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Betulinic acid against various cancers
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James Offline
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Betulinic acid against various cancers
Betulinic acid is found in various herbs including birch and chagas. All of the herbs that I am aware of containing betulinic acid have been used historically for the treatment of cancers. Medical studies have confirmed the anti-cancer effects of betulinic acid:


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

Selective cytotoxicity of betulinic acid on tumor cell lines, but not on normal cells.

"Betulinic acid is a triterpene with selective cytotoxicity against melanoma, neuroectodermal and malignant brain tumor cell lines. In this study the betulinic acid activity was evaluated, in comparison with doxorubicin, on different human neoplastic and non-neoplastic cell lines and on proliferating normal lymphocytes. Growth inhibition was evident in all the neoplastic cell lines independently on p53 status and histotype. Antiproliferative activity of betulinic acid was related to a cytotoxic effect on two p53 wild-type and on one p53 mutant cell lines and to a cytostatic effect on one p53 mutant melanoma clone. At the same concentrations, normal cells were unaffected indicating a selective effect of this agent. A cytotoxic activity of doxorubicin was evident on all the tested systems."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Conventional chemotherapeutic agents elicit mitochondrial permeabilization in an indirect fashion by induction of endogenous effectors that are involved in the physiologic control of apoptosis. However, an increasing number of experimental anticancer drugs, including lonidamine, arsenite, betulinic acid, CD437, and several amphipathic cationic alpha-helical peptides, act directly on mitochondrial membranes and/or on the PTPC. Such agents may induce apoptosis in circumstances in which conventional drugs fail to act because endogenous apoptosis induction pathways, such as those involving p53, death receptors, or apical caspase activation, are disrupted. "


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid is a naturally occurring pentacyclic triterpenoid. Betulinic acid has recently been selected by the National Cancer Institute for addition into the RAID (Rapid Access to Intervention in Development) programme. The agent exhibits potential anti-tumour activity and functions in this regard via apoptosis. "


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Recently, betulinic acid was identified as a highly selective inhibitor of human melanoma growth and was reported to induce apoptosis in these cells. We have investigated the growth-inhibitory properties of this compound alone and in combination with ionizing radiation in a panel of established human melanoma cell lines as well as in normal human melanocytes. Betulinic acid strongly and consistently suppressed the growth and colony-forming ability of all human melanoma cell lines investigated."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Neuroblastoma has long been recognized to show spontaneous regression during fetal development and in the majority of stage 4s infants < 1 year of age with disseminated disease. Stage 4s disease regresses with no chemotherapy in 50% of the patients. The mechanism by which this occurs is not understood but may be programmed cell death or apoptosis. Betulinic acid (BA) has been reported to induce apoptosis in human melanoma with in vitro and in vivo model systems. Melanoma, like neuroblastoma, is derived from the neural crest cell. We hypothesised that neuroblastoma cells have the machinery for programmed cell death and that apoptosis could be induced by betulinic acid. Nine human neuroblastoma cell lines were treated in vitro with BA at concentrations of 0-20 micrograms/ml for 0-6 days. Profound morphological changes were noted within 3 days. Cells withdrew their axonic-like extensions, became non-adherent and condensed into irregular dense spheroids typical of apoptotic cell death (ED50 = 14-17 micrograms/ml). DNA fragmentation analysis showed ladder formation in the 100-1200 bp region in 3/3 neuroblastoma cell lines treated with BA for 24-72 h. Thus, apparently BA does induce AP in neuroblastoma in vitro."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"BACKGROUND AND PROCEDURE: We identified BetA as a new cytotoxic agent active against neuroectodermal tumor cells including neuroblastoma, medulloblastoma, glioblastoma and Ewing sarcoma cells, representing the most common solid tumors of childhood. RESULTS: BetA induced apoptosis by a direct effect on mitochondria independent of accumulation of wild-type p53 protein and independent of death-inducing ligand/receptor systems such as CD95. Mitochondrial perturbations on treatment with BetA resulted in the release of soluble apoptogenic factors such as cytochrome c or AIF from mitochondria into the cytosol, where they induced activation of caspases. Overexpression of the anti-apoptotic proteins Bcl-2 or Bcl-X(L) that blocked loss of the mitochondrial membrane potential and cytochrome c release from mitochondria also conferred resistance to BetA. Most importantly, BetA exhibited potent antitumor activity on neuroblastoma cells resistant to CD95- or doxorubicin-triggered apoptosis and on primary tumor cells from patients with neuroectodermal tumors. CONCLUSIONS: Thus, BetA may be a promising new agent in the treatment of neuroectodermal tumors including neuroblastoma in vivo. "


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"For this purpose we used betulinic acid, a cytotoxic agent selective for melanoma, straightly perturbing mitochondrial functions. In fact, betulinic acid induced mitochondrial cytochrome c release and DNA fragmentation in both CD95-resistant and CD95-sensitive melanoma cell populations, independent of the Bax/Bcl-2 ratio."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid (BA) was identified by our group as a selective inhibitor of melanoma that functions by inducing apoptosis."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"The crude chloroform bark extract of Syncarpia glomulifera (Myrtaceae) shows antibacterial and cytotoxic activity. Bioactivity-directed separation led to the isolation of oleanolic acid-3-acetate, ursolic acid-3-acetate and betulinic acid. The relatively large abundance (10% of the crude extract) and high degree of activity of betulinic acid are responsible for the bioactivity of the crude bark extract."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"23-Hydroxybetulinic acid, a derivative of betulinic acid, was investigated for its apoptotic effect and the associated telomerase activity in human leukemia HL-60 cells. Apoptosis and bcl-2 were determined by flow cytometry analysis. A PCR-based telomeric repeat amplification protocol assay was used to detect telomerase activity. Results showed that 23-hydroxybetulinic acid induced growth arrest and apoptotic cell death in HL-60 cells. The apoptotic events were associated with concurrent down-regulation of bcl-2 and the telomerase activity. Our data suggest that 23-hydroxybetulinic acid may be a potential cytotoxic agent for treatment of cancer."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Three triterpenoids, betulinic acid, oleanolic acid, and ursolic acid, were isolated as their methyl esters (treatment with diazomethane) from diethyl ether extracts of almond hulls (Nonpareil variety) using flash chromatography and preparative high-performance liquid chromatography. The triterpenoids, which comprised approximately 1% of the hulls, were characterized using chromatographic and spectroscopic methods. These studies demonstrate that almond hulls are a rich source of these triterpenoids, which have reported anti-inflammatory, anti-HIV, and anti-cancer activities."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid (11), its methyl ester (12), lup-28-al-20(29)-ene-3beta-ol (9), and lup-28-al-20(29)-en-3-one (10) inhibited B16 2F2 cell proliferation by induction of apoptosis. "


