Regular ArticleAntioxidative and Protective Properties of Extracts from Leaves of the Artichoke (Cynara scolymus L.) against Hydroperoxide-Induced Oxidative Stress in Cultured Rat Hepatocytes
Abstract
Primary rat hepatocyte cultures exposed totert-butylhydroperoxide (t-BHP) or cumene hydroperoxide were used to assess the antioxidative and protective potential of water-soluble extracts of artichoke leaves. Both hydroperoxides stimulated the production of malondialdehyde (MDA), particularly when the cells were pretreated with diethylmaleate (DEM) in order to diminish the level of cellular glutathione (GSH). Addition of artichoke extracts did not affect basal MDA production, but prevented the hydroperoxide-induced increase of MDA formation in a concentration-dependent manner when presented simultaneously or prior to the peroxides. The effective concentrations (down to 0.001 mg/ml) were well below the cytotoxic levels of the extracts which started above 1 mg/ml. The protective potential assessed by the LDH leakage assay and the MTT assay closely paralleled the reduction in MDA production and largely prevented hepatocyte necrosis induced by the hydroperoxides. The artichoke extracts did not affect the cellular level of glutathione (GSH), but diminished the loss of total GSH and the cellular leakage of GSSG resulting from exposure tot-BHP. Chlorogenic acid and cynarin accounted for only part of the antioxidative principle of the extracts which was resistent against tryptic digestion, boiling, acidification, and other treatments, but was slightly sensitive to alkalinization. These results demonstrate that artichoke extracts have a marked antioxidative and protective potential. Primary hepatocyte cultures seem suitable for identifying the constituents responsible for these effects and for elucidating their possible mode of action.
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Valorization of unexploited artichoke leaves dust for obtaining of extracts rich in natural antioxidants
2021, Separation and Purification TechnologyThis study has developed an improved and fast microwave-assisted procedure for extraction of high yields of natural antioxidants from artichoke leaves dust. The material is derived as an abundant residue remained after processing for the industrial tea blends preparation, having no commercial value.
A key factors for optimization of the total polyphenolic (TPC) and flavonoid content (TFC) and antioxidant activities have been determined by using single factor experiments along with a response surface methodology. The optimal conditions for maximizing the combination of TPC/TFC and antioxidant activity were obtained as follows: ethanol concentration 67.81%, extraction time 50 s, liquid/solid ratio 41.78 mL/g, microwave power 180 W, whereas the corresponding responses resulted in: TPC − 205.59 ± 7.30 mg GAE/g dw, TFC − 79.75 ± 1.12 mg QE/g dw, and FRAP −1008.14 ± 37.15 mmolFe2+/g dw. Only 14.7 µg/mL of the extract concentration is required to inhibit 50% of DPPH free radicals.
A comparative study confirmed that the proposed procedure yielded higher TPC, TFC and antioxidant activities than available extraction methods. It highlights a several fold reduced extraction time, caring an eco-friendly principle for obtaining of antioxidants from industrial, medicinal crop residues, which would be further easily valorized in food and pharmaceutical industry.
Comparative biochemical and histopathological evaluations proved that receptacle is the most effective part of Cynara scolymus against liver and kidney damages
2020, Journal of EthnopharmacologyThe liver and kidney are among the most important organs in the body, where metabolic and elimination functions take place. During this process, liver and kidneys may suffer damage due to ingestion or formation of toxic metabolites leading to organ loss and even death. Artichoke (Cynara scolymus L.) leaf has long been recognized as a popular herbal remedy in traditional medicines with beneficial effects on liver.
In phytotherapy leaves are the part used to support the liver functions and for treatment of damage induced by various toxins, while fleshy receptacle is cooked as meal to support liver homeostasis. However, effects of other plant parts on liver such as stems, bracts have not much attracted the attention of scientific community so far. In this study we investigated comparatively the hepatoprotective and nephroprotective effects of different plant parts of artichoke, i.e. receptacles, outer bracts, inner bracts, and stems with that of leaves upon paracetamol-induction in rats.
Aqueous ethanol (80%) extracts obtained from the different parts of artichoke were administered for five consecutive days after paracetamol induction to rats. At the end of experimental period blood samples from the experimental animals were taken for biochemical tests, while livers and kidneys were removed for further histopathological evaluation.
The histopathological examinations of liver and kidney tissues revealed that the receptacle and stem extracts of the artichoke were the most effective parts by improving the experimentally induced pathology in both liver and kidney. Biochemical tests also supported the histopathological data; receptacle, stem and bract extracts reduced serum alanine transaminase (ALT) and aspartate transaminase (AST) levels, but not alkaline phosphatase (ALP), creatinine and blood urea nitrogen (BUN) levels.
Histopathological and biochemical studies have shown that receptacle and stem extracts of artichoke were found to exert higher protective activity on liver and kidney damage induced by paracetamol comparing to its bract and leaf extracts, the latest is officially recognized as herbal remedy.
