Influence of treatment of diabetic rats with combinations of pycnogenol, ?-carotene, and ?-lipoic acid on parameters of oxidative stress

Diabetic Keratopathy: Redox Signaling Pathways and Therapeutic Prospects

Diabetes mellitus, the most prevalent endocrine disorder, not only impacts the retina but also significantly involves the ocular surface. Diabetes contributes to the development of dry eye disease and induces morphological and functional corneal alterations, particularly affecting nerves and epithelial cells. These changes manifest as epithelial defects, reduced sensitivity, and delayed wound healing, collectively encapsulated in the context of diabetic keratopathy. In advanced stages of this condition, the progression to corneal ulcers and scarring further unfolds, eventually leading to corneal opacities. This critical complication hampers vision and carries the potential for irreversible visual loss. The primary objective of this review article is to offer a comprehensive overview of the pathomechanisms underlying diabetic keratopathy. Emphasis is placed on exploring the redox molecular pathways responsible for the aberrant structural changes observed in the cornea and tear film during diabetes. Additionally, we provide insights into the latest experimental findings concerning potential treatments targeting oxidative stress. This endeavor aims to enhance our understanding of the intricate interplay between diabetes and ocular complications, offering valuable perspectives for future therapeutic interventions.

Pycnogenol a promising remedy for diabetic keratopathy in experimentally induced corneal alkali burns in diabetic rats

AIM

This study aimed to investigate the efficiency of topically applied pycnogenol (PYC) in healing the standardized alkaline corneal ulcer in diabetic and normal rats.

MATERIALS AND METHODS

The corneal alkali-burn injury (CA-I) model was unilaterally developed in Wistar rats by filter paper saturated with 0.01 M of NaOH and touching the eyes for 45 s. Rats were divided into four groups: Normal control (NC), normal PYC (NPYC), diabetic control (DC), and diabetic PYC (DPYC). Both NPYC and DPYC groups were daily treated with PY eye drops three times, whereas NC and DC ones were treated with ordinary saline for six successive days.

RESULTS

The wound healing of corneal epithelial was improved in the NPYC group compared to the NC group. Meanwhile, it was significantly improved (P < 0.05) in the DPYC group than in the DC group. Histological examination revealed that corneal re-epithelialization was more accomplished in the DPYC group than in the DC group. In addition, the inflammatory cells were augmented in the DC group more than those in the DPYC one.

CONCLUSION

The findings obtained revealed the efficiency of PYC for enhancing the corneal re-epithelialization and reducing the inflammatory reaction post alkali burn in rats, and thus it could be beneficially valuable as a treatment for the diabetic keratopathy.

Adrenomedullin expression in aortic artery wall of diabetic rats given alpha lipoic acid

BACKGROUND

Diabetes mellitus (DM) is a major health problem predisposing to cardiovascular diseases. The aim of this study was to investigate the effects of alpha lipoic acid (ALA) on both the arterial wall of diabetic rats and the adrenomedullin (ADM) gene expression.

METHODS

Twenty-four Wistar Albino rats were divided into three groups as Control, DM + S, and DM + ALA. For DM model, a single dose of 40 mg/kg streptozotocin, for DM + ALA group, 100 mg/kg/day/4 weeks was administered. Hematoxylin & Eosin (H&E) staining was done and vascular endothelial growth factor (VEGF) was detected by immunohistochemical analysis in the artery wall. Total damage score of vessel wall (endothelial cell damage, media layer smooth muscle cell damage, and internal elastic lamina damage) and H score (immunoreactivity intensity) were calculated. Expression of ADM gene was measured by qRT-PCR.

RESULTS

In DM + S group, Total damage score of vessel wall were detected by light microscopy. There were statistically significant differences between the groups Control/DM + S and DM + S/DM + ALA in terms of the vessel total damage score and H score (p < 0.005). ADM expression was increased threefold in both DM + S and DM + ALA groups compared to the control group (p < 0.05).

