INTRODUCTION
Understanding the pathogenesis of chronic venous disease (CVD) and the clinical consequences of venous hypertension has motivated the search for successful treatments for this condition [1, 2]. The wide range of clinical presentations and patient complaints related to CVD often require complex treatments based on lifestyle modification, the use of compression stockings, pharmacotherapy, and/or surgical or other minimally invasive treatments [2].
Pharmacotherapy is an important component of CVD treatment, and a wide range of drugs is currently available [2, 3]. Despite the number of medications used and suggested for the treatment of CVD, the evidence-based confirmation of the efficacy of many of these drugs remains limited. A lack of properly designed trials and poor quality research cause significant difficulties in creating guidelines for proper CVD treatment. According to the guidelines proposed by the European Society for Vascular Surgery (2015), venoactive drugs should be considered as a treatment option for the swelling and pain caused by chronic venous disease [4]. The guidelines proposed by the American Venous Forum and the Society for Vascular Surgery published 4 years earlier suggest the use of this group of drugs for patients with pain and swelling due to chronic venous disease in countries where these drugs are available [5].
In a document published in 2014 (Management of the Chronic Venous Disease of the Lower Limbs: Guidelines According to the Scientific Evidence), Nicolaides et al. proposed using grades to recommend the use of venoactive drugs for the “relief of symptoms associated with CVD in patients in CEAP classes C0s to C6s and those with venous edema (CEAP class C3)” [2].
Pharmacological treatment grading proposals have been suggested in 2005 in an International Consensus Statement by Ramelet et al. and in 2008 in a Guideline Document proposed by Nicolaides et al. [3, 6]. Based on previous guideline documents and the available literature, in new guidelines introduced in 2014, the quality of EBM studies was assessed as moderate for the use of micronized purified flavonoid fraction (MPFF), rutosides, red vine leaf extracts, calcium dobesilate, horse chestnut seed extract, and Ruscus extract, and the quality of evidence for the use of non-micronized or synthetic diosmins, Ginkgo biloba, and other venoactive drugs was assessed as poor [2]. Based on an evaluation of the literature, a strong recommendation (Grade 1B according to the GRADE system) was proposed only for MPFF, and a weak recommendation was given for the use of the other abovementioned drugs, with a grade 2B recommendation for rutosides, red vine leaf extract, calcium dobesilate, Ruscus extract and horse chestnut seed extract and a grade 2C recommendation for non-micronized or synthetic diosmins and Ginkgo biloba [2].
Ongoing research on CVD pathogenesis and new clinical data on pharmacological treatments and their efficacy change our understanding of the goals and possibilities of pharmacological treatment. From the clinical point of view, effects on vein tonus, decreased swelling due to improved lymphatic drainage and decreased permeability of microcirculatory vessel walls, endothelially protective effects, and anti-inflammatory and inflammation inhibitory effects are the primary components expected of many phlebotropic drugs [2, 3]. Despite laboratory data confirming some of these activities, the often subjective character of the reported symptoms related to CVD, as well as the variety of clinical presentations, cause difficulties when attempting to objectively document the positive clinical effects of a particular drug.
As new studies aiming to find new targets for pharmacological treatment are proposed, there is an urgent need for the unification of study outcome criteria and their assessment in the field of CVD research. Many currently available studies use CEAP classification as well as the VAS (visual analog scale) as bases for the evaluation of patients and disease states, but quality of life and symptom assessments are necessary for the more precise evaluation of the efficacy of pharmacological treatments. The use of more complex complaint-oriented scales including the VCSS (Venous Clinical Severity Score) or a dedicated quality of life evaluation such as CIVIQ or VEINES-QOL/Sym questionnaires has been proposed [2, 7]. In this context, when searching for evidence-based justifications for the use of a particular venotonic agent, the potential role of properly performed studies should be emphasized.
