Investigation of the in vivo antioxidative activity of Cynara scolymus (artichoke) leaf extract in the streptozotocin-induced diabetic rat

An Overview of the Versatility of the Parts of the Globe Artichoke (Cynara scolymus L.), Its By-Products and Dietary Supplements

Cynara scolymus, also known as the globe artichoke or artichoke, is grown as a food, mainly in the Mediterranean, Canary Islands, and Egypt, as well as in Asia and South America. It has also been associated with various health benefits and is used in plant-based dietary supplements and herbal infusions. Its edible parts, consisting of the head or capitula, flower, and leaves, have shown various biological activities, including anti-cancer, hepatoprotective and antimicrobial potential. The leaves are mainly used in infusions and extracts for their health-promoting properties, although all their edible parts may also be consumed as fresh, frozen, or canned foods. However, its primary health-promoting activity is associated with its antioxidant potential, which has been linked to its chemical composition, particularly its phenolic compounds (representing 96 mg of gallic acid equivalent per 100 g of raw plant material) and dietary fiber. The main phenolic compounds in the heads and leaves are caffeic acid derivatives, while the flavonoids luteolin and apigenin (both present as glucosides and rutinosides) have also been identified. In addition, heat-treated artichokes (i.e., boiled, steamed or fried), their extracts, and waste from artichoke processing also have antioxidant activity. The present paper reviews the current literature concerning the biological properties of different parts of C. scolymus, its by-products and dietary supplements, as well as their chemical content and toxicity. The literature was obtained by a search of PubMed/Medline, Google Scholar, Web of Knowledge, ScienceDirect, and Scopus, with extra papers being identified by manually reviewing the references.

Water extract from artichoke ameliorates high-fat diet-induced non-alcoholic fatty liver disease in rats

BACKGROUND

The "multiple-hit" hypothesis is currently the most widely accepted theory for non-alcoholic fatty liver disease (NAFLD) pathogenesis. The present study aimed to investigate the effects of the water extract of artichoke (WEA) on NAFLD and its underlying mechanism.

METHODS

Rats were fed a high-fat diet (HFD) for 8 weeks to induce NAFLD and then treated with WEA at three doses (0.4, 0.8, and 1.6 g/kg body weight, BW) for 8 weeks. At the end of the intervention, serum biochemical parameters, hepatic antioxidant capacity, hepatic levels of pro-inflammatory cytokines, liver histopathology, hepatic inflammatory gene and lipid metabolism gene expression, and Akt and p-Akt (S473) protein levels were determined.

RESULTS

The body weight, liver weight, liver triglyceride (TG) and serum levels of TG, total cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, glucose, and insulin were all significantly reduced in the WEA-treated groups (0.8 and 1.6 g/kg BW) compared with the HFD group (P < 0.01). A significant decrease in hepatic content of malondialdehyde (P < 0.01) and glutathione (P < 0.01), as well as a significant increase in liver superoxide dismutase activity (P < 0.01) were observed in WEA-treated groups (0.8 and 1.6 g/kg BW) compared to the HFD group. In addition, there was a marked decrease in the hepatic levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in the WEA-treated groups compared to the HFD group (P < 0.01). In line with these findings, the histopathology of the livers of rats treated with WEA (0.8 and 1.6 g/kg BW) showed a decrease in steatosis, ballooning, and lobular inflammation. Mechanistically, the reduced hepatic TG content might be related to the downregulation of lipogenic genes (SREBP1c, FASN, SCD1) and upregulation of lipolytic gene (PPARα), and the improved insulin signaling might be associated with the observed increase in antioxidant activity and reduction in inflammation in the WEA-treated groups.

CONCLUSION

The hepatoprotective role of WEA in NAFLD may be attributed to its anti-steatotic, antioxidant, anti-inflammatory, and anti-insulin resistance effects.

Therapeutic Effects of Milk Thistle (Silybum marianum L.) and Artichoke (Cynara scolymus L.) on Nonalcoholic Fatty Liver Disease in Type 2 Diabetic Rats

BACKGROUND

At present, nonalcoholic fatty liver disease (NAFLD) does not have an approved pharmacologic therapy. The present study investigated the protective effects and possible mechanisms of milk thistle (Silybum marianum L.) and artichoke (Cynara scolymus L.) in treating NAFLD in type 2 diabetic rats.

METHODS

The NAFLD was established in rats after four weeks of type 2 diabetes induction. The animals were treated with pharmaceutical preparations of milk thistle (Livergol®) and artichoke (Atheromod-B®) extracts for eight weeks. After the end of the intervention, oral glucose tolerance, the serum parameters of oxidative stress, liver functional tests, and lipid profiles were evaluated. Histopathological changes were assessed by hematoxylin and eosin staining.

