Podophyllotoxin

Last updated
Podophyllotoxin
Podophyllotoxin2DCSD.svg
Clinical data
Trade names Condylox, [1] Wartec, others
Other names(5R,5aR,8aR,9R)-9-hydroxy-5-(3,4,5-trimethoxyphenyl)-5,8,8a,9-tetrahydrofuro[3',4':6,7]naphtho[2,3-d] [1,3]dioxol-6(5aH)-one
AHFS/Drugs.com Monograph
MedlinePlus a684055
Pregnancy
category
  • C
ATC code
Legal status
Legal status
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Elimination half-life 1.0 to 4.5 hours.
Identifiers
  • (10R,11R,15R,16R)-16-hydroxy-10-(3,4,5-trimethoxyphenyl)-4,6,13-trioxatetracyclo[7.7.0.03,7.011,15]hexadeca-1,3(7),8-trien-12-one
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard 100.007.502 OOjs UI icon edit-ltr-progressive.svg
Chemical and physical data
Formula C22H22O8
Molar mass 414.410 g·mol−1
3D model (JSmol)
Melting point 183.3 to 184 °C (361.9 to 363.2 °F)
  • COc1cc(cc(c1OC)OC)[C@@H]2c3cc4c(cc3[C@@H]([C@@H]5[C@@H]2C(=O)OC5)O)OCO4
  • InChI=1S/C22H22O8/c1-25-16-4-10(5-17(26-2)21(16)27-3)18-11-6-14-15(30-9-29-14)7-12(11)20(23)13-8-28-22(24)19(13)18/h4-7,13,18-20,23H,8-9H2,1-3H3/t13-,18+,19-,20-/m0/s1 Yes check.svgY
  • Key:YJGVMLPVUAXIQN-XVVDYKMHSA-N Yes check.svgY
 X mark.svgNYes check.svgY  (what is this?)    (verify)

Podophyllotoxin (PPT) is the active ingredient in Podofilox, which is a medical cream that is used to treat genital warts and molluscum contagiosum. [2] It is not recommended in HPV infections without external warts. [2] It can be applied either by a healthcare provider or the person themselves. [2]

Contents

It is a non-alkaloid toxin lignin extracted from the roots and rhizomes of Podophyllum species. [3] A less refined form known as podophyllum resin is also available, but has greater side effects. [4] [5]

Podophyllotoxin was first isolated in pure form in 1880 by Valerian Podwyssotzki (1818 – 28 January 1892), a Polish-Russian privatdozent at the University of Dorpat (now: Tartu, Estonia) and assistant at the Pharmacological Institute there. [6] [7] [8]

It is on the World Health Organization's List of Essential Medicines. [9]

Medical uses

Podophyllotoxin possesses a large number of medical applications, as it is able to stop replication of both cellular and viral DNA by binding necessary enzymes. It can additionally destabilize microtubules and prevent cell division. Because of these interactions it is considered an antimitotic drug, although modern medicine instead use less orally toxic derivatives when such effect is wanted. [10]

Podophyllotoxin cream is commonly prescribed as a potent topical antiviral. [11] It is used for the treatment of HPV infections with external warts as well as molluscum contagisum infections. [11] 0.5% PPT cream is prescribed for twice daily applications for 3 days followed by 4 days with no application, this weekly cycle is repeated for 4 weeks. [12] It can also be prescribed as a gel, as opposed to cream. PPT is also sold under the names condyline and warticon. [13]

Adverse effects

The most common side effects of podophyllotoxin cream are typically limited to irritation of tissue surrounding the application site, including burning, redness, pain, itching, swelling. [14] Application can be immediately followed by burning or itching. Small sores, itching and peeling skin can also follow, for these reasons it is recommended that application be done in a way that limits contact with surrounding, uninfected tissue [15]

Neither podophyllin resin nor podophyllotoxin lotions or gels are used during pregnancy because these medications have been shown to be embryotoxic in both mice and rats. Additionally, antimitotic agents are not typically recommended during pregnancy. [16] Additionally, it has not been determined if podophyllotoxin can pass into breast milk from topical applications and therefore it is not recommended for breastfeeding women. [17]