RUSCUS ACULEATUS EXTRACT AND RELATED COMPOUNDS: LABORATORY RESEARCH AND CLINICAL ACTIVITY
Ruscus aculeatus extract contains two major saponins: ruskogenin and neuroruskogenin. According to previous studies, the extract contains other saponins (including ruscin and ruscoside), many of which have described anticancer activities [8, 9]. Along with saponins, Ruscus aculeatus extract contains flavonoids, sterols (sitosterol, stigmasterol, and kempesterol), tyramine, coumarin, triterpens, lignoceric acid, glycolic acid, and benzofuranes [10-14]. Ruscus aculeatus extract has been used for many years to decrease sensations of leg heaviness and leg swelling. Among its confirmed activities, one of the major effects of Ruscus extract is the vasoconstrictive activity related to α-1 and α-2 receptor agonism in the vessel wall and the release of norepinephrine from adrenergic nerve endings [15-18]. Recently, new pathways of Ruscus extract activity have been discovered, suggesting a role for muscarinic receptor agonism. Acethylocholine muscarinic and nicotinic receptors are responsible for many different activities at the molecular and tissue levels, and muscarinic receptors are present on endothelial cells. As documented by Bouskela, muscarinic receptor agonism (expressed by Ruscus extract compounds) is at least partially responsible for venule vasoconstriction [19].
According to previous studies, Ruscus extract has effects not only on veins but also on the lymphatic and capillary vessels [15]. Various mechanisms for the activity of Ruscus extract in protecting microcirculation have been suggested, including vessel vasoconstriction leading to decreased venous hypertension and local protective activity related to endothelial cell protection and anti-inflammatory properties [15-17]. An important benefit of the administration of Ruscus aculeatus extract is the inhibition of histamine-induced increased vessel wall permeability [15, 20]. Ruscus extract also affects the early phase of inflammatory reactions, leading to the decreased rolling and adherence of leucocytes to the venous wall. According to recent research, both of the abovementioned processes are at least partially controlled by the muscarinic receptor pathway [15, 19]. In previous studies, the anti-inflammatory properties of Ruscus extract were also explained by an effect on the activation of adhesive molecule (ICAM-1) expression, and a role for Ruscus extract in the action of anti-elastase on decreased vessel wall permeability was suggested [21, 22]. Vasoconstrictive Ruscus activity appears to be hormone dependent; in a study by Miller et al., venous vasoconstriction increases in the presence of increased progesterone levels [23]. The benefits of Ruscus extract have also been documented in the lymphatic system and in lymphedema patients [15]. Among the suggested mechanisms for these benefits, along with the effect of Ruscus on decreased vessel permeability, lymph vessel constriction and increased veno-lymphatic return have been suggested [24, 25].
Concerning the clinical efficacy of Ruscus extract, several studies have examined Ruscus aculeatus extract as an active compound of a therapeutic regimen, but few studies focus on Ruscus extract as a unique pharmacological treatment. In a randomized, placebo controlled study performed on a group of 148 patients with chronic venous disease (using solid Ruscus extract only) Vanscheidt (2002) evaluated the results of Ruscus aculeatus extract administration (in capsules containing 4.5 mg of pure roscogenin administered twice daily) over 12 weeks. The primary endpoint of the study was decreased foot and ankle volume. Secondary parameters were changes in the circumference of the lower leg and ankle, changes in subjective symptoms and quality of life, overall efficacy and tolerability, and safety parameters. The administration of Ruscus aculeatus extract resulted in significant differences between the treatment groups (Ruscus extract capsules vs. placebo) in leg volume as well as changes in ankle and leg circumferences after 8 and 12 weeks. Simultaneously, improvements in subjective CVD symptoms (heavy, tired legs and the sensation of tension) and their severity were observed in patients administered Ruscus aculeatus extract. A positive correlation between changes in leg volume and changes in the symptoms of heavy lower legs, the sensation of tension, and tingling sensations was documented [26].
