Oxerutins (Venoruton): efficacy in chronic venous insufficiency--a double-blind, randomized, controlled study

Flavonoids and saponins: What have we got or missed?

BACKGROUND

Flavonoids and saponins are important bioactive compounds that have attracted wide research interests. This review aims to summarise the state of the art of the pharmacology, toxicology and clinical efficacy of these compounds.

METHODS

Data were retrieved from PubMed, Cochrane Library, Web of Science, Proquest, CNKI, Chongqing VIP, Wanfang, NPASS and HIT 2.0 databases. Meta-analysis and systematic reviews were evaluated following the PRISMA guideline. Statistical analyses were conducted using SPSS23.0.

RESULTS

Rising research trends on flavonoids and saponins were observed since the 1990s and the 2000s, respectively. Studies on pharmacological targets and activities of flavonoids and saponins represent an important area of research advances over the past decade, and these important resources have been documented in open-access specialised databases and can be retrieved with ease. The rising research on flavonoids and saponins can be attributed, at least in part, to their links with some highly investigated fields of research, e.g., oxidative stress, inflammation and cancer; i.e., 6.88% and 3.03% of publications on oxidative stress cited by PubMed in 1990 - 2021 involved flavonoids and saponins, respectively, significantly higher than the percentage involving alkaloids (1.88%). The effects of flavonoids concern chronic venous insufficiency, cervical lesions, diabetes, rhinitis, dermatopathy, prostatitis, menopausal symptoms, angina pectoris, male pattern hair loss, lymphocytic leukaemia, gastrointestinal diseases and traumatic cerebral infarction, etc, while those of saponins may have impact on venous oedema in chronic deep vein incompetence, erectile dysfunction, acute impact injuries and systemic lupus erythematosus, etc. The volume of in vitro research appears way higher than in vivo and clinical studies, with only 10 meta-analyses and systematic reviews (involving 290 interventional and observational studies), and 36 clinical studies on flavonoids and saponins. Data are sorely needed on pharmacokinetics, in vitro pan-assay interferences, purity of tested compounds, interactions in complex herbal extracts, real impact of anti-oxidative strategies, and mid- and long-term toxicities. To fill these important gaps, further investigations are warranted. On the other hand, drug interactions may cause adverse effects but might also be useful for synergism, with the goals of enhancing effects or of detoxifying. Furthermore, the interactions between phytochemicals and the intestinal microbiota are worth investigating as the field may present a promising potential for novel drug development.

Systematic literature review and network Meta-analysis of sulodexide and other drugs in chronic venous disease

OBJECTIVE

To assess the clinical efficacy of sulodexide, including a comparison with venoactive drugs (VAD) (micronized purified flavonoid fraction, MPFF; hydroxy-ethyl-rutosides, HR; calcium dobesilate;Ruscus extract combined with hesperidin methyl chalcone and vitamin C, Ruscus+HMC+VitC; horse chestnut seed extract, HCSE) and pentoxifylline in patients with chronic venous disease.

METHODS

We performed a literature search in MEDLINE, Embase, and Cochrane Library for randomized controlled trials (RCTs) and observational studies. Proportion of patients with complete venous ulcer healing was the primary outcome and lower leg volume, foot volume, ankle circumference and symptoms were the secondary outcomes. Bayesian network meta-analysis (NMA) was perfomed with random effects models using only RCTs. A meta-analysis of observational studies was performed for sulodexide because no RCT could be included in NMA for symptoms or signs.

RESULTS

Forty-five RCTs and eighteen observational studies were identified. Sulodexide was included only in a single NMA for the proportion of patients with complete ulcer healing and it showed to have the highest probability of being the best treatment (48%) compared with pentoxifylline (37%) and MPFF (16%). MPFF was the most effective treatment in reducing lower leg volume, CIVIQ-20 score and pain VAS scale while calcium dobesilate and Ruscus+HMC+VitC were the most effective in reducing foot volume and ankle circumference respectively.Meta-analyses of observational studies for sulodexide showed that it improves significantly the scoring of pain, feeling of swelling, heaviness and parasthesiae measured by Likert scales.

CONCLUSIONS

Sulodexide is at least as effective as pentoxifylline and more effective than MPFF in improving the rate of ulcer healing in patients with CVD. VADs are effective in improving venous symptoms and signs, as was also shown by sulodexide in the meta-analysis of observational studies. The relative effectiveness of sulodexide and VADs needs to be evaluated by an RCT in order to better inform clinical practice.

Important Flavonoids and Their Role as a Therapeutic Agent

Flavonoids are phytochemical compounds present in many plants, fruits, vegetables, and leaves, with potential applications in medicinal chemistry. Flavonoids possess a number of medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties. They also have neuroprotective and cardio-protective effects. These biological activities depend upon the type of flavonoid, its (possible) mode of action, and its bioavailability. These cost-effective medicinal components have significant biological activities, and their effectiveness has been proved for a variety of diseases. The most recent work is focused on their isolation, synthesis of their analogs, and their effects on human health using a variety of techniques and animal models. Thousands of flavonoids have been successfully isolated, and this number increases steadily. We have therefore made an effort to summarize the isolated flavonoids with useful activities in order to gain a better understanding of their effects on human health.

Phlebotonics for venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a condition in which veins are unable to transport blood unidirectionally towards the heart. CVI usually occurs in the lower limbs. It might result in considerable discomfort, with symptoms such as pain, itchiness and tiredness in the legs. Patients with CVI may also experience swelling and ulcers. Phlebotonics are a class of drugs often used to treat CVI. This is the second update of a review first published in 2005.