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Malignant brain tumors are the most common solid tumors in children. The overall prognosis for this group of patients is still poor, emphasizing the importance of more effective therapies. Betulinic acid (Bet A) has been described as a novel cytotoxic compound active against melanoma and neuroblastoma cells."

"Since Bet A did not exhibit cytotoxicity against murine neuronal cells in vitro, these findings suggest that Bet A may be a promising new agent for the treatment of medulloblastoma and glioblastoma cells that clearly warrants further pre-clinical and clinical evaluation."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"The chloroform extract of Vauquelinia corymbosa Correa has shown activity against the P-388 lymphocytic leukemia test system. The constituents responsible for this activity were identified as uvaol, ursolic acid, and betulinic acid. Their identity was proven by melting point; mixed melting point; elemental analysis; IR, PMR, and mass spectra; and preparation of derivatives."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Microbial transformation studies of the antimelanoma agent betulinic acid (1) were conducted."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Microbial transformation of betulin (1), a lupane-type triterpene obtained from the bark extract of white birch (Betula platyphylla Sukatshev var. japonica), and its chemical oxidation product, betulonic acid (2), by the fungus Chaetomium longirostre yielded 4,28-dihydroxy-3,4-seco-lup-20(29)-en-3-oic acid (3) and 4-hydroxy-3,4-seco-lup-20(29)-ene-3,28-dioic acid (4) from 1, and 4,7beta,17-trihydroxy-3,4-seco-28-norlup-20(29)-en-3-oic acid (5) and 7 beta,15 alpha-dihydoxy-3-oxolup-20(29)-en-28-oic acid (6) from 2. The four metabolites, 3-6, along with 1 and 2, were evaluated for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells as a primary screening test for inhibitors of tumor promotion. All of the triterpenes tested showed potent inhibitory effects, with the four metabolites 3-6 exhibiting the more potent effects."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"BACKGROUND: Betulinic acid, a naturally abundant, plant derived, pentacyclic triterpenoid possesses anti-HIV, anti-malarial and anti-inflammatory properties and has recently emerged as a potent anti-tumor compound."

"Dihydro betulinic acid is the most potent (IC50=0.5 mM) pentacyclic triterpenoid to inhibit eukaryotic topoisomerase I till date and can be exploited as a strong candidate for anti-tumor drug designing."

(Notice how the drug companies are planning on stealing another idea that herbalists have known and have been using for a long time?)


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Six ceanothane and 1-norceanothane derivatives (1, 2, 8-11) were prepared from ceanothic acid dibenzyl ester. These ring-A homologues of betulinic acid exhibited cytotoxic effects. Among these, 1-decarboxy-3-oxo-ceanothic acid (2) was found to be the most cytotoxic against OVCAR-3 and HeLa cancer cell lines, with an IC50 of 2.8 and 6.6 microg/mL, respectively, and an IC50 of 11.3 microg/mL against normal cell line FS-5."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"The finding supports the idea that betulinic acid acts as anti-melanoma agent via inhibition of aminopeptidase N activity."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"We investigated the sequence of these events in SHEP neuroblastoma cells transfected with Bcl-2 or Bcl-X(L) using two different drugs, namely, doxorubicin (Doxo), which activates the CD95/CD95 ligand (CD95-L) system, and betulinic acid (Bet A), which does not enhance the expression of CD95 or CD95-L and which, as shown here, directly targets mitochondria. Apoptosis induced by both drugs was inhibited by Bcl-2 or Bcl-X(L) overexpression or by bongkrekic acid, an agent that stabilizes mitochondrial membrane barrier function, suggesting a critical role for mitochondria. "


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid has been modified at C-3, C-20, and C-28 positions and the toxicity of the derivatives has been evaluated against cultured human melanoma (MEL-2) and human epidermoid carcinoma of the mouth (KB) cell lines. This preliminary investigation demonstrates that simple modifications of the parent structure of betulinic acid can produce potentially important derivatives, which may be developed as antitumor drugs."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"This investigation demonstrates that amino acid conjugates of betulinic acid can produce potentially important derivatives, which may be developed as antitumor agents."

( Why does betulinic acid have to be developed in to an antitumor agent since it is already an antitumor agent?)


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid (BetA), a pentacyclic triterpene, is a selective apoptosis-inducing agent that works directly in mitochondria."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid is a known inducer of apoptosis in human melanoma that is most effective under conditions of low pH."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Indeed, unlike conventional anti tumour drugs which trigger pro-apoptotic signal transduction pathways upstream mitochondria, several compounds were shown to act directly on mitochondria to induce apoptosis. These drugs include betulinic acid, lonidamine, arsenic trioxide and two retinoids like CD437/AHPN and fenretinide/4-HPR. This review summarizes new data concerning these drugs targetted to mitochondria and highlights the new perspective they may offer in cancer therapy."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"CONCLUSIONS: Lupeol and betulin suppress superoxide generation by preventing tyrosyl phosphorylation of a 45.0-kDa protein in human neutrophils, and may have pharmaceutical applications."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Three triterpenes were isolated from Diospyros leucomelas and identified as betulin, betulinic acid, and ursolic acid. They showed anti-inflammatory activity in the carrageenan and serotonin paw edema tests and TPA and EPP ear edema tests. "

(Remember that inflammation has been shown to play a role in cancer formation.)


