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Plant Science Today (PST)

Research Articles

Vol. 13 No. 3 (2026)

Identification of phenolic compounds from Carica papaya L. var. Red Lady peels and their in vitro anti-inflammatory activity

DOI
https://doi.org/10.14719/pst.12444
Submitted
27 October 2025
Published
02-06-2026 — Updated on 10-08-2026
Versions

Abstract

Papaya peels, habitually discarded as waste, have immense potential to be used as a promising source of bioactive molecules. The current study involves the identification of important phenolic compounds from papaya peels and their anti-inflammatory roles on lipopolysaccharide (LPS) stimulated RAW 264.7 macrophage cells. Papaya peel extracts (non-polar to polar solvents) were subjected to column-based chromatography followed by thin-layer chromatography for isolating and purifying the phytochemical constituents. The purified compounds were identified using FT-IR, HPLC, LC-MS, 1H and 13C NMR spectra. A total of four phenolic compounds, namely syringic acid, epicatechin, vanillic acid and cinnamic acid, were isolated from papaya peel of the Red Lady variety. In vitro anti-inflammatory activity was assessed by cyclooxygenase (COX), lipoxygenase (LOX), myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) assays.  Cinnamic acid and epicatechin exhibited the highest inhibitory activity (65–75 %), comparable to the standard drug diclofenac. Vanillic acid and syringic acid showed moderate but statistically significant inhibition (40–55 %) across the tested enzymes. All experiments were performed in triplicate (n = 3) and results were expressed as mean ± standard deviation. The findings suggest that papaya peel-derived phenolic compounds possess a multi-target anti-inflammatory mechanism and may serve as promising candidates for the treatment of chronic inflammatory disorders. Thus, papaya peel can be used for pharmaceutical purposes rather than as a throwaway waste.

