Publicação
Chitosan-xanthan gum-based hydrogels loaded with essential oil distillation by-products of Aloysia citrodora Paláu for antimicrobial systems
| Resumo: | Hydrogels, 3D hydrophilic networks formed by oppositely charged biopolymers like chitosan and xanthan gum, offer a safe, non-toxic, and biocompatible option for delivery applications. Essential oil (EO) by-products, such as hydrosols and wastewater, are sources of antioxidant and antimicrobial compounds, but their high dilution can limit direct applications. In this context, this work focused on the development of hydrogels via electrostatic complexation incorporating hydrosol and wastewater by-products from the steam distillation of Aloysia citrodora Palau, using a two-stage approach: (a) initial loading during hydrogel formation and (b) subsequent reloading of the hydrogels to further enhance the concentration of bioactive compounds. The effect of pH (4, 7, and 11) on polymer complexation was evaluated, as it influences polymer-polymer and polymer-bioactive compound interactions by modifying the protonation and deprotonation states of their functional groups. This effect was evident in swelling, release kinetics, morphology, and rheological properties. Fourier-transform infrared (FTIR) analysis confirmed the successful formation of the polymer complex. Neutral pH hydrogels showed the highest hydrosol entrapment (70.3%) and were selected as the most promising systems. Biological characterisation showed that the reloading process enhanced bioactivity. Wastewater-load-reload improved antioxidant capacity, driven by the high phenolic content. Moreover, hydrosol-loaded-reload systems exhibited antimicrobial activity, with bactericidal effects against Staphylococcus aureus and Escherichia coli, outperforming both unloaded and loaded systems. These findings highlight the potential of loading and reloading steps to valorise EO by-products, producing sustainable, functional hydrogels with high bioactivity, suitable for food, pharmaceutical, medical, and biotechnological applications. |
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| Autores principais: | Almeida, Heloísa H.S. |
| Outros Autores: | Santamaria-Echart, Arantzazu; Amaral, Joana S.; Aquino, Leandro Lima; Rodrigues, Alírio E.; Barreiro, Filomena |
| Assunto: | Chitosan Xanthan gum Hydrogel Essential oil by-products Waste valorisation Hydrosols Antimicrobial activity |
| Ano: | 2026 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Hydrogels, 3D hydrophilic networks formed by oppositely charged biopolymers like chitosan and xanthan gum, offer a safe, non-toxic, and biocompatible option for delivery applications. Essential oil (EO) by-products, such as hydrosols and wastewater, are sources of antioxidant and antimicrobial compounds, but their high dilution can limit direct applications. In this context, this work focused on the development of hydrogels via electrostatic complexation incorporating hydrosol and wastewater by-products from the steam distillation of Aloysia citrodora Palau, using a two-stage approach: (a) initial loading during hydrogel formation and (b) subsequent reloading of the hydrogels to further enhance the concentration of bioactive compounds. The effect of pH (4, 7, and 11) on polymer complexation was evaluated, as it influences polymer-polymer and polymer-bioactive compound interactions by modifying the protonation and deprotonation states of their functional groups. This effect was evident in swelling, release kinetics, morphology, and rheological properties. Fourier-transform infrared (FTIR) analysis confirmed the successful formation of the polymer complex. Neutral pH hydrogels showed the highest hydrosol entrapment (70.3%) and were selected as the most promising systems. Biological characterisation showed that the reloading process enhanced bioactivity. Wastewater-load-reload improved antioxidant capacity, driven by the high phenolic content. Moreover, hydrosol-loaded-reload systems exhibited antimicrobial activity, with bactericidal effects against Staphylococcus aureus and Escherichia coli, outperforming both unloaded and loaded systems. These findings highlight the potential of loading and reloading steps to valorise EO by-products, producing sustainable, functional hydrogels with high bioactivity, suitable for food, pharmaceutical, medical, and biotechnological applications. |
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