RUSCUS ACULEATUS EXTRACT AS PART OF THE COMBINED PHARMACOLOGICAL TREATMENT OF CHRONIC VENOUS DISEASE
Ruscus aculeatus extract can be used as an individual treatment or as a mixture with other venotonic substances in combination therapies. In the current classification of venoactive drugs, Ruscus aculeatus extract is considered a saponin. However, as mentioned above, Ruscus extract also contains other biologically active substances, such as flavonoids [3].
Few studies focused on CVD symptom treatment are dedicated to the administration of Ruscus extract alone. Most of the currently available evidence focuses on the evaluation of a commonly used combination of drugs consisting of Ruscus aculeatus extract, hesperidin methyl chalcone (HMC), and ascorbic acid. Trimethyl hesperidin chalcone is a derivative of the flavonoid hesperidin that exhibits various venoprotective effects including a potential influence on the decrease of vessel wall permeability and venous tone [3, 27, 28]. The number of previously performed studies as well as the growing body of evidence concerning this combined treatment allow important clinical conclusions to be drawn.
The positive influence of the combined treatment (Ruscus extract + HMC + ascorbic acid) was confirmed in the laboratory and in clinical studies [15, 27, 28–30]. Similar to the activity of Ruscus extract, the combination of drugs including Ruscus has vasoconstrictive effects based not only on Ruscus activity but also on the properties of HMC [15, 17, 29]. Thebault, testing the activity of the combined treatment (Ruscus extract + HMC+ ascorbic acid; Cyclo 3 Fort, Pier Fabre, France), documented an additive vasoconstriction effect of HMC (the administration of Ruscus extract resulted in a 50% decrease in vein dilation, while the administration of HMC led to a 40% decrease in vein dilation) [30]. Jager conducted a duplex Doppler-based study dedicated to the effect of the same combined treatment (Cyclo 3 Fort) on the deep and superficial venous system and documented the presence of deep vein vasoconstriction with an increase in the flow parameters in the deep vein system of the leg after Cyclo 3 Fort administration [31].
The positive effects of the combined treatment were also confirmed at the microcirculatory level. Bouaziz et al. suggested an influence of the combined drug (Ruscus aculeatus extract, HMC, and ascorbic acid) on endothelial cell protection. In this study, Ruscus extract inhibited the hypoxia-induced activation of endothelial cells (resulting in decreased ATP content, phospholipase A2 activation, and increased neutrophil adherence to endothelial cells). According to this study, both Ruscus extract and HMC were able to reduce a hypoxia-induced decrease in ATP, and the effect of the combined treatment appears to be additive [32]. In another study, Bouskela et al. documented the influence of the abovementioned pharmacological treatment on the microvascular permeability induced by various agents in hamster cheek pouches [17]. The effect of the combined treatment (Ruscus, HMC, and ascorbic acid) on capillary wall permeability was also documented in diabetic patients [33].
Clinical plethysmographic studies have also produced interesting results. Bocccalon performed a double blind, placebo-controlled study with Ruscus extract, HMC, and ascorbic acid in 20 CVD patients and examined heat-induced vein distension and post-occlusion venous flow plethysmographically. According to the results of this study, the proposed pharmacological treatment decreased induced vein distention and improved normal vein drainage compared with the placebo group [34]. Improvements to venous tone and capillary sealing were confirmed after treatment with the combination of Ruscus extract, hesperidin methyl chalcone, and ascorbic acid in other studies [27, 28]. Rudofsky assessed venous capacity (VC) reduction and tissue volume decreases after the administration of the abovementioned treatment in healthy volunteers and documented a statistically significant decrease in both parameters [27]. In another clinical, prospective, capillaroscopy assessment-based study, in a group of 124 CVD patients treated pharmacologically for 8 weeks with the combined treatment, decreased CVD symptom severity (including heaviness, cramps, and edema) corresponded with decreased intracapillary fluid collection, reduced efferent loop thickening, decreased pericapillary beds, and decreased megacapillaries upon capillaroscopic examination [35]. In another recently published prospective study, the combination of Ruscus extract, HMC, and ascorbic acid was used in a group of 65 women (class C2s and C3s), and significant improvements in the plethysmographically evaluated venous refilling time correlated with improvements in functional CVD symptom severity [36].
