Schisandrin B enhances the glutathione redox cycling and protects against oxidant injury in different types of cultured cells

Ferroptosis: action and mechanism of chemical/drug-induced liver injury

Drug-induced liver injury (DILI) is characterized by hepatocyte injury, cholestasis injury, and mixed injury. The liver transplantation is required for serious clinical outcomes such as acute liver failure. Current studies have found that many mechanisms were involved in DILI, such as mitochondrial oxidative stress, apoptosis, necroptosis, autophagy, ferroptosis, etc. Ferroptosis occurs when hepatocytes die from iron-dependent lipid peroxidation and plays a key role in DILI. After entry into the liver, where some drugs or chemicals are metabolized, they convert into hepatotoxic substances, consume reduced glutathione (GSH), and decrease the reductive capacity of GSH-dependent GPX4, leading to redox imbalance in hepatocytes and increase of reactive oxygen species (ROS) and lipid peroxidation level, leading to the undermining of hepatocytes; some drugs facilitated the autophagy of ferritin, orchestrating the increased ion level and ferroptosis. The purpose of this review is to summarize the role of ferroptosis in chemical- or drug-induced liver injury (chemical/DILI) and how natural products inhibit ferroptosis to prevent chemical/DILI.

Dietary Plant Polyphenols as the Potential Drugs in Neurodegenerative Diseases: Current Evidence, Advances, and Opportunities

Neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD), are characterized by the progressive degeneration of neurons. Although the etiology and pathogenesis of neurodegenerative diseases have been studied intensively, the mechanism is still in its infancy. In general, most neurodegenerative diseases share common molecular mechanisms, and multiple risks interact and promote the pathologic process of neurogenerative diseases. At present, most of the approved drugs only alleviate the clinical symptoms but fail to cure neurodegenerative diseases. Numerous studies indicate that dietary plant polyphenols are safe and exhibit potent neuroprotective effects in various neurodegenerative diseases. However, low bioavailability is the biggest obstacle for polyphenol that largely limits its adoption from evidence into clinical practice. In this review, we summarized the widely recognized mechanisms associated with neurodegenerative diseases, such as misfolded proteins, mitochondrial dysfunction, oxidative damage, and neuroinflammatory responses. In addition, we summarized the research advances about the neuroprotective effect of the most widely reported dietary plant polyphenols. Moreover, we discussed the current clinical study and application of polyphenols and the factors that result in low bioavailability, such as poor stability and low permeability across the blood-brain barrier (BBB). In the future, the improvement of absorption and stability, modification of structure and formulation, and the combination therapy will provide more opportunities from the laboratory into the clinic for polyphenols. Lastly, we hope that the present review will encourage further researches on natural dietary polyphenols in the treatment of neurodegenerative diseases.

Pterostilbene attenuates liver injury and oxidative stress in intrauterine growth-retarded weanling piglets

OBJECTIVES

The aim of the present study was to investigate the potential of pterostilbene, a beneficial component primarily found in blueberries, to alleviate the intrauterine growth retardation (IUGR)-induced early liver injury and oxidative stress in a porcine model.

METHODS

Thirty-six IUGR piglets and an equal number of normal birth weight (NBW) counterparts received a diet with or without pterostilbene (250 mg/kg diet) during the first week post-weaning. Parameters related to the hepatic injury, oxidative stress, and antioxidant defense mechanisms were analyzed.

RESULTS

Relative to NBW, IUGR induced liver injury, which corresponded to increments in circulating alanine transaminase activity and hepatic apoptotic cell rate, superoxide radical generation, and the accumulation of oxidative damage products (P < 0.05). Administering pterostilbene reduced plasma transaminase activities, decreased hepatocyte apoptosis rate, and prevented the augmented levels of hepatic superoxide anion, 8-hydroxy-2 deoxyguanosine, and 4-hydroxynonenal-modified protein (P < 0.05). In terms of the hepatic antioxidant function, pterostilbene was efficient in improving the superoxide dismutase activity and the metabolic cycle between reduced glutathione and its oxidized form (P < 0.05). The pterostilbene-supplemented diet facilitated the nuclear translocation of nuclear factor erythroid-2-related factor 2 (NRF2) and promoted the expression levels of superoxide dismutase 2 in the liver of IUGR piglets (P < 0.05).

CONCLUSION

This study indicates that pterostilbene treatment has an auxiliary therapeutic potential to ameliorate early liver injury in IUGR neonates, presumably by stimulating the NRF2 signals and the associated antioxidant function.

