Ethanol Extract of Cirsium japonicum var. ussuriense Kitamura Exhibits the Activation of Nuclear Factor Erythroid 2-Related Factor 2-dependent Antioxidant Response Element and Protects Human Keratinocyte HaCaT Cells Against Oxidative DNA Damage

Research progress on skin photoaging and oxidative stress

Skin photoaging, which is a kind of exogenous aging, refers to skin elasticity degradation, skin roughening, and wrinkle formation processes because of cascading reactions of a series of kinases after growth factor receptors and cytokine receptors are activated on a cell surface under the UV effect. An extensively recognized skin photoaging mechanism is free radical-oxidative stress concept, proposed by Sohal who represents the authority of the US aging studies. Over the past decade, many new developments in the oxidative stress mechanism have been achieved in terms of the occurrence, development, prevention, and treatment of photodamage.

Current evidence to support the therapeutic potential of flavonoids in oxidative stress-related dermatoses

BACKGROUND

Skin, as a crucial external defense organ, is more vulnerable to oxidative stress (OS) insult, reactive oxygen species (ROS)-mediated OS in particular. OS results from a redox imbalance caused by various extrinsic stimuli and occurs once the oxidants production overwhelming the antioxidants capacity, through mediating in DNA damage, lipid peroxidation (LPO), protein oxidation and a serial of signaling pathways activation/inactivation, thereby offering favorable conditions for the occurrence and development of numerous diseases especially some dermatoses, e.g. psoriasis, vitiligo, skin photodamage, skin cancer, systemic sclerosis (SSc), chloasma, atopic dermatitis (AD), pemphigus, etc. Targeting OS molecular mechanism, a variety of anti-OS agents emerge, in which flavonoids, natural plant extracts, stand out.

OBJECTIVES

To discuss the possible mechanisms of OS mediating in dermatoses and summarize the properties of flavonoids as well as their applications in OS-related skin disorders.

METHODS

Published papers on flavonoids and OS-related skin diseases were collected and reviewed via database searching on PubMed, MEDLINE and Embase, etc.

RESULTS

It has been confirmed that flavonoids, belonging to polyphenols, are a class of plant secondary metabolites widely distributed in various plants and possess diverse bioactivities especially their potent antioxidant capacity. Moreover, flavonoids benefit to suppress OS via eliminating free radicals and mediating the corresponding signals, further excellently working in the prevention and management of OS-related skin diseases.

CONCLUSION

Flavonoids have the potential therapeutic effects on oxidative stress-related dermatoses. However, more studies on specific mechanism as well as the dosage of flavonoids are needed in future.

Comparison of the Hepatoprotective Effects of Four Endemic Cirsium Species Extracts from Taiwan on CCl₄-Induced Acute Liver Damage in C57BL/6 Mice

Species of Cirsium (Asteraceae family) have been used in folk hepatoprotective medicine in Taiwan. We collected four Cirsium species—including the aerial part of Cirsium arisanense (CAH), the aerial part of Cirsium kawakamii (CKH), the flower part of Cirsium japonicum DC. var. australe (CJF), and Cirsii Herba (CH)—and then made extractions from them with 70% methanol. We compared the antioxidant contents and activities of these four Cirsium species extracts by a spectrophotometric method and high-performance liquid chromatography⁻photodiode array detector (HPLC-DAD). We further evaluated the hepatoprotective effects of these extracts on CCl₄-induced acute liver damage in C57BL/6 mice. The present study found CAH possesses the highest antioxidant activity among the four Cirsium species, and these antioxidant activities are closely related to phenylpropanoid glycoside (PPG) contents. The extracts decreased serum ALT and AST levels elevated by injection with 0.2% CCl₄. However, only CJF and CH decreased hepatic necrosis. Silibinin decreased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and hepatic necrosis caused by CCl₄. CJF and CH restored the activities of hepatic antioxidant enzymes and decreased hepatic malondialdehyde (MDA) levels. CJF further restored the expression of hepatic antioxidant enzymes including Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-superoxide dismutase (Mn-SOD), and glutathione S-transferase (GST) proteins. HPLC chromatogram indicated that CKH, CJF, and CH contained silibinin diastereomers (α and β). Only CJF contained diosmetin. Hence, the hepatoprotective mechanism of CJF against CCl₄-induced acute liver damage might be involved in restoring the activities and protein expression of the hepatic antioxidant defense system and inhibiting hepatic inflammation, and these hepatoprotective effects are related to the contents of silibinin diastereomers and diosmetin.