OBJECTIVES

To assess the efficacy and safety of phlebotonics administered orally or topically for treatment of signs and symptoms of lower extremity CVI.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and Clinicaltrials.gov trials register up to 12 November 2019. We searched the reference lists of the articles retrieved by electronic searches for additional citations. We also contacted authors of unpublished studies.

SELECTION CRITERIA

We included randomised, double-blind, placebo-controlled trials (RCTs) assessing the efficacy of phlebotonics (rutosides, hidrosmine, diosmine, calcium dobesilate, chromocarbe, Centella asiatica, disodium flavodate, French maritime pine bark extract, grape seed extract and aminaftone) in patients with CVI at any stage of the disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of included RCTs. We estimated the effects of treatment by using risk ratios (RRs), mean differences (MDs) and standardized mean differences (SMDs), according to the outcome assessed. We calculated 95% confidence intervals (CIs) and percentage of heterogeneity (I2). Outcomes of interest were oedema, quality of life (QoL), assessment of CVI and adverse events. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We identified three new studies for this update. In total, 69 RCTs of oral phlebotonics were included, but only 56 studies (7690 participants, mean age 50 years) provided quantifiable data for the efficacy analysis. These studies used different phlebotonics (28 on rutosides, 11 on hidrosmine and diosmine, 10 on calcium dobesilate, two on Centella asiatica, two on aminaftone, two on French maritime pine bark extract and one on grape seed extract). No studies evaluating topical phlebotonics, chromocarbe, naftazone or disodium flavodate fulfilled the inclusion criteria. Moderate-certainty evidence suggests that phlebotonics probably reduce oedema slightly in the lower legs, compared with placebo (RR 0.70, 95% CI 0.63 to 0.78; 13 studies; 1245 participants); and probably reduce ankle circumference (MD -4.27 mm, 95% CI -5.61 to -2.93 mm; 15 studies; 2010 participants). Moderate-certainty evidence shows that phlebotonics probably make little or no difference in QoL compared with placebo (SMD -0.06, 95% CI -0.22 to 0.10; five studies; 1639 participants); and similarly, may have little or no effect on ulcer healing (RR 0.94, 95% CI 0.79 to 1.13; six studies; 461 participants; low-certainty evidence). Thirty-seven studies reported on adverse events. Pooled data suggest that phlebotonics probably increase adverse events slightly, compared to placebo (RR 1.14, 95% CI 1.02 to 1.27; 37 studies; 5789 participants; moderate-certainty evidence). Gastrointestinal disorders were the most frequently reported adverse events. We downgraded our certainty in the evidence from 'high' to 'moderate' because of risk of bias concerns, and further to 'low' because of imprecision.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that phlebotonics probably reduce oedema slightly, compared to placebo; moderate-certainty evidence of little or no difference in QoL; and low-certainty evidence that these drugs do not influence ulcer healing. Moderate-certainty evidence suggests that phlebotonics are probably associated with a higher risk of adverse events than placebo. Studies included in this systematic review provided only short-term safety data; therefore, the medium- and long-term safety of phlebotonics could not be estimated. Findings for specific groups of phlebotonics are limited due to small study numbers and heterogeneous results. Additional high-quality RCTs focusing on clinically important outcomes are needed to improve the evidence base.

Rindera graeca (Boraginaceae) Phytochemical Profile and Biological Activities

Rindera graeca is a Greek endemic plant of the Boraginaceae family which has never been studied before. Consequently, this study attempted to phytochemically examine the aerial parts of this species. Nine phenolic secondary metabolites were identified, consisting of seven caffeic acid derivatives and two flavonol glucosides, namely rutin and quercetin-3-rutinoside-7-rhamnoside. These flavonoids, together with rosmarinic acid, were isolated via column chromatography and structurally determined through spectral analysis. Quercetin-3-rutinoside-7-rhamnoside is an unusual triglycoside, which is identified for the first time in Rindera genus and among Boraginaceae plants. This metabolite was further examined with thermal analysis and its 3D structure was simulated, revealing some intriguing information on its interaction with biological membrane models, which might have potential applications in microcirculation-related conditions. R. graeca was also analyzed for its pyrrolizidine alkaloids content, and it was found to contain echinatine together with echinatine N-oxide and rinderine N-oxide. Additionally, the total phenolic and flavonoid contents of R. graeca methanol extract were determined, along with free radical inhibition assays. High total phenolic content and almost complete inhibition at experimental doses at the free radical assays indicate a potent antioxidant profile for this plant. Overall, through phytochemical analysis and biological activity assays, insight was gained on an endemic Greek species of the little-studied Rindera genus, while its potential for further applications has been assessed.

