Wealth from by-products: an attempt to synthesize valuable gold nanoparticles from Brassica oleracea var. acephala cv. Galega stems


In the last years, the growth of the world’s population has resulted in an increase in the demand for food. Vegetables and fruit are essential for human nutrition but, regrettably, half the fruit and vegetables produced worldwide are wasted. The food industry generates tons of by-products during processing, for instance, peels, seeds and stems, which still possess bioactive compounds that can be of interest for other applications. The Brassicaceae species includes some of the most consumed vegetables worldwide known for their antioxidant activity associated with the presence of phenolic compounds. In this study, the stems of Brassica oleracea var. acephala cv. Galega (hereafter BG) were employed to prepare an aqueous extract. Then, its antioxidant potential was evaluated by means of the in vitro analysis of its ability to scavenge the free radical 1,1-diphenyl-2-picryl-hydrazyl (DPPH), the quantification of the total phenolic content and the analysis of the reducing power. Furthermore, the stem aqueous extract was employed to produce gold nanoparticles (AuNPs), acting as a reducing and stabilizing agent. AuNPs were characterized by UV–Visible and Fourier transform infrared spectroscopy. The size and shape of the nanoparticles was analyzed by the acquisition of transmission electron microscopy images, confirming the formation of spherical AuNPs with mean diameters of 25.08 ± 3.73 nm. Finally, three antioxidant assays were performed in the extract after the synthesis of AuNPs. The synthesis of AuNPs employing BG stem extract was revealed to be a good alternative for the revalorization of Brassica by-products.

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  1. 1.

    Sertova, N.M.: Contribution of nanotechnology in animal and human health care. Adv. Mater. Lett. 11, 20091552–20091559 (2020)

    CAS  Article  Google Scholar 

  2. 2.

    Falahati, M., Attar, F., Sharifi, M., Saboury, A.A., Salihi, A., Aziz, F.M., Kostova, I., Burda, C., Priecel, P., Lopez-Sanchez, J., Laurent, S., Hooshmand, N., El-Sayed, M.: Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine. BBA Gen. Subj. 1864, 129435–129462 (2020)

    CAS  Article  Google Scholar 

  3. 3.

    Goddard, Z.R., Marín, M.J., Russell, D.A., Searcey, M.: Active targeting of gold nanoparticles as cancer therapeutics. Chem. Soc. Rev. 49, 8774–8789 (2020)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  4. 4.

    Kang, M.S., Lee, S.Y., Kim, K.S., Han, D.W.: State of the art biocompatible gold nanoparticles for cancer theragnosis. Pharmaceutics. 12, 1–22 (2020)

    Google Scholar 

  5. 5.

    Rana, A., Yadav, K., Jagadevan, S.: A comprehensive review on green synthesis of nature-inspired metal nanoparticles: mechanism, application and toxicity. J. Clean. Prod. 272, 122880–122880 (2020)

    CAS  Article  Google Scholar 

  6. 6.

    Gour, A., Jain, N.K.: Advances in green synthesis of nanoparticles. Artif. Cells Nanomed. Biotechnol. 47, 844–851 (2019)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  7. 7.

    Kalimuthu, K., Cha, B.S., Kim, S., Park, K.S.: Eco-friendly synthesis and biomedical applications of gold nanoparticles: a review. Microchem. J. 152, 104296–104315 (2020)

    CAS  Article  Google Scholar 

  8. 8.

    Lee, K.X., Shameli, K., Yew, Y.P., Teow, S., Jahangirian, H., Rafiee-Moghaddam, R., Webster, T.J.: Recent developments in the facile bio-synthesis of gold nanoparticles (AuNPs) and their biomedical applications. Int. J. Nanomed. 15, 275–300 (2020)

    CAS  Article  Google Scholar 

  9. 9.

    González-Ballesteros, N., Rodríguez-Argüelles, M.C.: Seaweeds: a promising bionanofactory for ecofriendly synthesis of gold and silver nanoparticles. In: Torres, M.D., Kraan, S., Dominguez, H. (eds.) Advances in green and sustainable chemistry. Sustainable seaweed tecnologies cultivation, biorefinery, and applications, pp. 507–541. Elsevier, Amsterdam (2020)

    Google Scholar 

  10. 10.

    Augustine, R., Hasan, A.: Emerging applications of biocompatible phytosynthesized metal/metal oxide nanoparticles in healthcare. J. Drug Deliv. Sci. Technol. 56, 101516–101528 (2020)

    CAS  Article  Google Scholar 

  11. 11.

