With central European approval in January 2016 for a betulin-oleogel (Episalvan), used to accelerate wound closure in partial thickness wounds, the herbal active ingredient triterpene dry extract (betulin), from birch bark, was introduced into therapy for the first time. Clinical evidence of accelerated wound healing was provided in a new study design by means of intraindividual comparison of split-thickness skin graft donor wounds and burn wounds. Clinical results of a phase II study evidencing accelerated wound healing in the rare disease epidermolysis bullosa are also available, and a pivotal multi-centre phase III study is currently being conducted. The mode of action affects all three phases of wound healing (inflammation, migration, and differentiation), and it has been possible, in some cases, to shed light on this down to the molecular level. After temporary stimulation of the inflammatory phase, the keratinocytes migrate more rapidly to the wound closure and, finally, epidermal differentiation is stimulated. With this project, we have shown that scientifically founded new developments in phytotherapy are possible in Europe. The active ingredient is new and its indication is for the first time clearly proven in studies. Betulin-oleogel is the first drug of its indication and is patented until 2030. In addition, it is the first phytotherapeutic agent in surgery, and thus opens up a new therapeutic area for phytotherapy. The birch bark contains about 22% betulin in its cork tissue, meaning that the active ingredient is sustainably available from Northern Europe's wood-processing industry on a scale of several 100,000 t/a.

ZusammenfassungDer pflanzliche Wirkstoff Triterpentrockenextrakt (Betulin) aus der Birkenrinde wurde durch 2 weltweit patentierte Erfindungen, die „Betulin-Emulsion“ und das „Betulin-Oleogel“, für die Anwendung an der Haut erschlossen. Die tensidfreie Betulin-Emulsion führte zur Entwicklung der Kosmetikserie Imlan. Systematische kosmetische Studien zeigten eine Schutzwirkung von Imlan gegen den irritierenden Effekt von starken Tensiden, die als Emulgatoren oder Schaumbildner Verwendung fanden und finden, wie z. B. Natriumdodecylsulfat.Das wasserfreie Betulin-Oleogel wurde zum Arzneimittel Episalvan mit dem klinischen Nachweis der beschleunigten Wundheilung entwickelt. Im Januar 2016 erfolgte die zentrale europäische Zulassung für das Arzneimittel.

ZusammenfassungDas Projekt umfasst die Erschließung des pflanzlichen Wirkstoffs Triterpentrockenextrakt (Betulin) aus der Birkenrinde für die Wundheilung:▪ mit den weltweit patentierten Erfindungen der „Betulin-Emulsion“ und des „Betulin-Oleogels“,▪ dem innovativen klinischen Nachweis der beschleunigten Wundheilung,▪ der publizierten Aufklärung der Wirkweise bei der Wundheilung bis auf die molekulare Ebene▪ und der zentralen Europäischen Zulassung mit Qualitäts-, Unbedenklichkeits- und Wirksamkeitsnachweis im Januar 2016 für das Arzneimittel Episalvan.Mit diesem Projekt haben wir gezeigt, dass wissenschaftlich fundierte Neuentwicklungen in der Phytotherapie in Europa möglich sind. Der Wirkstoff ist neu und die Indikation ist erstmals mit Studien evident belegt. Episalvan ist das erste Arzneimittel seiner Indikation und bis 2030 patentgeschützt. Zugleich ist es das erste Phytotherapeutikum in der Chirurgie, erschließt also ein neues Therapiefeld für die Phytotherapie.Die Birkenrinde enthält in dem weißen Korkgewebe durchschnittlich 22 % Betulin, sodass der Wirkstoff nachhaltig aus der holzverarbeitenden Industrie Nordeuropas im Maßstab von mehreren 100 000 t jährlich zur Verfügung steht. Neben seinem höchsten Wert als Arzneimittel haben wir mit dem Aufbau eines innovativen kontinuierlichen Extraktionsverfahrens eine bisher ungenutzte pflanzliche Feinchemikalie der nachhaltigen industriellen Nutzung deutlich nähergebracht.