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"A new pentacyclic lupane-type triterpene derivative, 3-O-[9(Z)-octadecenoyl]betulinic acid (1), and betulinic acid (2) were also isolated and identified. All isolates as well as pure linoleic, oleic and stearic acids were evaluated for their inhibitory effects against both cyclooxygenases-1 (COX-1) and -2 (COX-2)."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Cold-pressed, non-raffinated evening primrose oil was found to contain lipophilic radical scavengers. A highly enriched fraction of these compounds could be obtained from the oil by extraction with aqueous ethanol and subsequent liquid-liquid partitioning with petroleum. LC-DAD-MS analysis revealed that the fraction contained three aromatic compounds with identical UV and ESI-MS spectra. The compounds were isolated by RP-HPLC and their structures established by chemical and spectroscopic means as 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. The morolic acid derivative was a new compound. The three esters exhibited pronounced radical scavenging activity against the stable 2,2-diphenyl-1-picrylhydrazyl radical and were potent inhibitors of neutrophil elastase and cyclooxygenase-1 and -2 in vitro. "

(Cold pressed evening primrose oil is readily available in health food stores. Make sure it is cold pressed and not hexane extracted.)


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Conclusions: These results suggest that in human melanoma cells Mcl-1 is (i) of functional relevance for survival and (ii) subject to dual regulation by the MAP- kinase pathway and a pathway involving protein kinase B/Akt, the latter of which is modulated in response to betulinic acid."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"DNA topoisomerases (Topos) are enzymes that play a crucial role in DNA metabolism events such as replication, transcription, recombination, and chromosome segregation at mitosis. Thus, Topo inhibitors could be expected to have antitumor effects. Naturally occurring lupane- and oleanane-type triterpenoids isolated from the bark of Phyllanthus flexuosus were screened for human Topos I and II inhibitory activities. Olean-12-en-3 beta,15 alpha-diol (1), olean-12-en-3 beta,15 alpha,24-triol (3), lupeol (4), and betulin (6) were found to be selective catalytic inhibitors of human Topo II activity with IC(50) values in the range of 10-39 microM."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"The new phenolic compound, 3,5-dihydroxy-4-methoxy phenethyl alcohol, named alphitol, and betulinic acid were from the bark of Alphitonia zizyphoides. The chemical structure of alphitol was determined by mass spectrometry in combination with one and two dimensional NMR, including HMBC. Both compounds inhibited prostaglandin biosynthesis in vitro, alphitol with an IC50 value of 0.66mM, which is of the same magnitude as acetyl salicylic acid."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Our data suggest that betulinic acid exerts its inhibitory effect partly by increasing p53 without a comparable effect on p21WAF1."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

"Betulinic acid might be promising as an antitumor agent toward solid tumors because the interior pH of tumor tissues is generally lower than in normal tissues."


http://www.ncbi.nlm.nih.gov/entrez/query...t=Abstract

Sterol and triterpene derivatives from plants inhibit the effects of a tumor promoter, and sitosterol and betulinic acid inhibit tumor formation in mouse skin two-stage carcinogenesis.

"A single topical application of 1 microgram of 12-O-tetradecanoylphorbol- 13-acetate (TPA) to the ears of mice was shown to induce edema, and this TPA-induced inflammation was inhibited by 4-methylsterol and triterpene derivatives. The ED50 of these compounds against TPA-induced inflammation was 0.1-3 mumol. Phytosterols had only slight inhibitory effects. Furthermore, application of 5 micrograms TPA to mouse skin rapidly caused accumulation of ornithine decarboxylase (ODC). Similarly, sitosterol and lupane-type triterpene derivatives markedly inhibited this TPA-induced ODC accumulation. In addition, 5 mumol betulinic acid markedly inhibited the promoting effect of 2.5 micrograms TPA applied twice weekly on skin tumor formation in mice initiated with 50 micrograms of 7,12-dimethylbenz[a]anthracene, and 5 mumol of sitosterol caused slight suppression. Thus, the inhibitory effects of sterol and triterpene derivatives on TPA-induced inflammation roughly parallelled their inhibitory activities against tumor promotion."

http://www.MountainMistBotanicals.com
10-27-2012 03:35 PM
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James Offline
Administrator
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Posts: 2,827
Joined: Feb 2012
Reputation: 15
Post: #2
RE: Betulinic acid against various cancers
More abstracts:

https://www.ncbi.nlm.nih.gov/pubmed/11107130

https://www.ncbi.nlm.nih.gov/pubmed/22407812

https://www.ncbi.nlm.nih.gov/pubmed/22553354

https://www.ncbi.nlm.nih.gov/pubmed/12953308

https://www.ncbi.nlm.nih.gov/pubmed/21598174

https://www.ncbi.nlm.nih.gov/pubmed/23158079



Anticancer Drugs. 2010 Mar;21(3):215-27.

Betulinic acid, a natural compound with potent anticancer effects.

Abstract

New therapies using novel mechanisms to induce tumor cell death are needed with plants playing a crucial role as a source for potential anticancer compounds. One highly promising class of natural compounds are the triterpenoids with betulinic acid (BetA) as the most prominent representative. In-vitro studies have identified this agent as potently effective against a wide variety of cancer cells, also those derived from therapy-resistant and refractory tumors, whereas it has been found to be relatively nontoxic for healthy cells. In-vivo preclinically applied BetA showed some remarkable anticancer effects and a complete absence of systemic toxicity in rodents. BetA also cooperated with other therapies to induce tumor cell death and several potent derivatives have been discovered. Its antitumor activity has been related to its direct effects on mitochondria where it induces Bax/Bak-independent cytochrome-c release.



Apoptosis. 2009 Feb;14(2):191-202.

Betulinic acid induces cytochrome c release and apoptosis in a Bax/Bak-independent, permeability transition pore dependent fashion.

