[Treatment of actinic keratoses with birch bark extract: a pilot study]

Structured Emulgels by Interfacial Assembly of Terpenes and Nanochitin

Interfacial assemblies formed by colloidal complexation are effective in multiphase stabilization, as shown in structured liquids and Pickering emulgels. Herein, we demonstrate a type of biobased colloidal system that spontaneously stabilizes an organic phase in a continuous hydrogel phase. Specifically, a triterpene extracted from bark (betulin, BE) is added to an organic phase containing a coniferous resin (rosin acid, a diterpene). BE is shown to take part in strong noncovalent interactions with the nanochitin dispersed in the aqueous (hydrogel) phase, leading to a complex of high interfacial activity. The viscoelastic response of the system is rationalized by the presence of a superstable structured dual network. When used as a templating material, the emulgel develops into structured liquids and cryogels. The herein introduced all-biobased type of nanoparticle surfactant system forms a gel ("emulsion-filled" with "aggregated droplets") that features the functional benefits of both betulin and nanochitin.

A Triterpenoid Lupeol as an Antioxidant and Anti-Neuroinflammatory Agent: Impacts on Oxidative Stress in Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease illustrated by neuronal dysfunctions, leading to memory weaknesses and personality changes mostly in the aged population worldwide. The exact cause of AD is unclear, but numerous studies have addressed the involvement of oxidative stress (OS), induced by reactive oxygen species (ROS), to be one of the leading causes in developing AD. OS dysregulates the cellular homeostasis, causing abnormal protein and lipid metabolism. Nutrition plays a pivotal role in modulating the antioxidant system and decreases the neuronal ROS level, thus playing an important therapeutic role in neurodegenerative diseases, especially in AD. Hence, medicinal herbs and their extracts have received global attention as a commercial source of antioxidants Lupeol. Lupeol is a pentacyclic triterpenoid and has many biological functions. It is available in fruits, vegetables, and medicinal plants. It has shown effective antioxidant and anti-inflammatory properties, and higher blood-brain barrier permeability. Also, the binding and inhibitory potentials of Lupeol have been investigated and proved to be effective against certain receptor proteins and enzymes in AD studies by computational molecular docking approaches. Therefore, AD-related research has gained interest in investigating the therapeutic effects of Lupeol. However, despite its beneficial effects in AD, there is still a lack of research in Lupeol. Hence, we compiled in this analysis all preclinical research that looked at Lupeol as an antioxidant and anti-inflammatory agent for AD.

Antioxidative and Antimicrobial Evaluation of Bark Extracts from Common European Trees in Light of Dermal Applications

Plant species have developed effective defense strategies for colonizing diverse habitats and protecting themselves from numerous attacks from a wide range of organisms, including insects, vertebrates, fungi, and bacteria. The bark of trees in particular constitutes a number of components that protect against unwanted intruders. This review focuses on the antioxidative, dermal immunomodulatory, and antimicrobial properties of bark extracts from European common temperate trees in light of various skin pathogens, wound healing, and the maintenance of skin health. The sustainability aspect, achieved by utilizing the bark, which is considered a byproduct in the forest industry, is addressed, as are various extraction methods applied to retrieve extracts from bark.

New Herbal Biomedicines for the Topical Treatment of Dermatological Disorders

Herbal extracts and isolated plant compounds play an increasing role in the treatment of skin disorders and wounds. Several new herbal drugs, medicinal products and cosmetic products for the treatment of various skin conditions have been developed in recent years. In this nonsystematic review, we focus on herbal drugs that were tested in controlled clinical studies or in scientifically sound preclinical studies. The herbal biomedicines are intended to treat atopic dermatitis (St. John's wort, licorice, tormentil, bitter substances, evening primrose), psoriasis (araroba tree, lace flower, barberry bark, indigo, turmeric, olibanum, St. John's wort), actinic keratosis (birch bark, petty spurge), herpes simplex (lemon balm, sage and rhubarb), rosacea (green tea, licorice, tormentil) and acne vulgaris (tea tree oil, green tea, hop), or to improve photo protection (green tea, Dyer's weed, cocoa tree, carotinoids, licorice), aesthetic dermatology (licorice, pine bark, gotu kola) and wound healing (birch bark, onion).

