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Author

Melanie N. Laszczyk

Bio: Melanie N. Laszczyk is an academic researcher from University Medical Center Freiburg. The author has contributed to research in topic(s): Betulin & Betulinic acid. The author has an hindex of 10, co-authored 15 publication(s) receiving 1246 citation(s).
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Journal ArticleDOI
TL;DR: Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark display various pharmacological effects while being devoid of prominent toxicity and are promising leading compounds for the development of new multi-targeting bioactive agents.
Abstract: 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.

441 citations


Journal ArticleDOI
TL;DR: This review summarizes the potential of triterpenes belonging to the lupane, oleanane or ursane group, to treat cancer by different modes of action and utilisation of different plants as their sources is of interest.
Abstract: Today cancer treatment is not only a question of eliminating cancer cells by induction of cell death. New therapeutic strategies also include targeting the tumour microenvironment, avoiding angiogenesis, modulating the immune response or the chronic inflammation that is often associated with cancer. Furthermore, the induction of redifferentiation of dedifferentiated cancer cells is an interesting aspect in developing new therapy strategies. Plants provide a broad spectrum of potential drug substances for cancer therapy with multifaceted effects and targets. Pentacyclic triterpenes are one group of promising secondary plant metabolites. This review summarizes the potential of triterpenes belonging to the lupane, oleanane or ursane group, to treat cancer by different modes of action. Since Pisha et al. reported in 1995 that betulinic acid is a highly promising anticancer drug after inducing apoptosis in melanoma cell lines in vitro and in vivo, experimental work focused on the apoptosis inducing mechanisms of betulinic acid and other triterpenes. The antitumour effects were subsequently confirmed in a series of cancer cell lines from other origins, for example breast, colon, lung and neuroblastoma. In addition, in the last decade many studies have shown further effects that justify the expectation that triterpenes are useful to treat cancer by several modes of action. Thus, triterpene acids are known mainly for their antiangiogenic effects as well as their differentiation inducing effects. In particular, lupane-type triterpenes, such as betulin, betulinic acid and lupeol, display anti-inflammatory activities which often accompany immune modulation. Triterpene acids as well as triterpene monoalcohols and diols also show an antioxidative potential. The pharmacological potential of triterpenes of the lupane, oleanane or ursane type for cancer treatment seems high; although up to now no clinical trial has been published using these triterpenes in cancer therapy. They provide a multitarget potential for coping with new cancer strategies. Whether this is an effective approach for cancer treatment has to be proven. Because various triterpenes are an increasingly promising group of plant metabolites, the utilisation of different plants as their sources is of interest. Parts of plants, for example birch bark, rosemary leaves, apple peel and mistletoe shoots are rich in triterpenes and provide different triterpene compositions.

387 citations


Journal ArticleDOI
TL;DR: Preliminary pharmacokinetics of betulin and results of a subchronic toxicity study of TE in rats and dogs show triterpene extract from birch bark is safe, its betulin is bioavailable and in addition to published triterpenes biological activities TE provides high potential for further pharmaceutical and pharmacological research.
Abstract: 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.

101 citations


Journal ArticleDOI
TL;DR: 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.
Abstract: 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.

81 citations


Journal ArticleDOI
Constance Huyke1, Juliane Reuter1, Mirko Rödig1, Astrid Kersten  +4 moreInstitutions (1)
TL;DR: Betulin‐based oleogel prepared from a standardized triter‐pene dry extract from birch bark represents a new topical agent with anti‐inflammatory and anti‐tumor potential.
Abstract: Summary 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 antiinflammatory 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 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.

71 citations


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Journal ArticleDOI
TL;DR: An updated classification scheme based on molecular pathophysiology will bring greater clarity to discourse while catalyzing new hypotheses both at the bench and at the bedside, supplanting a clinical classification that has served well but is opaque to the genetic, immunologic, and therapeutic interrelationships now before us.
Abstract: The autoinflammatory diseases are characterized by seemingly unprovoked episodes of inflammation, without high-titer autoantibodies or antigen-specific T cells The concept was proposed ten years ago with the identification of the genes underlying hereditary periodic fever syndromes This nosology has taken root because of the dramatic advances in our knowledge of the genetic basis of both mendelian and complex autoinflammatory diseases, and with the recognition that these illnesses derive from genetic variants of the innate immune system Herein we propose an updated classification scheme based on the molecular insights garnered over the past decade, supplanting a clinical classification that has served well but is opaque to the genetic, immunologic, and therapeutic interrelationships now before us We define six categories of autoinflammatory disease: IL-1β activation disorders (inflammasomopathies), NF-κB activation syndromes, protein misfolding disorders, complement regulatory diseases, disturbances in cytokine signaling, and macrophage activation syndromes A system based on molecular pathophysiology will bring greater clarity to our discourse while catalyzing new hypotheses both at the bench and at the bedside