RESULTS

Treatment with preparations of milk thistle and artichoke nonsignificantly improved glucose tolerance in diabetic rats. Both preparations significantly improved serum superoxide dismutase activity and the level of malondialdehyde. Although treatment with milk thistle reduced serum activity of aspartate aminotransferase and serum levels of triglyceride (TG), total cholesterol, and low-density lipoprotein-cholesterol, artichoke extracts only attenuated the serum level of TG. Milk thistle also effectively protected the liver from histological changes.

CONCLUSIONS

Milk thistle could be a promising pharmacological option for the treatment of NAFLD. Nonetheless, long-term randomized clinical trials are necessary to confirm the observed results.

Oxidative stress and immune aberrancies in attention-deficit/hyperactivity disorder (ADHD): a case-control comparison

The objective of this study is to compare oxidative stress and immune biomarkers between attention-deficit/hyperactivity disorder (ADHD) patients and controls without ADHD. A case-control comparison between 57 paediatric (6-12 years) untreated ADHD patients from the Antwerp University Hospital and 69 controls without ADHD from random schools in Flanders, Belgium, was conducted. Erythrocyte glutathione (GSH) and plasma lipid-soluble antioxidants (retinol, α-tocopherol, γ-tocopherol, retinyl palmitate, β-carotene, and co-enzyme Q10) were determined by HPLC with electrochemical detection, plasma malondialdehyde (MDA) by HPLC with fluorescence detection, plasma cytokines (interleukin (IL)-1β, IL-5, IL-6, IL-8, IL-10, tumour necrosis factor (TNF) and interferon (INF)-γ) and immunoglobulins (IgE, IgG and IgM) by flow cytometry and urinary 8-hydroxy-2'deoxyguanosine (8-OHdG) levels by ELISA assay. Dietary habits were determined by a food frequency questionnaire. Plasma MDA levels were on average 0.031 µM higher in patients than in controls (p < 0.05), and a trend for higher urinary 8-OHdG was observed. Erythrocyte GSH and plasma retinyl palmitate levels, as well as IgG and IgE levels, were higher in patients than in controls as well (on average 93.707 µg/ml, 0.006 µg/ml, 301.555 µg/ml and 125.004 µg/ml, resp., p < 0.05). Finally, a trend for lower plasma IL-5 levels was observed. After Bonferroni correction for multiple testing, the difference in GSH levels remained statistically significant (nominally significant for retinyl palmitate), while significance was lost for MDA, IgG and IgE levels. Dietary habits do not appear to cause the observed differences. These results point at the potential involvement of slight oxidative stress and immune disturbances in ADHD.

The antioxidant activity of artichoke (Cynara scolymus): A systematic review and meta-analysis of animal studies

Current evidence has shown antioxidant activity of artichoke as a potent source of antioxidant compounds. However, it seems that the antioxidant activity of artichoke has not yet been reviewed. Therefore, the present study was designed to perform a systematic review of human studies, animal models, and in vitro systems and to conduct a meta-analysis of animal studies on the antioxidant effects of artichoke. We searched four electronic databases till April 2018 using relevant keywords. All English language articles were assessed. For animal studies, standardized mean difference was pooled using a random effects model. The included studies were evaluated for eligibility and risk of bias. Thirty-nine articles (two human, 23 animal, and 14 in vitro studies) were reviewed. The results of in vitro systems supported the antioxidant effect of artichoke, whereas limited clinical trials indicated no change or a slight improvement of antioxidant status. Finding of animal studies indicated that artichoke extract supplementation increased superoxide dismutase, catalase, glutathione, and glutathione peroxidase level in liver, as well as, decreased malondialdehyde level in liver and plasma of animals with induced disease significantly compared with comparison group. This meta-analysis provided convincing evidence for antioxidant activity of artichoke in animals.

Luteolin-Enriched Artichoke Leaf Extract Alleviates the Metabolic Syndrome in Mice with High-Fat Diet-Induced Obesity

This current study aimed to elucidate the effects and possible underlying mechanisms of long-term supplementation with dietary luteolin (LU)-enriched artichoke leaf (AR) in high-fat diet (HFD)-induced obesity and its complications (e.g., dyslipidemia, insulin resistance, and non-alcoholic fatty liver disease) in C57BL/6N mice. The mice were fed a normal diet, an HFD, or an HFD plus AR or LU for 16 weeks. In the HFD-fed mice, AR decreased the adiposity and dyslipidemia by decreasing lipogenesis while increasing fatty acid oxidation, which contributed to better hepatic steatosis. LU also prevented adiposity and hepatic steatosis by suppressing lipogenesis while increasing biliary sterol excretion. Moreover, AR and LU prevented insulin sensitivity by decreasing the level of plasma gastric inhibitory polypeptide and activity of hepatic glucogenic enzymes, which may be linked to the lowering of inflammation as evidenced by the reduced plasma interleukin (IL)-6, IL-1β, and plasminogen activator inhibitor-1 levels. Although the anti-metabolic syndrome effects of AR and LU were similar, the anti-adiposity and anti-dyslipidemic effects of AR were more pronounced. These results in mice with diet-induced obesity suggest that long-term supplementation with AR can prevent adiposity and related metabolic disorders such as dyslipidemia, hepatic steatosis, insulin resistance, and inflammation.