Comparison of Centella with Flavonoids for Treatment of Symptoms in Hemorrhoidal Disease and After Surgical Intervention: A Randomized Clinical Trial

Phlebotonics’ effects were evaluated to reduce time-to-stop bleeding and anal irritation in 130 patients who complained of hemorrhoidal disease (HD); bleeding and pain after hemorrhoidectomy (31 patients) and hemorrhoidal thrombosis (34 patients) in the short time. Sixty patients were randomized to receive the routine treatment (both conservative and surgical) (control Group C). The treated group (both conservative and surgical) was divided into two subgroups: one treated with flavonoids (Group A, n = 73), the other with Centella (Group B, n = 66). Time-to-stop bleeding was checked at baseline and checkups (0 up to day 42). Healing was estimated with Kaplan-Meier method, the Kruskal-Wallis test estimated changes in the VAS scores. The HD median time-to-stop bleeding was 2 weeks for Groups A and B; 3 weeks for Group C. VAS scores comparison among Groups (irritation): A vs C, p = 0.007; B vs C, p = 0.041; and A vs B, p = 0.782 resulted respectively. As for operated hemorrhoids, the time-to-stop bleeding was 3 and 4 weeks in Groups A and B and 5 in Group C. Histopathology showed an association between flavonoids and piles’ fibrosis (p = 0.008). Phlebotonics in HD, as well as after surgery, showed significant beneficial effects. Flavonoids are the most effective phlebotonics against bleeding and anal irritation.

Therapeutic potential of natural compounds in inflammation and chronic venous insufficiency

The term varicose vein refers to the twisted and swollen vein visible under the skin surface which occurs most commonly in the leg. Epidemiological studies report a varying percentage of incidences from 2 to 56% in men and <1-60% in women. Venous insufficiency is most often caused by the damage to the valves and walls of the veins. The mechanism of varicose vein formation is complex. It is, however, based on hypotensive blood vessels, hypoxia, and other mechanisms associated with inflammation. This work describes mechanisms related to the formation and development of the varicose vein. It discusses risk factors, pathogenesis of chronic venous disease, markers of the epithelial and leukocyte activation, state of hypoxia and inflammation, reactive oxygen species (ROS) generation, and oxidative stress. Additionally, this paper describes substances of plant origin used in the treatment of venous insufficiency. It also considers the structure of the molecules, their properties, and their mechanisms of action, the structure-activity relationship and chemical properties of flavonoids and other substances. The flavonoids include quercetin derivatives, micronized purified flavonoid fraction (Daflon), natural pine bark extract (Pycnogenol), and others such as triterpene saponine, extracts from Ruscus aculeatus and Centella asiatica, Ginkgo biloba extract, coumarin dereivatives that are used in chronic venous insufficiency. Flavonoids are natural substances found in plants, including fruits, vegetables, flowers, and others. They are important to the circulatory system and critical to blood vessels and the blood flow. Additionally, they have antioxidant, antiinflammatory properties.

The Significance of Pain in Chronic Venous Disease and its Medical Treatment

Chronic venous disease (CVeD) is a highly prevalent condition in the general population, and it has a significant impact on quality of life. While it is usually manifested by obvious signs, such as varicose veins and venous ulcers, other symptoms of the disease are less specific. Among the other symptoms, which include heaviness, swelling, muscle cramps and restless legs, pain is the symptom that most frequently compels CVeD patients to seek medical aid. However, there is a substantial discrepancy between pain severity and clinically detectable signs of CVeD, questioned by several opposing studies. Further evaluation is needed to clarify this subject, and to analyse whether pain development predicts objective CVeD progression. General management of CVeD starts with advising lifestyle changes, such as lowering body mass index and treating comorbidities. However, the mainstay of treatment is compression therapy, with the additional use of pharmacological substances. Venoactive drugs proved to be the drugs of choice for symptom alleviation and slowing the progression of CVeD, with micronized purified flavonoid fraction being the most effective one. Interventional therapy is reserved for advanced stages of the disease.

A Review of the Microcirculation in Skin in Patients With Chronic Venous Insufficiency: The Problem and the Evidence Available for Therapeutic Options

Impairment of the cutaneous microcirculation is a major predisposing factor in inflammation and ulceration in patients with chronic venous insufficiency (CVI). Increase of capillary filtration rate predisposes to the formation of edema. Local lymphedema is a complication of CVI, often underdiagnosed. This review is focused on CVI but excludes the complication of ulceration. Treatment of microcirculatory dysfunction can be done by pharmacologic intervention or compression therapy or using a combination of both. This review is focused on drugs that have been evaluated by randomized prospective controlled trials. The following compounds are discussed: horse chestnut seed extracts, flavonoids, red vine leaves extracts, total triterpenic fraction of Centella asiatica (L), prociadins, calcium dobesilate, and pentoxifylline. The microcirculatory effects of compression therapy using bandages or stockings are also reviewed. The major microcirculatory effects that have been shown are the reduction of capillary filtration rate and improvements in levels of transcutaneous partial pressures of oxygen and carbon dioxide (TcPO2 and TcPCO2). Available data suggest that a combination of pharmacologic and compression therapy may have some additive effects.

Circulating Endothelial Cells in Venous Blood as a Marker of Endothelial Damage in Chronic Venous Insufficiency: Improvement with Venoruton

Damage to endothelial cells is common in vascular disorders and in reactions associated with transplantation. An elevated number of circulating endothelial cells indicates the extent of endothelial damage in a variety of disorders. In chronic venous insufficiency (CVI), the number of endothelial cells is abnormally increased, and this can be considered an important indication of endothelial damage. A group of 23 subjects with two levels of CVI (severe and very severe with previous ulcerations) with an increased endothelial cell count (seen by microscopy) was studied and treated for 4 weeks with oral Venoruton (0-[beta-hydroxyethyl]-rutosides) (1 g/day) to evaluate the effects of treatment on the circulating endothelial cells in blood taken from a peripheral leg vein. The controls comprised two groups with comparable age and sex distribution, one of healthy individuals and one of CVI subjects. After 4 weeks, a significant decrease was noted in endothelial cells both in subjects with CVI and in those with very severe CVI with previous ulcerations. This study suggests that endothelial cells may play a significant role in venous disease, being both an indication of severe disease and a further problem in itself. The use of Venoruton appears to decrease the number of circulating endothelial cells. This suggests an important role of this compound in protecting the endothelium and offers new potentially important therapeutic options that are not limited only to venous disease.