Podophyllotoxin cream is safe for topical use; however, it can cause CNS depression as well as enteritis if ingested. The podophyllum resin from which podophyllotoxin is derived has the same effect. [18]

Mechanism of action

Podophyllotoxin destabilizes microtubules by binding tubulin and thus preventing cell division. [19] [20] In contrast, some of its derivatives display binding activity to the enzyme topoisomerase II (Topo II) during the late S and early G2 stage. For instance, etoposide binds and stabilizes the temporary DNA break caused by the enzyme, disrupts the reparation of the break through which the double-stranded DNA passes, and consequently stops DNA unwinding and replication. [21] Mutants resistant to either podophyllotoxin, or to its topoisomerase II inhibitory derivatives such as etoposide (VP-16), have been described in Chinese hamster cells. [22] [23] The mutually exclusive cross-resistance patterns of these mutants provide a highly specific means to distinguish the two kinds of podophyllotoxin derivatives. [23] [24] Mutant Chinese hamster cells resistant to podophyllotoxin are affected in a protein P1 that was later identified as the mammalian HSP60 or chaperonin protein. [25] [26] [27]

Furthermore, podophyllotoxin is classified as an arytetralin lignan for[ dubious – discuss ] its ability to bind and deactivate DNA. [28] It and its derivates bind Topo II and prevent its ability to catalyze rejoining of DNA that has been broken for replication. Lastly, experimental evidence has shown that these arytetralin lignans can interact with cellular factors to create chemical DNA adducts, thus further deactivating DNA. [28]

Chemistry

Structural characteristic

The structure of podophyllotoxin was first elucidated in the 1930s. [29] Podophyllotoxin bears four consecutive chiral centers, labelled C-1 through C-4 in the following image. The molecule also contains four almost planar fused rings. The podophyllotoxin molecule includes a number of oxygen containing functional groups: an alcohol, a lactone, three methoxy groups, and an acetal. [30]

Podophyllotoxin structure.png

Derivatives of podophyllotoxin are synthesized as properties of the rings and carbon 1 through 4 are diversified. For example, ring A is not essential to antimitotic activity. Aromatization of ring C leads to loss of activity, possibly from ring E no longer being placed on the axial position. In addition, the stereochemistry at C-2 and C-3 configures a trans-lactone, which has more activity than the cis counterpart. Chirality at C-1 is also important as it implies an axial position for ring E. [30]

Biosynthesis

The biosynthetic route of podophyllotoxin was not completely eludicidated for many years; however, in September 2015, the identity of the six missing enzymes in podophyllotoxin biosynthesis were reported for the first time. [31] Several prior studies have suggested a common pathway starting from coniferyl alcohol being converted to (+)-pinoresinol in the presence of a one-electron oxidant [10] through dimerization of stereospecific radical intermediate. Pinoresinol is subsequently reduced in the presence of co-factor NADPH to first lariciresinol, and ultimately secoisolariciresinol. Lactonization on secoisolariciresinol gives rise to matairesinol. Secoisolariciresinol is assumed to be converted to yatein through appropriate quinomethane intermediates, [10] leading to podophyllotoxin.

Podophyllotoxinbiosynthesis2015.png

A sequence of enzymes involved has been reported to be dirigent protein (DIR), to convert coniferyl alcohol to (+)-pinocresol, which is converted by pinocresol-lariciresinol reductase (PLR) to (-)-secoisolariciresinol, which is converted by sericoisolariciresinol dehydrogenase (SDH) to (-)-matairesinol, which is converted by CYP719A23 to (-)-pluviatolide, which is likely converted by Phex13114 (OMT1) to (-)-yatein, which is converted by Phex30848 (2-ODD) to (-)-deoxypodophyllotoxin. [31] Though not proceeding through the last step of producing podophyllotoxin itself, a combination of six genes from the mayapple enabled production of the etoposide aglycone in tobacco plants. [31]