Schisandrin B protects human keratinocyte-derived HaCaT cells from tert-butyl hydroperoxide-induced oxidative damage through activating the Nrf2 signaling pathway

Schisandrin B (Sch B), an active extract of Schisandra chinensis, has demonstrated antioxidant activity in a number of in vitro and in vivo models. In the present study, the capacity of Sch B to protect against oxidative injury in keratinocytes using the human keratinocyte‑derived HaCaT cell line was investigated. To induce oxidative injury, tert‑Butyl hydroperoxide (tBHP) was employed. The results indicate that Sch B efficiently reduced tBHP‑induced cell death, reactive oxygen species (ROS) generation, protein oxidation, lipid peroxidation and DNA damage. Sch B also effectively attenuated the loss of mitochondrial membrane potential (MMP), and restored adenosine triphosphate (ATP) levels in tBHP‑injured HaCaT cells. Furthermore, Sch B enhanced the expression of key antioxidant enzymes, including catalase, heme oxygenase‑1, glutathione peroxidase, and superoxide dismutase, and further engaged the nuclear factor‑erythroid 2‑related factor 2 (Nrf2) signaling pathway by modulating its phosphorylation through activating multiple upstream kinases, including protein kinase B, adenosine monophosphate‑activated protein kinase and mitogen‑activated protein kinases (MAPKs). The present study suggests that Sch B provides a protective effect in keratinocytes in response to oxidative injury via reinforcing the endogenous antioxidant defense system. Therefore, it may be applied as an adjuvant therapy or in health foods to delay the skin aging process and the onset of skin diseases caused by oxidative stress.

Yang/Qi invigoration: an herbal therapy for chronic fatigue syndrome with yang deficiency?

According to traditional Chinese medicine (TCM) theory, Yang and Qi are driving forces of biological activities in the human body. Based on the crucial role of the mitochondrion in energy metabolism, we propose an extended view of Yang and Qi in the context of mitochondrion-driven cellular and body function. It is of interest that the clinical manifestations of Yang/Qi deficiencies in TCM resemble those of chronic fatigue syndrome in Western medicine, which is pathologically associated with mitochondrial dysfunction. By virtue of their ability to enhance mitochondrial function and its regulation, Yang- and Qi-invigorating tonic herbs, such as Cistanches Herba and Schisandrae Fructus, may therefore prove to be beneficial in the treatment of chronic fatigue syndrome with Yang deficiency.

Time and dose relationships between schisandrin B- and schisandrae fructus oil-induced hepatotoxicity and the associated elevations in hepatic and serum triglyceride levels in mice

Background

Schisandrin B (Sch B), a dibenzocyclooctadiene compound, is isolated from schisandrae fructus (SF). This study was conducted to compare the time- and dose-response between Sch B- and SF oil (SFO)-induced changes in hepatic and serum parameters in mice.

Methods

Institute of Cancer Research (ICR) mice were given a single oral dose of Sch B (0.125–2 g/kg) or SFO (0.3–5 g/kg). Serum alanine aminotransferase (ALT) activity, hepatic malondialdehyde, and triglyceride (TG) levels were measured at increasing time intervals within 6–120 hours postdosing.

Results

Serum ALT activity was elevated by 60%, with maximum effect (E_max) =45.77 U/L and affinity (K_D) =1.25 g/kg at 48–96 hours following Sch B, but not SFO, treatment. Sch B and SFO treatments increased hepatic malondialdehyde level by 70% (E_max =2.30 nmol/mg protein and K_D =0.41 g/kg) and 22% (E_max =1.42 nmol/mg protein and K_D =2.56 g/kg) at 72 hours postdosing, respectively. Hepatic index was increased by 16%–60% (E_max =11.01, K_D =0.68 g/kg) and 8%–32% (E_max =9.88, K_D =4.47 g/kg) at 12–120 hours and 24–120 hours after the administration of Sch B and SFO, respectively. Hepatic TG level was increased by 40%–158% and 35%–85%, respectively, at 12–96 hours and 6–48 hours after Sch B and SFO treatment, respectively. The values of E_max and K_D for Sch B/SFO-induced increase in hepatic TG were estimated to be 22.94/15.02 μmol/g and 0.78/3.03 g/kg, respectively. Both Sch B and SFO increased serum TG (up to 427% and 123%, respectively), with the values of E_max =5.50/4.60 mmol/L and K_D =0.43/2.84 g/kg, respectively.

Conclusion

The findings indicated that Sch B/SFO-induced increases in serum/hepatic parameters occurred in a time-dependent manner, with the time of onset being serum TG level < hepatic TG level < hepatic index < serum ALT activity. However, the time of recovery of these parameters to normal values varied as follow: serum TG level < hepatic TG level and liver injury < hepatic index. The E_max and affinity of Sch B on tissue/enzyme/receptor were larger than those of SFO.

Novel mouse model of combined hyperlipidemia associated with steatosis and liver injury by a single-dose intragastric administration of schisandrin B/cholesterol/bile salts mixture

Hyperlipidemia is referred to as hypercholesterolemia, hypertriglyceridemia, or both in combined hyperlipidemia. Here, a novel mouse model of combined hyperlipidemia is described. Mice were orally given a single dose of a modeling agent (MA) made of a mixture of schisandrin B/cholesterol/bile salts (1/2/0.5 g/kg) suspended in olive oil. MA treatment increased serum triglycerides (TG) and total cholesterol (TC) (up to 422% and 100% at 12 - 96 h post-treatment, respectively) and hepatic TG and TC (up to 220% and 26%, respectively) in a time- and dose-dependent manner, associated with elevation of high-density lipoprotein and low-density lipoprotein levels. Serum alanine/aspartate aminotransferase activities, indicators of liver cell damage, were also elevated (up to 198%) at 48 and 72 h post-MA treatment. Fenofibrate blocks MA-induced hyperlipidemia, lipid accumulation in the liver, as well as liver injury. Oral administration of a mixture of schisandrin B, cholesterol, and bile salt could generate an interesting mouse model of combined hyperlipidemia associated with hepatic steatosis and steatohepatitis.

