CoChat
Sign Up
Cited by 20Skin Protection and AgingPhotochromic and Fluorescence ChemistrySynthesis of Organic Compounds

The Involvement of Xanthone and (E)-Cinnamoyl Chromophores for the Design and Synthesis of Novel Sunscreening Agents

Open access
Popiół, Justyna, Gunia-Krzyżak, Agnieszka, Słoczyńska, Karolina, Koczurkiewicz-Adamczyk, Paulina, Piska, Kamil, Wójcik-Pszczoła, Katarzyna, Żelaszczyk, Dorota, Krupa, Anna +3 more·2020·International Journal of Molecular Sciences
DOI 10.3390/ijms22010034PMC PMC7792956
Open this paper in CoChat — free accountOpen PDF

Abstract

Excessive UV exposure contributes to several pathological conditions like skin burns, erythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorption, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290–369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPFin vitro of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at concentrations up to 50 µM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Additionally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.3390/ijms22010034

Cites

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Compounds reported by Popiół et al. possess action against UVA and UVB radiation, in contrast to compounds with a simple xanthone scaffold reported by Resende et al.

    “Comparing these two groups of xanthones, the combination of the cinnamoyl and xanthonic moieties allows the correct electronic delocalisation, which improves the UV absorber properties and, because of that, compounds reported by Popiół et al. [26] possess action against UVA and UVB radiation, in contrast to compounds with a simple xanthone scaffold reported by Resende et al. [142].”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [26]

    Section 2.3 (page unavailable) reports that compounds 9 and 10 absorb in both the UVB and UVA II regions, supporting the claim for some of Popiół et al.’s compounds. It also describes compound 16 as a UVB absorber, so the source does not support the implication that all its reported compounds act against both UVA and UVB. The comparison with Resende et al. is attached to a separate citation and is not assessed here. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • The combination of cinnamoyl and xanthonic moieties allows correct electronic delocalisation, which improves UV absorber properties.

    “Comparing these two groups of xanthones, the combination of the cinnamoyl and xanthonic moieties allows the correct electronic delocalisation, which improves the UV absorber properties and, because of that, compounds reported by Popiół et al. [26] possess action against UVA and UVB radiation, in contrast to compounds with a simple xanthone scaffold reported by Resende et al. [142].”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [26]

    The Introduction says the authors combined cinnamoyl and xanthone chromophores to seek broader UV absorption, and Results §2.3 reports that some resulting compounds absorb in both the UVB and UVA II regions. But the Introduction attributes electron delocalization specifically to octinoxate, not to the combined chromophores; the paper does not establish that delocalization explains the derivatives’ improved absorption. Results §2.3 also identifies compound 16 chiefly as a UVB absorber, so the UVA/UVB finding does not apply to every compound. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

  • Compound 166 absorbs both UVA and UVB radiation.

    “Compound 166 was revealed to be the most promising, displaying λc of 381 nm, confirming the ability to absorb both UVA and UVB radiations and with a SPF of 19.69 [26].”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [26]

  • Compound 166 displays a λc of 381 nm.

    “Compound 166 was revealed to be the most promising, displaying λc of 381 nm, confirming the ability to absorb both UVA and UVB radiations and with a SPF of 19.69 [26].”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [26]

  • Compound 166 has an SPF of 19.69.

    “Compound 166 was revealed to be the most promising, displaying λc of 381 nm, confirming the ability to absorb both UVA and UVB radiations and with a SPF of 19.69 [26].”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [26]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

No citation lists for this paper

No citation lists for this paper yet — checked again daily.