Chemical synthesis

Podophyllotoxin has been successfully synthesized in a laboratory; however, synthesis mechanisms require many steps, resulting in a low overall yield. It therefore remains more efficient to obtain podophyllotoxin from natural sources. [32]

Four routes have been used to synthesize podophyllotoxin with varying success: an oxo ester route, [33] lactonization of a dihydroxy acid, [34] cyclization of a conjugate addition product, [35] and a Diels-Alder reaction. [36]

Derivatives

Podophyllotoxin and its derivatives are used as cathartic, purgative, antiviral agent, vesicant, antihelminthic, and antitumor agents. Podophyllotoxin derived antitumor agents include etoposide and teniposide. [10] [37] These drugs have been successfully used in therapy against numerous cancers including testicular, breast, pancreatic, lung, stomach, and ovarian cancers. [32]

Derivatives of podophyllotoxin that have been engineered for their ability to fight tumors. Podophyllotoxin antitumor derivatives.png
Derivatives of podophyllotoxin that have been engineered for their ability to fight tumors.

Natural abundance

Podophyllotoxin is present at concentrations of 0.3% to 1.0% by mass in the rhizome of the American mayapple (Podophyllum peltatum). [21] [39] Another common source is the rhizome of Sinopodophyllum hexandrum Royle (Berberidaceae).

It is biosynthesized from two molecules of coniferyl alcohol by phenolic oxidative coupling and a series of oxidations, reductions and methylations. [21]

Related Research Articles

<span class="mw-page-title-main">Chalcone</span> Chemical compound

Chalcone is the organic compound C6H5C(O)CH=CHC6H5. It is an α,β-unsaturated ketone. A variety of important biological compounds are known collectively as chalcones or chalconoids. They are widely known bioactive substances, fluorescent materials, and chemical intermediates.

The lignans are a large group of low molecular weight polyphenols found in plants, particularly seeds, whole grains, and vegetables. The name derives from the Latin word for "wood". Lignans are precursors to phytoestrogens. They may play a role as antifeedants in the defense of seeds and plants against herbivores.

<span class="mw-page-title-main">Etoposide</span> Chemotherapy medication

Etoposide, sold under the brand name Vepesid among others, is a chemotherapy medication used for the treatments of a number of types of cancer including testicular cancer, lung cancer, lymphoma, leukemia, neuroblastoma, and ovarian cancer. It is also used for hemophagocytic lymphohistiocytosis. It is used by mouth or injection into a vein.

<span class="mw-page-title-main">Teniposide</span> Chemical compound

Teniposide is a chemotherapeutic medication used in the treatment of childhood acute lymphocytic leukemia (ALL), Hodgkin's lymphoma, certain brain tumours, and other types of cancer. It is in a class of drugs known as podophyllotoxin derivatives and slows the growth of cancer cells in the body.

Topoisomerase inhibitors are chemical compounds that block the action of topoisomerases, which are broken into two broad subtypes: type I topoisomerases (TopI) and type II topoisomerases (TopII). Topoisomerase plays important roles in cellular reproduction and DNA organization, as they mediate the cleavage of single and double stranded DNA to relax supercoils, untangle catenanes, and condense chromosomes in eukaryotic cells. Topoisomerase inhibitors influence these essential cellular processes. Some topoisomerase inhibitors prevent topoisomerases from performing DNA strand breaks while others, deemed topoisomerase poisons, associate with topoisomerase-DNA complexes and prevent the re-ligation step of the topoisomerase mechanism. These topoisomerase-DNA-inhibitor complexes are cytotoxic agents, as the un-repaired single- and double stranded DNA breaks they cause can lead to apoptosis and cell death. Because of this ability to induce apoptosis, topoisomerase inhibitors have gained interest as therapeutics against infectious and cancerous cells.

<span class="mw-page-title-main">Dihydrofolic acid</span> Chemical compound

Dihydrofolic acid (conjugate base dihydrofolate) (DHF) is a folic acid (vitamin B9) derivative which is converted to tetrahydrofolic acid by dihydrofolate reductase. Since tetrahydrofolate is needed to make both purines and pyrimidines, which are building blocks of DNA and RNA, dihydrofolate reductase is targeted by various drugs to prevent nucleic acid synthesis.