941 citations


Journal ArticleDOI
28 Apr 2009-PLOS ONE
TL;DR: BE induces apoptosis utilizing a similar mechanism as BetA and is prevented by cyclosporin A (CsA), which indicates that BE has potent anti-tumor activity especially in combination with cholesterol.
Abstract: Betulinic Acid (BetA) and its derivatives have been extensively studied in the past for their anti-tumor effects, but relatively little is known about its precursor Betulin (BE). We found that BE induces apoptosis utilizing a similar mechanism as BetA and is prevented by cyclosporin A (CsA). BE induces cell death more rapidly as compared to BetA, but to achieve similar amounts of cell death a considerably higher concentration of BE is needed. Interestingly, we observed that cholesterol sensitized cells to BE-induced apoptosis, while there was no effect of cholesterol when combined with BetA. Despite the significantly enhanced cytotoxicity, the mode of cell death was not changed as CsA completely abrogated cell death. These results indicate that BE has potent anti-tumor activity especially in combination with cholesterol.

564 citations


Journal ArticleDOI
TL;DR: Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark display various pharmacological effects while being devoid of prominent toxicity and are promising leading compounds for the development of new multi-targeting bioactive agents.
Abstract: 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.

441 citations


Journal ArticleDOI
TL;DR: This review summarizes the potential of triterpenes belonging to the lupane, oleanane or ursane group, to treat cancer by different modes of action and utilisation of different plants as their sources is of interest.
Abstract: Today cancer treatment is not only a question of eliminating cancer cells by induction of cell death. New therapeutic strategies also include targeting the tumour microenvironment, avoiding angiogenesis, modulating the immune response or the chronic inflammation that is often associated with cancer. Furthermore, the induction of redifferentiation of dedifferentiated cancer cells is an interesting aspect in developing new therapy strategies. Plants provide a broad spectrum of potential drug substances for cancer therapy with multifaceted effects and targets. Pentacyclic triterpenes are one group of promising secondary plant metabolites. This review summarizes the potential of triterpenes belonging to the lupane, oleanane or ursane group, to treat cancer by different modes of action. Since Pisha et al. reported in 1995 that betulinic acid is a highly promising anticancer drug after inducing apoptosis in melanoma cell lines in vitro and in vivo, experimental work focused on the apoptosis inducing mechanisms of betulinic acid and other triterpenes. The antitumour effects were subsequently confirmed in a series of cancer cell lines from other origins, for example breast, colon, lung and neuroblastoma. In addition, in the last decade many studies have shown further effects that justify the expectation that triterpenes are useful to treat cancer by several modes of action. Thus, triterpene acids are known mainly for their antiangiogenic effects as well as their differentiation inducing effects. In particular, lupane-type triterpenes, such as betulin, betulinic acid and lupeol, display anti-inflammatory activities which often accompany immune modulation. Triterpene acids as well as triterpene monoalcohols and diols also show an antioxidative potential. The pharmacological potential of triterpenes of the lupane, oleanane or ursane type for cancer treatment seems high; although up to now no clinical trial has been published using these triterpenes in cancer therapy. They provide a multitarget potential for coping with new cancer strategies. Whether this is an effective approach for cancer treatment has to be proven. Because various triterpenes are an increasingly promising group of plant metabolites, the utilisation of different plants as their sources is of interest. Parts of plants, for example birch bark, rosemary leaves, apple peel and mistletoe shoots are rich in triterpenes and provide different triterpene compositions.

387 citations


Journal ArticleDOI
TL;DR: Results indicate that betulin given i.p. has a similar efficacy in attenuating the neuromuscular effects of B. jararacussu venom in vivo and could be a useful complementary measure to antivenom therapy for treating snakebite.
Abstract: We confirmed the ability of the triterpenoid betulin to protect against neurotoxicity caused by Bothrops jararacussu snake venom in vitro in mouse isolated phrenic nerve-diaphragm (PND) preparations and examined its capability of in vivo protection using the rat external popliteal/sciatic nerve-tibialis anterior (EPSTA) preparation. Venom caused complete, irreversible blockade in PND (40 μg/mL), but only partial blockade (~30%) in EPSTA (3.6 mg/kg, i.m.) after 120 min. In PND, preincubation of venom with commercial bothropic antivenom (CBA) attenuated the venom-induced blockade, and, in EPSTA, CBA given i.v. 15 min after venom also attenuated the blockade (by ~70% in both preparations). Preincubation of venom with betulin (200 μg/mL) markedly attenuated the venom-induced blockade in PND; similarly, a single dose of betulin (20 mg, i.p., 15 min after venom) virtually abolished the venom-induced decrease in contractility. Plasma creatine kinase activity was significantly elevated 120 min after venom injection in the EPSTA but was attenuated by CBA and betulin. These results indicate that betulin given i.p. has a similar efficacy as CBA given i.v. in attenuating the neuromuscular effects of B. jararacussu venom in vivo and could be a useful complementary measure to antivenom therapy for treating snakebite.

371 citations


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Performance
Metrics

Author's H-index: 10

No. of papers from the Author in previous years
YearPapers
20121
20102
20095
20083
20071
20063