References

  1. 1. Food and Agriculture Organisation of the United Nations. FAOSTAT statistical database. Rome: FAO; 2023.
  2. 2. National Horticulture Board. Horticultural statistics at a glance 2022. Ministry of Agriculture and Farmers Welfare, Government of India; 2022.
  3. 3. Ajila CM, Prasada Rao UJS. Mango peel dietary fibre: composition and associated bound phenolics. J Funct Foods. 2013;5(1):444–50. https://doi.org/10.1016/j.jff.2012.12.002
  4. 4. Galanakis CM. Recovery of high-added-value components from food wastes: conventional, emerging technologies and commercialised applications. Trends Food Sci Technol. 2012;26(2):68–87. https://doi.org/10.1016/j.tifs.2012.03.003
  5. 5. Mirabella N, Castellani V, Sala S. Current options for the valorisation of food manufacturing waste: a review. J Clean Prod. 2014;65:28–41. https://doi.org/10.1016/j.jclepro.2013.10.051
  6. 6. Malle E, Furtmüller PG, Sattler W, Obinger C. Myeloperoxidase: a target for new drug development? Br J Pharmacol. 2007;152(6):838–54. https://doi.org/10.1038/sj.bjp.0707358
  7. 7. Lawrence T. The nuclear factor NF-κB pathway in inflammation. Cold Spring Harb Perspect Biol. 2009;1(6): a001651. https://doi.org/10.1101/cshperspect.a001651
  8. 8. Aktan F. iNOS-mediated nitric oxide production and its regulation. Life Sci. 2004;75(6):639–53. https://doi.org/10.1016/j.lfs.2003.10.028
  9. 9. Granado-Serrano AB, Martín MA, Bravo L, Goya L, Ramos S. Epicatechin attenuates TNF-ɑ-induced inflammatory response in human hepatoma cells via inhibition of NF-κB and MAPK pathways. Free Radic Biol Med. 2010;49(3):321–32. https://doi.org/10.1016/j.freeradbiomed.2010.04.024
  10. 10. Schroeter H, Heiss C, Balzer J, Kleinbongard P, Keen CL, Hollenberg NK, et al. (-)-Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans. Proc Natl Acad Sci U S A. 2006;103(4):1024–9. https://doi.org/10.1073/pnas.0510168103
  11. 11. Madamanchi NR, Vendrov A, Runge MS. Oxidative stress and vascular disease. Arterioscler ThrombVasc Biol. 2005;25(1):29–38. https://doi.org/10.1161/01.ATV.0000150654.51087.17
  12. 12. Kim HP, Son KH, Chang HW, Kang SS. Anti-inflammatory plant flavonoids and cellular action mechanisms. J Pharmacol Sci. 2004;96(3):229–245. https://doi.org/10.1254/jphs.CRJ04003X
  13. 13. Ma Q. Role of Nrf2 in oxidative stress and toxicity. Annu Rev Pharmacol Toxicol. 2013; 53:401–26. https://doi.org/10.1146/annurev-pharmtox-011112-140320
  14. 14. Kaspar JW, Niture SK, Jaiswal AK. Nrf2: INrf2 (Keap1) signalling in oxidative stress. Free Radic Biol Med. 2009;47(9):1304–9. https://doi.org/10.1016/j.freeradbiomed.2009.07.035
  15. 15. Sova M. Antioxidant and antimicrobial activities of cinnamic acid derivatives. Mini Rev Med Chem. 2012;12(8):749–67. https://doi.org/10.2174/138955712801264792
  16. 16. Dai J, Mumper RJ. Plant phenolics: extraction, analysis and their antioxidant and anticancer properties. Molecules. 2010;15(10):7313–52. https://doi.org/10.3390/molecules15107313
  17. 17. Snyder LR, Kirkland JJ, Dolan JW. Introduction to modern liquid chromatography. 3rd ed. Hoboken (NJ): John Wiley & Sons; 2010.
  18. 18. Niessen WMA. Liquid chromatography–mass spectrometry. 3rd ed. Boca Raton (FL): CRC Press; 2006.
  19. 19. Coates J. Interpretation of infrared spectra: a practical approach. In: Meyers RA, editor. Encyclopedia of analytical chemistry. Chichester (UK): John Wiley & Sons; 2000.
  20. 20. Socrates G. Infrared and Raman characteristic group frequencies: tables and charts. 3rd ed. Chichester (UK): John Wiley & Sons; 2004.
  21. 21. Raschke WC, Baird S, Ralph P, Nakoinz I. Functional macrophage cell lines transformed by Abelson leukaemia virus. Cell. 1978;15(1):261–7. https://doi.org/10.1016/0092-8674(78)90019-1
  22. 22. Walker MC, Gierse JK. In vitro assays for cyclooxygenase activity and inhibitor characterisation. In: Methods Mol Biol. 2010; 644:131–44.
  23. 23. Axelrod B, Cheesbrough TM, Laakso S. Lipoxygenase from soybeans: EC 1.13.11.12 linoleate: oxygen oxidoreductase. Methods Enzymol.1981;71:441–51. https://doi.org/10.1016/0076-6879(81)71055-3
  24. 24. Bradley PP, Priebat DA, Christensen RD, Rothstein G. Measurement of cutaneous inflammation: estimation of neutrophil content with an enzyme marker. J Invest Dermatol. 1982;78(3):206–9. https://doi.org/10.1111/1523-1747.ep12506462
  25. 25. Salter M, Duffy C, Garthwaite J, Strijbos PJ. Ex vivo measurement of brain tissue nitrite and nitrate accurately reflects nitric oxide synthase activity in vivo. J Neurochem. 1996;66(4):1683–90. https://doi.org/10.1046/j.1471-4159.1996.66041683.x
  26. 26. Li X, Jiang Q, Wang T, Liu J, Chen D. Comparison of the antioxidant effects of quercetin, catechin and syringic acid. Food Chem. 2016; 197:1124–30. https://doi.org/10.1016/j.foodchem.2015.11.110
  27. 27. National Institute of Standards and Technology. Syringic acid (CAS No. 530-57-4). NIST Chemistry Web Book; 2023. https://webbook.nist.gov/cgi/cbook.cgi?ID=C530574
  28. 28. Dong MW. Modern HPLC for practising scientists. 2nd ed. Hoboken (NJ): John Wiley & Sons; 2016.
  29. 29. Jung J, Lee JH, Bae KH, Jeong CS. Anti-gastric actions of eugenol and cinnamic acid isolated from Cinnamomi ramulus. Yakugaku Zasshi. 2011;131(7):1103–10.
  30. 30. Gini TG, Jeya Jothi G. Column chromatography and HPLC analysis of phenolic compounds in the fractions of Salvinia molesta Mitchell. Egypt J Basic Appl Sci. 2018; 5:197–203. https://doi.org/10.1016/j.ejbas.2018.05.010
  31. 31. Zunjar V, Dash RP, Jivrajani M, Trivedi B, Nivsarkar M. Antithrombocytopenic activity of carpaine and alkaloidal extract of Carica papaya Linn. leaves in busulfan-induced thrombocytopenic Wistar rats. J Ethnopharmacol. 2016; 181:20–27. https://doi.org/10.1016/j.jep.2016.01.035
  32. 32. Sagar NA, Pareek S, Sharma S, Yahia EM, Lobo MG. Fruit and vegetable waste: bioactive compounds, their extraction and possible utilisation. Compr Rev Food Sci Food Saf. 2018;17(3):512–31. https://doi.org/10.1111/1541-4337.12330
  33. 33. Yocum GT, Hwang JJ, Mikami M, Danielsson J, Kuforiji AS, Emala CW. Ginger and its bioactive component 6-shogaol mitigate lung inflammation in a murine asthma model. Am J Physiol Lung Cell Mol Physiol. 2020;318(2): L296–L303. https://doi.org/10.1152/ajplung.00249.2019
  34. 34. Kaur S, Singh V, Chopra HK, Panesar PS. Extraction and characterisation of phenolic compounds from mandarin peels using conventional and green techniques: a comparative study. Discover Food. 2024; 4:60.
  35. 35. Lubaina AS, Renjith PR, Ananthakrishnan R, Ragesh R Nair. Isolation of ferulic acid - a bioactive phenolic compound from pineapple peel and evaluation of its in vitro anti-inflammatory potential. Int J Pharm Sci Drug Res. 2021;13(5):565–73. https://doi.org/10.25004/IJPSDR.2021.130515
  36. 36. Habeeba KU, Rasmi AR. Anti-inflammatory and in silico docking studies of Litseae ligustrina (Nees) Hook.f. (Lauraceae) leaf constituents. Nat Prod Res. 2024;1-8. https://doi.org/10.1080/14786419.2024.2385023

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