<span class="mw-page-title-main">Camptothecin</span> Chemical compound

Camptothecin (CPT) is a topoisomerase inhibitor. It was discovered in 1966 by M. E. Wall and M. C. Wani in systematic screening of natural products for anticancer drugs. It was isolated from the bark and stem of Camptotheca acuminata, a tree native to China used in traditional Chinese medicine. It has been used clinically in China for the treatment of gastrointestinal tumors. CPT showed anticancer activity in preliminary clinical trials, especially against breast, ovarian, colon, lung, and stomach cancers. However, it has low solubility and adverse effects have been reported when used therapeutically, so synthetic and medicinal chemists have developed numerous syntheses of camptothecin and various derivatives to increase the benefits of the chemical, with good results. Four CPT analogues have been approved and are used in cancer chemotherapy today: topotecan, irinotecan, belotecan, and trastuzumab deruxtecan. Camptothecin has also been found in other plants including Chonemorpha fragrans.

<span class="mw-page-title-main">Adenosine kinase</span> Enzyme

Adenosine kinase is an enzyme that catalyzes the transfer of gamma-phosphate from Adenosine triphosphate (ATP) to adenosine (Ado) leading to formation of Adenosine monophosphate (AMP). In addition to its well-studied role in controlling the cellular concentration of Ado, AdK also plays an important role in the maintenance of methylation reactions. All S-adenosylmethionine-dependent transmethylation reactions in cells lead to production of S-adenosylhomocysteine (SAH), which is cleaved by SAH hydrolase into Ado and homocysteine. The failure to efficiently remove these end products can result in buildup of SAH, which is a potent inhibitor of all transmethylation reactions. The disruption of AdK gene (-/-) in mice causes neonatal hepatic steatosis, a fatal condition characterized by rapid microvesicular fat infiltration, leading to early postnatal death. The liver was the main organ affected in these animals and in it the levels of adenine nucleotides were decreased, while those of SAH were elevated. Recently, missense mutations in the AdK gene in humans which result in AdK deficiency have also been shown to cause hypermethioninemia, encephalopathy and abnormal liver function.

<span class="mw-page-title-main">DNA polymerase beta</span> Protein-coding gene in the species Homo sapiens

DNA polymerase beta, also known as POLB, is an enzyme present in eukaryotes. In humans, it is encoded by the POLB gene.

<span class="mw-page-title-main">Enterolactone</span> Chemical compound

Enterolactone is a organic compound classified as an enterolignan. It is formed by the action of intestinal bacteria on plant lignan precursors present in the diet.

<span class="mw-page-title-main">Plant sources of anti-cancer agents</span>

Plant sources of anti-cancer agents are plants, the derivatives of which have been shown to be usable for the treatment or prevention of cancer in humans.

<span class="mw-page-title-main">Pinoresinol</span> Chemical compound

Pinoresinol is a tetrahydrofuran lignan found in Styrax sp., Forsythia suspensa, and in Forsythia koreana. It is also found in the caterpillar of the cabbage butterfly, Pieris rapae where it serves as a defence against ants.

Ruthenium anti-cancer drugs are coordination complexes of ruthenium complexes that have anticancer properties. They promise to provide alternatives to platinum-based drugs for anticancer therapy. No ruthenium anti-cancer drug has been commercialized.

Secoisolariciresinol dehydrogenase (EC 1.1.1.331) is an enzyme with the systematic name (-)-secoisolariciresinol:NAD+ oxidoreductase. This enzyme catalyses the following chemical reaction:

<span class="mw-page-title-main">Eudistomin</span>

Eudistomins are β-carboline derivatives, isolated from ascidians, like Ritterella sigillinoides, Lissoclinum fragile, or Pseudodistoma aureum.