Phlebotonics for venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a common condition caused by valvular dysfunction with or without associated obstruction, usually in the lower limbs. It might result in considerable discomfort with symptoms such as pain, itchiness and tiredness in the legs. Patients with CVI may also experience swelling and ulcers. Phlebotonics are a class of drugs often used to treat CVI. This is an update of a review first published in 2005.

OBJECTIVES

To assess the efficacy and safety of phlebotonics administered both orally and topically for treatment of signs and symptoms of lower extremity CVI.

SEARCH METHODS

For this update, the Cochrane Vascular Trials Search Co-ordinator (TSC) searched the Specialised Register (August 2015), as well as the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7). The reference lists of the articles retrieved by electronic searches were searched for additional citations. We also contacted pharmaceutical companies and searched the World Health Organization (WHO) International Clinical Trials Registry Platform Search Portal for ongoing studies (last searched in August 2015).

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled trials (RCTs) assessing the efficacy of rutosides, hidrosmine, diosmine, calcium dobesilate, chromocarbe, Centella asiatica, disodium flavodate, french maritime pine bark extract, grape seed extract and aminaftone in patients with CVI at any stage of the disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of included RCTs. We estimated the effects of treatment by using risk ratios (RRs), mean differences (MDs) and standardised mean differences (SMDs), according to the outcome assessed. We calculated 95% confidence interval (CIs) and percentage of heterogeneity (I(2)). Additionally, we performed sensitivity analyses.

MAIN RESULTS

We included 66 RCTs of oral phlebotonics, but only 53 trials provided quantifiable data (involving 6013 participants; mean age 50 years) for the efficacy analysis: 28 for rutosides, 10 hidrosmine and diosmine, nine calcium dobesilate, two Centella asiatica, two aminaftone, two french maritime pine bark extract and one grape seed extract. No studies evaluating topical phlebotonics, chromocarbe, naftazone or disodium flavodate fulfilled the inclusion criteria.Moderate-quality evidence suggests that phlebotonics reduced oedema in the lower legs compared with placebo. Phlebotonics showed beneficial effects among participants including reduced oedema (RR 0.70, 95% CI 0.63 to 0.78; I(2) = 20%; 1245 participants) and ankle circumference (MD -4.27 mm, 95% CI -5.61 to -2.93 mm; I(2) = 47%; 2010 participants). Low-quality evidence reveals no difference in the proportion of ulcers cured with phlebotonics compared with placebo (RR 0.94, 95% CI 0.79 to 1.13; I(2) = 5%; 461 participants). In addition, phlebotonics showed greater efficacy for trophic disorders, cramps, restless legs, swelling and paraesthesia, when compared with placebo. We identified heterogeneity for the variables of pain, itching, heaviness, quality of life and global assessment by participants. For quality of life, it was not possible to pool the studies because heterogeneity was high. However, high-quality evidence suggests no differences in quality of life for calcium dobesilate compared with placebo (MD -0.60, 95% CI -2.15 to 0.95; I(2) = 40%; 617 participants), and low-quality evidence indicates that in the aminaftone group, quality of life was improved over that reported in the placebo group (MD -10.00, 95% CI -17.01 to - 2.99; 79 participants). Moderate-quality evidence shows that the phlebotonics group had greater risk of non-severe adverse events than the placebo group (RR 1.21, 95% CI 1.05 to 1.41; I(2) = 0; 3975 participants). Gastrointestinal disorders were the most frequently reported adverse events.

AUTHORS' CONCLUSIONS

Moderate-quality evidence shows that phlebotonics may have beneficial effects on oedema and on some signs and symptoms related to CVI such as trophic disorders, cramps, restless legs, swelling and paraesthesia when compared with placebo but can produce more adverse effects. Phlebotonics showed no differences compared with placebo in ulcer healing. Additional high-quality RCTs focused on clinically important outcomes are needed to improve the evidence base.

The efficiency of O-(beta-hydroxyethyl)-rutosides in reducing the incidence of superficial venous insufficiency in patients with calf muscle pump dysfunction

Objective We aimed to evaluate the efficiency of O-(beta-Hydroxyethyl)-rutosides (Oxerutin) in reducing the incidence of venous system disease among patients with calf muscle pump dysfunction secondary to immobilization due to lower-limb fractures. Methods A total of 60 patients with lower-limb fractures and immobilized in plaster casts were included in this study randomized into control (n = 30; mean: 30.37 ± 6.03 years; 73.3% males; no treatment) and experiment (n = 30; mean: 31.67 ± 4.76 years; 66.6% males; Oxerutin, 500 mg po q12hr) treatment groups. Doppler ultrasound was performed to evaluate the effect of oxerutin on the alterations in the venous circulation. Results Patients in the control group were determined to be more commonly affected from the below-knee immobilization in terms of venous dysfunction in the great saphenous vein in the below-knee region when compared with the patients in the oxerutin treatment group (46.7 vs. 13.3%, respectively; p = 0.011). Incidence of reflux in the small saphenous vein was more common in the control group during the healing period when compared with the experiment group (40.0 vs. 10.0%, respectively; p = 0.017). None of the patients developed venous thrombosis. Conclusions In conclusion, the impairment of the lower extremity muscle pump should be considered as an important risk factor for venous disease, and should be evaluated. O-(beta-Hydroxyethyl)-rutosides during 6-8 week cast immobilization for a lower limb fracture may be an effective prophylactic regimen in reducing the incidence of reflux in the below-knee superficial veins.