CONCLUSIONS

ALA may have positive effect on the vessel damage in diabetic rats. However, no significant decrease in ADM expression levels was observed in diabetic rats after ALA administration and we considered that the protective effect of ALA is independent of adrenomedullin. Further studies with different doses and durations of ALA administrations are required to investigate the changes in ADM expression.

Effects of phytochemicals against diabetes

Diabetes mellitus, a chronic metabolic disease, characterized by elevated levels of blood glucose and insufficiency in production and action of insulin is the seventh leading cause of death worldwide. Numerous studies have shown that diabetes mellitus is associated with increased formation of free radicals and decrease in antioxidant potential. In the patients with diabetes mellitus, the levels of antioxidant parameters are found to decrease, hence in many studies phytochemicals which can exert antioxidant and free radical scavenging activities, are suggested to improve the insulin sensitivity. Several phytoactive compounds such as flavonoids, lignans, prophenylphenols, are also found to combat the complications of diabetes. This chapter mainly focuses on the relationship between diabetes mellitus and preventive roles of various phytochemicals on diabetes via their antioxidant properties.

Toll-Like Receptor-Dependent Immunomodulatory Activity of Pycnogenol®

BACKGROUND

Pycnogenol® (PYC), an extract of French maritime pine bark, is widely used as a dietary supplement. PYC has been shown to exert anti-inflammatory actions via inhibiting the Toll-like receptor 4 (TLR4) pathway. However, the role of the other receptors from the TLR family in the immunomodulatory activity of PYC has not been described so far.

AIM

The aim of this study was to investigate whether PYC might exert its immunomodulatory properties through cell membrane TLRs (TLR1/2, TLR5, and TLR2/6) other than TLR4. Moreover, the effect of gastrointestinal metabolism on the immunomodulatory effects of PYC was investigated.

FINDINGS

We showed that intact non-metabolized PYC dose-dependently acts as an agonist of TLR1/2 and TLR2/6 and as a partial agonist of TLR5. PYC on its own does not agonize or antagonize TLR4. However, after the formation of complexes with lipopolysaccharides (LPS), it is a potent activator of TLR4 signaling. Gastrointestinal metabolism of PYC revealed the immunosuppressive potential of the retentate fraction against TLR1/2 and TLR2/6 when compared to the control fraction containing microbiota and enzymes only. The dialyzed fraction containing PYC metabolites revealed the capacity to induce anti-inflammatory IL-10 secretion. Finally, microbially metabolized PYC affected the colonic microbiota composition during in vitro gastrointestinal digestion.

CONCLUSIONS

This study showed that gastrointestinal metabolism of PYC reveals its biological activity as a potential inhibitor of TLRs signaling. The results suggest that metabolized PYC acts as a partial agonist of TLR1/2 and TLR2/6 in the presence of the microbiota-derived TLR agonists (retentate fraction) and that it possesses anti-inflammatory potential reflected by the induction of IL-10 from THP-1 macrophages (dialysate fraction).

Preventive role of Pycnogenol® against the hyperglycemia-induced oxidative stress and DNA damage in diabetic rats

Diabetes mellitus, a complex progressive metabolic disorder, leads to some oxidative stress related complications. Pycnogenol^® (PYC), a plant extract obtained from Pinus pinaster, has been suggested to be effective in many diseases including diabetes, cancer, inflammatory and immune system disorders. The mechanisms underlying the effects of PYC in diabetes need to be elucidated. The aim of this study was to determine the effects of PYC treatment (50 mg/kg/day, orally, for 28 days) on the DNA damage and biochemical changes in the blood, liver, and kidney tissues of experimental diabetic rats. Changes in the activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase enzymes, and the levels of 8-hydroxy-2'-deoxyguanosine, total glutathione, malondialdehyde, insulin, total bilirubin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, high density lipoprotein, low density lipoprotein, total cholesterol, and triglyceride were evaluated. DNA damage was also determined in the whole blood cells and the liver and renal tissue cells using the alkaline comet assay. PYC treatment significantly ameliorated the oxidative stress, lipid profile, and liver function parameters as well as DNA damage in the hyperglycemic rats. The results show that PYC treatment might improve the hyperglycemia-induced biochemical and physiological changes in diabetes.