References 57 · Cited by 20

Research works printed but not linked: 52

  1. [1]Maier T. Korting H.C. Sunscreens—Which and what for? Skin Pharmacol. Physiol. 2005 18 253 262 10.1159/000087606 16113595 · DOI
  2. [2]Kim S. Choi K. Occurrences, toxicities, and ecological risks of benzophenone-3, a common component of organic sunscreen products: A mini-review Environ. Int. 2014 70 143 157 10.1016/j.envint.2014.05.015 24934855 · DOI
  3. [3]Fabbrocini G. Triassi M. Mauriello M.C. Torre G. Annunziata M.C. de Vita V. Pastore F. D’Arco V. Monfrecola G. Epidemiology of skin cancer: Role of some environmental factors Cancers 2010 2 1980 1989 10.3390/cancers2041980 24281212 PMC3840456 · DOI
  4. [4]Durrer S. Maerkel K. Schlumpf M. Lichtensteiger W. Estrogen target gene regulation and coactivator expression in rat uterus after developmental exposure to the ultraviolet filter 4-methylbenzylidene camphor Endocrinology 2005 146 2130 2139 10.1210/en.2004-1272 15705771 · DOI
  5. [5]Schlumpf M. Kypke K. Vökt C.C. Birchler M. Durrer S. Faass O. Ehnes C. Fuetsch M. Gaille C. Henseler M. Endocrine active UV filters: Developmental toxicity and exposure through breast milk Chimia 2008 62 345 351 10.2533/chimia.2008.345 · DOI
  6. [6]Gilbert E. Pirot F. Bertholle V. Roussel L. Falson F. Padois K. Commonly used UV filter toxicity on biological functions: Review of last decade studies Int. J. Cosmet. Sci. 2013 35 208 219 10.1111/ics.12030 23237547 · DOI · Paper page
  7. [7]Herzog B. Hueglin D. Osterwalder U. New Sunscreen Actives Sunscreens. Regulations and Commercial Development 3rd ed. Shaath N.A. Taylor & Francis Boca Raton, FL, USA 2005 291 320 10.1201/b14170 · DOI
  8. [8]Baker L.A. Clark S.L. Habershon S. Stavros V.G. Ultrafast Transient Absorption Spectroscopy of the Sunscreen Constituent Ethylhexyl Triazone J. Phys. Chem. Lett. 2017 8 2113 2118 10.1021/acs.jpclett.7b00633 28437110 · DOI
  9. [9]Bino A. Baldisserotto A. Scalambra E. Dissette V. Vedaldi D.E. Salvador A. Durini E. Manfredini S. Design, synthesis and biological evaluation of novel hydroxy-phenyl-1H-benzimidazoles as radical scavengers and UV-protective agents J. Enzym. Inhib. Med. Chem. 2017 32 527 537 10.1080/14756366.2016.1265523 PMC6010047 28114824 · DOI · Paper page
  10. [10]Popiół J. Gunia-Krzyżak A. Piska K. Żelaszczyk D. Koczurkiewicz P. Słoczyńska K. Wójcik-Pszczoła K. Krupa A. Kryczyk-Poprawa A. Żesławska E. Discovery of Novel UV-Filters with Favorable Safety Profiles in the 5-Arylideneimidazolidine-2,4-dione Derivatives Group Molecules 2019 24 2321 10.3390/molecules24122321 PMC6630718 31238526 · DOI · Paper page
  11. [11]Gunia-Krzyżak A. Słoczyńska K. Popiół J. Koczurkiewicz P. Marona H. Pękala E. Cinnamic acid derivatives in cosmetics: Current use and future prospects Int. J. Cosmet. Sci. 2018 40 356 366 10.1111/ics.12471 29870052 · DOI
  12. [13]Stiefel C. Schwack W. Photoprotection in changing times—UV filter efficacy and safety, sensitization processes and regulatory aspects Int. J. Cosmet. Sci. 2015 37 2 30 10.1111/ics.12165 25256657 · DOI
  13. [15]Shaath N.A. Ultraviolet filters Photochem. Photobiol. Sci. 2010 9 464 469 10.1039/b9pp00174c 20354639 · DOI
  14. [16]Hanson K.M. Narayanan S. Nichols V.M. Bardeen C.J. Photochemical degradation of the UV filter octyl methoxycinnamate in solution and in aggregates Photochem. Photobiol. Sci. 2015 14 1607 1616 10.1039/C5PP00074B 26035445 · DOI
  15. [17]Cidade H. Rocha V. Palmeira A. Marques C. Tiritan M.E. Ferreira H. Lobo J.S. Almeida I.F. Sousa M.E. Pinto M. In silico and in vitro antioxidant and cytotoxicity evaluation of oxygenated xanthone derivatives Arab. J. Chem. 2020 13 17 26 10.1016/j.arabjc.2017.01.006 · DOI
  16. [18]Klesiewicz K. Karczewska E. Budak A. Marona H. Szkaradek N. Anti-Helicobacter pylori activity of some newly synthesized derivatives of xanthone J. Antibiot. 2016 69 825 834 10.1038/ja.2016.36 27025351 · DOI
  17. [19]Gobbi S. Rampa A. Bisi A. Belluti F. Valenti P. Caputo A. Zampiron A. Carrara M. Synthesis and antitumor activity of new derivatives of xanthen-9-one-4-acetic acid J. Med. Chem. 2002 45 4931 4939 10.1021/jm020929p 12383019 · DOI
  18. [20]Szkaradek N. Sypniewski D. Żelaszczyk D. Gałka S. Borzdziłowska P. Marona H. Bednarek I. Influence of New Synthetic Xanthones on the Proliferation and Migration Potential of Cancer Cell Lines In Vitro Anticancer Agents Med. Chem. 2019 19 1949 1965 10.2174/1871520619666190405113519 30950354 · DOI