<span class="mw-page-title-main">Titanocene Y</span> Organotitanium compound

Titanocene Y also known as bis[(p-methoxybenzyl)cyclopentadienyl]titanium(IV) dichloride or dichloridobis(η5-(p-methoxybenzyl)cyclopentadienyl)titanium is an organotitanium compound that has been investigated for use as an anticancer drug.

<i>Sinopodophyllum</i> Genus of flowering plants belonging to the barberry family

Sinopodophyllum is an herbaceous perennial plant in the family Berberidaceae, described as a genus in 1979. It includes only one known species, Sinopodophyllum hexandrum, native to Afghanistan, Bhutan, northern India, Kashmir, Nepal, Pakistan, and western China. Common names include Himalayan may apple and Indian may apple.

<span class="mw-page-title-main">Estramustine</span> Chemical compound

Estramustine is an estrogen and cytostatic antineoplastic agent which was never marketed. It is a carbamate derivative of estradiol and acts in part as a prodrug of estradiol in the body. Estramustine phosphate, the C17β phosphate ester of estramustine and a prodrug of estramustine, estromustine, estradiol, and estrone, is marketed and used in the treatment of prostate cancer.

<span class="mw-page-title-main">Ellipticine</span> Chemical compound

Ellipticine is a tetracyclic alkaloid first extracted from trees of the species Ochrosia elliptica and Rauvolfia sandwicensis, which inhibits the enzyme topoisomerase II via intercalative binding to DNA.

A podophyllotoxin hybrid is a molecule that obtained by combination of podophyllotoxin with other active pharmacophore that is ether designed to interact with multiple target, improve the biological properties or enhance the efficacy of target molecule. Since podophyllotoxin has an extensive pharmacological properties, this compound has been studied in term seeking for potential novel therapeutics. Molecule hybridization is a recent strategy in medicinal area to overcome the pharmacokinetic issues, toxicity, lowering side effects of drugs also reduce the potential resistance in cancer cells. Research development in podophyllotoxin hybrid is mainly focused on anti-cancer properties.