Inhibitory effects against α-glucosidase and α-amylase of the flavonoids-rich extract from Scutellaria baicalensis shoots and interpretation of structure-activity relationship of its eight flavonoids by a refined assign-score method

A flavonoids-rich extract of Scutellaria baicalensis shoots and its eight high content flavonoids were investigated for their inhibitory effects against α-glucosidase and α-amylase. Results show that abilities of the extract in inhibiting the two enzymes were obviously higher than those of acarbose. Moreover, inhibitory abilities of all the eight individual flavonoids against the two enzymes show exactly a same order (i.e., apigenin > baicalein > scutellarin > chrysin > apigenin-7-O-glucuronide > baicalin > chrysin-7-O-glucuronide > isocarthamidin-7-O-glucuronide), and their structure-activity relationship could be well-interpretated by the refined assign-score method. Furthermore, based on the inhibitory abilities and their contents in the extract, it was found that the eight flavonoids made predominant contributions, among which baicalein and scutellarin played roles as preliminary contributors, to overall inhibitory effects of the extract against the two enzymes. Beyond these, contributions of the eight flavonoids to the overall enzyme inhibitory activity were compared with those to the overall antioxidant activity characterized in our recent study, and it could be inferred that within the basic flavonoid structure the hydroxyl on C-4' of ring B was more effective than that on C-6 of ring A in enzyme inhibitory activities while they behaved inversely in antioxidant activities; scutellarin and apigenin contributed more to the overall enzyme inhibitory activity, and baicalin and scutellarin, to the overall antioxidant activity of the extract; and flavonoids of the extract, apart from directly inhibiting enzymes, might also be conducive to curing type 2 diabetes via scavenging various free radicals caused by increased oxidative stresses.

A systematic review and meta-analysis of the effects of pycnogenol on plasma lipids

BACKGROUND

Pycnogenol, the standardized flavonoid-rich extract from the bark of French maritime pine (Pinus pinaster Ait), has been shown to modify a number of cardiovascular risk factors. However, that Pycnogenol modulates plasma lipid levels is unclear due to the inconsistent findings.

OBJECTIVE

To examine the impact of Pycnogenol on lipid profile through a meta-analysis of available controlled clinical trials.

METHODS

Controlled trials assessing the effects of Pycnogenol on lipid parameters (total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides) were identified by electronic search in Medline and Scopus. Weighed mean difference (WMD) and 95% confidence interval (CI) were calculated as effect size using random-effects meta-analysis. Sensitivity and meta-regression (for Pycnogenol dose and duration of supplementation) analyses were carried out using leave-one-out and unrestricted maximum likelihood methods, respectively.

RESULTS

A total of 7 trials comprising 442 patients (226 in the Pycnogenol and 216 in the control group) were identified. Meta-analysis did not reveal any significant effect of Pycnogenol on lipid parameters: total cholesterol: WMD: -0.03 mmol/L, 95% CI: -0.34 to 0.28, P = .83; LDL-C: WMD: -0.07 mmol/L, 95% CI: -0.29 to 0.15, P = .54; HDL-C: WMD: 0.00 mmol/L, 95% CI: -0.04 to 0.05, P = .86; and triglycerides: WMD: 0.05 mmol/L, 95% CI: -0.12 to 0.23, P = .55. All these effect sizes were robust in sensitivity analyses. Apart from a dose-effect association for the effect of Pycnogenol on LDL-C, there was no other association between Pycnogenol dose or its duration of supplementation with changes in any of the lipid parameters.

CONCLUSION

Current clinical evidence does not suggest any significant effect of Pycnogenol on fasting lipid profile.