Abstract

Betulinic acid (BetA) is a plant-derived pentacyclic triterpenoid that exerts potent anti-cancer effects in vitro and in vivo, but is non toxic to untransformed cells. In our previous study we observed that BetA consistently induced cell death in a broad panel of tumor cell lines. Apoptosis induced by BetA involves activation of caspases, PARP cleavage and DNA fragmentation and was suggested to depend on the mitochondrial pathway. However, conflicting results have been reported with respect to the role of the pro- and anti-apoptotic members of the Bcl-2 family, which are often aberrantly regulated in tumors and thereby confer growth and survival advantages. Here we show that BetA-induced apoptosis critically depends on the release of cytochrome c from the mitochondria and formation of the apoptosome. Nevertheless, over-expression of Bcl-2 or Bcl-XL only provides limited protection against BetA-induced apoptosis. More importantly, Bax/Bak deficient cells are as sensitive to BetA as their wild-type counterparts, suggesting that cytochrome c is released in a non-classical fashion. In agreement, pre-incubation with cyclosporin A indicated a crucial role for the mitochondrial permeability transition pore (PT) in the induction of apoptosis. Our observations therefore indicate that BetA affects mitochondria and induces cytochrome c release directly via PT Pore. This is only temporarily prevented by anti-apoptotic members of the Bcl-2 family, but independent of Bax and Bak. These findings help to explain the remarkable broad efficacy of BetA against tumor cells of different origin and its effect in tumor cells that are resistant to other chemotherapeutic agents.



Klin Padiatr. 1999 Jul-Aug;211(4):319-22.

Betulinic acid: a new chemotherapeutic agent in the treatment of neuroectodermal tumors.

Abstract

We identified betulinic acid (BetA) as a new cytotoxic agent active against neuroectodermal tumor cells including neuroblastoma, medulloblastoma, glioblastoma and Ewing's sarcoma cells representing the most common solid tumors of childhood. BetA induced apoptosis independent of wild-type p53 protein and accumulation of death-inducing ligand/receptor systems such as CD95. BetA had a direct effect on mitochondria resulting in the release of soluble apoptogenic factors such as cytochrome c or AIF from mitochondria into the cytosol where they induced activation of caspases. Overexpression of the anti-apoptotic proteins Bcl-2 or Bcl-XL that blocked loss of the mitochondrial membrane potential and cytochrome c release from mitochondria conferred resistance to BetA at the level of mitochondrial dysfunction, protease activation and nuclear fragmentation. Neuroblastoma cells resistant to CD95- or doxorubicin-triggered apoptosis remained sensitive to treatment with BetA suggesting that BetA may bypass some forms of resistance. Moreover, BetA exhibited potent antitumor activity on primary tumor cell cultures from all neuroblastoma (4/4), all medulloblastoma (4/4) and most glioblastoma patients (20/24) ex vivo. These findings suggest that BetA may be a promising new agent in the treatment of neuroectodermal tumors in vivo.


Cancer Res. 1997 Nov 1;57(21):4956-64.

Betulinic acid triggers CD95 (APO-1/Fas)- and p53-independent apoptosis via activation of caspases in neuroectodermal tumors.

Abstract

Betulinic acid (BA), a melanoma-specific cytotoxic agent, induced apoptosis in neuroectodermal tumors, such as neuroblastoma, medulloblastoma, and Ewing's sarcoma, representing the most common solid tumors of childhood. BA triggered an apoptosis pathway different from the one previously identified for standard chemotherapeutic drugs. BA-induced apoptosis was independent of CD95-ligand/receptor interaction and accumulation of wild-type p53 protein, but it critically depended on activation of caspases (interleukin 1beta-converting enzyme/Ced-3-like proteases). FLICE/MACH (caspase-8), considered to be an upstream protease in the caspase cascade, and the downstream caspase CPP32/YAMA/Apopain (caspase-3) were activated, resulting in cleavage of the prototype substrate of caspases PARP. The broad-spectrum peptide inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, which blocked cleavage of FLICE and PARP, also completely abrogated BA-triggered apoptosis. Cleavage of caspases was preceded by disturbance of mitochondrial membrane potential and by generation of reactive oxygen species. Overexpression of Bcl-2 and Bcl-XL conferred resistance to BA at the level of mitochondrial dysfunction, protease activation, and nuclear fragmentation. This suggested that mitochondrial alterations were involved in BA-induced activation of caspases. Furthermore, Bax and Bcl-xs, two death-promoting proteins of the Bcl-2 family, were up-regulated following BA treatment. Most importantly, neuroblastoma cells resistant to CD95- and doxorubicin-mediated apoptosis were sensitive to treatment with BA, suggesting that BA may bypass some forms of drug resistance. Because BA exhibited significant antitumor activity on patients' derived neuroblastoma cells ex vivo, BA may be a promising new agent for the treatment of neuroectodermal tumors in vivo.


J Biol Chem. 1998 Dec 18;273(51):33942-8.

Activation of mitochondria and release of mitochondrial apoptogenic factors by betulinic acid.

Abstract

Different classes of anticancer drugs may trigger apoptosis by acting on different subcellular targets and by activating distinct signaling pathways. Here, we report that betulinic acid (BetA) is a prototype cytotoxic agent that triggers apoptosis by a direct effect on mitochondria. In isolated mitochondria, BetA directly induces loss of transmembrane potential independent of a benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone-inhibitable caspase. This is inhibited by bongkrekic acid, an agent that stabilizes the permeability transition pore complex. Mitochondria undergoing BetA-induced permeability transition mediate cleavage of caspase-8 (FLICE/MACH/Mch5) and caspase-3 (CPP32/Yama) in a cell-free system. Soluble factors such as cytochrome c or apoptosis-inducing factor released from BetA-treated mitochondria are sufficient for cleavage of caspases and nuclear fragmentation. Addition of cytochrome c to cytosolic extracts results in cleavage of caspase-3, but not of caspase-8. However, supernatants of mitochondria, which have undergone permeability transition, and partially purified apoptosis-inducing factor activate both caspase-8 and caspase-3 in cytosolic extracts and suffice to activate recombinant caspase-8. These findings show that induction of mitochondrial permeability transition alone is sufficient to trigger the full apoptosis program and that some cytotoxic drugs such as BetA may induce apoptosis via a direct effect on mitochondria. Free full text.