Investigational drugs currently in phase II clinical trials for actinic keratosis

INTRODUCTION

Actinic keratoses (AKs) are limited areas of irregular epidermal growth on a background of excessive solar exposure. The entire sun-damaged skin is considered a field of cancerization with multiple visible and subclinical lesions. AK management requires field-directed therapies to block lesion relapse and prevent squamous cell carcinoma (SCC).

AREAS COVERED

In this review, we focused on phase II clinical trials for AKs, involving well-known agents and newer molecules such as proapoptotic drugs (VDA-1102, SR-T100, oleogel-S10, ICVT, eflornithine), immunomodulants (isotretinoin, tretinoin) and chemopreventive agents (nicotinamide, perillyl alcohol, liposomal T4N5). We used the website 'ClinicalTrials.Gov' as main reference. We selected and discussed completed and ongoing trials and analysed chemical structure and mechanism of action of the investigated molecules.

EXPERT OPINION

AK therapy should be tailored on the patient's profile considering first of all the age and site of the AKs, which are relevant parameters for local immune response. The new molecules could be combined to obtain a synergic effect blocking the different steps of skin tumorigenesis. Phase II trials highlight a new therapeutic opportunity to block selectively cell proliferation regulators and work both on the field of cancerization and on the AKs currently present.

Botanicals With Dermatologic Properties Derived From First Nations Healing: Part 1—Trees

Introduction:

First Nations people have a long history of working with medicinal plants used to treat skin diseases. The purpose was to assess the dermatologic therapeutic potential of western red cedar, white spruce, birch, balsam poplar, and black spruce.

Methods:

Based on expert recommendations, 5 trees were selected that were used in First Nations medicine for cutaneous healing and have potential and/or current application to dermatology today. We searched several databases up to June 12, 2014.

Results:

Western red cedar’s known active principal compound, β-thujaplicin, has been studied in atopic dermatitis. White spruce’s known active principal compound, 7-hydroxymatairesinol, has anti-inflammatory activity, while phase II clinical trials have been completed on a birch bark emulsion for the treatment of actinic keratoses, epidermolysis bullosa, and the healing of split thickness graft donor sites. Balsam poplar has been used clinically as an anti-aging remedy. Black spruce bark contains higher amounts of the anti-oxidant trans-resveratrol than red wine.

Discussion:

North American traditional medicine has identified important botanical agents that are potentially relevant to both cosmetic and medical dermatology. This study is limited by the lack of good quality evidence contributing to the review. The article is limited to 5 trees, a fraction of those used by First Nations with dermatological properties.

Ex vivo Skin Permeation of Betulin from Water-in-Oil Foams

Triterpenes of the outer bark of birch are known to improve wound healing. An oleogel with these triterpenes as active principle is approved by the European Medicines Agency. As foams can be applied without touching the skin, they might be an advantageous application form. A comparable wound-healing effect can be expected when the permeation flux of the triterpenes from different types of formulations, namely oleogels, water-in-oil emulsions and water-in-oil foams, is similar. The tested formulations were based on three lipids (medium-chain trigylcerides, sunflower oil and paraffin) which differ in their polarity and solvent power for the triterpenes. Infinite dose permeation experiments were performed using porcine skin which was injured by either tape stripping or skin grafting. The results showed that steady-state permeation flux and lag time depend clearly on the depth of the skin lesion. Moreover, it was substantially affected by the lipid used as basis for the different formulations. In contrast, the different formulation types showed a comparable permeation behaviour leading to the conclusion that all formulation types can be used alike for the treatment of wounds, and the results that have already been obtained with oleogels can be directly translated to the foam with its superior use properties.