References

  1. ↑ "What is Condylox?" (in German). Retrieved 2018-08-15.
  2. 1 2 3 "Podofilox". The American Society of Health-System Pharmacists. Retrieved 8 December 2016.
  3. ↑ Xu H, Lv M, Tian X (2009). "A review on hemisynthesis, biosynthesis, biological activities, mode of action, and structure-activity relationship of podophyllotoxins: 2003-2007". Current Medicinal Chemistry. 16 (3): 327–49. doi:10.2174/092986709787002682. PMID   19149581.
  4. ↑ "Podophyllum Resin". The American Society of Health-System Pharmacists. Retrieved 8 December 2016.
  5. ↑ World Health Organization (2009). Stuart MC, Kouimtzi M, Hill SR (eds.). WHO Model Formulary 2008. World Health Organization. p. 307. hdl: 10665/44053 . ISBN   9789241547659.
  6. ↑ See:
  7. ↑ Cragg GM, Kingston DG, Newman DJ (2011). Anticancer Agents from Natural Products, Second Edition (2 ed.). CRC Press. p. 97. ISBN   9781439813836.
  8. ↑ Shah Z, Gohar UF, Jamshed I, Mushtaq A, Mukhtar H, Zia-Ui-Haq M, et al. (April 2021). "Podophyllotoxin: History, Recent Advances and Future Prospects". Biomolecules. 11 (4): 603. doi: 10.3390/biom11040603 . PMC   8073934 . PMID   33921719.
  9. ↑ World Health Organization (2021). World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. hdl: 10665/345533 . WHO/MHP/HPS/EML/2021.02.
  10. 1 2 3 4 Gordaliza M, García PA, del Corral JM, Castro MA, Gómez-Zurita MA (September 2004). "Podophyllotoxin: distribution, sources, applications and new cytotoxic derivatives". Toxicon. 44 (4): 441–59. Bibcode:2004Txcn...44..441G. doi:10.1016/j.toxicon.2004.05.008. PMID   15302526.
  11. 1 2 Ardalani H, Avan A, Ghayour-Mobarhan M (2016). "Podophyllotoxin: a novel potential natural anticancer agent". Avicenna Journal of Phytomedicine. 7 (4): 285–294. PMC   5580867 . PMID   28884079.
  12. ↑ "Podofilox Monograph for Professionals - Drugs.com". Drugs.com. Retrieved 2018-05-06.
  13. ↑ "Podophyllotoxin for anogenital warts; Podophyllotoxin info". patient.info. Retrieved 2018-05-06.
  14. ↑ Longstaff E, von Krogh G (April 2001). "Condyloma eradication: self-therapy with 0.15-0.5% podophyllotoxin versus 20-25% podophyllin preparations--an integrated safety assessment". Regulatory Toxicology and Pharmacology. 33 (2): 117–37. doi:10.1006/rtph.2000.1446. PMID   11350195.
  15. ↑ "PRODUCT INFORMATION WARTEC® SOLUTION" (PDF). GlaxoSmithKline Australia Pty Ltd. Retrieved 6 January 2013.
  16. ↑ Sundharam JA (July 1989). "Is Podophyllin Safe for Use in Pregnancy?". Archives of Dermatology. 125 (7): 1000–1. doi:10.1001/archderm.1989.01670190134022. PMID   2742385.
  17. ↑ "Podophyllotoxin | DermNet New Zealand". www.dermnetnz.org. Retrieved 2018-05-06.
  18. ↑ Moher LM, Maurer SA (August 1979). "Podophyllum toxicity: case report and literature review". The Journal of Family Practice. 9 (2): 237–40. PMID   458391.
  19. ↑ Ardalani H, Avan A, Ghayour-Mobarhan M (2017-06-01). "Podophyllotoxin: a novel potential natural anticancer agent". Avicenna Journal of Phytomedicine. 7 (4): 285–294. doi:10.22038/ajp.2017.8779. PMC   5580867 . PMID   28884079. S2CID   2231369.
  20. ↑ Gordaliza M, Castro MA, del Corral JM, Feliciano AS (December 2000). "Antitumor properties of podophyllotoxin and related compounds". Current Pharmaceutical Design. 6 (18): 1811–1839. doi:10.2174/1381612003398582. PMID   11102564.
  21. 1 2 3 Canel C, Moraes RM, Dayan FE, Ferreira D (2000). "Molecules of Interest: Podophyllotoxin". Phytochemistry . 54 (2): 115–120. doi:10.1016/s0031-9422(00)00094-7. PMID   10872202.
  22. ↑ Gupta RS, Ho TK, Moffat MR, Gupta R (January 1982). "Podophyllotoxin-resistant mutants of Chinese hamster ovary cells. Alteration in a microtubule-associated protein". The Journal of Biological Chemistry. 257 (2): 1071–1078. doi: 10.1016/S0021-9258(19)68309-2 . PMID   7054166.
  23. 1 2 Gupta RS (April 1983). "Genetic, biochemical, and cross-resistance studies with mutants of Chinese hamster ovary cells resistant to the anticancer drugs, VM-26 and VP16-213". Cancer Research. 43 (4): 1568–1574. PMID   6831403.