J Biol Chem. 1998 Dec 18;273(51):33942-8.

Activation of mitochondria and release of mitochondrial apoptogenic factors by betulinic acid.

Abstract

Different classes of anticancer drugs may trigger apoptosis by acting on different subcellular targets and by activating distinct signaling pathways. Here, we report that betulinic acid (BetA) is a prototype cytotoxic agent that triggers apoptosis by a direct effect on mitochondria. In isolated mitochondria, BetA directly induces loss of transmembrane potential independent of a benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone-inhibitable caspase. This is inhibited by bongkrekic acid, an agent that stabilizes the permeability transition pore complex. Mitochondria undergoing BetA-induced permeability transition mediate cleavage of caspase-8 (FLICE/MACH/Mch5) and caspase-3 (CPP32/Yama) in a cell-free system. Soluble factors such as cytochrome c or apoptosis-inducing factor released from BetA-treated mitochondria are sufficient for cleavage of caspases and nuclear fragmentation. Addition of cytochrome c to cytosolic extracts results in cleavage of caspase-3, but not of caspase-8. However, supernatants of mitochondria, which have undergone permeability transition, and partially purified apoptosis-inducing factor activate both caspase-8 and caspase-3 in cytosolic extracts and suffice to activate recombinant caspase-8. These findings show that induction of mitochondrial permeability transition alone is sufficient to trigger the full apoptosis program and that some cytotoxic drugs such as BetA may induce apoptosis via a direct effect on mitochondria. Free full text.


Nat Med. 1995 Oct;1(10):1046-51.

Discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of apoptosis.

Abstract

As a result of bioassay-guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma-specific cytotoxic agent. In follow-up studies conducted with athymic mice carrying human melanomas, tumour growth was completely inhibited without toxicity. As judged by a variety of cellular responses, antitumour activity was mediated by the induction of apoptosis. Betulinic acid is inexpensive and available in abundant supply from common natural sources, notably the bark of white birch trees. The compound is currently undergoing preclinical development for the treatment or prevention of malignant melanoma.


Clin Cancer Res. 2003 Jul;9(7):2866-75.

Betulinic acid-induced programmed cell death in human melanoma cells involves mitogen-activated protein kinase activation.

Abstract

Betulinic acid, a naturally occurring triterpene found in the bark of the white birch tree, has been demonstrated to induce programmed cell death with melanoma and certain neuroectodermal tumor cells. We demonstrate currently that treatment of cultured UISO-Mel-1 (human melanoma cells) with betulinic acid leads to the activation of p38 and stress activated protein kinase/c-Jun NH(2)-terminal kinase [widely accepted proapoptotic mitogen-activated protein kinases (MAPKs)] with no change in the phosphorylation of extracellular signal-regulated kinases (antiapoptotic MAPK). Moreover, these results support a link between the MAPKs and reactive oxygen species (ROS). As demonstrated previously, cells treated with betulinic acid generate ROS. Preincubation of cells with antioxidants blocks the process of programmed cell death, and prevents the phosphorylation of p38 and stress activated protein kinase/c-Jun NH(2)-terminal kinase. These data suggest that ROS act upstream of the MAPKs in the signaling pathway of betulinic acid. In addition to mediating these responses, treatment of cells with betulinic acid resulted in a gradual depolarization of mitochondrial membrane potential, a phenomenon established to contribute to the induction of programmed cell death. Interestingly, p38 was capable of partially modulating this perturbation, and investigations of mitochondria-associated apoptotic events indicate no involvement of known caspases. These data provide additional insight in regard to the mechanism by which betulinic acid induces programmed cell death in cultured human melanoma cells, and it likely that similar responses contribute to the antitumor effect mediated with human melanoma carried in athymic mice.


Nat Med. 1995 Oct;1(10):1046-51.

Discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of apoptosis.

Abstract

As a result of bioassay-guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma-specific cytotoxic agent. In follow-up studies conducted with athymic mice carrying human melanomas, tumour growth was completely inhibited without toxicity. As judged by a variety of cellular responses, antitumour activity was mediated by the induction of apoptosis. Betulinic acid is inexpensive and available in abundant supply from common natural sources, notably the bark of white birch trees. The compound is currently undergoing preclinical development for the treatment or prevention of malignant melanoma.


Cancer Res. 2007 Mar 15;67(6):2816-23.

Betulinic acid inhibits prostate cancer growth through inhibition of specificity protein transcription factors.

Abstract

Betulinic acid is a pentacyclic triterpene natural product initially identified as a melanoma-specific cytotoxic agent that exhibits low toxicity in animal models. Subsequent studies show that betulinic acid induces apoptosis and antiangiogenic responses in tumors derived from multiple tissues; however, the underlying mechanism of action is unknown. Using LNCaP prostate cancer cells as a model, we now show that betulinic acid decreases expression of vascular endothelial growth (VEGF) and the antiapoptotic protein survivin. The mechanism of these betulinic acid-induced antiangiogenic and proapoptotic responses in both LNCaP cells and in tumors is due to activation of selective proteasome-dependent degradation of the transcription factors specificity protein 1 (Sp1), Sp3, and Sp4, which regulate VEGF and survivin expression. Thus, betulinic acid acts as a novel anticancer agent through targeted degradation of Sp proteins that are highly overexpressed in tumors.


BMC Cancer. 2011 Aug 24;11:371. doi: 10.1186/1471-2407-11-371.

Betulinic acid inhibits colon cancer cell and tumor growth and induces proteasome-dependent and -independent downregulation of specificity proteins (Sp) transcription factors.