E-p-Methoxycinnamoyl-α-l-rhamnopyranosyl Ester, a Phenylpropanoid Isolated from Scrophularia buergeriana, Increases Nuclear Factor Erythroid-Derived 2-Related Factor 2 Stability by Inhibiting Ubiquitination in Human Keratinocytes

The nuclear factor erythroid-derived 2-related factor 2 (Nrf2) is a key regulator of gene expression during oxidative stress and drug detoxification. Thus, identifying Nrf2 activators to protect from possible cell damage is necessary. In this study, we investigated whether E-p-methoxycinnamoyl-α-l-rhamnopyranosyl ester (MCR), a phenylpropanoid isolated from Scrophularia buergeriana, can activate Nrf2 signaling in human keratinocytes (HaCaT). First, we determined the dose- and time-dependent effects of MCR on the expression and activity of Nrf2. The antioxidant response element-luciferase reporter assay and western blot analysis results showed that MCR markedly induced Nrf2 activity and its protein expression, respectively. Further, MCR increased both the mRNA and protein levels of heme-oxygenase-1, one of the Nrf2 target genes, in the cells. Interestingly, we found that Nrf2 stability was remarkably enhanced by MCR. Furthermore, ubiquitin-dependent proteasomal degradation of Nrf2 was significantly reduced by MCR. Thus, MCR might afford skin protection by enhancing Nrf2 stability or by blocking its proteasomal degradation.

Hispidulin-7-O-Neohesperidoside from Cirsium japonicum var. ussuriense Attenuates the Production of Inflammatory Mediators in LPS-Induced Raw 264.7 Cells and HT-29 Cells

Background:

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract and involves secretion of inflammatory mediators. The flavone diglycoside hispidulin-7-O-neohesperidoside (HN) isolated from the methanolic extract of aerial parts of Cirsium japonicum var. ussuriense, but its pharmacologic activities, with the exception of alleviation of alcohol toxicity, have not been investigated to date.

Objective:

The aim of the present study was to investigate the anti-inflammatory activities of HN for the treatment of chronic inflammatory illnesses, including IBD.

Materials and Methods:

In lipopolysaccharide (LPS)-induced RAW264.7 cells and HT-29 cells, the effects of HN on cell viability and nitric oxide (NO) production were examined via MTT assay and the Griess reaction, respectively. The expression levels of interleukin (IL)-1α, IL-8, and tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) protein levels were measured by enzyme-linked immunosorbent assay and Western blotting, respectively.

Results:

HN concentration-dependently inhibited NO production in LPS-induced RAW 264.7 cells. Treatment with HN considerably downregulated the levels of the pro-inflammatory cytokines, IL-1β and TNF-α and the iNOS protein level in LPS-induced RAW 264.7 cells. Furthermore, HN inhibited the production of the chemotactic cytokine, IL-8, in LPS-induced HT-29 cells.

Conclusion:

HN has potential as an anti-inflammatory agent to prevent and/or treat IBD.

SUMMARY

Hispidulin-7-O-neohesperidoside (HN) is flavone diglycoside isolated from the methanolic extract of aerial parts of Cirsium japonicum var. ussuriense.

HN concentration-dependently inhibited NO production and considerably downregulated the levels of the proinflammatory cytokines, IL-1β and TNF-α, and the iNOS protein level in LPS-induced RAW 264.7 cells.

HN inhibited the production of the chemotactic cytokine, IL-8, in LPS-induced HT-29 cells.

HN has potential as an anti-inflammatory agent to prevent and/or treat IBD.

Abbreviations used: IBD: Inflammatory bowel disease, HN: hispidulin-7-O-neohesperidoside, LPS: lipopolysaccharide, NO: nitric oxide, IL: interleukin, TNF: tumor necrosis factor, iNOS: inducible nitric oxide synthase, CD: Crohn's disease, UC: ulcerative colitis, RT: room temperature, DMEM: Dulbecco's modified Eagle's medium, FBS: fetal bovine serum, PBS: phosphate buffered saline, SDS: sodium dodecyl sulfate, PVDF: polyvinylidene difluoride, SD: standard deviation

Effects of Hypericum Scabrum extract on anxiety and oxidative stress biomarkers in rats fed a long-term high-fat diet

The continuous and long-term consumption of a high-fat diet (HFD) leads to weight gain and obesity. A HFD and obesity increase the risks of psychiatric disorders, such as anxiety and depression. In this study, we investigated the effects of a Hypericum Scabrum (H. scabrum) extract, which is an antioxidant, on anxiety in rats fed a long-term HFD. Sixty male Wistar rats were divided into the following six groups: (1) Control (standard diet), (2) Ext100 [standard diet supplemented with extract (100 mg/kg once/day)], (3) Ext300 [standard diet supplemented with extract (300 mg/kg once/day)], (4) HFD, (HFD), (5) HFD + Ext100, and (6) HFD + Ext300. The groups were fed their diet for 3 months. Anxiety was measured with the elevated plus-maze test. At the end of the study, blood samples were taken, and biochemical parameters and oxidative stress biomarker levels were determined in the plasma. Compared to the control group, the HFD group exhibited significant decreases in both the time in the open arms and number of entries into the open arms. H. scabrum extract supplementation significantly increased these parameters in the HFD-fed groups. The HFD significantly increased serum malondialdehyde levels and significantly decreased total glutathione levels, while H. scabrum extract supplementation significantly reversed these parameters. In conclusion, these results showed that a HFD increased anxiety behavior. In contrast, H. scabrum extract supplementation had anxiolytic effects and reversed the effects of the HFD, which suggested that the effects of H. scabrum extract supplementation were due to its strong antioxidant properties.