Nutritional supplements and their effect on glucose control

As diabetes mellitus (DM) continues to be a growing health concern, many people have been turning to natural health products (NHPs) in order to manage this condition, adjunctive to, or even in place of conventional therapies. In order to keep up with this trend, research focussing on the efficacy and mechanisms behind the most common NHPs has been growing amongst the scientific community. The purpose of this chapter is to search and compile scientific literature focussing on the most commonly used NHPs in diabetes treatment, so to educate health professionals on the efficacy, safety and dosage of these products. From our findings, it is apparent that there are promising results from many studies on the potential benefit of NHPs in the treatment of diabetes. Nonetheless, many of the herbs and single nutraceuticals still require further studies in order to confirm safety, dosage and potential interactions with standard conventional therapies. Soluble fibre, alpha lipoic acid, milk thistle, prickly pear cactus and pycnogenol appear to be the most beneficial in the treatment of diabetes.

Alterations in kidney tissue following zinc supplementation to STZ-induced diabetic rats

Diabetes mellitus is a chronic disease characterized by anomalies forming in carbohydrate, lipid, protein metabolisms and the incidence of this disease varies widely throughout the world. Zinc is an important element which is essential for life and is present in nature. In this study, the animals were divided into four groups. These groups were named as untreated; zinc sulfate; streptozotocin (STZ); STZ and zinc sulfate. STZ (65 mg/kg) was dissolved in a freshly prepared 0.01 M pH 4.5 citrate buffer and given with intraperitoneal injection in a single dose. Zinc sulfate (100mg/kg) was dissolved in distilled water and given to the animals by gavage at a daily dose for 60 days. The rats were sacrificed under ether anesthesia. This study was aimed to investigate histological and biochemical changes of zinc supplementation on the kidney tissue in STZ-induced diabetic rats. In the current study, histological and histochemical observations showed that the occurred degenerative changes decreased after giving zinc in the kidney tissue of diabetic group. Kidney glutathione (GSH) levels decreased and lipid peroxidation (LPO), nonenzymatic glycosylation (NEG), urea and creatinine levels increased in diabetic rats. GSH levels increased, while LPO, NEG, urea and creatinine levels decreased in the kidney with administration of zinc to diabetic rats. As a result, we observed curative effects of zinc given to diabetic rats. We can say that zinc may be an important antioxidant for the treatment of secondary complications of diabetes in kidney tissue.

A 5-year follow-up of antioxidant supplementation in type 2 diabetic retinopathy

PURPOSE

This study was designed to evaluate the effect of antioxidant supplementation on diabetic retinopathy (DR) over a 5-year follow-up period. To our knowledge, this is the first such clinical trial performed.

METHODS

We recruited 105 type 2 diabetic patients with nonproliferative DR. A complete ophthalmic checkup and a plasma determination of oxidative (malonyldialdehyde [MDA]) and antioxidant parameters (total antioxidant status [TAS]) were obtained as the baseline. One part of the cohort was randomly assigned to oral antioxidant supplementation at nutritional doses. The same examinations were performed with 97 diabetic patients who completed the 5-year follow-up period. The best-corrected visual acuity, DR score, MDA, and TAS values were compared at the beginning and the end of the follow-up.

RESULTS

Best-corrected visual acuity did not change during the follow-up, irrespective of supplementation. However, the retinopathy stage showed a retardation of progression in the subgroup with supplementation, but worsened in the subgroup with no antioxidant supplementation. Furthermore, the antioxidant supplementation group maintained its antioxidant plasma status levels, which was related to decreased oxidative plasma activity.

CONCLUSIONS

Oral antioxidant supplementation could be a useful adjunctive long-term therapy in the treatment of nonproliferative DR.