    Chandra, H., Kumari, P., Bontempi, E., Yadav, S.: Medicinal plants: treasure trove for green synthesis of metallic nanoparticles and their biomedical applications. Biocatal. Agric. Biotechnol. 24, 101518–101518 (2020)

    Article  Google Scholar 

  12. 12.

    Bao, Z., Lan, C.Q.: Advances in biosynthesis of noble metal nanoparticles mediated by photosynthetic organisms—a review. Colloids Surf. B. Biointerfaces. 184, 110519–110519 (2019)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  13. 13.

    Wang, D., Markus, J., Wang, C., Kim, Y.J., Mathiyalagan, R., Aceituno-Castro, V., Ahn, S., Yang, D.C.: Green synthesis of gold and silver nanoparticles using aqueous extract of Cibotium barometz root. Artif. Cells Nanomed. Biotechnol. 45, 1548–1555 (2017)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  14. 14.

    Lafarga, T., Viñas, I., Bobo, G., Simó, J., Aguiló-Aguayo, I.: Effect of steaming and sous vide processing on the total phenolic content, vitamin C and antioxidant potential of the genus Brassica. Innov. Food Sci. Emerg. Technol. 47, 412–420 (2018)

    CAS  Article  Google Scholar 

  15. 15.

    Liang, J.L., Yeow, C.C., Teo, K.C., Gnanaraj, C., Chang, Y.P.: Valorizing cabbage (Brassica oleracea L. var. capitata) and capsicum (Capsicum annuum L.) wastes: in vitro health promoting activities. J. Food Sci. Technol. 56, 4696–4704 (2019)

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  16. 16.

    Amron, N.A., Konsue, N.: Antioxidant capacity and nitrosation inhibition of cruciferous vegetable extracts. Int. Food Res. J. 25, 65–73 (2018)

    CAS  Google Scholar 

  17. 17.

    Poveda, J., Zabalgogeazcoa, I., Soengas, P., Rodríguez, V.M., Cartea, M.E., Abilleira, R., Velasco, P.: Brassica oleracea var. acephala (kale) improvement by biological activity of root endophytic fungi. Sci. Rep. 10, 1–12 (2020)

    Article  CAS  Google Scholar 

  18. 18.

    Yadav, M., Kaur, P.: A review on exploring phytosynthesis of silver and gold nanoparticles using genus Brassica. Int. J. Nanopart. 10, 165–177 (2018)

    CAS  Article  Google Scholar 

  19. 19.

    Armesto, J., Carballo, J., Martínez, S.: Physicochemical and phytochemical properties of two phenotypes of Galega kale (Brassica oleracea L. var. acephala cv. Galega). J. Food Biochem. 39, 439–448 (2015)

    CAS  Article  Google Scholar 

  20. 20.

    Fuente, B., López-García, G., Máñez, V., Alegría, A., Barberá, R., Cilla, A.: Antiproliferative effect of bioaccessible fractions of four Brassicaceae microgreens on human colon cancer cells linked to their phytochemical composition. Antioxidants. 9, 1–15 (2020)

    Article  CAS  Google Scholar 

  21. 21.

    Armesto, J., Gómez-Limia, L., Carballo, J., Martínez, S.: Effects of different cooking methods on the antioxidant capacity and flavonoid, organic acid and mineral contents of Galega Kale (Brassica oleracea var. acephala cv. Galega). Int. J. Food Sci. Nutr. 70, 136–149 (2018)

    PubMed  Article  CAS  PubMed Central  Google Scholar 

  22. 22.

    Michalak, M., Szwajgier, D., Paduch, R., Kukula-Koch, W., Waśko, A., Polak-Berecka, M.: Fermented curly kale as a new source of gentisic and salicylic acids with antitumor potential. J. Funct. Foods. 67, 1–10 (2020)

    Article  CAS  Google Scholar 

  23. 23.

    Jeong, S.J., Lee, J.S., Lee, H.G.: Nanoencapsulation of synergistic antioxidant fruit and vegetable concentrates and their stability during in vitro digestion. J. Sci. Food Agric. 100, 1056–1063 (2020)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  24. 24.