Effects of a new nutraceutical substance on clinical and molecular parameters in patients with chronic venous ulceration

Pathophysiological events involved in the onset of chronic venous ulceration (CVU) are inflammation, activation of polymorphonucleates (PMNs) and secretion of proteases such as matrix metalloproteinases (MMPs), which degrade extracellular matrix (ECM) that is a support for vascular and tissutal wall. MMPs, neutrophil gelatinase-associated lipocalin (NGAL) and inflammatory cytokines are overexpressed in CVUs and they could play a central role in pathophysiological mechanisms of skin lesion and delayed wound healing. Bioflavonoids, such as diosmin and other compounds, appear to have several provessel function activities including anti-inflammatory, antioxidant and phlebotonic effects and are widely used in the treatment of chronic venous disease (CVD)-related problems. In this article, we evaluated the effects of Axaven(®) , a new nutraceutical on both clinical and molecular parameters in patients with CVUs. During the study period, 83 patients with CVUs of both sexes were enrolled and divided into two groups: group A (treated group): 25 females and 19 males (median age is 67·7 years) received standard treatment (compression therapy and surgical correction of superficial venous incompetence) + Axaven(®) once a day for 8 months as adjunctive treatment. Group B (control group): 24 females and 15 males (median age is 65·2 years) were treated only with basic treatment according to their clinical conditions. In our study, the administration of Axaven(®) in patients with CVUs was able to decrease inflammatory cytokines, MMPs and NGAL, inducing an improvement of both symptoms with an increase of the speed of wound healing.

A systematic review of the efficacy and tolerability of hydroxyethylrutosides for improvement of the signs and symptoms of chronic venous insufficiency

WHAT IS KNOWN AND OBJECTIVE

Rutoside (rutin; quercetin rutinoside) is a glycoside found in various plant products, including apples, citrus fruits and cranberries. Hydroxyethylrutosides (HR) are semisynthetic derivatives sold as standardized products for the treatment of chronic venous insufficiency (CVI). Commercially available products include Relvène(®) (France), Venoruton(®) (Switzerland) and Paroven(®) (United Kingdom). However, the evidence for their efficacy is inconclusive. The aim of this systematic review was to evaluate the evidence of efficacy and tolerability of hydroxyethylrutosides for CVI.

METHODS

We searched electronic databases such as the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and CINAHL, and publisher databases, conference proceedings and references lists for randomized controlled trials published in English and non-English languages. We also performed hand searches for additional trials. We included all trials that assessed the effectiveness of HR for CVI. Comparisons include HR (with or without compression bandaging) vs. placebo (with or without compression bandaging) or HR vs. compression bandaging alone. Two review authors independently selected studies, extracted data and assessed risks of bias in the included trials.

RESULTS AND DISCUSSION

The search identified 1474 records. Only 15 trials involving 1643 participants met our inclusion criteria. A meta-analysis based on similar studies that compared HR with placebo showed that HR significantly reduced symptoms of pain (SMD -1·07, 95% CI -1·44 to -0·70), symptoms of heavy legs (OR 0·50; 95% CI 0·28-0·91) and cramps (SMD -1·07, 95% CI -1·45 to -0·69). No serious adverse effect due to HR was reported.

WHAT IS NEW AND CONCLUSION

The findings showed that HR produced modest improvements in several symptoms of CVI. However, all the included trials were of limited quality, and therefore, better-quality trials are still required to draw firm conclusions on the usefulness of HR for CVI.

Treatment of endothelial cell with flavonoids modulates transendothelial leukocyte migration

Objective:

This study aimed to investigate the influence of the flavonoid oxerutin (Venoruton®, Novartis, Basel, Switzerland) on endothelial cell apoptosis and transendothelial migration of peripheral blood mononuclear cells and to elucidate the potential mechanisms affecting these processes.

Methods:

Human endothelial cells were treated with Venoruton to assess the potential effect on apoptosis and on the transendothelial migration process. Endothelial nitric oxide synthase and inducible nitric oxide synthase expression in endothelial cell after Venoruton treatment as well as reactive oxygen species levels were analyzed.

Results:

Low-dose Venoruton shows a protective effect on endothelial cells and inhibits transendothelial migration of peripheral blood mononuclear cells through an endothelial monolayer, but high-dose Venoruton inversely elevated transendothelial migration of peripheral blood mononuclear cells. Meanwhile, a dose-dependent action of Venoruton on endothelial cell apoptosis could be observed. Endothelial nitric oxide synthase and inducible nitric oxide synthase expression were gradually increased in endothelial cells with increasing Venoruton dosage. In addition, reactive oxygen species were significantly reduced by 0.1 mM and 0.5 mM Venoruton and elevated after high dose treatment.

Conclusion:

These data suggest that the increased transendothelial migration of peripheral blood mononuclear cells is related to the excessive activation of the nitric oxide-axis and subsequent relaxation of the endothelial cells.