Several other studies have documented the positive influence of combined Ruscus-based drug therapy on CVD symptom severity and on decreased leg edema [15, 37, 38]. Rieger, in a randomized, controlled, double-blind study performed in an orthostatic position, documented a significant decrease of calf and foot swelling after treatment with Ruscus extract, HMC, and ascorbic acid [37]. Cluzan treated patients with secondary lymphedema of the upper limb after breast cancer therapy with Cyclo 3 Fort or placebo and documented an arm volume reduction of 12.9% after 3 months of therapy [25]. Di Pieri, in a placebo controlled study performed in Italy with Ruscus aculeatus extract, HMC, and ascorbic acid (Cyclo 3 Fort), reported a statistically significant improvement in CVD-related symptoms [39]. Guex et al., in a study performed on Latin American patients, observed a significant decrease in CVD clinical symptom severity and a significant improvement in the quality of life in C0s-C3 CVD patients [40]. A meta-analysis of the efficacy of the combination of Ruscus extract, HMC, and ascorbic acid for the treatment of chronic venous disease patients was presented by Boyle et al. [41]. In this analysis, the results of 20 placebo controlled randomized double blind studies and 5 randomized studies against a comparison drug in patients with CVD were evaluated (the study population included 10,246 patients). The combined treatment significantly reduced the severity of pain, heaviness, cramps, and paresthesia. A reduction in the severity of leg edema and decreases in calf and ankle circumference were also observed, but these differences were not statistically significant [41].
Very few head to head comparisons of phlebotropic drugs have been performed. In 1999, a comparison of Cyclo 3 Fort and hydroxyethylrutosides in chronic venous and lymphatic incompetence was performed by Beltramino et al. [42]. In this study, the symptoms of chronic venous lymphatic insufficiency, including heavy, tired, and swollen legs or leg pain were evaluated at baseline and after 30, 60, and 90 days of treatment. In both groups, a reduction in CVD complaints was observed, which was more rapid in the group of patients administered Cyclo 3 Fort. Both groups exhibited reduced swelling, but after 90 days of treatment, this reduction was observed only in the group treated with Cyclo 3 Fort [42]. In another study, the efficacy of the combined treatment (Ruscus extract, HMC, and ascorbic acid) was compared with the administration of micronized diosmin [43]. In this randomized study of 100 patients, the reduction of symptoms (heavy legs, cramps, breast tension, pelvic congestion, edema of the lower limbs) and reduced ankle circumference were found in both groups with equivalent efficacy, but the initial decrease in symptom severity was more rapid in patients taking a Ruscus-containing drug regimen (symptoms were evaluated when treatment began, and 15 and 60 days after the start of treatment).