  19. [21]Żelaszczyk D. Lipkowska A. Szkaradek N. Słoczyńska K. Gunia-Krzyżak A. Librowski T. Marona H. Synthesis and preliminary anti-inflammatory evaluation of xanthone derivatives Heterocycl. Commun. 2018 24 231 236 10.1515/hc-2017-0215 · DOI
  20. [22]Telang M. Dhulap S. Mandhare A. Hirwani R. Therapeutic and cosmetic applications of mangiferin: A patent review Expert Opin. Ther. Pat. 2013 23 1561 1580 10.1517/13543776.2013.836182 24066838 · DOI · Paper page
  21. [23]Kim H.S. Song J.H. Youn U.J. Hyun J.W. Jeong W.S. Lee M.Y. Choi H.J. Lee H.K. Chae S. Inhibition of UVB-induced wrinkle formation and MMP-9 expression by mangiferin isolated from Anemarrhena asphodeloides Eur. J. Pharmacol. 2012 689 38 44 10.1016/j.ejphar.2012.05.050 22683868 · DOI
  22. [24]Kawakami C.M. Gaspar L.R. Mangiferin and naringenin affect the photostability and phototoxicity of sunscreens containing avobenzone J. Photochem. Photobiol. B Biol. 2015 151 239 247 10.1016/j.jphotobiol.2015.08.014 26318281 · DOI
  23. [25]Żelaszczyk D. Jakubczyk M. Pytka K. Rapacz A. Walczak M. Janiszewska P. Pańczyk K. Żmudzki P. Słoczyńska K. Marona H. Design, synthesis and evaluation of activity and pharmacokinetic profile of new derivatives of xanthone and piperazine in the central nervous system Bioorg. Med. Chem. Lett. 2019 29 126679 10.1016/j.bmcl.2019.126679 31537425 · DOI
  24. [26]Marona H. Eckstein M. Krupinska J. Mazur J. Piotrowicz J. Cebo B. Synthesis and some biological properties of 2-xanthonylalkyl- (alkoxy) carboxylic acids Pol. J. Pharmacol. Pharm. 1986 38 107 114 3489931
  25. [27]Eckstein M. Marona H. Preparation and properties of some 2-mercaptomethylxanthones Pol. J. Chem. 1981 12 1281 1285 10.1002/chin.198111249 · DOI
  26. [28]Davies J.S.H. Lamb F. Suschitzky H. 367. Studies in the xanthone series. Part II. Preparation and reactions of 1-formyl-2-hydroxyxanthone J. Chem. Soc. 1958 1790 10.1039/jr9580001790 · DOI
  27. [29]Lin C.-N. Liou S.-S. Ko F.-N. Teng C.-M. γ-pyrone compounds. IV: Synthesis and antiplatelet effects of mono- and dioxygenated xanthones and xanthonoxypropanolamine J. Pharm. Sci. 1993 82 11 16 10.1002/jps.2600820103 8429484 · DOI
  28. [30]Guerre C. Thull U. Gaillard P. Carrupt P.A. Testa B. Fernandes E. Silva F. Pinto M. Pinto M.M.M. Wolfender J.L. Natural and synthetic xanthones as monoamine oxidase inhibitors: Biological assay and 3D-QSAR Helv. Chim. Acta 2001 84 552 570 10.1002/1522-2675(20010321)84:33.0.CO;2-X · DOI
  29. [31]Marona H. Szkaradek N. Kubacka M. Bednarski M. Filipek B. Cegla M. Szneler E. Synthesis and Evaluation of Some Xanthone Derivatives for Anti-Arrhythmic, Hypotensive Properties and Their Affinity for Adrenergic Receptors Arch. Pharm. 2008 341 90 98 10.1002/ardp.200700156 18240129 · DOI
  30. [32]Marona H. Szkaradek N. Karczewska E. Trojanowska D. Budak A. Bober P. Przepiórka W. Cegla M. Szneler E. Antifungal and antibacterial activity of the newly synthesized 2-xanthone derivatives Arch. Pharm. 2009 342 9 18 10.1002/ardp.200800089 19051197 · DOI
  31. [33]Boyce C.B.C. Milborrow B.V. A Simple Assessment of Partition Data for Correlating Structure and Biological Activity Using Thin-Layer Chromatography Nature 1965 208 537 539 10.1038/208537a0 · DOI
  32. [34]Pękala E. Marona H. Estimating the lipophilicity of a number of 2-amino-1-cyclohexanol derivatives exhibiting anticonvulsant activity Biomed. Chromatogr. 2009 23 543 550 10.1002/bmc.1153 19277952 · DOI
  33. [36]Lee C.K. Uchida T. Kitagawa K. Yagi A. Kim N. Goto S. Relationship between Lipophilicity and Skin Permeability of Various Drugs from an Ethanol/Water/Lauric Acid System Biol. Pharm. Bull. 1994 17 1421 1424 10.1248/bpb.17.1421 7874070 · DOI
  34. [39]Couteau C. Pommier M. Paparis E. Coiffard L.J.M. Study of the efficacy of 18 sun filters authorized in European Union tested in vitro Die Pharm. Int. J. Pharm. Sci. 2007 62 449 452 10.1691/ph.2007.6.6247 17663193 · DOI
  35. [40]Couteau C. Paparis E. Chauvet C. Coiffard L. Tris-biphenyl triazine, a new ultraviolet filter studied in terms of photoprotective efficacy Int. J. Pharm. 2015 487 120 123 10.1016/j.ijpharm.2015.03.077 25843762 · DOI