Abstract

BACKGROUND:

Betulinic acid (BA) inhibits growth of several cancer cell lines and tumors and the effects of BA have been attributed to its mitochondriotoxicity and inhibition of multiple pro-oncogenic factors. Previous studies show that BA induces proteasome-dependent degradation of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 in prostate cancer cells and this study focused on the mechanism of action of BA in colon cancer cells.

METHODS:

The effects of BA on colon cancer cell proliferation and apoptosis and tumor growth in vivo were determined using standardized assays. The effects of BA on Sp proteins and Sp-regulated gene products were analyzed by western blots, and real time PCR was used to determine microRNA-27a (miR-27a) and ZBTB10 mRNA expression.

RESULTS:

BA inhibited growth and induced apoptosis in RKO and SW480 colon cancer cells and inhibited tumor growth in athymic nude mice bearing RKO cells as xenograft. BA also decreased expression of Sp1, Sp3 and Sp4 transcription factors which are overexpressed in colon cancer cells and decreased levels of several Sp-regulated genes including survivin, vascular endothelial growth factor, p65 sub-unit of NFκB, epidermal growth factor receptor, cyclin D1, and pituitary tumor transforming gene-1. The mechanism of action of BA was dependent on cell context, since BA induced proteasome-dependent and proteasome-independent downregulation of Sp1, Sp3 and Sp4 in SW480 and RKO cells, respectively. In RKO cells, the mechanism of BA-induced repression of Sp1, Sp3 and Sp4 was due to induction of reactive oxygen species (ROS), ROS-mediated repression of microRNA-27a, and induction of the Sp repressor gene ZBTB10.

CONCLUSIONS:

These results suggest that the anticancer activity of BA in colon cancer cells is due, in part, to downregulation of Sp1, Sp3 and Sp4 transcription factors; however, the mechanism of this response is cell context-dependent.



Exp Dermatol. 2005 Oct;14(10):736-43.

Betulinic acid induces apoptosis in skin cancer cells and differentiation in normal human keratinocytes.

Abstract

Betulinic acid (BA), a pentacyclic triterpene of plant origin, induces cell death in melanoma cells and other malignant cells of neuroectodermal origin. Little is known about additional biological effects in normal target cells. We show, in this study, that BA induces differentiation as well as cell death in normal human keratinocytes (NHK). Cytotoxicity profiles of BA are compared among normal human keratinocytes, HaCaT cells, IGR1 melanoma cells and normal melanocytes. As expected, BA is toxic to all cell types, normal and malignant, but varies in its cytotoxic potency and in the extent of induction of apoptotic vs. necrotic cell death in the four different skin cell types. Apoptosis is proved by annexin V and Apo2.7 binding and by DNA fragmentation. Induction of differentiation-associated antigens in keratinocytes--filaggrin and involucrin--is demonstrated, together with specific morphological changes in treated cell cultures. BA, apart from its cytotoxic activities in cellular systems, is capable of inducing differentiation of NHK into corneocytes without immediately provoking apoptotic cell death.


Toxicol Lett. 2005 Mar 15;155(3):343-51.

Betulinic acid induces apoptosis in human chronic myelogenous leukemia (CML) cell line K-562 without altering the levels of Bcr-Abl.

Abstract

Betulinic acid (BA), a plant derived triterpenoid, isolated from various sources shows cytotoxicity in cell lines of melanoma, neuroectodermal and malignant brain tumors. Chronic myelogenous leukemia (CML) is characterized by Philadelphia chromosome (Bcr-Abl), a molecular abnormality leading to the intrinsic tyrosine kinase activity that provides growth and survival advantage to the cells. Present study describes the cytotoxicity of BA on human CML cell line K-562, positive for Bcr-Abl. The decrease in the viability of K-562 cells treated with BA at different concentrations and time intervals was assessed using MTT assay. Cell death induced by BA was determined to be apoptotic as measured by FACS analysis of PI stained nuclei, PS externalization by Annexin-V fluorescence and characteristic DNA fragmentation. DiOC6(3) fluorescent probe determined alterations in the mitochondrial membrane potential (MMP). RT-PCR confirmed the expression levels of Bcr-Abl in controls and K-562 cells treated with BA. The rapid loss of MMP of K-562 cells upon treatment with BA shows the direct activation of apoptosis at the level of mitochondria, overcoming the resistance of the high levels of expression of Bcr-Abl.


Int J Mol Sci. 2008 Jun;9(6):1096-107.

Betulinic Acid for cancer treatment and prevention.

Abstract

Betulinic acid is a natural product with a range of biological effects, for example potent antitumor activity. This anticancer property is linked to its ability to induce apoptotic cell death in cancer cells by triggering the mitochondrial pathway of apoptosis. In contrast to the cytotoxicity of betulinic acid against a variety of cancer types, normal cells and tissue are relatively resistant to betulinic acid, pointing to a therapeutic window. Compounds that exert a direct action on mitochondria present promising experimental cancer therapeutics, since they may trigger cell death under circumstances in which standard chemotherapeutics fail. Thus, mitochondrion-targeted agents such as betulinic acid hold great promise as a novel therapeutic strategy in the treatment of human cancers.



Drug Discov Today. 2009 Sep;14(17-18):885-90.

Targeting mitochondrial apoptosis by betulinic acid in human cancers.

Abstract

Betulinic acid (BA) is a naturally occurring pentacyclic triterpene that exhibits a variety of biological activities including potent antitumor properties. This anticancer activity has been linked to its ability to directly trigger mitochondrial membrane permeabilization, a central event in the apoptotic process that seals the cell's fate. In contrast to the potent cytotoxicity of BA against a variety of cancer types, non-neoplastic cells as well as normal tissue remain relatively resistant to BA, thus pointing to a therapeutic window. Because agents that exert a direct action on mitochondria may bypass resistance to conventional chemotherapeutics, there is increasing interest to develop such compounds as experimental cancer therapeutics. Thus, mitochondrion-targeted agents such as BA hold great promise as a novel approach to overcome certain forms of drug resistance in human cancers.