Improvements of venous tone with pycnogenol in chronic venous insufficiency: an ex vivo study on venous segments

This study evaluated the stretching and dilatation of venous segments ex vivo in subjects with primary varicose veins in comparison with comparable segments from subjects that used the supplement Pycnogenol (150 mg/d) for 3 months before surgery. Subjects with varicose veins and chronic venous insufficiency voluntarily used Pycnogenol for a period of at least 3 months. The segments of veins removed with surgery (in 30 subjects that had used Pycnogenol and in 10 comparable control subjects that had not used the supplement) were compared with normal, unused vein segments harvested for bypass grafting. The segments were suspended and a weight was attached to the distal part of the veins for 3 minutes and dilated with pressurized water. Digital images were recorded; the veins were measured before and after stretching to evaluate elongation. The manipulation of the vein segment was minimal. Tests were completed within 20 minutes after harvesting the veins. All segments were 4 cm long. The stretching test indicated a significantly higher level of passive elongation in control, varicose segments (2.29; 0.65 mm) in comparison with 1.39; 0.2 mm in vein segments from Pycnogenol-using patients. The dilation test showed an average higher dilation (2.19; 0.3 mm) in control varicose veins in comparison with varicose veins from Pycnogenol-using patients (1.32; 0.7 mm) (p < 0.05). Stretching and dilatation were lower in veins from Pycnogenol-using subjects (p < 0.05). The measurement of destretching and the recovery after dilatation indicated a better tone and recovery of the original size/shape in varicose segments from patients using Pycnogenol. Varicose segments had a more significant persistent dilatation and elongation in comparison with normal vein segments. Pycnogenol seems to decrease passive dilatation and stretching and gives vein walls a greater tonic recovery and elasticity that allows the vein to recover its original shape after dynamic stresses.

Treatment of chronic venous disease with flavonoids: recommendations for treatment and further studies

OBJECTIVES

A variety of studies have suggested that flavonoids are effective for the treatment of CVD. However, many questions remain about their mechanism of action and when, how, and for what signs and symptoms they should be used.

METHOD

A panel of experts in CVD met in Budapest, Hungary in December 2011 to discuss the current state of knowledge of CVD and the role of flavonoids in its treatment. The discussion was based on a literature search in the current databases. The goals of this paper are recommendations for further studies on the use of flavonoids in the treatment of CVD.

RESULTS

There is good evidence to recommend the use of flavonoids in the treatment of CVD. However, because of the poor quality of some older clinical trials, inadequate reporting, and insufficient information, much work is still needed to firmly establish their clinical efficacy and to determine when and how they should be employed. In particular, long-term randomized, placebo-controlled, double-blind studies are needed to establish the efficacy and safety of flavonoids. Additional studies are also needed to establish their mechanism of action, pharmacokinetics, toxicity, and cost-effectiveness.

CONCLUSIONS

Aside from good evidence for the use of flavonoids in CVD further studies are indicated to establish long term treatment in this indication.

An essential difference in the reactivity of the glutathione adducts of the structurally closely related flavonoids monoHER and quercetin

During the scavenging of free radicals flavonoids are oxidized to electrophilic quinones. Glutathione (GSH) can trap these quinones, thereby forming GSH-flavonoid adducts. The aim of this study was to compare the stability of the GSH-flavonoid adduct of 7-mono-O-(β-hydroxyethyl)rutoside (monoHER) with that of quercetin. It was found that GSH-quercetin reacts with the thiol N-acetyl-L-cysteine (NAC) to form NAC-quercetin, whereas GSH-monoHER does not react with NAC. In addition, the adduct of the monoHER quinone with the dithiol dithiothreitol (DTT) is relatively stable, whereas the DTT-quercetin adduct is readily converted into quercetin and DTT disulfide. These differences in reactivity of the thiol-flavonoid adducts demonstrate that GSH-monoHER is much more stable than GSH-quercetin. This difference in reactivity was corroborated by molecular quantum chemical calculations. Thus, although both flavonoid quinones are rapidly scavenged by GSH, the advantage of monoHER is that it forms a stable conjugate with GSH, thereby preventing a possible spread of toxicity. These findings demonstrate that even structurally comparable flavonoids behave differently, which will be reflected in the biological effects of these flavonoids.

An essential difference between the flavonoids monoHER and quercetin in their interplay with the endogenous antioxidant network

Antioxidants can scavenge highly reactive radicals. As a result the antioxidants are converted into oxidation products that might cause damage to vital cellular components. To prevent this damage, the human body possesses an intricate network of antioxidants that pass over the reactivity from one antioxidant to another in a controlled way. The aim of the present study was to investigate how the semi-synthetic flavonoid 7-mono-O-(β-hydroxyethyl)-rutoside (monoHER), a potential protective agent against doxorubicin-induced cardiotoxicity, fits into this antioxidant network. This position was compared with that of the well-known flavonoid quercetin. The present study shows that the oxidation products of both monoHER and quercetin are reactive towards thiol groups of both GSH and proteins. However, in human blood plasma, oxidized quercetin easily reacts with protein thiols, whereas oxidized monoHER does not react with plasma protein thiols. Our results indicate that this can be explained by the presence of ascorbate in plasma; ascorbate is able to reduce oxidized monoHER to the parent compound monoHER before oxidized monoHER can react with thiols. This is a major difference with oxidized quercetin that preferentially reacts with thiols rather than ascorbate. The difference in selectivity between monoHER and quercetin originates from an intrinsic difference in the chemical nature of their oxidation products, which was corroborated by molecular quantum chemical calculations. These findings point towards an essential difference between structurally closely related flavonoids in their interplay with the endogenous antioxidant network. The advantage of monoHER is that it can safely channel the reactivity of radicals into the antioxidant network where the reactivity is completely neutralized.