The acceleration of wound healing is a major surgical concern. A triterpene extract from birch bark (Betulae cortex) experimentally enhances keratinocyte differentiation in vitro and accelerates wound healing ex vivo. We conducted an open, blind-evaluated, controlled, prospective, randomized (1:1) phase II clinical trial in patients requiring split-thickness skin graft transplantation at two university hospitals in Germany. Donor sites on the upper legs were covered with a moist silicone-coated dressing. Oleogel-S10 ointment containing 10% birch bark extract was randomly applied to the distal or proximal half of the wound, with the other half serving as an intraindividual control, for 14 days after the skin graft surgery. The primary efficacy variable was faster reepithelialization as determined from macrophotographs by independent, blinded experts. Twenty-four patients were randomized and completed the trial. After the 14-day test period, the planned interim analysis revealed a highly significant (p < 0.0001) superiority of Oleogel-S10 in the primary efficacy variable and the trial was terminated early due to ethical concerns. The treatment side was also better reepithelialized and more similar to normal skin after 3 months. In conclusion, Oleogel-S10 significantly accelerated reepithelialization at split-thickness skin graft donor sites. Treatment with Oleogel-S10 was safe and well tolerated. i 2014 S. Karger AG, Basel

Purpose Mistletoe extracts are often used in complementary cancer therapy although the efficacy of that therapy is controversially discussed. Approved mistletoe extracts contain mainly water soluble compounds of the mistletoe plant, i.e. mistletoe lectins. However, mistletoe also contains water-insoluble triterpenoids (mainly oleanolic acid) that have anti-tumorigenic effects. To overcome their loss in watery extracts we have solubilized mistletoe triterpenoids with cyclodextrins, thus making them available for in vivo cancer experiments. Experimental design B16.F10 subcutaneous melanoma bearing C57BL/6 mice were treated with new mistletoe extracts containing both water soluble compounds and solubilized triterpenoids. Tumor growth and survival was monitored. In addition, histological examinations of the tumor material and tumor surrounding tissue were performed. Results Addition of solubilized triterpenoids increased the anti-tumor effects of the mistletoe extracts, resulting in reduced tumor growth and prolonged survival of the mice. Histological examination of the treated tumors showed mainly tumor necrosis and some apoptotic cells with active caspase-3 and TUNEL staining. A significant decrease of CD31-positive tumor blood vessels was observed after treatment with solubilized triterpenoids and different mistletoe extracts. Conclusion We conclude that the addition of solubilized mistletoe triterpenoids to conventional mistletoe extracts improves the efficacy of mistletoe treatment and may represent a novel treatment option for malignant melanoma.

Herbal tea can be prepared by infusion or maceration at room temperature resulting in different compositions of extractable constituents, which possibly influences the mode of action or safety profile. Knowledge on this topic is limited. The aim of this study was to investigate the substantial differences between infusion and maceration as recommended preparation methods for the preparation of herbal mistletoe tea, a traditional remedy against cardiovascular diseases. No active substances are known but analytical marker substances such as proteins, triterpenoids, phenylpropane derivatives and flavonoids can be quantified within the herb and the different herbal tea preparations. Whereas phenylpropane derivatives were completely extracted by infusion and maceration, neither method dissolved viscotoxins. 43% of mistletoe lectins were extracted by maceration, whereas by infusion they are inactivated by thermal degradation. By contrast, oleanolic acid and betulinic acid are present in higher concentrations in infusates compared with macerates, but even infusion extracted less than 2%. Infusion extracted 43% of flavonoid-like substances and maceration only 31%. In conclusion this study determines some differences between both extraction methods on the profile of solved substances. The relevance of it should be determined in studies dealing with the efficacy of herbal mistletoe tea.

It has been shown recently that triterpenes inhibit cancer cell growth of various cell types in vitro. In this work, the effect of highly purified triterpenes (TE) with betulin as the major compound (>80% w/w) on cell proliferation, apoptosis, and differentiation of human keratinocytes was analyzed in vitro, ex vivo, and in vivo. In vitro, TE increased calcium influx into primary keratinocytes and upregulated various differentiation markers including keratin 10. TE also specifically increased the expression of the non-selective transient receptor potential canonical (subtype) 6 (TRPC6) in keratinocytes, and knocking down TRPC6 inhibited keratin 10 upregulation. Ex vivo, in human skin explants TE induced the expression of TRPC6 in the epidermis and increased DNA fragmentation of terminally differentiating keratinocytes. Topical treatment with TE of actinic keratoses, that represent in situ squamous cell carcinomas with disturbed epithelial differentiation, resulted in downgrading of aberrant Ki67 expression and upregulation of keratin 10 in vivo. Our data indicate that TE promotes keratinocyte differentiation in vitro and in vivo. This effect seems to be mediated at least in part by TRPC6.

Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of new multi-targeting bioactive agents. Screening of 39 plant materials identified triterpene rich (> 0.1% dry matter) plant parts. Plant materials with high triterpene concentrations were then used to obtain dry extracts by accelerated solvent extraction resulting in a triterpene content of 50 - 90%. Depending on the plant material, betulin (birch bark), betulinic acid (plane bark), oleanolic acid (olive leaves, olive pomace, mistletoe sprouts, clove flowers), ursolic acid (apple pomace) or an equal mixture of the three triterpene acids (rosemary leaves) are the main components of these dry extracts. They are quantitatively characterised plant extracts supplying a high concentration of actives and therefore can be used for development of phytopharmaceutical formulations.

JDDG: Journal der Deutschen Dermatologischen GesellschaftVolume 7, Issue 2 p. 128-134 Therapie von aktinischen Keratosen mit einem neuen Betulin-basierten Oleogel; eine prospektive, randomisierte, vergleichende Pilotstudie Constance Huyke, Constance Huyke Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorJuliane Reuter, Juliane Reuter Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorMirko Rödig, Mirko Rödig Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorAstrid Kersten, Astrid Kersten Dermato-Histopathologie Dr. Laaff, Sasbacher Str. 10, D-79111 FreiburgSearch for more papers by this authorMelanie Laszczyk, Melanie Laszczyk Birken GmbH, Streiflingsweg 11, D-75223 Niefern-ÖschelbronnSearch for more papers by this authorArmin Scheffler, Armin Scheffler Birken GmbH, Streiflingsweg 11, D-75223 Niefern-ÖschelbronnSearch for more papers by this authorDorothee Nashan, Dorothee Nashan Studienzentrum für dermatologische Onkologie, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorChristoph Schempp, Christoph Schempp Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this author Constance Huyke, Constance Huyke Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorJuliane Reuter, Juliane Reuter Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorMirko Rödig, Mirko Rödig Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorAstrid Kersten, Astrid Kersten Dermato-Histopathologie Dr. Laaff, Sasbacher Str. 10, D-79111 FreiburgSearch for more papers by this authorMelanie Laszczyk, Melanie Laszczyk Birken GmbH, Streiflingsweg 11, D-75223 Niefern-ÖschelbronnSearch for more papers by this authorArmin Scheffler, Armin Scheffler Birken GmbH, Streiflingsweg 11, D-75223 Niefern-ÖschelbronnSearch for more papers by this authorDorothee Nashan, Dorothee Nashan Studienzentrum für dermatologische Onkologie, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this authorChristoph Schempp, Christoph Schempp Kompetenzzentrum Skintegral®, Universitäts-Hautklinik, Universitätsklinikum Freiburg, Hauptstr. 7, D-79102 FreiburgSearch for more papers by this author First published: 26 January 2009 https://doi.org/10.1111/j.1610-0387.2008.06865_supp.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume7, Issue2February 2009Pages 128-134 RelatedInformation

During the last two decades triterpenes have attracted attention because of their pharmacological potential. Triterpene extract (TE) from outer bark of birch consisting mainly of betulin is able to form an oleogel which was successfully tested in the treatment of actinic keratosis. Some aspects of TE in vitro pharmacology are already known. Now we show preliminary pharmacokinetics of betulin and results of a subchronic toxicity study of TE in rats and dogs. Because of poor aqueous solubility of the TE-triterpenes (< 0.1 microg/mL respectively), for pharmacokinetic studies it was suspended in sesame oil (rats, i.p.) and PEG 400 / 0.9 % NaCl (dogs, s.c.). I.p. administered, betulin, the main component of TE, shows time dependency over a period of 4 h and reaches a dose-independent serum level of 0.13 microg/mL. Dose dependency was observed with s.c. administration. At 300 mg/kg a maximum plasma concentration of 0.33 microg/mL betulin was detected after 28 daily applications. The subchronic toxicity study showed no toxicity of TE in rats (i.p.) and dogs (s.c.). In conclusion, triterpene extract from birch bark is safe, its betulin is bioavailable and in addition to published triterpene biological activities TE provides high potential for further pharmaceutical and pharmacological research.