Artichoke leaf extract and use in metabolic syndrome as an antioxidant
2020, Pathology: Oxidative Stress and Dietary AntioxidantsOxidative stress (OS), an imbalance between prooxidants and antioxidants, may play a role in the pathophysiology of metabolic syndrome. There is debate about whether OS is causal or merely associated to metabolic syndrome. Substantial evidence indicated the importance of the potential natural antioxidants in the restoration of impaired redox state in patients with metabolic syndrome. Artichoke leaf extract (ALE), an extract from the antioxidant-rich herb, is potentially involved in the prevention and treatment of free radical–related diseases mainly by neutralization of reactive oxygen species (ROS) formed during oxidative damage, and improving the antioxidant defense system. A recent meta-analysis of animal studies demonstrated the antioxidant activity of ALE in experimentally induced disease. Indeed, the supplementation with ALE resulted in decreased concentration of oxidized low-density lipoprotein (ox-LDL) in patients with metabolic syndrome. The mechanisms involved in the antioxidant properties of ALE are complex and multifactorial. Although, the antioxidant capacity of ALE has been demonstrated in experimental studies, there are limited human studies in patients with metabolic syndrome.
The interaction of FTO-rs9939609 polymorphism with artichoke leaf extract effects on cardiometabolic risk factors in hypertriglyceridemia: A randomized clinical trial
2019, Advances in Integrative MedicineHypertriglyceridemia is associated with an increased risk of cardiovascular disease. The potential favorable effects of artichoke leaf extract (ALE) on anthropometric and metabolic indices may affect by fat mass and obesity associated (FTO)-rs9939609 polymorphism. This study was designed to evaluate the effects of ALE supplementation on cardiometabolic risk factors in hypertriglyceridemic patients regarding the interaction of rs9939609-FTO polymorphism with intervention outcomes.
In this double-blind placebo-controlled randomized clinical trial, 52 patients with hypertriglyceridemia randomly allocated to receive ALE (1800 mg/day as four tablets) or matching placebo (consisting of corn starch, lactose, and avicel) for 12 weeks. The measurement of anthropometric indices, fasting blood sugar (FBS), and lipid profile was performed before and after the intervention. The FTO-rs9939609 polymorphism was genotyped by polymerase chain reaction-restriction length polymorphism (PCR-RFLP). The interaction was tested using two-way ANOVA.
Forty-eight patients completed the trial (intervention, n = 24, placebo = 24). ALE and placebo groups were similar in the baseline characteristics. ALE supplementation did not change anthropometric indices and metabolic parameters. However, there was a significant interaction between FTO-rs9939609 polymorphism and TC, LDL-C, and TG level response to ALE supplementation. Moreover, significant changes in TG level were observed in A allele carriers compared to subjects with TT genotype.
No significant effect of ALE supplementation was shown on anthropometric and biochemical indices in Iranian hypertriglyceridemic patients. However, rs9939609 variant of FTO gene seems to affect lipid profile response to ALE supplementation. Further clinical trials with larger sample size are suggested to clarify the possible interaction between rs9939609 variant or other variants of FTO gene and ALE supplementation in hypertriglyceridemia.
Contribution of human UDP-glucuronosyltransferases to the antioxidant effects of propolis, artichoke and silymarin
2019, PhytomedicineThe popularity of herbal medicines is rapidly increasing in many countries including the Western world where many individuals turn to natural products, because they promise a safe and natural remedy for a broad variety of health disorders or the prevention of disease development. Although therapy with a number of herbal products has demonstrated a promising potential and efficacy, insufficient information exists concerning their pharmacodynamics, pharmacokinetics and mode of action.
Aim of this study was to examine the role of human detoxifying UDP-glucuronosyltransferases (UGTs) in the mechanism underlying the protective antioxidant effects reported for propolis, artichoke and silymarin.
UGT1A induction was analyzed by reporter gene assays, siRNA mediated knockdown and enzyme activity assays. Antioxidant activity was measured using a hydrogen peroxide colorimetric assay.
We identified propolis, artichoke and silymarin as potent activators of UGT1A transcription and enzyme activity in KYSE70 cells mediated by aryl hydrocarbon receptor AhR and nuclear factor E2-related factor 2 (Nrf2) signaling. Propolis, artichoke and silymarin significantly decreased tertiary butylhydroquinone (tBHQ)-induced hydrogen peroxide levels. This protective effect was significantly reduced by siRNA mediated knockdown of UGT1A expression.
In conclusion, this study provides a possible molecular mechanism for protective antioxidant effects associated with the herbal drugs propolis, artichoke and silymarin. The herbal drug-mediated transcriptional upregulation of human detoxifying UGT1A enzymes via activation of AhR and Nrf2 leads to reduced hydrogen peroxide and oxidative stress. Because of UGT1A activation, the intake of these drugs could affect the therapeutic efficacy of other drugs when these also undergo metabolism by glucuronidation.
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Correspondence should be addressed to the author at Physiologisch-chemisches Institut, University of Tübingen, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany. Fax: +49 / 7071 / 296390.