To summarize the available EBM-based knowledge on the efficacy of Ruscus aculeatus extract, HMC, and ascorbic acid (constituents of Cyclo 3 Fort) in improving individual venous symptoms and edema, a systematic review and meta-analysis of randomized double-blind placebo-controlled trials was recently presented by Kakkos and Allaert. [44]. This meta-analysis focused on 10 RCTs including 719 patients with CVD symptoms; the influence of pharmacological treatment with Cyclo 3 Fort on patients with leg edema was also analyzed [25, 38, 44-51]. According to the results, Ruscus extract, HMC, and ascorbic acid were statistically superior to placebo in reducing all analyzed CVD symptoms, including both global symptoms and the number of symptoms in a qualitative analysis. When analyzing individual CVD-related leg symptoms, statistically significant reductions in leg pain, heaviness, fatigue, sensations of swelling, cramps, pruritus, and paresthesia were observed. Ruscus-based therapy was also found to be superior to placebo at significantly reducing objectively estimated venous edema. Observations based on qualitative evaluations confirmed a significant reduction in global symptoms, as well as in pain and heaviness, analyzed as both continuous and categorical variables. The severity of cramps, pruritus, and paresthesia were reduced when assessed as continuous variables but not when evaluated as categorical variables. In the treatment of leg edema, Ruscus-based therapy statistically significantly reduced ankle circumference in comparison with placebo. The authors of this meta-analysis conclude that based on the high-quality evidence available, Ruscus extract-based pharmacological treatment is highly effective at reducing objectively measured leg edema (ankle circumference and leg/foot volume) as well as CVD symptoms such as leg pain, heaviness, the feeling of swelling, fatigue, cramps, pruritus, and paresthesia, as well as global symptoms and the total number of venous symptoms in patients with CVD. As mentioned above, the meta-analysis performed by Kakkos was based on the evaluation of randomized prospective trials and on the selection of high-quality trials. The conclusion of this analysis is also supported by a number of prospective observational studies and laboratory research. Ruscus aculeatus extract (especially in combined treatment with HMC and ascorbic acid) is among those drugs with high-quality evidence for their clinical efficacy in CVD treatment. As in most studies, a wide range of CVD patients was enrolled, and future studies should focus on the selection of patients with the highest clinical benefit from the implementation of pharmacological treatment.
CONCLUSIONS
The variety of possibilities for the pharmacological treatment of chronic venous disease enables pharmacological intervention using various compounds that address different mechanisms of chronic venous disease-related pathology. Despite a relatively extensive theoretical background and previous laboratory research, the clinical efficacy of pharmacological treatment requires clinical proof based on properly performed clinical studies. The current evidence concerning Ruscus aculeatus extract as a component of combined treatment (with HMC and ascorbic acid) suggests the need to upgrade the position of this drug in the current CVD pharmacotherapy guidelines.
The author declares no conflict of interest.
References
1. Bergan J.J., Schmid-Schönbein G.W., Smith P.D., Nicolaides A.N., Boisseau M.R., Eklof B. Chronic venous disease. N Engl J Med 2006; 355: 488-498.
2. Nicolaides A, Kakkos S, Eklof B, Perrin M, Nelzen O, Neglen P, Partsch H, Rybak Z. Management of chronic venous disorders of the lower limbs – guidelines according to scientific evidence. Int Angiol 2014; 33: 87-20.
3. Ramelet A.A., Boisseau M.R., Allegra C., Nicolaides A., Jaeger K., Carpentier P., Cappelli R., Forconi S. Veno-active drugs in the management of chronic venous disease. An international consensus statement: current medical position prospective views and final resolution. Clin Hemorheol Microcirc 2005; 33: 309-319.
4. Editor’s Choice – Management of Chronic Venous Disease: Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS). Wittens C., Davies A.H., Bćkgaard N., Broholm R., Cavezzi A., Chastanet S., de Wolf M., Eggen C., Giannoukas A., Gohel M., Kakkos S., Lawson J., Noppeney T., Onida S., Pittaluga P., Thomis S., Toonder I., Vuylsteke M., Kolh P., de Borst G.J., Chakfé N, Debus S, Hinchliffe R, Koncar I, Lindholt J, de Ceniga M.V., Vermassen F., Verzini F., De Maeseneer M.G., Blomgren L., Hartung O., Kalodiki E., Korten E., Lugli M., Naylor R., Nicolini P., Rosales A.; European Society for Vascular Surgery. Eur J Vasc Endovasc Surg 2015; 49: 678-737.
5. Gloviczki P., Comerota A.J., Dalsing M.C., Eklof B.G., Gillespie D.L., Gloviczki M.L., Lohr J.M., McLafferty RB, Meissner MH, Murad MH, Padberg FT, Pappas PJ, Passman MA, Raffetto J.D., Vasquez M.A., Wakefield T.W.; Society for Vascular Surgery; American Venous Forum. The care of patients with varicose veins and associated chronic venous diseases: clinical practice guidelines of the Society for Vascular Surgery and the American Venous Forum. J Vasc Surg 2011; 53 (5 Suppl): 2S-48S.