Triterpenes for Well-Balanced Scar Formation in Superficial Wounds

Triterpenes are demonstrably effective for accelerating re-epithelialisation of wounds and known to improve scar formation for superficial lesions. Among the variety of triterpenes, betuline is of particular medical interest. Topical betuline gel (TBG) received drug approval in 2016 from the European Commission as the first topical therapeutic agent with the proven clinical benefit of accelerating wound healing. Two self-conducted randomized intra-individual comparison clinical studies with a total of 220 patients involved in TBG treatment of skin graft surgical wounds have been screened for data concerning the aesthetic aspect of wound healing. Three months after surgery wound treatment with TBG resulted in about 30% of cases with more discreet scars, and standard of care in about 10%. Patients themselves appreciate the results of TBG after 3 months even more (about 50%) compared to standard of care (about 10%). One year after surgery, the superiority of TBG counts for about 25% in comparison with about 10%, and from the patients’ point of view, for 25% compared to 4% under standard of care. In the majority of wound treatment cases, there is no difference visible between TBG treatment and standard of care after 1 year of scar formation. However, in comparison, TBG still offers a better chance for discreet scars and therefore happens to be superior in good care of wounds.

The new esters derivatives of betulin and betulinic acid in epidermoid squamous carcinoma treatment - In vitro studies

BACKGROUND

Betulinic acid and betulin are triterpenes with documented cytotoxic properties toward various cell lines. Unfortunately both betulinic acid and its metabolic precursor, betulin, are very poorly soluble in aqueous buffers, thus their bioavailability and bio-distribution are insufficient in terms of medical applications.

OBJECTIVE

To investigate the specific anticancer role of the newly synthesized betulin derivatives in human epidermoid carcinoma cells.

METHODS

In the present study we synthesized five amino acid esters of betulin. For the synthesis we selected alanine (Boc-l-Ala-OH, negative control) and four basic amino acids - natural lysine (Boc-l-Lys(Boc)-OH) and three its unnatural derivatives (Boc-l-Dap(Boc)-OH, Boc-l-Dab(Boc)-OH, and Boc-l-Orn(Boc)-OH). Boc-protected amino acids were most convenient for the synthesis. All new esters have one (betulin-l-Ala-NH2) or two free amino groups which significantly increase their solubility in water and facilitate their transport through the cell membrane. It is worth noting that the biological activity of new esters of betulin is positive correlated with the length of the side chain of l-amino acid. The highest biological activity displayed compound containing lysine side chain (Lys, -CH2-CH2-CH2-CH2-NH2). Considering the biological activity, other derivatives can be set in the following series: Orn (-CH2-CH2-CH2-NH2)>Dab (-CH2-CH2-NH2)>Dap (-CH2-NH2)>Ala (CH3)>betulin. New betulin esters were tested in normal human keratinocytes (HaCaT) and human epidermoid carcinoma cells (A431). To assess cytotoxicity, MTT test was performed after 24, 48 and 72h of incubation with the test compounds at a concentration range of 0.75-100μM. In case of apoptotic activity, a TUNEL method and comet assay were performed. Additionally expression of caspase-3 and PARP1 was evaluated immunocytochemically.

RESULTS

The highest cytotoxicity in cells induced skin cancer new compounds, particularly compound containing a lysine side chain (IC50=7μM) and ornithine (IC50=10μM). The highest number of apoptotic cells was observed in case incubation with compound containing Orn, Dab and Dap side chain.

CONCLUSIONS

The new betulin ester derivatives display enhanced antitumor activity compared to their non-modified precursors. It is worth emphasizing their specific toxicity against epidermoid carcinoma cells.

Comprehensive review on betulin as a potent anticancer agent

Numerous plant-derived substances, and their derivatives, are effective antitumour and chemopreventive agents. Yet, there are also a plethora of tumour types that do not respond, or become resistant, to these natural substances. This requires the discovery of new active compounds. Betulin (BE) is a pentacyclic triterpene and secondary metabolite of plants abundantly found in the outer bark of the birch tree Betulaceae sp. BE displays a broad spectrum of biological and pharmacological properties, among which the anticancer and chemopreventive activity attract most of the attention. In this vein, BE and its natural and synthetic derivatives act specifically on cancer cells with low cytotoxicity towards normal cells. Although the antineoplastic mechanism of action of BE is not well understood yet, several interesting aspects of BE's interactions are coming to light. This review will summarize the anticancer and chemopreventive potential of BE in vitro and in vivo by carefully dissecting and comparing the doses and tumour lines used in previous studies, as well as focusing on mechanisms underlying its activity at cellular and molecular level, and discuss future prospects.

