Honokiol Protects the Kidney from Renal Ischemia and Reperfusion Injury by Upregulating the Glutathione Biosynthetic Enzymes

Glutathione (GSH) is an endogenous antioxidant found in plants, animals, fungi, and some microorganisms that protects cells by neutralizing hydrogen peroxide. Honokiol, an active ingredient of Magnolia officinalis, is known for antioxidant, anti-inflammatory, and anti-bacterial properties. We investigated the protective mechanism of honokiol through regulating cellular GSH in renal proximal tubules against acute kidney injury (AKI). First, we measured cellular GSH levels and correlated them with the expression of GSH biosynthetic enzymes after honokiol treatment in human kidney-2 (HK-2) cells. Second, we used pharmacological inhibitors or siRNA-mediated gene silencing approach to determine the signaling pathway induced by honokiol. Third, the protective effect of honokiol via de novo GSH biosynthesis was investigated in renal ischemia-reperfusion (IR) mice. Honokiol significantly increased cellular GSH levels by upregulating the subunits of glutamate-cysteine ligase (Gcl)—Gclc and Gclm. These increases were mediated by activation of nuclear factor erythroid 2-related factor 2, via PI3K/Akt and protein kinase C signaling. Consistently, honokiol treatment reduced the plasma creatinine, tubular cell death, neutrophil infiltration and lipid peroxidation in IR mice and the effect was correlated with upregulation of Gclc and Gclm. Conclusively, honokiol may benefit to patients with AKI by increasing antioxidant GSH via transcriptional activation of the biosynthetic enzymes.

Rutaecarpine may improve neuronal injury, inhibits apoptosis, inflammation and oxidative stress by regulating the expression of ERK1/2 and Nrf2/HO-1 pathway in rats with cerebral ischemia-reperfusion injury

BACKGROUND

Cerebral ischemia-reperfusion (CI/R) injury is a more serious brain injury caused by the recovery of blood supply after cerebral ischemia for a certain period of time. Rutaecarpine (Rut) is an alkaloid isolated from Evodia officinalis with various biological activities. Previous studies have shown that Rut has a certain protective effect on ischemic brain injury, but the specific molecular mechanism is still unknown.

METHODS

In this study, a rat model of CI/R was established to explore the effects and potential molecular mechanisms of Rut on CI/R injury in rats.

RESULTS

The results showed that Rut alleviated neuronal injury induced by CI/R in a dose-dependent manner. Besides, Rut inhibited neuronal apoptosis by inhibiting the activation of caspase 3 and the expression of Bax. In addition, Rut alleviated the inflammatory response and oxidative stress caused by CI/R through inhibiting the production of pro-inflammatory factors (IL-6 and IL-1β), lactate dehydrogenase (LDH), malondialdehyde (MDA) and ROS, and increased the levels of anti-inflammatory factors (IL-4 and IL-10) and superoxide dismutase (SOD). Biochemically, Western blot analyses showed that Rut inhibited the phosphorylation of ERK1/2 and promoted the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) pathway-related proteins (Nrf2, heme oxygenase 1 (HO-1) and NAD (P) H-quinone oxidoreductase 1) in a dose-dependent manner. These results show that Rut may alleviate brain injury induced by CI/R by regulating the expression of ERK1/2 and the activation of Nrf2/HO-1 pathway.

CONCLUSION

In conclusion, these results suggest that Rut may be used as an effective therapeutic agent for damage caused by CI/R.

Phyllanthin and hypophyllanthin from Phyllanthus amarus ameliorates immune-inflammatory response in ovalbumin-induced asthma: role of IgE, Nrf2, iNOs, TNF-α, and IL's

Background: Asthma is a chronic airway immunoinflammatory disorder characterized by airway remodeling. Phyllanthus amarus has been reported to possess antioxidant and anti-inflammatory potential. Aim: To evaluate the possible mechanism of action of isolated phytoconstituents from P. amarus (PA) against ovalbumin (OVA)-induced experimental airway hyperresponsiveness (AHR). Material and method: Phyllanthin and hypophyllanthin were isolated and characterized (HPLC) from the methanolic extract of PA. AHR was induced in Sprague-Dawley rats by OVA-challenged, and animals were treated with PA (50, 100, and 200 mg/kg, p.o.) for 28 days. Results: The HPLC analysis showed the presence of phyllanthin and hypophyllanthin in methanolic extract of PA at RT of 25.243 and 26.832 min, respectively. OVA-induced alterations in hemodynamic parameters, lung functions test, peripheral blood oxygen level, total, and differential cell count in Bronchoalveolar Lavage Fluid was significantly attenuated (p < .05) by PA (100 and 200 mg/kg). It also significantly decreased (p < .05) the levels of total protein and albumin in serum, BALF, and lungs. OVA-induced increase in IgE (total and OVA-specific), and oxido-nitrosative stress (SOD, GSH, MDA, and NO) levels were significantly (p < .05) decreased by PA. RT-PCR analysis revealed that elevated oxido-nitrosative stress (Nrf2 and iNOs), immune-inflammatory makers (HO-1, TNF-α, IL-1β, and TGF-β1), Th2 cytokines (IL-4 and IL-6) levels were significantly attenuated (p < .05) by PA. PA also attenuated histological and ultrastructural aberrations induced by OVA. Conclusion: Results of the present investigation demonstrated that the presence of phyllanthin and hypophyllanthin in P. amarus alleviated Th2 response in OVA-induced AHR via modulation of endogenous markers in a murine model of asthma. Thus, phyllanthin and hypophyllanthin may be a new therapeutic approach for the management of asthma.