6. Nicolaides A.N., Allegra C., Bergan J., Bradbury A., Cairols M., Carpentier P. Management of chronic venous disorders of the lower limbs: guidelines according to scientific evidence. Int Angiol 2008; 27: 1-5.
7. Perrin M., Eklof B., van Rij A., Labropoulos N., Vasquez M., Nicolaides A., Blattler W., Bouhassira D., Bouskela E., Carpentier P., Darvall K., Maeseneer M., Flour M., Guex J.J., Hamel-Desnos C., Kakkos S., Launois R., Lugli M., Maleti O., Mansilha A., Neglén P, Rabe E., Shaydakov E. Venous symptoms: the SYM Vein Consensus statement developed under the auspices of the European Venous Forum. Int Angiol 2016; 35: 374-398.
8. Mimaki Y., Kuroda M., Kameyama A., Yokosuka A., Sashida Y. Aculeoside B, a new bisdesmosidic spirostanol saponin from the underground parts of Ruscus aculeatus. J Nat Prod 1998; 61: 1279-1282.
9. Mimaki Y., Kuroda M., Yokosuka A., Sashida Y. A spirostanol saponin from the underground parts of Ruscus aculeatus. Phytochemistry 1999; 51: 689-692.
10. Mimaki Y., Kuroda M., Kameyama A., Yokosuka A., Sashida Y. New steroidal constituents of the underground parts of Ruscus aculeatus and their cytostatic activity on HL-60 cells. Chem Pharm Bull (Tokyo) 1998; 46: 298-303.
11. De Marino S., Festa C., Zollo F., Iorizzi M. Novel steroidal components from the underground parts of Ruscus aculeatus L. Molecules 2012; 17: 14002-14014.
12. Barbič M., Schmidt T.J., Jürgenliemk G. Novel phenyl-1-benzoxepinols from butcher’s broom (Rusci rhizoma). Chem Biodivers 2012; 9: 1077-1083.
13. Dunouau C., Bellé R., Oulad-Ali A., Anton R., David B. Triterpenes and sterols from Ruscus aculeatus. Planta Med 1996; 62: 189-190.
14. de Combarieu E., Falzoni M., Fuzzati N., Gattesco F., Giori A., Lovati M., Pace R. Identification of Ruscus steroidal saponins by HPLC-MS analysis. Fitoterapia 2002; 73: 583-596.
15. Jawien A., Bouskela E., Allaert F.A., Nicolaïdes A.N. The place of Ruscus extract, hesperidin methyl chalcone, and vitamin C in the management of chronic venous disease. Int Angiol 2017; 36: 31-41.
16. Bouskela E., Cyrino F.Z., Marcelon G. Effects of Ruscus extract on the internal diameter of arterioles and venules of the hamster cheek pouch microcirculation. J Cardiovasc Pharmacol 1993; 22: 221-224.
17. Bouskela E., Cyrino F.Z., Marcelon G. Possible mechanisms for the venular constriction elicited by Ruscus extract on hamster cheek pouch.J Cardiovasc Pharmacol 1994; 24: 165-170.
18. Berg D. Venous constriction by local administration of ruscus extract. Fortschr Med. 1990; 108: 473-476.
19. Rauly-Lestienne I., Heusler P., Cussac D., Lantoine-Adam F., de Almeida Cyrino F.Z.G., Bouskela E. Contribution of muscarinic receptors to in vitro and in vivo effects of Ruscus extract. Microvasc Res. 2017; 114: 1-11.
20. Bouskela E., Cyrino F.Z., Marcelon G. Possible mechanisms for the inhibitory effect of Ruscus extract on increased microvascular permeability induced by histamine in hamster cheek pouch. J Cardiovasc Pharmacol. 1994; 24: 281-285.