Lack of activity of betulin-based Oleogel-S10 in the treatment of actinic keratoses: a randomized, multicentre, placebo-controlled double-blind phase II trial

BACKGROUND

Betulinic acid and other triterpenes have shown strong antitumour activity in vitro and in vivo. A triterpene extract of birch bark formed the base of Oleogel-S10 and allowed topical application. Two previous trials have shown efficacy and tolerability in the treatment of actinic keratoses (AKs) with betulin-based Oleogel-S10.

OBJECTIVES

To confirm the efficacy and tolerability/safety of Oleogel-S10 in the treatment of AKs in a multicentre placebo-controlled study.

METHODS

Patients (n = 165) were treated topically for 3 months in a four-arm parallel study design, randomly allocated to A (n = 53) Oleogel-S10 once daily, B (n = 51) Oleogel-S10 twice daily, or C (n = 25) or D (n = 28) placebo (petroleum jelly) once or twice daily, respectively. Clinical efficacy in this double-blind study was assessed by the investigators. Final and baseline biopsies were evaluated by central histopathology.

RESULTS

Complete clearance of the target lesions was seen in 4% of patients in group A and 7% in group B, but not in the placebo groups. A clearance rate of > 75% was seen for 15% and 18% of patients in groups A and B, respectively, and for 13% in the placebo groups. These differences were not statistically significant. Histopathologically, 43·9% of patients showed a downgrading or clearance of the marker AK with no significant differences between the groups. Treatment with Oleogel-S10 was well tolerated. The tolerability as assessed by the investigator was mostly 'very good' (78·8%), followed by 'good' (18·2%) and only 1·2% assessed it as 'intolerable'. Patient-assessed tolerability was graded mostly 'very good' (56·4%) or 'good' (34·5%).

CONCLUSIONS

Treatment with Oleogel-S10 was well tolerated during a treatment period of 3 months, yet was no better than placebo in terms of efficacy in the treatment of AKs.

Medicinal plants of the genus Betula--traditional uses and a phytochemical-pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Trees and shrubs of the genus Betula (Betulaceae) inhabit various ecosystems in temperate and boreal climate zones of the northern hemisphere. The healing properties of Betula bark and bark extracts have been known for a long time in traditional medicine in different parts of the world. Several species of Betula have traditionally been used for the treatment of various inflammatory diseases including arthritis. The purpose of this review is to provide updated, comprehensive and categorized information on the botany, traditional uses, phytochemistry and pharmacological and toxicological research of Betula species in order to explore their therapeutic potential and evaluate future research opportunities.

MATERIALS AND METHODS

All the available information on various species belonging to the genus Betula was collected via electronic search (using Pubmed, SciFinder, Scirus, Google Scholar, JCCC@INSTIRC and Web of Science) and a library search for articles published in peer-reviewed journals.

RESULTS

Although over a hundred Betula species are found distributed globally, about 7 different species of Betula have been documented for their traditional uses. Phytochemical research on Betula species has led to the isolation of triterpenoids, diarylheptanoids, phenylbutanoids, lignans, phenolics and flavonoids. Crude extracts, fractions and phytochemical constituents isolated from Betula showed a wide spectrum of in vitro and in vivo pharmacological activities like immunomodulatory, anti-inflammatory, antimicrobial, antiviral, antioxidant, antidiabetic, dermatological, gastroprotective and hepatoprotective. Antiarthritic and anticancer are the two major areas of research conducted on these species. The anti-carcinogenic effects of Betula bark, betulin as well as betulinic acid have been extensively studied.

CONCLUSIONS

Several species belonging to the genus Betula are widely used in traditional medicine. Betula platyphylla and Betula pendula have specifically been found to be potentially useful in the treatment of degenerative joint disease. There is convincing evidence in experimental animal models in support of their anti-carcinogenic effects. However, it would be worthwhile to investigate the biochemical and physiological mechanisms as well as detailed preclinical toxicity, bioavailability, pharmacokinetics and pharmacodynamics of the different biologically active extracts as well as molecules in sufficient detail. An integrated and holistic approach is required for tapping the full potentials of this important genus.