The potential role of combined antioxidant treatment on pancreas of STZ-diabetic mice

In diabetes, cells and tissues are damaged due to the imbalance between production of free radicals and removal of them. The effective biologic antioxidants for oxidative stress such as α-lipoic acid, vitamin E and selenium are effective in diminishing oxidative damage such as membrane lipid peroxidation. The experiment aimed to investigate the oxidative stress occurring in mitochondrial and cytoplasmic fraction of pancreatic tissues in streptozotocin-diabetic mice and the possible effects of α-lipoic acid + vitamin E + selenium combination on oxidative damage and antioxidative system by using microscopic and biochemical methods. The mice were divided into five groups. These groups were treated by citrate buffer, the solvents of the antioxidants, combined the antioxidants [α-lipoic acid (50 mg/kg), vitamin E (100 mg/kg), selenium (0.25 mg/kg)], streptozotocin (40 mg/kg × 5), combined the antioxidants and streptozotocin. The mice were sacrificed by cervical dislocation. In the experimental group given combined antioxidants following results were observed compared to diabetic group: increased percent insulin-positive cell area; decreased blood glucose levels; increased manganase superoxide dismutase activities and unsignificantly increased superoxide dismutase activities; unsignificantly decreased lipid peroxidase levels in both of fraction; unsignificantly decreased in mitochondrial fraction and unsignificantly increased in cytosolic fraction for catalase levels; not any alteration glutathione levels; not any activity in both of fraction for glutathione peroxidase. We can say that by taking the blood glucose levels and immunohistochemical results into account, the combination of triple antioxidants has a partly positive effect on diabetes. This positive effect could increase when trying different doses of combined antioxidant treatment.

Impact of plant extracts tested in attention-deficit/hyperactivity disorder treatment on cell survival and energy metabolism in human neuroblastoma SH-SY5Y cells

Plant extracts such as Hypericum perforatum and Pycnogenol have been tested as alternatives to the classical ADHD drugs. It has been possible to describe neuroprotective effects of such plant extracts. A reduction of ADHD symptoms could be shown in clinical studies after the application of Pycnogenol, which is a pine bark extract. The impacts of the standardized herbal extracts Hypericum perforatum, Pycnogenol and Enzogenol up to a concentration of 5000 ng/mL on cell survival and energy metabolism in human SH-SY5Y neuroblastoma cells has been investigated in the present examination. Hypericum perforatum significantly decreased the survival of cells after treatment with a concentration of 5000 ng/mL, whereas lower concentrations exerted no significant effects. Pycnogenol( induced a significant increase of cell survival after incubation with a concentration of 32.25 ng/mL and a concentration of 250 ng/mL. Other applied concentrations of Pycnogenol failed to exert significant effects. Treatment with Enzogenol did not lead to significant changes in cell survival.Concerning energy metabolism, the treatment of cells with a concentration of 5000 ng/mL Hypericum perforatum led to a significant increase of ATP levels, whereas treatment with a concentration of 500 ng/mL had no significant effect. Incubation of cells with Pycnogenol and Enzogenol exerted no significant effects.None of the tested substances caused any cytotoxic effect when used in therapeutically relevant concentrations.

Protective effect of beta-carotene on methotrexate-induced oxidative liver damage

In this study, the authors aimed to investigate the role of oxidative stress on the hepatic damage caused by methotrexate (MTX) and the possible protective effects of beta-carotene against this damage. The rats were divided into four groups as control, MTX (20 mg/kg ip), beta-carotene (10 mg/kg/day ip) + MTX, and beta-carotene. Histopathologic alterations were evaluated for defining the liver damage. The tissue, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GP-x) contents and serum aspartate aminotransferase (AST) and alanine aminotranferase (ALT) activities were also examined. Histopathologic damage for each group score findings have been determined as control: 0.66 +/- 0.33; MTX: 7.0 +/- 0.68; beta-carotene + MTX: 3.3 +/- 0.42; and beta-carotene: 0.5 +/- 0.3. In the MTX-treated group, MDA, AST, and ALT values were increased, while SOD and GP-x values were decreased compared with the control group. In the beta-carotene + MTX-treated group, AST and ALT values significantly decreased, while all other parameters were similar to the control group. This study shows that beta-carotene has a protective effect on MTX-induced oxidative hepatic damage. Consequently, it seems that an antioxidant agents like beta-carotene may be useful in decreasing the side effects of chemotherapy.