21. Facino R.M., Carini M., Stefani R., Aldini G., Saibene L. Anti-elastase and anti-hyaluronidase activities of saponins and sapogenins from Hedera helix, Aesculus hippocastanum, and Ruscus aculeatus: factors contributing to their efficacy in the treatment of venous insufficiency. Arch Pharm (Weinheim). 1995; 328: 720-724.
22. Huang Y.L., Kou J.P., Ma L., Song J.X., Yu B.Y. Possible mechanism of the anti-inflammatory activity of ruscogenin: role of intercellular adhesion molecule-1 and nuclear factor-kappaB. J Pharmacol Sci 2008; 108: 198-205.
23. Miller V.M., Marcelon G., Vanhoutte P.M. Progesterone augments the venoconstrictor effect of Ruscus without altering adrenergic reactivity. Phlebology 1991; 6: 261-268.
24. Marcelon G., Pouget G., Tisné-Versailles J. Effect of Ruscus on the adrenoceptors of the canine lymphatic thoracic duct. Phlebology 1988; 3, 109-112.
25. Cluzan R.V., Alliot F., Ghabboun S., Pascot M. Treatment of secondary lymphedema of the upper limb with CYCLO 3 FORT. Lymphology. 1996; 29: 29-35.
26. Vanscheidt W., Jost V., Wolna P., Lücker P.W., Müller A., Theurer C., Patz B., Grützner K.I. Efficacy and safety of a Butcher’s broom preparation (Ruscus aculeatus L. extract) compared to placebo in patients suffering from chronic venous insufficiency. Arzneimittelforschung 2002; 52: 243-250.
27. Rudofsky G., Nobbe F. Wirkung eines Kombinationspraparates auf die venekapazitat. Fortschr Med 1982; 100: 1217-1220.
28. Rudofsky G. Improving venous tone and capillary sealing. Effect of a combination of Ruscus extract and hesperidine methyl chalcone in healthy probands in heat stress. Fortschr Med 1989; 107: 55-58.
29. Weindorf N., Schultz-Ehrenburg U. Kontrollierte Studie zur oralen venentonisierung der primären varikosis mit Ruscus aculeatus und trimethylhespiridinchalkon. Z Hautkr 1987; 62: 28-38.
30. Thebault J.J. Untersuchungen zur wirkung eines phlebotonikums. Fortschr Med 1983; 101: 1206-1212.
31. Jager K., Eichlisberger R., Jeanneret C., Lobs K.H. Pharmacodynamic effects of ruscus extract (cyclo – 3 Fort ) on superficial and deep veins in patients with primary varicose veins. Assesmsnet by dupelxsonograoy. Clin Drug Invest 1999; 17: 265-273.
32. Bouaziz N., Michiels C., Janssens D., Berna N., Eliaers F., Panconi E. Effect of Ruscus extract and hesperidin methylchalcone on hypoxia- induced activation of endothelial cells. Int Angiol 1999; 18: 306-312.
33. Svensjö E., Bouskela E., Cyrino F.Z., Bougaret S. Antipermeability effects of Cyclo 3 Fort in hamsters with moderate diabetes. Clin Hemorheol Microcirc 1997; 17: 385-388.
34. Boccalon H. Ciclo 3 Fort (FABROVEN caps) and antagonism of plethysmographic disturbances observed upon exposure to heat: preliminary results. Phlebology 1988; 3 (Suppl 1): 59-62.
35. Aguilar Peralta G.R., Arévalo Gardoqui J., Llamas Macías F.J., Navarro Ceja V.H., Mendoza Cisneros S.A., Martínez Macías C.G. Clinical and capailaroscopic evaluation in the teratment of chronic venous insufficiency with Ruscus aculeatus, hesperidin methylchalcone and ascorbinic acid in venous insufficiency treatment of ambulatory patients. Int Angiol 2007; 26: 378-384.