Actinic keratosis: rationale and management

Actinic keratoses (AKs) are common skin lesions heralding an increased risk of developing squamous cell carcinoma (SCC) and other skin malignancies, arising principally due to excessive ultraviolet (UV) exposure. They are predominantly found in fair-skinned individuals, and increasingly, are a problem of the immunosuppressed. AKs may regress spontaneously, remain stable or transform to invasive SCC. The risk of SCC increases for those with more than 5 AKs, and the majority of SCCs arise from AKs. The main mechanisms of AK formation are inflammation, oxidative stress, immunosuppression, impaired apoptosis, mutagenesis, dysregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been implicated in the formation of some AKs. Understanding these mechanisms guides the rationale behind the current available treatments for AKs. One of the main principles underpinning the management of AKs is that of field cancerization. Wide areas of skin are exposed to increasing amounts of UV light and other environmental insults as we age. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also large areas where crops of AKs may appear. The skin between lesions is exposed to the same insults and is likely to contain as-yet undetectable preclinical lesions or areas of dysplastic cells. The whole affected area is known as the ‘field’. Management is therefore divided into lesion-directed and field-directed therapies. Current therapies include lesion-directed cryotherapy and/or excision, and topical field-directed creams: 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy and ingenol mebutate. Combining lesion- and field-directed therapies has yielded good results and several novel therapies are under investigation. Treatment is variable and tailored to the individual making a gold standard management algorithm difficult to design. This literature review article aims to describe the rationale behind the best available therapies for AKs in light of current understanding of pathophysiology and epidemiology. A PubMed and MEDLINE search of literature was performed between January 1, 2000 and September 18, 2013. Where appropriate, articles published prior to this have been referenced. This is not a systematic review or meta-analysis, but aims to highlight the most up to date understanding of AK disease and its management.

Anthroposophic medicine: an integrative medical system originating in europe

Anthroposophic medicine is an integrative multimodal treatment system based on a holistic understanding of man and nature and of disease and treatment. It builds on a concept of four levels of formative forces and on the model of a three-fold human constitution. Anthroposophic medicine is integrated with conventional medicine in large hospitals and medical practices. It applies medicines derived from plants, minerals, and animals; art therapy, eurythmy therapy, and rhythmical massage; counseling; psychotherapy; and specific nursing techniques such as external embrocation. Anthroposophic healthcare is provided by medical doctors, therapists, and nurses. A Health-Technology Assessment Report and its recent update identified 265 clinical studies on the efficacy and effectiveness of anthroposophic medicine. The outcomes were described as predominantly positive. These studies as well as a variety of specific safety studies found no major risk but good tolerability. Economic analyses found a favorable cost structure. Patients report high satisfaction with anthroposophic healthcare.

Study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation

Background

Pentacyclic triterpenes, mainly betulin and betulinic acid, are valuable anticancer agents found in the bark of birch tree. This study evaluates birch bark extracts for the active principles composition.

Results

New improved extraction methods were applied on the bark of Betula pendula in order to reach the maximum content in active principles. Extracts were analyzed by HPLC-MS, Raman, SERS and ¹³C NMR spectroscopy which revealed a very high yield of betulin (over 90%). Growth inhibiting effects were measured in vitro on four malignant human cell lines: A431 (skin epidermoid carcinoma), A2780 (ovarian carcinoma), HeLa (cervix adenocarcinoma) and MCF7 (breast adenocarcinoma), by means of MTT assay. All of the prepared bark extracts exerted a pronounced antiproliferative effect against human cancer cell lines. In vivo studies involved the anti-inflammatory effect of birch extracts on TPA-induced model of inflammation in mice.

Conclusions

The research revealed the efficacy of the extraction procedures as well as the antiproliferative and anti-inflammatory effects of birch extracts.