Pharmacological treatment in patients with C4, C5 and C6 venous disease

Background

A range of surgical, endovenous, physical and medical treatments are available for patients with chronic venous disease. The aim of this review was to evaluate the evidence for pharmacological agents used for the treatment of chronic venous disease.

Methods

A literature search was performed using Pubmed, Embase, Cochrane and Google Scholar databases. The initial search terms ‘varicose vein’, ‘venous ulcer’, ‘venous disease’ and ‘lipodermatosclerosis’ were used to identify relevant clinical studies of pharmacotherapy in patients with chronic venous disease (C4–C6).

Results

A huge range of naturally occurring and synthetic drugs have been studied in patients with chronic venous disease. For patients with C4 venous disease, micronized purified flavonoid fraction (MPFF), oxerutin, rutosides and calcium dobesilate may reduce venous symptoms and oedema. MPFF and pentoxifylline have been shown to improve venous ulcer healing when used in addition to multilayer compression bandaging. The clinical benefits of other medications remain unproven. Reliability of meta-analyses was limited by study heterogeneity, small sample sizes and lack of long-term follow-up.

Conclusions

In prospective randomized studies, MPFF (Daflon®), other flavonoid derivatives and pentoxifylline have demonstrated clinical benefits in patients with C4–C6 venous disease. Pharmacotherapy should be part of a range of treatment options in the modern management of patients with chronic venous disorders.

Calcium dobesilate and oxerutin: effectiveness of combination therapy

Objectives

Chronic venous insufficiency (CVI) is an important cause of discomfort and inability to work. Hydroxyethylrutosides (Venoruton®; 0-[beta-hydroxyethyl]-rutosides) has been used for decades for the treatment of CVI. Studies have reported symptomatic relief and a decreased capillary filtration after the administration of the oral preparations. Calcium dobesilate is a synthetic venoactive drug acting on several levels. It inhibits capillary permeability; it has antioxidant properties; and it inhibits the synthesis of prostaglandins and thromboxanes, reducing platelet and erythrocyte aggregation, as well as blood viscosity. The aim of this study is to determine whether the combination of both drugs is more effective in decreasing patients' complaints.

Methods

One hundred and fifty patients with primary venous insufficiency were randomized into three groups: Group A receiving calcium dobesilate only, Group B receiving oxerutin only and Group C receiving both calcium dobesilate and oxerutin. Patients were evaluated with a questionnaire before and four weeks after treatment regarding following parameters: itching, fatigue, heaviness, numbness, cramp, swelling and sensitiveness. Patients rated their symptoms from 0 to 4 (0: absent; 1: mild; 2: moderate; 3: severe; 4: very severe).

Results

Complaints, which were scored by patients before and after treatment, decreased. Among the single-drug groups, itching score decreased more in Group B, whereas scores of fatigue, heaviness, numbness, cramp and swelling decreased more in Group A. But the difference was not significant, statistically. But all complaints decreased significantly in Group C. Difference of scores after treatment revealed no statistical significance in Group A and B, but scores of Group C produced a significant difference when compared with Group A and B.

Conclusion

Results demonstrate that a combination of calcium dobesilate and oxerutin shows a better improvement of complaints. These observations have to be confirmed in larger series with objective tests. Changes of quality of life after a combination therapy might also be of interest.

Effect of rutin on warfarin anticoagulation and pharmacokinetics of warfarin enantiomers in rats

Objectives

The effects of the flavonoid rutin on the anticoagulant activity of oral warfarin and the protein binding and pharmacokinetics of its enantiomers were investigated in rats.

Methods

A single dose of racemic warfarin, 1.5 mg/kg, was administered orally to rats either alone or on day 5 of an 8-day oral regimen of rutin, 1 g/kg daily.

Results

Rutin reduced the anticoagulant effect of racemic warfarin, evident as a 31% reduction in the area under the prothrombin complex activty–time curve (P &lt; 0.05).

Key findings

Rutin had no apparent effect on pre-treatment baseline blood coagulation. It enhanced the in-vitro serum protein binding of S- and R-warfarin (reflected by 40% and 26% reductions in unbound fraction, respectively), and thus restricted distribution by 33 and 21%, respectively. Treatment with rutin significantly decreased the elimination half-life of S-warfarin by 37% as a result of the 69% increase in unbound clearance of the S-enantiomer. This effect was attributed to a significant 77% increase in the unbound formation clearance of the overall oxidative and reductive metabolites, and an increase in the unbound renal clearance of the more potent S-enantiomer of warfarin.

Conclusions

Concurrent rutin administration is likely to reduce the anticoagulant effect of racemic warfarin, reflecting a significant decrease in the elimination half-life of the more potent S-enantiomer.

Characterization of the glutathione conjugate of the semisynthetic flavonoid monoHER

Flavonoids protect against oxidative stress by scavenging free radicals. During this protection flavonoids are oxidized. The oxidized flavonoids formed are often reactive. Consequently, protection by flavonoids can result in the formation of toxic products. In this study the oxidation of 7-mono-O-(beta-hydroxyethyl)rutoside (monoHER), which is a constituent of the registered drug Venoruton, was studied in the absence and presence of glutathione (GSH). MonoHER was oxidized by horseradish peroxidase/H(2)O(2). Spectrophotometric and HPLC analysis showed that in the presence of GSH, a monoHER-GSH conjugate was formed, which was identified as 2'-glutathionyl monohydroxyethylrutoside by mass spectrometric analysis and (1)H NMR. Preferential formation of this glutathione adduct in the B ring at C2' was confirmed by molecular quantum chemical calculations. This conjugate was also detected in the bile fluid of a healthy volunteer after iv administration of monoHER, demonstrating its formation in vivo. These results indicate that in the process of offering protection against free radicals, monoHER is converted into an oxidation product that is reactive toward thiols. The formation of this thiol-reactive oxidation product is potentially harmful. Thus, the supposed beneficial effect of monoHER as an antioxidant may be accompanied by the formation of products with an electrophilic, toxic potential.