Dietary Fructus Schisandrae extracts and fenofibrate regulate the serum/hepatic lipid-profile in normal and hypercholesterolemic mice, with attention to hepatotoxicity

Background

Schisandra, a globally distributed plant, has been widely applied to health care products. Here, we investigated the effects of dietary intake of Fructus Schisandrae chinensis (FSC), both aqueous and ethanolic extracts (AqFSC, EtFSC), on serum/hepatic lipid contents in normal diet (ND)- and high-fat/cholesterol/bile salt diet (HFCBD)-fed mice.

Methods

Male ICR mice were fed with ND or HFCBD, supplemented with 1 and 4% of AqFSC and EtFSC, respectively, or 0.1% fenofibrate, for 13 days. Lipids were determined according to the manufacture’s instructions.

Results

EtFSC, but not AqFSC, significantly elevated hepatic triglyceride (TG) in mice fed with ND. Feeding mice with HFCBD increased serum total cholesterol (TC), high density lipoprotein (HDL) and low density lipoprotein (LDL) levels as well as alanine aminotransferase (ALT) activity. Supplementation with AqFSC, EtFSC or fenofibrate significantly reduced hepatic TC and TG levels. However, AqFSC and EtFSC supplementation increased serum HDL and LDL levels in mice fed with HFCBD. Fenofibrate increased serum HDL and reduced serum LDL contents in hypercholesterolemic mice. EtFSC reduced, but fenofibrate elevated, serum ALT activity in both normal and hypercholesterolemic mice. While fenofibrate reduced serum TC, TG, and HDL levels in mice fed with ND, it increased serum HDL and reduced serum LDL and TC levels in mice fed with HFCBD. Hepatomegaly was found in normal and hypercholesterolemic mice fed with diet supplemented with fenofibrate.

Conclusions

Feeding mice with AqFSC and EtFSC ameliorated the HFCBD-induced hepatic steatosis. In addition, EtFSC may offer protection against hepatic injury in hypercholesterolemic mice.

Schizandrin prevents dexamethasone-induced cognitive deficits

OBJECTIVE

To model glucocorticoid-induced cognitive impairment and evaluate the neuroprotection by schizandrin (Sch) against dexamethasone (Dex)-induced neurotoxicity in vivo and in vitro.

METHODS

Cerebral cortical cells from neonatal Sprague-Dawley rats (within 24 hours after birth) were cultured for 9 days, and then treated with Dex (10(-4), 10(-5), 10(-6) or 10(-7) mol/L) for 24 h or pretreated with 10(-4) mol/L Dex for 24 h followed by 10, 20, 40, or 80 μmol/L Sch for 48 h. Cell viability was assessed using the MTT assay. Immunofluorescence and real-time PCR for MAP2 were performed to confirm the effects of Dex on neurite outgrowth. In vivo, kunming mice were randomly divided into six groups: control [(intragastric (i.g.) vehicle for 42 days]; Dex group I (5 mg/kg · d(-1) Dex i.g. treatment for 28 days followed by i.g. vehicle for 14 days); Dex group II (Dex i.g. for 42 days); Dex + Sch (Dex i.g. for 28 days followed by 5, 15, or 45 mg/kg · d(-1) Sch i.g. for 14 days). Learning and memory were assessed by Morris water maze test. Histological examination was used to assess pathology and apoptosis in neurons.

RESULTS

Compared to the Dex groups, Sch increased cell viability in a dose-dependent manner, improved performance in the Morris water maze and ameliorated the morphological changes.

CONCLUSION

Sch has neuroprotective effects against insults induced by glucocorticoid.

Schisandrin B as a hormetic agent for preventing age-related neurodegenerative diseases

Oxidative stress and mitochondrial dysfunction have been implicated in the pathogenesis of neurodegenerative diseases, with the latter preceding the appearance of clinical symptoms. The energy failure resulting from mitochondrial dysfunction further impedes brain function, which demands large amounts of energy. Schisandrin B (Sch B), an active ingredient isolated from Fructus Schisandrae, has been shown to afford generalized tissue protection against oxidative damage in various organs, including the brain, of experimental animals. Recent experimental findings have further demonstrated that Sch B can protect neuronal cells against oxidative challenge, presumably by functioning as a hormetic agent to sustain cellular redox homeostasis and mitoenergetic capacity in neuronal cells. The combined actions of Sch B offer a promising prospect for preventing or possibly delaying the onset of neurodegenerative diseases, as well as enhancing brain health.