell survival was measured by methyl thiazolyl tetrazolium (MTT) assay, and by the detections of lactate dehydrogenase (LDH) activity and cardiac troponin I (cTn-I) content in cultured supernatant. Cell apoptosis was measured by Hoechst 33342/propidium iodide (PI) staining, Annexin-V/PI staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Intracellular reactive oxygen species (ROS) production, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were measured to examine antioxidant activity. Mitochondrial membrane potential and release of cytochrome c were measured to examine mitochondrial changes. The expressions of anti-oxidant, pro-apoptosis and anti-apoptosis proteins were measured by performing western blotting assay. Inhibitor LY294002 was used to confirm the regulation effect of CDAE on PI3K/Akt signaling pathway. CDAE pretreatment prevents H/R-induced cardiomyocytes oxidative stress and apoptosis through activation of PI3K/Akt signaling pathway.