  24. ↑ Gupta RS (February 1983). "Podophyllotoxin-resistant mutants of Chinese hamster ovary cells: cross-resistance studies with various microtubule inhibitors and podophyllotoxin analogues". Cancer Research. 43 (2): 505–512. PMID   6848174.
  25. ↑ Picketts DJ, Mayanil CS, Gupta RS (July 1989). "Molecular cloning of a Chinese hamster mitochondrial protein related to the "chaperonin" family of bacterial and plant proteins". The Journal of Biological Chemistry. 264 (20): 12001–12008. doi: 10.1016/S0021-9258(18)80166-1 . PMID   2568357.
  26. ↑ Jindal S, Dudani AK, Singh B, Harley CB, Gupta RS (May 1989). "Primary structure of a human mitochondrial protein homologous to the bacterial and plant chaperonins and to the 65-kilodalton mycobacterial antigen". Molecular and Cellular Biology. 9 (5): 2279–2283. doi:10.1128/mcb.9.5.2279. PMC   363030 . PMID   2568584.
  27. ↑ Trevor AJ, Katzung BG, Kruidering-Hall M, Masters SB (2013). "Chapter 54: Cancer Chemotherapy". Pharmacology examination & board review (10th ed.). New York: McGraw-Hill Medical. ISBN   978-0-07-178923-3.
  28. 1 2 Botta B, Delle Monache G, Misiti D, Vitali A, Zappia G (September 2001). "Aryltetralin lignans: chemistry, pharmacology and biotransformations". Current Medicinal Chemistry. 8 (11): 1363–1381. doi:10.2174/0929867013372292. hdl: 11576/1887588 . PMID   11562272.
  29. ↑ Borsche W, Niemann J (1932). "Über Podophyllin". Justus Liebigs Ann. Chem. 494: 126–142. doi:10.1002/jlac.19324940113.
  30. 1 2 You Y (2005). "Podophyllotoxin derivatives: current synthetic approaches for new anticancer agents". Current Pharmaceutical Design. 11 (13): 1695–717. doi:10.2174/1381612053764724. PMID   15892669.
  31. 1 2 3 Lau W, Sattely ES (September 2015). "Six enzymes from mayapple that complete the biosynthetic pathway to the etoposide aglycone". Science. 349 (6253): 1224–8. Bibcode:2015Sci...349.1224L. doi:10.1126/science.aac7202. PMC   6861171 . PMID   26359402.
  32. 1 2 Canel C, Moraes RM, Dayan FE, Ferreira D (May 2000). "Podophyllotoxin". Phytochemistry. 54 (2): 115–20. Bibcode:2000PChem..54..115C. doi:10.1016/s0031-9422(00)00094-7. PMID   10872202.
  33. ↑ Kende AS, King ML, Curran DP (June 1981). "Total synthesis of (.+-.)-4'-demethyl-4-epipodophyllotoxin by insertion-cyclization". The Journal of Organic Chemistry. 46 (13): 2826–2828. doi:10.1021/jo00326a056.
  34. ↑ Macdonald DI, Durst T (August 1988). "A highly stereoselective synthesis of podophyllotoxin and analogues based on an intramolecular Diels-Alder reaction". The Journal of Organic Chemistry. 53 (16): 3663–3669. doi:10.1021/jo00251a003.
  35. ↑ Ziegler F, Schwartz JA (March 1978). "Synthetic studies on lignan lactones: aryl dithiane route to (.+-.)-podorhizol and (.+-.)-isopodophyllotoxone and approaches to the stegane skeleton". The Journal of Organic Chemistry. 43 (5): 985–991. doi:10.1021/jo00399a040.
  36. ↑ Klemm LH, Olson DR, White DV (December 1971). "Intramolecular Diels-Alder reactions. VII. Electroreduction of .alpha.,.beta.-unsaturated esters. I. Synthesis of rac-deoxypicropodophyllin by intramolecular Diels-Alder reaction plus trans addition of hydrogen". The Journal of Organic Chemistry. 36 (24): 3740–3743. doi:10.1021/jo00823a017.
  37. ↑ Damayanthi Y, Lown JW (June 1998). "Podophyllotoxins: current status and recent developments". Current Medicinal Chemistry. 5 (3): 205–52. doi:10.2174/0929867305666220314204426. PMID   9562603. S2CID   247493530.
  38. ↑ Liu YQ, Tian J, Qian K, Zhao XB, Morris-Natschke SL, Yang L, Nan X, Tian X, Lee KH (January 2015). "Recent progress on C-4-modified podophyllotoxin analogs as potent antitumor agents". Medicinal Research Reviews. 35 (1): 1–62. doi:10.1002/med.21319. PMC   4337794 . PMID   24827545.
  39. ↑ Hartwell JL, Schrecker AW (1951). "Components of Podophyllin. V. The Constitution of Podophyllotoxin". Journal of the American Chemical Society . 73 (6): 2909–2916. doi:10.1021/ja01150a143.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.