  36. [42]Ferrero L. Pissavini M. Dehais A. Marguerie S. Zastrow L. Importance of substrate roughness for in vitro sun protection assessment Int. J. Cosmet. Sci. 2007 29 59 10.1111/j.1467-2494.2007.00340_2.x · DOI
  37. [43]Vielhaber G. Grether-Beck S. Koch O. Johncock W. Krutmann J. Sunscreens with an absorption maximum of ≥360 nm provide optimal protection against UVA1-induced expression of matrix metalloproteinase-1, interleukin-1, and interleukin-6 in human dermal fibroblasts Photochem. Photobiol. Sci. 2006 5 275 282 10.1039/b516702g 16520862 · DOI
  38. [44]Hojerová J. Medovcíková A. Mikula M. Photoprotective efficacy and photostability of fifteen sunscreen products having the same label SPF subjected to natural sunlight Int. J. Pharm. 2011 408 27 38 10.1016/j.ijpharm.2011.01.040 21277959 · DOI
  39. [45]Garoli D. Pelizzo M.G. Bernardini B. Nicolosi P. Alaibac M. Sunscreen tests: Correspondence between in vitro data and values reported by the manufacturers J. Dermatol. Sci. 2008 52 193 204 10.1016/j.jdermsci.2008.06.010 18755574 · DOI
  40. [46]Couteau C. El-Boury S. Paparis E. Sébille-Rivain V. Coiffard L.J.M. In vitro UV-A protection factor (PF-UVA) of organic and inorganic sunscreens Pharm. Dev. Technol. 2009 14 369 372 10.1080/10837450802683966 19630696 · DOI
  41. [47]Gaspar L.R. Maia Campos P.M.B.G. Evaluation of the photostability of different UV filter combinations in a sunscreen Int. J. Pharm. 2006 307 123 128 10.1016/j.ijpharm.2005.08.029 16289662 · DOI
  42. [48]Schlumpf M. Cotton B. Conscience M. Haller V. Steinmann B. Lichtensteiger W. In vitro and in vivo estrogenicity of UV screens Environ. Health Perspect. 2001 109 239 244 10.1289/ehp.01109239 PMC1240241 11333184 · DOI
  43. [49]Ullmann F. Kipper H. Ueber Methoxy-chlor-benzoësäure Berichte Der Dtsch. Chem. Gesellschaft. 1905 38 2120 2126 10.1002/cber.190503802155 · DOI
  44. [50]Pickert M. Frahm A.W. Substituted Xanthones as Antimycobacterial agents, Part 1: Synthesis and Assignment of 1H/13C NMR Chemical Shifts Arch. Pharm. 1998 331 177 192 10.1002/(SICI)1521-4184(199805)331:5<177::AID-ARDP177>3.0.CO;2-K 9691249 · DOI
  45. [52]Eckstein M. Marona H. Mazur J. Synthesis and some biological properties of substituted xanthone-2-carboxylic acids Pol. J. Pharmacol. Pharm. 1983 35 159 167 6604908
  46. [53]Marona H. Pękala E. Filipek B. Maciąg D. Szneler E. Pharmacological properties of some aminoalkanolic derivatives of xanthone Die Pharm. 2001 56 567 572 11487977
  47. [54]de Oliveira C.A. Peres D.D. Rugno C.M. Kojima M. Pinto C.S.A.O. Consiglieri V.O. Keneko T.M. Rosado C. Mota J. Velasco M.V.R. Functional photostability and cutaneous compatibility of bioactive UVA sun care products J. Photochem. Photobiol. B Biol. 2015 148 154 159 10.1016/j.jphotobiol.2015.04.007 25920069 · DOI
  48. [56]Flückiger-Isler S.B. Braun K. Gervais V. Hasler-Nguyen N. Reimann R. Van Gompel J. Wunderlich H. Engelhardt G. Assessment of the performance of the Ames II assay: A collaborative study with 19 coded compounds Mutat. Res. 2004 558 181 197 10.1016/j.mrgentox.2003.12.001 15036131 · DOI
  49. [57]Flückiger-Isler S. Kamber M. Direct comparison of the Ames microplate format (MPF) test in liquid medium with the standard Ames pre-incubation assay on agar plates by use of equivocal to weakly positive test compounds Mutat. Res. Genet. Toxicol. Environ. Mutagen. 2012 747 36 45 10.1016/j.mrgentox.2012.03.014 22579797 · DOI
  50. [59]Umbuzeiro Gde A. Rech C. Correia S. Bergamasco A. Cardenette G. Flückiger-Isler S. Kamber M. Comparison of the Salmonella/microsome microsuspension assay with the new microplate fluctuation protocol for testing the mutagenicity of environmental samples Environ. Mol. Mutagen. 2009 405 31 38 10.1002/em.20504 19484728 · DOI
  51. [60]Reifferscheid G. Maes H.M. Allner B. Badurova J. Belkin S. Bluhm K. Brauer F. Bressling J. Domeneghetti S. Elad T. International round-robin study on the Ames fluctuation test Environ. Mol. Mutagen. 2012 53 185 197 10.1002/em.21677 22246666 · DOI
  52. [61]Smith K.E.C. Heringa M.B. Uytewaal M. Mayer P. The dosing determines mutagenicity of hydrophobic compounds in the Ames II assay with metabolic transformation: Passive dosing versus solvent spiking Mutat. Res. Genet. Toxicol. Environ. Mutagen. 2013 750 12 18 10.1016/j.mrgentox.2012.07.006 22989744 · DOI