Protective effects of Pycnogenol on hyperglycemia-induced oxidative damage in the liver of type 2 diabetic rats

Abnormal regulation of glucose and impaired carbohydrate utilization that result from a defective or deficient insulin are the key pathogenic events in type 2 diabetes mellitus (T2DM). Experimental and clinical studies have shown the antidiabetic effects of Pycnogenol (PYC). However, the protective effects of PYC on the liver, a major metabolic organ which primarily involves in glucose metabolism and maintains the normal blood glucose level in T2DM model have not been studied. The present study evaluated the beneficial effect of PYC, French maritime pine bark extract, on hyperglycemia and oxidative damage in normal and diabetic rats. Diabetes was induced by feeding rats with a high-fat diet (HFD; 40%) for 2 weeks followed by an intraperitoneal (IP) injection of streptozotocin (STZ; 40 mg/kg; body weight). An IP dose of 10mg/kg PYC was given continually for 4 weeks after diabetes induction. At the end of the 4-week period, blood was drawn and the rats were then sacrificed, and their livers dissected for biochemical and histopathological assays. In the HFD/STZ group, levels of glycosylated hemoglobin (HbA1c), significantly increased, while hepatic glycogen level decreased. PYC supplementation significantly reversed these parameters. Moreover, supplementation with PYC significantly ameliorated thiobarbituric reactive substances, malonaldehyde, protein carbonyl, glutathione and antioxidant enzymes [glutathione-S-transferase, catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase] in the liver of HFD/STZ rats. These results were supported with histopathological examinations. Although detailed studies are required for the evaluation of the exact protective mechanism of PYC against diabetic complications, these preliminary experimental findings demonstrate that PYC exhibits antidiabetic effects in a rat model of type 2 DM by potentiating the antioxidant defense system. These finding supports the efficacy of PYC for diabetes management.

The 'vitamin E regeneration system' (VERS) and an algorithm to justify antioxidant supplementation in diabetes--a hypothesis

In studies of vitamin E effectiveness in diabetes, there are still controversies surrounding negative observational and positive experimental results. However, there is no controversy that antioxidant vitamin E is regenerated from its pro-oxidant tocopheroxyl radical by a network of interacting co-antioxidants. The network of interacting co-antioxidants has only been studied individually. The hypothesis we propose is that a vitamin E regeneration system (VERS) model based on the complex interactions of the co-antioxidants provides a rationale for vitamin E supplementation as a therapeutic adjunct in diabetes. Furthermore, the factors considered prior to the use of Vitamin E as a supplement in diabetes research and therapy, the effectiveness of vitamin E supplementation and the limitations have been identified in the literature. There is no single study of vitamin E supplementation or efficacy that has determined vitamin E levels in combination with all of the co-antioxidants that interact to regenerate oxidised vitamin E. Therefore, there is a lack of good evidence for or against vitamin E being unilaterally depleted in the antioxidant network. There is also lack of rationale for choice of co-antioxidant supplementation. In essence, the normal conditions for effective antioxidant activity of vitamin E supplementation have yet to be fully explored. We propose a coherent model of VERS, and recommend that VERS status needs to be assessed, as part of evidence-based clinical practice to determine whether vitamin E should be recommended for the diabetic patient. We also propose an algorithm, based on the antioxidant activity and confounding factors, to guide the formulation of a credible hypothesis for clinical trials in assessing the function of vitamin E and treatment outcomes. The proposed model hinges on pertinent questions that have to be addressed to avoid organising a clinical trial that has been identified as biased.