36. Allaert F.A., Hugue C., Cazaubon M., Renaudin J.M., Clavel T., Escourrou P. Correlation between improvement in functional signs and plethysmographic parameters during venoactive treatment (Cyclo 3 Fort). Int Angiol 2011; 30: 272-277.
37. Rieger H. Efficacy of a combination drug in patients with chronic venous insufficiency under orthostatic conditions. Phlebology 1988; 3(Suppl 1): 127-130.
38. Cappelli R., Nicora M., Di Perri T. Use of extract of Ruscus aculeatus in venous disease in the lower limbs. Drugs Exp Clin Res 1988; 14: 277-283.
39. Di Pierri T., Agus G.B. Clinical research with Cyclo 3 in Italy. Phlebology 1988; 3(Suppl 1): 131-132.
40. Guex J.J., Avril L., Enrici E., Enriquez E., Lis C., Taïeb C. Quality of life improvement in Latin American patients suffering from chronic venous disorder using a combination of Ruscus aculeatus and hesperidin methyl-chalcone and ascorbic acid (quality study). Int Angiol 2010; 29: 525-532.
41. Boyle P., Diehm C., Robertson C. Meta-analysis of clinical trials of Cyclo 3 Fort in the treatment of chronic venous insufficiency. Int Angiol 2003; 22: 250-262.
42. Beltramino R., Penenory A., Buceta A.M. An open-label randomized multicenter study comparing the efficacy and safety of cyclo -3 fort versus hydroxy ethyl rutoside in chronic venous lymphatic insufcicency. Angiology. 2000; 51: 535-544.
43. Monteil Seurin J. Insuffissance veino lymphatique; étude comparative de Cyclo 3 Fort (Fabroven) versus Diosmine micronisée. Comptes Rendus de Thérapeutique et de Pharmacologie Clinique 1993; 109: 3-7.
44. Kakkos S.K., Allaert F.A. Efficacy of Ruscus extract, HMC and vitamin C, constituents of Cyclo 3 fort®, on improving individual venous symptoms and edema: a systematic review and meta-analysis of randomized double-blind placebo-controlled trials. Int Angiol 2017; 36: 93-106.
45. Altenkamp H. Efficacy of antivaricotic drugs can be measured objectively. Phlebologie in der Praxis 1987; 2: 9-20
46. Elbaz C., Nebot F., Reinharez D. Insuffisance veineuse des membres inférieurs étude controleé de l’action du Cyclo 3. Phlébologie 1976; 29: 77-84.
47. Le Devehat C., Lemoine A., Roux E., Cirette B., Vimeux M., Martinaggi P. Aspects clinique et hémodynamique de Cyclo 3 dans l’insuffisance veineuse. Angéiologie 1984; 3: 119-122.
48. Parrado F., Buzzi A. A study of the efficacy and tolerability of a preparation containing Ruscus aculeatus in the treatment of chronic venous insufficiency of the lower limbs. Clin Drug Investig 1999; 18: 255-61
49. Questel R., Walrant P. Bilan de l’essai randomisé Veinobiase contre placebo dans l’unsuffisance veineuse: observation de la microcirculation per capillarographie conjonctivale. Gazette Medicale de France 1983; 90: 508-14
50. Rudofsky G., Diehm C., Gruß J.D., Hartmann M., Schultz-Ehrenburg H.K., Bisler H. Chronic venous insufficiency. Treatment with Ruscus extract and trimethylhesperidin chalcone. MMW Munch Med Wochenschr 1990; 132: 205-210.
51. Sentou Y., Bernard-Fernier M.F., Demarez J.P., Laurent D., Cauquil J. Symptomatologie et pléthysmographie: Parallélisme des resultants obtenus lors d’un traitement par Cyclo 3 de patientes porteuses d’une insuffisance neineuse chronique (étude en double insu contre placebo). Gazette Medicale 1985; 92: 73-77.