Mistletoe (Viscum album L.) contains the triterpene acids oleanolic acid (OA) and betulinic acid (BA), which were found to have anti-tumour properties. In this study, the solubilities of OA and BA were studied in water (up to 0.02 microg/mL in each case) and in alkaline solutions of 10 mM trisodium phosphate (pH 11.5; OA: 77.2 microg/mL; BA: 40.1 microg/mL). Furthermore, triterpene acids were quantified in aqueous mistletoe extracts (pH 7.3; drug to extract ratio 1:25). OA (1.1 microg/mL) and BA (0.9 microg/mL) were extracted with a yield of less than 5%. Preparing plant extracts with basic pH values resulted in a triterpene acid content of 9.3 microg/mL OA and 5.2 microg/mL BA (pH 12.1), reaching neither the solubility limits nor a complete extraction of the plant material. The triterpene acid content of neutral plant extracts above the solubility limit could be due to interactions with biocolloids. Interaction studies were performed by gel permeation chromatography. Different mechanisms of the dissolution at pH 7.3 and pH 10.2 are discussed.

Triterpenes are biologically active secondary plant substances that display antimicrobial, hepatoprotective and anti-inflammatory effects. However, the poor solubility of triterpenes in both polar and non-polar solvents as well as expensive purification procedures have prevented the large-scale isolation of these compounds for medicinal purposes. Here, we describe a novel quantitative extraction method of triterpenes from the outer bark of birch (Betula species) in which betulin, a lupan triterpene, predominates. The resulting highly purified triterpene extract (TE) in the form of a dry powder contains betulin as the major compound, but also betulinic acid, lupeol, erythrodiol and oleanolic acid. We have found that this TE is able to form an oleogel, thus providing an opportunity for the topical application of pharmacologically relevant amounts of triterpenes. Furthermore, we have investigated the TE in comparison to its major isolated compounds in cell culture experiments with human immortalized keratinocytes and skin cancer cells. We could demonstrate dose-dependent cytotoxic and apoptosis-inducing effects of TE and betulin. These experimental data support the notion from a previous clinical study that TE from the outer bark of birch might represent a new tool for the topical treatment of skin cancer and skin cancer precursors like actinic keratoses.

Summary Background: Birch bark contains a variety of apoptosis‐inducing and anti‐inflammatory substances such as betulinic acid, betulin, oleanolic acid and lupeol. Therefore, birch bark extract may be effective in the treatment of actinic keratoses. To address this issue, a pilot study using a standardized birch bark ointment was performed. Methods: Twenty‐eight patients with actinic keratoses were enrolled in this prospective, non‐randomized pilot study. Fourteen patients were treated with birch bark ointment only; fourteen patients received a combination therapy with cryotherapy and birch bark ointment. Treatment response was assessed clinically after two months. Results: Clearing of more than 75 % of the lesions was seen in 79 % of the patients treated with birch bark ointment monotherapy. The response rate of the combined treatment modality was 93 %. Therapy with birch bark ointment was well tolerated. Conclusion: In this pilot study, a standardized birch bark extract was effective in the treatment of actinic keratoses. This therapy is easy to perform and it has no side effects. Birch bark ointment may be a new therapeutic option for actinic keratoses.

Summary Background: Birch bark contains a variety of apoptosis‐inducing and anti‐inflammatory substances such as betulinic acid, betulin, oleanolic acid and lupeol. Therefore, birch bark extract may be effective in the treatment of actinic keratoses. To address this issue, a pilot study using a standardized birch bark ointment was performed. Methods: Twenty‐eight patients with actinic keratoses were enrolled in this prospective, non‐randomized pilot study. Fourteen patients were treated with birch bark ointment only; fourteen patients received a combination therapy with cryotherapy and birch bark ointment. Treatment response was assessed clinically after two months. Results: Clearing of more than 75 % of the lesions was seen in 79 % of the patients treated with birch bark ointment monotherapy. The response rate of the combined treatment modality was 93 %. Therapy with birch bark ointment was well tolerated. Conclusion: In this pilot study, a standardized birch bark extract was effective in the treatment of actinic keratoses. This therapy is easy to perform and it has no side effects. Birch bark ointment may be a new therapeutic option for actinic keratoses.