Prophylactic role of coenzyme Q10 and Cynara scolymus L on doxorubicin-induced toxicity in rats: Biochemical and immunohistochemical study

Objective:

The study aims to evaluate the protective effects of coenzyme Q10 (CoQ10) and Cynara scolymus L (CS) on doxorubicin (dox)-induced toxicity.

Materials and Methods:

Sixty male rats were divided into six groups. Group 1 as a control. Group 2 received dox (10 mg/kg) intraperitoneally. Group 3 received CoQ10 (200 mg/kg). Group 4 received CS (500 mg/kg). Group 5 received CoQ10 (200 mg/kg) and dox (10 mg/kg). Group 6 received CS (500 mg/kg) and dox (10 mg/kg). The rats were then evaluated biochemically and immunohistochemically.

Results:

Dox produced a significant deterioration of hepatic and renal functional parameters. Moreover, an upsurge of oxidative stress and nitrosative stress markers. The expression of alpha-smooth muscle actin (α-SMA) was increased and proliferating cell nuclear antigen (PCNA) expression was decreased. Administration of CoQ10 and CS resulted in a significant improvement of hepatic and renal functional parameters, and an improvement of both α-SMA and PCNA.

Conclusion:

It is concluded that pretreatment with CoQ10 and CS is associated with up-regulation of favorable protective enzymes and down-regulation of oxidative stress. That can be advised as a supplement to dox-treated patients.

Cynaropicrin attenuates UVB-induced oxidative stress via the AhR-Nrf2-Nqo1 pathway

Due to its antioxidant and anti-inflammatory activities, artichoke (Cynara scolymus) has been used as folk medicine to treat various diseases. Cynaropicrin (Cyn), a sesquiterpene lactone, is the major bioactive phytochemical in the artichoke; however, its pharmacological mechanism remains unknown. Because some phytochemicals exert their antioxidant activity by activating aryl hydrocarbon receptor (AhR), leading to subsequent induction of the antioxidant pathway including nuclear factor E2-related factor 2 (Nrf2) and

NAD(P)H

quinone oxidoreductase 1 (Nqo1), we investigated whether Cyn also activates the AhR-Nrf2-Nqo1 pathway. Cyn indeed induced the activation (nuclear translocation) of AhR, leading to nuclear translocation of Nrf2 and dose-dependent upregulation of Nrf2 and Nqo1 mRNAs in human keratinocytes. The Cyn-induced AhR-Nrf2-Nqo1 activation was AhR- and Nrf2-dependent, as demonstrated by the observation that it was absent in keratinocytes transfected by siRNA against either AhR or Nrf2. In accordance with these findings, Cyn actively inhibited generation of reactive oxygen species from keratinocytes irradiated with ultraviolet B (UVB) in a Nrf2-dependent manner. Cyn also inhibited the production of proinflammatory cytokines such as interleukin 6 and tumor necrosis factor-α from UVB-treated keratinocytes. Our findings demonstrate that Cyn is a potent activator of the AhR-Nrf2-Nqo1 pathway, and could therefore be applied to prevention of UVB-induced photo aging.

Artichoke, cynarin and cyanidin downregulate the expression of inducible nitric oxide synthase in human coronary smooth muscle cells

Artichoke (Cynara scolymus L.) is one of the world’s oldest medicinal plants with multiple health benefits. We have previously shown that artichoke leaf extracts and artichoke flavonoids upregulate the gene expression of endothelial-type nitric oxide synthase (eNOS) in human endothelial cells. Whereas NO produced by the eNOS is a vasoprotective molecule, NO derived from the inducible iNOS plays a pro-inflammatory role in the vasculature. The present study was aimed to investigate the effects of artichoke on iNOS expression in human coronary artery smooth muscle cells (HCASMC). Incubation of HCASMC with a cytokine mixture led to an induction of iNOS mRNA expression. This iNOS induction was concentration- and time-dependently inhibited by an artichoke leaf extract (1–100 µg/mL, 6 h or 24 h). Consistently, the artichoke leaf extract also reduced cytokine-induced iNOS promoter activation and iNOS protein expression. In addition, treatment of HCASMC with four well-known artichoke compounds (cynarin > cyanidin > luteolin ≈ cynaroside) led to a downregulation iNOS mRNA and protein expression, with cynarin being the most potent one. In conclusion, artichoke contains both eNOS-upregulating and iNOS-downregulating compounds. Such compounds may contribute to the beneficial effects of artichoke and may per se have therapeutic potentials.