Betulin complex in γ-cyclodextrin derivatives: properties and antineoplasic activities in in vitro and in vivo tumor models

Given the present high incidence of melanoma and skin cancer, interest in potential drugs of plant origin has increased significantly. Pentacyclic lupane-type triterpenes are widely distributed in plants, offering numerous pharmacological benefits. Betulin is an important compound in the bark of Betula pendula Roth and has important therapeutic properties, including antitumor activities. Its biological effect is limited by its poor water solubility, which can be improved by cyclodextrin complexation. The best results have been obtained by using a novel cyclodextrin derivative, octakis-[6-deoxy-6-(2-sulfanyl ethanesulfonate)]-γ-CD. The complexes between betulin and the previously mentioned cyclodextrin were analyzed by scanning electron microscopy (SEM)and differential scanning calorimetry (DSC) and pharmacologically evaluated in vitro (MTT and immunocytochemistry tests) and in vivo in C57BL/6J mice. The solubility of betulin is improved by cyclodextrin complexation, which creates a stable complex that improves the in vitro and in vivo properties of the active compound.

[Clinical research on anthroposophic medicine:update of a health technology assessment report and status quo]

BACKGROUND AND OBJECTIVE

In 2005 a Health Technology Assessment (HTA) report analyzed efficacy, effectiveness, safety, utilization and costs of Anthroposophic Medicine (AM). After a recent referendum of the ‘Swiss Population pro Complementary Medicine’ (May 2009) this HTA report was updated.

DESIGN

Update of the HTA report by a systematic review.

METHODS

Methods corresponded to the existing HTA report and the guidelines of the Swiss Federal Office of Public Health. For clinical studies four databases and a specialized journal were searched, and extensive expert consultations were used. Studies were selected according to predefined inclusion criteria, data were extracted, and methodological quality was assessed individually.

RESULTS

70 new clinical studies were found. Altogether, 265 clinical studies investigated efficacy and effectiveness of AM: 38 randomized controlled trials, 36 prospective and 49 retrospective non-randomized controlled trials as well as 90 prospective and 52 retrospective trials without control groups. They investigated a wide spectrum of AM treatments in a multitude of diseases; the whole AM system in 38 trials, non-pharmacological therapies in 10 trials, AM mistletoe products in cancer therapy in 133 trials, and other AM medication treatments in 84 trials. Most studies showed a positive result for AM. Methodological quality differed substantially; some studies showed major limitations, others were reasonably well conducted. Trials with better quality still showed a positive result. External validity was usually high. Side effects or other risks were rare and usually described to be mild or moderate. Studies regarding safety showed a good tolerability altogether.

CONCLUSION

Trials of varying design and quality in a variety of diseases predominantly describe good clinical outcomes for AM, only marginal side effects, high satisfaction of patients with regard to results and safety and presumably slightly less costs. Further high-quality evaluations are desirable.

Which plant for which skin disease? Part 2: Dermatophytes, chronic venous insufficiency, photoprotection, actinic keratoses, vitiligo, hair loss, cosmetic indications

This paper continues our review of scientifically evaluated plant extracts in dermatology. After plants effective against dermatophytes, botanicals with anti-edema effects in chronic venous insufficiency are discussed. There is good evidence from randomized clinical studies that plant extracts from grape vine leaves (Vitis vinifera), horse chestnut (Aesculus hippocastanum), sea pine (Pinus maritima) and butcher's broom (Ruscus aculeatus) can reduce edema in chronic venous insufficiency. Plant extracts from witch hazel (Hamamelis virginiana), green tea (Camellia sinensis), the fern Polypodium leucotomos and others contain antioxidant polyphenolic compounds that may protect the skin from sunburn and photoaging when administered topically or systemically. Extracts from the garden spurge (Euphorbia peplus) and from birch bark (Betula alba) have been shown to be effective in the treatment of actinic keratoses in phase II studies. Some plant extracts have also been investigated in the treatment of vitiligo, various forms of hair loss and pigmentation disorders, and in aesthetic dermatology.