Mistletoe (Viscum album L.) extracts, used in cancer therapy, contain several antitumor and immunologically active ingredients of which the cytotoxic mistletoe lectins and the immunoactive vesicles of chloroplast membranes are particularly important. We have investigated interactions between vesicles and lectins with respect to the question of synergistic or antagonistic effects. First we used biochemical methods. Lectin binding to vesicles was dependent on the pH-value and ionic strength of the buffers used. The strongest interaction was observed at low pH-values and at low ionic strength. Using immunological methods, we found that the combination of lectins and vesicles showed a strong amplifying synergistic effect on the stimulation of lymphocyte proliferation. We found an antagonistic effect in terms of cytotoxicity. In summary, these results demonstrate a significant influence of vesicles on all commonly used methods of determination of mistletoe lectins.

Mistletoe (Viscum album L.) extracts, used in cancer therapy, contain several antitumor and immunologically active ingredients of which the cytotoxic mistletoe lectins and the immunoactive vesicles of chloroplast membranes are particularly important. We have investigated interactions between vesicles and lectins with respect to the question of synergistic or antagonistic effects. First we used biochemical methods. Lectin binding to vesicles was dependent on the pH-value and ionic strength of the buffers used. The strongest interaction was observed at low pH-values and at low ionic strength. Using immunological methods, we found that the combination of lectins and vesicles showed a strong amplifying synergistic effect on the stimulation of lymphocyte proliferation. We found an antagonistic effect in terms of cytotoxicity. In summary, these results demonstrate a significant influence of vesicles on all commonly used methods of determination of mistletoe lectins.

The shear rate in thin liquid film flow on a rotating disk is governed by the flow rate of the polymer solution and the rotation rate of the disk. Despite this fact we show that shear degradation is determined solely by the rotation rate, whereas a variation of the flow rate has no distinct effect. Also no significant influence of the polymer concentration in a range of 1–10 mg/ml could be observed. Threshold values of the rotation rate that cause shear degradation in different samples of dextran and purified polysaccharides of Viscum album L. berries are reported and changes in the molecular weight distributions of these samples are shown. Some of the polymers are presumably deformed in their geometrical shape under the influence of shearing. In gel permeation chromatography these polymers are eluted after polymers with lower masses, so that most probably the hydrodynamic radii of the deformed polymer particles are smaller while their molar masses are larger. A mathematical analysis of the light scattering data gives evidence to this assumption. Degradation rates of the dextran samples are compared with results of a previous study.

An aqueous mistletoe extract containing liposome-like vesicles from chloroplast membranes develops a photohaemolytic activity, which is a function of the temperature. This is correlated with the degradation of chlorophyll. The photolytic activity of the chlorophyllides initially produced in the process was detected by haemolysis. The quantification of the chlorophyllides was performed using HPLC. On being exposed to light, the isolated green vesicle fraction bleaches out extremely rapidly in the presence of traces of oxygen. In this process, the photolytic activity also disappears. In crude extracts, this only occurs to a small extent.

Mistletoe (Viscum album) extracts are widely used in adjuvant cancer therapy. We have investigated the in vitro responsiveness of T cells from mistletoe-treated cancer patients and untreated healthy donors to various preparations of mistletoe extracts. Proliferation of peripheral blood mononuclear cells from treated but not from untreated patients was observed in response to therapeutically used mistletoe extracts prepared from apple (mali) or pine (pini) host trees. The strongest proliferation was induced by a vesicle preparation of mali extract. Activation was strongly inhibited by interleukin-10. Using a newly developed flow-cytometry assay, we determined that cell growth was restricted to CD4 T cells. Analysis with a panel of monoclonal antibodies against the variable region of the T cell receptor β chain (Vβ) revealed an oligoclonal pattern of CD4 T cell activation. These results indicate that therapeutic administration of mistletoe extracts sensitizes a restricted set of CD4 T lymphocytes in mistletoe-treated patients.