    Šamec, D., Urlić, B., Salopek-Sondi, B.: Kale (Brassica oleracea var. acephala) as a superfood: review of the scientific evidence behind the statement. Crit. Rev. Food Sci. Nutr. 59, 2411–2422 (2018)

    PubMed  Article  CAS  PubMed Central  Google Scholar 

  25. 25.

    Fuente, B., López-García, G., Máñez, V., Alegría, A., Barberá, R., Cilla, A.: Evaluation of the bioaccessibility of antioxidant bioactive compounds and minerals of four genotypes of Brassicaceae microgreens. Foods. 8, 1–16 (2019)

    Google Scholar 

  26. 26.

    Demirbas, A., Kislakci, E., Karaagac, Z., Onal, I., Ildiz, N., Ocsoy, I.: Preparation of biocompatible and stable iron oxide nanoparticles using anthocyanin integrated hydrothermal method and their antimicrobial and antioxidant properties. Mater. Res. Express. 6, 1–8 (2019)

    Article  CAS  Google Scholar 

  27. 27.

    Osuntokun, J., Onwudiwe, D.C., Ebenso, E.E.: Green synthesis of ZnO nanoparticles using aqueous Brassica oleracea L. var. italica and the photocatalytic activity. Green Chem. Lett. Rev. 12, 444–457 (2019)

    CAS  Article  Google Scholar 

  28. 28.

    Pillai, A.M., Sivasankarapillai, V.S., Rahdar, A., Joseph, J., Sadeghfar, F., Anuf, R.A., Rajesh, K., Kyzas, G.Z.: Green synthesis and characterization of zinc oxide nanoparticles with antibacterial and antifungal activity. J. Mol. Struct. 1211, 1–8 (2020)

    Article  CAS  Google Scholar 

  29. 29.

    Singh, A., Sharma, B., Deswal, R.: Green silver nanoparticles from novel Brassicaceae cultivars with enhanced antimicrobial potential than earlier reported Brassicaceae members. J. Trace Elem. Med. Biol. 47, 1–11 (2018)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  30. 30.

    Kumar, B., Smita, K., Cumbal, L., Debut, A.: Phytosynthesis of silver nanoparticles using andean cabbage: Structural characterization and its application. Mater. Today Proc. 21, 2079–2086 (2020)

    CAS  Article  Google Scholar 

  31. 31.

    Imanzadeh, G., Hadi, R.: Brassica oleraceae, a versatile plant for green synthesis of silver nanoparticles. Iran. Chem. Commun. 6, 70–77 (2018)

    Google Scholar 

  32. 32.

    Kuppusamy, P., Ichwan, S.J.A., Parine, N.R., Yusoff, M.M., Maniam, G.P., Govindan, N.: Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties. J. Environ. Sci. 29, 151–157 (2015)

    CAS  Article  Google Scholar 

  33. 33.

    Ranjitham, A.M., Suja, R., Caroling, G., Tiwari, S.: In vitro evaluation of antioxidant, antimicrobial, anticancer activities and characterisation of Brassica oleracea var. bortrytis L. synthesized silver nanoparticles. Int. J. Pharm. Pharm. Sci. 5, 239–251 (2013)

    Google Scholar 

  34. 34.

    Subramaniyan, S.A., Kang, D.R., Belal, S.A., Choe, H.S., Shim, K.S.: A comparative study of biologically and chemically fabricated synthesized AgNPs’ supplementation with respect to heat-shock proteins, survival, and hatching rates of chicken embryos: an in ovo study. J. Clust. Sci. 29, 129–139 (2018)

    Article  CAS  Google Scholar 

  35. 35.

    Sivakumar, A.S., Krishnaraj, C., Sheet, S., Rampa, D.R., Kang, D.R., Belal, S.A., Kumar, A., Hwang, I.H., Yun, S.I., Lee, Y.S., Shim, K.S.: Interaction of silver and gold nanoparticles in mammalian cancer: as real topical bullet for wound healing a comparative study. Cell. Dev. Biol. Anim. 53, 632–645 (2017)

    CAS  Article  Google Scholar 

  36. 36.

    Sundaram, C.S., Sivakumar, J., Suresh Kumar, S., Ramesh, P.L.N., Zin, T., Mahadeva Rao, U.S.: Antibacterial and anticancer potential of Brassica oleracea var. acephala using biosynthesised copper nanoparticles. Med. J. Malays. 75, 677–684 (2020)

    CAS  Google Scholar 

  37. 37.