Botanicals in dermatology: an evidence-based review

Botanical extracts and single compounds are increasingly used in cosmetics but also in over-the-counter drugs and food supplements. The focus of the present review is on controlled clinical trials with botanicals in the treatment of acne, inflammatory skin diseases, skin infections, UV-induced skin damage, skin cancer, alopecia, vitiligo, and wounds. Studies with botanical cosmetics and drugs are discussed, as well as studies with botanical food supplements. Experimental research on botanicals was considered to a limited extent when it seemed promising for clinical use in the near future. In acne therapy, Mahonia, tea tree oil, and Saccharomyces may have the potential to become standard treatments. Mahonia, Hypericum, Glycyrrhiza and some traditional Chinese medicines appear promising for atopic dermatitis. Some plant-derived substances like dithranol and methoxsalen (8-methoxypsoralen) [in combination with UVA] are already accepted as standard treatments in psoriasis; Mahonia and Capsicum (capsaicin) are the next candidates suggested by present evidence. Oral administration and topical application of antioxidant plant extracts (green and black tea, carotenoids, coffee, and many flavonoids from fruits and vegetables) can protect skin from UV-induced erythema, early aging, and irradiation-induced cancer. Hair loss and vitiligo are also traditional fields of application for botanicals. According to the number and quality of clinical trials with botanicals, the best evidence exists for the treatment of inflammatory skin diseases, i.e. atopic dermatitis and psoriasis. However, many more controlled clinical studies are needed to determine the efficacy and risks of plant-derived products in dermatology. Safety aspects, especially related to sensitization and photodermatitis, have to be taken into account. Therefore, clinicians should not only be informed of the beneficial effects but also the specific adverse effects of botanicals used for dermatologic disorders and cosmetic purposes.

Pentacyclic triterpene distribution in various plants - rich sources for a new group of multi-potent plant extracts

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.

[Precancerous and early invasive carcinomas: non-surgical treatment of head and facial skin]

Chronic exposure to sunlight with its high proportion of high energy ultraviolet light is the main cause of the common cutaneous precancerous lesions and carcinomas of the head and neck. This causes a field cancerization effect frequently with multiple actinic keratoses (AKs), basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). Although demonstrating the best cure rates and lowest recurrence rates, surgical excision rapidly progresses to its limits. Field cancerization requires field therapy. Non-specific caustic agents may remove superficial lesions, however, the modern therapeutic modalities such as topical cytotoxic treatment with 5-fluorouracil, photodynamic therapy with 5-aminolevulinic acid (ALA) or its methyl ester (MeALA), the topical immune response modifier imiquimod or the local application of the cyclooxygenase inhibitor diclofenac are more specific and effective. Intralesional and perilesional injections of cytotoxic agents and interferons as well as the new targeted anti-cancer drugs are further alternatives. The most important aspect, however, is the prophylaxis of chronic photodamage.

A preliminary pharmacokinetic study of betulin, the main pentacyclic triterpene from extract of outer bark of birch (Betulae alba cortex)

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.

Treatment of actinic keratoses with a novel betulin-based oleogel. A prospective, randomized, comparative pilot study

BACKGROUND

Actinic keratoses (AK) are squamous cell carcinomas in situ and require treatment. Betulin-based oleogel prepared from a standardized triterpene dry extract from birch bark represents a new topical agent with anti-inflammatory and anti-tumor potential.

PATIENTS AND METHODS

In the prospective, randomized, monocentric phase 2a study 45 patients with < 10 AK were included and randomly assigned to one of the three treatment groups. Intervention consisted of topical betulin-based oleogel twice daily versus cryotherapy with liquid nitrogen versus the combination of cryotherapy with topical betulin-based oleogel. Treatment response was assessed clinically after three months. The clinical response was graded into complete clearing (100 %), therapy responders (> 75 % clearing of the lesions) and non-responders (< 75 % clearing). Additionally, punch biopsies were obtained from some patients before and at the end of treatment.

RESULTS

Therapy with betulin-based oleogel was well tolerated.Three patients discontinued therapy because of personal reasons. After three months, the 100% (and > 75%) clearing rates of the lesions were as follows: 64% (86%) with betulin-based oleogel (n = 14),79% (93%) with cryotherapy (n = 14),and 71% (71%) with the combined therapy (n = 14). Histological analysis of biopsies taken before and after treatment (n = 8) showed a reduced degree of dysplasia in the epidermis in all study arms.

CONCLUSIONS

Betulin-based oleogel seems to be an effective novel approach in the topical treatment of actinic keratoses. However,the clinical and histological findings of the present pilot study have to be verified against placebo with larger case numbers.