Treatment of chronic venous insufficiency

Chronic venous insufficiency (CVI) results from venous hypertension secondary to superficial or deep venous valvular reflux. Treatment modalities are aimed at reducing venous valvular reflux, thereby inhibiting the ensuing pathologic inflammatory process. Compression therapy using pumps, bandaging, and/or graded compression stockings is the mainstay of treatment for CVI. Compression therapy has been shown to be effective in reducing venous hypertension retarding the development of inflammation and pathologic skin changes. Pharmacologic agents such as diuretics and topical steroid creams reduce swelling and pain short term but offer no long-term treatment advantage. Herbal supplements may reduce the inflammatory response to venous hypertension, but are not licensed by the US Food and Drug Administration, and vary in their efficacy, quality, and safety. However, several randomized controlled trials using the herbal horse chestnut seed extract containing aescin have shown short-term improvement in signs and symptoms of CVI. Endovascular and surgical techniques aimed at treatment of primary and secondary venous valvular reflux have been shown to improve venous hemodynamics promoting healing of venous ulcers and improving quality of life. The newer endovascular treatments of varicose veins using laser, radiofrequency ablation, and chemical foam sclerotherapy show some promise.

Phlebotonics for venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a common condition caused by inadequate blood flow through the veins, usually in the lower limbs. It can result in considerable discomfort with symptoms such as pain, itchiness and tiredness in the legs. Sufferers may also experience swelling and ulcers. Phlebotonics are a class of drugs that are often used to treat CVI.

OBJECTIVES

To assess the efficacy of oral or topical phlebotonics.

SEARCH STRATEGY

We searched the Cochrane Peripheral Vascular Diseases Group trials register (April 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2005), MEDLINE (January 1966 to April 2005), EMBASE (January 1980 to April 2005) and reference lists of articles. We also contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised, double blind, placebo-controlled trials (RCTs) assessing the efficacy of rutosides, hidrosmine, diosmine, calcium dobesilate, chromocarbe, centella asiatica, disodium flavodate, french maritime pine bark extract, grape seed extract and aminaftone in CVI patients at any stage of the disease.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. The effects of treatment were estimated by relative risk (RR) or by standardised mean differences (SMD) by applying a random effects statistical model. Sensitivity analyses were also performed.

MAIN RESULTS

Fifty-nine RCTs of oral phlebotonics were included, but only 44 trials involving 4413 participants contained quantifiable data for the efficacy analysis: 23 of rutosides, ten of hidrosmine and diosmine, six of calcium dobesilate, two of centella asiatica, one of french maritime pine bark extract, one of aminaftone and one of grape seed extract. No studies evaluating topical phlebotonics, chromocarbe, naftazone or disodium flavodate fulfilled the inclusion criteria. Outcomes included oedema, venous ulcers, trophic disorders, subjective symptoms (pain, cramps, restless legs, itching, heaviness, swelling and paraesthesias), global assessment measures and side effects. The results of many variables were heterogeneous. Phlebotonics showed some global benefit (i.e. oedema reduction) (relative risk 0.72, 95% confidence interval 0.65 to 0.81). The benefit for the remaining CVI signs and symptoms must be evaluated by phlebotonic group. There were no quantifiable data on quality of life.

AUTHORS' CONCLUSIONS

There is not enough evidence to globally support the efficacy of phlebotonics for chronic venous insufficiency. There is a suggestion of some efficacy of phlebotonics on oedema but this is of uncertain clinical relevance. Due to the limitations of current evidence, there is a need for further randomised, controlled clinical trials with greater attention paid to methodological quality.

Treatment of the common cold with troxerutin

The rutosides are naturally occurring flavonoids that have documented effects on capillary permeability and edema. The purpose of this study was to assess the effect of troxerutin, one of the rutosides, on the symptoms of the common cold. Ninety-four volunteers with common cold symptoms were recruited for participation in the study. Volunteers were randomized to either active treatment (n=49) with troxerutin (50 mg) and Zn gluconate (25 mg) or control treatment (n=45) with 10 mg Zn gluconate. Symptoms were assessed by subjective symptom score prior to treatment and then daily for the next 4 days. The total symptom score over the 4 days of study treatment was 27.7+/-2.0 (mean+/-SEM) and 33.0+/-2.6 in the active and control groups, respectively (p=0.10, unpaired t-test). The total daily symptom score on day 1 was reduced by 11% compared to baseline in the active group and by 1% in the control group (p=0.03). Evaluation of the effect of treatment on individual symptoms revealed a significant effect on rhinorrhea. The total rhinorrhea score over the course of the study was 3.7+/-0.4 in the active group compared to 5.1+/-0.5 in the control group (p=0.025, unpaired t-test). Daily rhinorrhea scores were significantly lower in the active group on study days 1 and 3. Based on this preliminary study, the possibility that the rutosides might provide a safe and effective treatment for rhinorrhea in the common cold deserves systematic evaluation.