Authors
Popiół, J., Gunia-Krzyżak, A., Słoczyńska, K., Koczurkiewicz-Adamczyk, P., Piska, K., Wójcik-Pszczoła, K., Żelaszczyk, D., Krupa, A., Żmudzki, P., Marona, H., & Pękala, E.
Affiliations
  • Jagiellonian University (PL)
  • Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
  • Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
ORCID
Venue
International Journal of Molecular Sciences
Publisher
MDPI AG
Published
2020-12-22
Volume
22
Issue
1
Pages
34
ISSN
1422-0067 (ISSN-L)
DOI
10.3390/ijms22010034
PMC
PMC7792956
OpenAlex
W3114586439
Cited by
20
References
57
Citations by year
2026: 5 · 2025: 3 · 2024: 6 · 2023: 2 · 2022: 3 · 2021: 1
FWCI
1.09
Type
journal article
Language
en
Open access
Licence
Locations
  • International Journal of Molecular Sciences (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, other-oa)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Jagiellonian University Repository (Jagiellonian University) (submittedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Narodowe Centrum Nauki (2016/21/B/NZ7/01756)
Topics
  • Health Sciences › Medicine › Dermatology › Skin Protection and Aging
  • Physical Sciences › Materials Science › Materials Chemistry › Photochromic and Fluorescence Chemistry
  • Health Sciences › Medicine › Pharmacology › Synthesis of Organic Compounds
Keywords
UV filters, xanthone derivatives, UVB absorption, UVA/UVB ratio, photoprotection, photostability, cytotoxicity, estrogenic activity, skin aging, topical cream formulation, structure-activity design
MeSH terms
Cinnamomum zeylanicum, Humans, Mutagenicity Tests, Skin, Spectrophotometry, Ultraviolet, Structure-Activity Relationship, Sunburn, Sunscreening Agents, Ultraviolet Rays, Molecular Structure, Skin Aging, Xanthones

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review