Naunyn Schmiedebergs Arch Pharmacol. 2006 Oct;374(1):11-20.

Betulinic acid decreases expression of bcl-2 and cyclin D1, inhibits proliferation, migration and induces apoptosis in cancer cells.

Abstract

Betulinic acid (BA) is a pentacyclic triterpene found in many plant species, among others in the bark of white birch Betula alba. BA was reported to display a wide range of biological effects, including antiviral, antiparasitic, antibacterial and anti-inflammatory activities, and in particular to inhibit growth of cancer cells. The aim of the study was further in vitro characterization of BA anticancer activity. In this study, we demonstrated a remarkable antiproliferative effect of BA in all tested tumor cell cultures including neuroblastoma, rabdomyosarcoma-medulloblastoma, glioma, thyroid, breast, lung and colon carcinoma, leukemia and multiple myeloma, as well as in primary cultures isolated from ovarian carcinoma, cervical carcinoma and glioblastoma multiforme. Furthermore, we have shown that BA decreased cancer cell motility and induced apoptotic cell death. We also observed decrease of bcl2 and cyclin D1 genes expression, and increase of bax gene expression after betulinic acid treatment. These findings demonstrate the anticancer potential of betulinic acid and suggest that it may be taken into account as a supportive agent in the treatment of cancers with different tissue origin.


Cancer Lett. 2007 Jun 18;251(1):132-45. Epub 2006 Dec 13.

Broad in vitro efficacy of plant-derived betulinic acid against cell lines derived from the most prevalent human cancer types.

Abstract

Betulinic acid (BA) is a widely available plant-derived triterpene with reported activity against cancer cells of neuroectodermal origin and leukaemias. Treatment with BA was shown to protect mice against transplanted human melanoma and led to tumor regression. In contrast, cells from healthy tissues were resistant to BA and toxic side-effects in animals were absent. These findings have raised interest in the chemotherapeutical anti-cancer potential of BA. A comprehensive assessment of the efficacy of BA against the clinically most important cancer types is currently lacking. Therefore, we tested the in vitro sensitivity of broad cell line panels derived from lung, colorectal, breast, prostate and cervical cancer, which are the prevalent cancer types characterized with highest mortalities in woman and men. Multiple assays were used in order to allow a reliable assessment of anti-cancer efficacy of BA. After 48 h of treatment with BA, cell viability as assessed with MTT and cell death as measured with propidium iodide exclusion showed clear differences in sensitivity between cell lines. However, in all cell lines tested colony formation was completely halted at remarkably equal BA concentrations that are likely attainable in vivo. Our results substantiate the possible application of BA as a chemotherapeutic agent for the most prevalent human cancer types.


Zhonghua Zhong Liu Za Zhi. 2008 Aug;30(8):588-92.

[Effect of betulinic acid on proliferation and apoptosis in Jurkat cells and its mechanism].
[Article in Chinese]

Abstract

OBJECTIVE:

To investigate the anticancer effects of betulinic acid (BA) on Jurkat cells in vitro and its molecular mechanism.

METHODS:

The effects of betulinic acid on the growth of Jurkat cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was assessed by Hoechst33258 staining and annexin-V/PI double-labeled cytometry. The effect of betulinic acid on the cell cycle of Jurkat cells was studied by propidium iodide staining. RT-PCR and Western blot were used to analyze the changes of cyclin D3, bcl-xl mRNA and protein levels in Jurkat cells after treatment with betulinic acid.

RESULTS:

The proliferation of Jurkat cells was decreased in betulinic acid-treated group at a 24 h IC50 value of 70.0 micromol/L. The effect of betulinic acid to induce apoptosis in Jurkat cells was in a time- and dose-dependent manner. Jurkat cells treated with betulinic acid showed an increase of G0/G1 phase and decrease of S phase. The Jurkat cells treated with 0, 20, 60, 100 micromol/L betulinic acid for 24 h, showed an increased G0/G1 phase from 31.0% to 58.8%, whereas decreased S phase from 61.5% to 35.8%, respectively. PBMC was less sensitive to the cytotoxic effect of betulinic acid than Jurkat cells. The expression of cyclin D3, bcl-xl mRNA and protein were decreased sharply in Jurkat cells treated with betulinic acid.

CONCLUSION:

Betulinic acid can inhibit the proliferation of Jurkat cells by regulating the cell cycle that arrests cells at G0/G1 phase and induces apoptosis in Jurkat cells. The antitumor effects of betulinic acid may be related to down-regulation of the expression of cyclin D3 and bcl-xl.


J Huazhong Univ Sci Technolog Med Sci. 2008 Dec;28(6):634-8. doi: 10.1007/s11596-008-0604-9. Epub 2008 Dec 24.

Effects of betulinic acid on proliferation and apoptosis in Jurkat cells and its in vitro mechanism.

Abstract

The anti-cancer effects of betulinic acid (BA) on Jurkat cells and its in vitro mechanism were examined by using MTT assay. Apoptosis was detected by using Hoechst33258 staining and annexin-V/PI double-labeled cytometry. The effects of betulinic acid on the cell cycle of Jurkat cells were studied by propidium iodide method. RT-PCR and Western blotting were used to analyze the changes of cyclin D3, bcl-xl mRNA and protein levels in Jurkat cells after treatment with betulinic acid. Our results showed the proliferation of Jurkat cells was decreased in betulinic acid-treated group with a 24-h IC50 value being 70.00 mumol/L. Betulinic acid induced apoptosis of Jurkat cells in a time- and dose-dependent manner. The number of Jurkat cells treated with betulinic acid showed an increase in G(0)/G(1) phase and decrease in S phase. After treatment with 0, 20, 60, 100 mumol/L betulinic acid for 24 h, the number of Jurkat cells was increased from (31.00+/-1.25)% to (58.84+/-0.32)% in G(0)/G(1) phase, whereas it was decreased from (61.45+/-1.04)% to (35.82+/-1.95)% in S phase. PBMCs were less sensitive to the cytotoxicity of betulinic acid than Jurkat cells. The expressions of cyclin D3, bcl-xl mRNA and protein were decreased sharply in Jurkat cells treated with betulinic acid. It is concluded that betulinic acid is able to inhibit the proliferation of Jurkat cells by regulating the cell cycle, arrest cells at G(0)/G(1) phase and induce the cell apoptosis. The anti-tumor effects of betulinic acid are related to the down-regulated expression of cyclin D3 and bcl-xl.