    Prasad, P.R., Kanchi, S., Naidoo, E.B.: In-vitro evaluation of copper nanoparticles cytotoxicity on prostate cancer cell lines and their antioxidant, sensing and catalytic activity: One-pot green approach. J. Photochem. Photobiol. B Biol. 161, 375–382 (2016)

    CAS  Article  Google Scholar 

  38. 38.

    Piruthiviraj, P., Margret, A., Krishnamurthy, P.P.: Gold nanoparticles synthesized by Brassica oleracea (Broccoli) acting as antimicrobial agents against human pathogenic bacteria and fungi. Appl. Nanosci. 6, 467–473 (2016)

    CAS  Article  Google Scholar 

  39. 39.

    Clemente, I., Ristori, S., Pierucci, F., Muniz-Miranda, M., Salvatici, M.C., Giordano, C., Meacci, E., Feis, A., Gonnelli, C.: Gold nanoparticles from vegetable extracts using different plants from the market: a study on stability Shape and Toxicity. Chem. Sel. 2, 9777–9782 (2017)

    CAS  Google Scholar 

  40. 40.

    González-Ballesteros, N., Prado-López, S., Rodríguez-González, J.B., Lastra-Valdor, M., Rodríguez-Argüelles, M.C.: Green synthesis of gold nanoparticles using brown seaweed Cystoseira baccata: its activity in colon cancer cells. Colloids Surf. B. Biointerfaces. 153, 190–198 (2017)

    PubMed  Article  CAS  PubMed Central  Google Scholar 

  41. 41.

    González-Ballesteros, N., Rodríguez-González, J.B., Rodríguez-Argüelles, M.C.: Harnessing the wine dregs: an approach towards a more sustainable synthesis of gold and silver nanoparticles. J. Photochem. Photobiol. B 178, 302–309 (2018)

    PubMed  Article  CAS  PubMed Central  Google Scholar 

  42. 42.

    Bhattacharjee, S.: DLS and zeta potential—what they are and what they are not? J. Control. Release. 235, 337–351 (2016)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  43. 43.

    Carneiro-da-Cunha, M.G., Cerqueira, M.A., Souza, B.W.S., Teixeira, J.A., Vicente, A.A.: Influence of concentration, ionic strength and pH on zeta potential and mean hydrodynamic diameter of edible polysaccharide solutions envisaged for multinanolayered films production. Carbohydr. Polym. 85, 522–528 (2011)

    CAS  Article  Google Scholar 

  44. 44.

    Bishnoi, A., Kumar, S., Joshi, N.: Wide-angle X-ray diffraction (WXRD): technique for characterization of nanomaterials and polymer nanocomposites. In: Thomas, S., Thomas, R., Zachariah, A.K., Mishra, R.K. (eds.) Microscopy methods in nanomaterials characterization, pp. 313–337. Elsevier, Amsterdam (2017)

    Google Scholar 

  45. 45.

    Sotelo Pérez, T., Velasco, P., Soengas, P., Rodriguez, V.M., Cartea, M.E.: Modification of leaf glucosinolate contents in Brassica oleracea by divergent selection and effect on expression of genes controlling glucosinolate pathway. Front. Plant Sci. 7, 1–12 (2016)

    Google Scholar 

  46. 46.

    Armesto, J., Gómez-Limia, L., Carballo, J., Martínez, S.: Impact of vacuum cooking and boiling and refrigerated storage on the quality of Galega kale (Brassica oleracea var. acephala cv. Galega). LWT Food Sci. Technol. 79, 267–277 (2017)

    CAS  Article  Google Scholar 

  47. 47.

    Armesto, J., Gomez, L.L., Carballo, J., Martinez, S.: Effects of different cooking methods on some chemical and sensory properties of Galega kale. Int. J. Food Sci. Technol. 51, 2071–2080 (2016)

    CAS  Article  Google Scholar 

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This work was supported by the Xunta de Galicia Ref.: ED431C 2018/54-GRC.

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Correspondence to M. Carmen Rodríguez-Argüelles.

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González-Ballesteros, N., Vidal-González, J. & Rodríguez-Argüelles, M.C. Wealth from by-products: an attempt to synthesize valuable gold nanoparticles from Brassica oleracea var. acephala cv. Galega stems. J Nanostruct Chem (2021). https://doi.org/10.1007/s40097-021-00389-7

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  • Brassica oleracea
  • Green synthesis
  • Gold nanoparticles
  • By-products
  • Antioxidant activity