Rapid relief of signs/symptoms in chronic venous microangiopathy with pycnogenol: a prospective, controlled study

The aim of this study was to investigate the clinical efficacy of oral Pycnogenol (Horphag Research Ltd, UK) in patients with severe chronic venous insufficiency. Patients with severe venous hypertension (chronic venous insufficiency, ankle swelling) and history of venous ulcerations were treated with Pycnogenol. Patients received oral Pycnogenol (50 mg capsules, 3 times daily for a total of 150 mg daily) for 8 weeks. A group of 21 patients was included in the treatment group and 18 equivalent patients were observed as controls (no treatment during the observation period). All 21 patients (age 53 years; range, 42-60 years; M:F=11:10) in the treatment group completed the 8-week study. Also the 18 controls completed the follow-up period. There were no drop-outs. The average ambulatory venous pressure was 59.3 (SD 7.2; range 50-68) with a refilling time shorter than 10 seconds (average 7.6; SD 3). There were no differences in ambulatory venous pressure or refilling time between the treatment and control patients. The duration of the disease-from the first signs/symptoms-was on average 5.7 years (SD 2.1). At 4 and 8 weeks, in all Pycnogenol-treated subjects, microcirculatory and clinical evaluations indicated a progressive decrease in skin flux, indicating an improvement in the level of microangiopathy; a significant decrease in capillary filtration; a significant improvement in the symptomatic score; and a reduction in edema. There were no visible effects in controls. In conclusion, this study confirms the fast clinical efficacy of Pycnogenol in patients with chronic venous insufficiency and venous microangiopathy. The study indicates the significant clinical role of Pycnogenol in the management, treatment and control of this common clinical problem. The treatment may be also useful to prevent ulcerations by controlling the level of venous microangiopathy.

Effect of polyphenolic extract, Pycnogenol, on the level of 8-oxoguanine in children suffering from attention deficit/hyperactivity disorder

The purpose of this randomized, double-blind and placebo controlled study was to test the effect of polyphenolic extract of pine bark Pycnogenol (Pyc) on the level of oxidized purines represented by 8-oxo-7,8-dihydroguanine (8-oxoG) and on the total antioxidant status (TAS) in children with attention deficit/hyperactivity disorder (ADHD).We have found significantly increased damage to DNA in ADHD children when compared to controls. 8-oxoG was significantly lower after 1 month of Pyc administration in comparison to the beginning state and to placebo group. TAS in ADHD children was lower in comparison to controls. After Pyc administration, TAS was elevated but statistically significant increase was recorded after 1 month of termination of Pyc application. Improvement of DNA damage and TAS after Pyc administration is associated with the improvement of attention in ADHD children. In conclusion, Pycnogenol(R) administration reduces oxidative damage to DNA, normalizes TAS and improves attention of ADHD children. Explanation of mutual relation between oxidative damage to DNA, TAS and symptoms of ADHD and mechanism of Pyc's action needs further investigations.

The effect of polyphenolic extract from pine bark, Pycnogenol on the level of glutathione in children suffering from attention deficit hyperactivity disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) belongs to the neurodevelopmental disorders characterized by impulsivity, distractibility and hyperactivity. In the pathogenesis of ADHD genetic and non-genetic factors play an important role. It is assumed that one of non-genetic factors should be oxidative stress. Pycnogenol, an extract from the pine bark, consists of bioflavonoids, catechins, procyanidins and phenolic acids. Pycnogenol acts as powerful antioxidant, chelating agent; it stimulates the activities of some enzymes, like SOD, eNOS, and exhibits other biological activities.

AIM

The aim of this randomized, double-blind, placebo-controlled trial was to investigate the influence of administered Pycnogenol or placebo on the level of reduced (GSH) and oxidized (GSSG) glutathione in children suffering from ADHD and on total antioxidant status (TAS). This is the first investigation of the redox glutathione state in relation to ADHD.

RESULTS

One month of Pycnogenol administration (1 mg/kg body weight/day) caused a significant decrease in GSSG and a highly significant increase in GSH levels as well as improvement of GSH/GSSG ratio in comparison to a group of patients taking a placebo. TAS in children with ADHD was decreased in comparison with reference values. Pycnogenol administration normalizes TAS of ADHD children.