Zhonghua Zhong Liu Za Zhi. 2007 Mar;29(3):176-80.

[Effect of deguelin on proliferation and apoptosis of lymphoma Daudi cells and its mechanism].
[Article in Chinese]

Abstract

OBJECTIVE:

To investigate the anticancer effects and molecular mechanism of deguelin on human Burkitt's lymphoma Daudi cells in vitro and compare the cytotoxicity of deguelin on Daudi cells and human peripheral blood monocular cells (HPBMC).

METHODS:

The effects of deguelin on the growth of Daudi cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5 diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was assessed through Hoechst 33258 staining and annexin V/PI double-labeled cytometry. The effect of deguelin on the cell cycle of Daudi cells was studied by propidium iodide method. The expressions of cyclin D1 and pRb were checked by Western blot.

RESULTS:

The proliferation of Daudi cells was decreased in deguelin-treated group with a 24 h IC50 value of 51. 55 nmol/L. Deguelin induced Daudi cells apoptosis in a time- and dose-dependent manner. Daudi cells treated with deguelin showed an increase of G0/G1 phase and decrease of S phase. The Daudi cells treated with 0, 5, 10, 20, 40 nmol/L deguelin for 24 h, showed an increased Go/G, phase from 37.34% to 56.56% , whereas decreased S phase from 37.72% to 21.36%, respectively. PBMC was less sensitive to the cytotoxic effect of deguelin than Daudi cells. The expression of cyclin D1 and pRb protein were decreased in Daudi cells treated with deguelin.

CONCLUSION:

Deguelin can inhibit the proliferation of Daudi cells by regulating the cell cycle that arrest cells at G0/G1 phase and inducing apoptosis. Moreover, deguelin demonstrats low toxicity in PBMC but selectively induces apoptosis of Daudi cells. The antitumor effects of deguelin may be related to down-regulation of the expression of cyclin D1 and pRb protein


J Huazhong Univ Sci Technolog Med Sci. 2010 Aug;30(4):453-7. doi: 10.1007/s11596-010-0448-y. Epub 2010 Aug 17.

Antitumor effect of betulinic acid on human acute leukemia K562 cells in vitro.

Abstract

The effects of betulinic acid (BA), a pentacyclic lupane-type triterpene, on the cell viability, cell cycle and apoptosis in human leukemia K562 cells were investigated. The effects of BA on the growth of K562 cells were studied by MTT assay. Apoptosis was assayed through Annexin V/propidium iodide (PI) double-labeled cytometry. The effects of BA on the cell cycle of K562 cells were studied by a PI method. The expression of Bax and capase-3 was detected by using Western blot. The results showed that BA was cytotoxic to K562 cells with an IC50 of 21.26 microg/mL at 24 h. After treating K562 cells with 10 microg/mL BA for 72 h, the number of cells was reduced by 58%. BA induced apoptosis of K562 cells in a time- and dose-dependent manner. The proportion of cells in G0/G1 and G2/M phases was decreased and that in S phase was increased after K562 cells were treated with BA for 24 h. BA treatment also increased the expression of the pro-apoptotic proteins Bax and caspase-3. It suggested that BA could inhibit the proliferation of K562 cells through the induction of cell cycle arrest and apoptosis. The antitumor effects of BA were related with up-regulation of the expression of Bax and caspase-3 proteins. BA may qualify for the development of new therapies for leukemia.


Basic Clin Pharmacol Toxicol. 2009 Dec;105(6):425-32. doi: 10.1111/j.1742-7843.2009.00471.x. Epub 2009 Oct 12.

Betulin elicits anti-cancer effects in tumour primary cultures and cell lines in vitro.

Abstract

Betulin is a pentacyclic triterpene found in many plant species, among others, in white birch bark. The aim of the study was in vitro characterization of the anticancer activity of betulin in a range of human tumour cell lines (neuroblastoma, rhabdomyosarcoma-medulloblastoma, glioma, thyroid, breast, lung and colon carcinoma, leukaemia and multiple myeloma), and in primary tumour cultures isolated from patients (ovarian carcinoma, cervical carcinoma and glioblastoma multiforme). In this study, we demonstrated a remarkable anti-proliferative effect of betulin in all tested tumour cell cultures. Neuroblastoma (SK-N-AS) and colon carcinoma (HT-29) were the most sensitive to the anti-proliferative effect of betulin. Furthermore, betulin altered tumour cells morphology, decreased their motility and induced apoptotic cell death. These findings demonstrate the anti-cancer potential of betulin and suggest that they may be applied as an adjunctive measure in cancer treatment.


Molecules. 2009 Apr 24;14(4):1639-51.

Comparision of the cytotoxic effects of birch bark extract, betulin and betulinic acid towards human gastric carcinoma and pancreatic carcinoma drug-sensitive and drug-resistant cell lines.

Abstract

Betulin and betulinic acid are naturally occurring pentacyclic triterpenes showing cytotoxicity towards a number of cancer cell lines. These compounds can be found in the bark of the many plants. In this report we have compared the cytotoxic activity of crude birch bark extract and purified betulin and betulinic acid towards human gastric carcinoma (EPG85-257) and human pancreatic carcinoma (EPP85-181) drug-sensitive and drug-resistant (daunorubicin and mitoxantrone) cell lines. Our results show significant differences in sensitivity between cell lines depending on the compound used, and suggest that both betulin and betulinic acid can be considered as a promising leads in the treatment of cancer. Free full text.

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