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Abstract(s)
A procura e o desenvolvimento de novos agentes antimicrobianos resultam da crescente preocupaĆ§Ć£o com o impacto do uso dos agentes disponĆveis comercialmente no meio ambiente e da ameaƧa crescente que os seus efeitos indesejados produzem nos ecossistemas. AlĆ©m disso, nos Ćŗltimos anos, com a propagaĆ§Ć£o do coronavĆrus SARS-CoV-2 (COVID-19), a utilizaĆ§Ć£o de produtos de limpeza e desinfetantes das mĆ£os em forma de gĆ©is, toalhetes hĆŗmidos ou outros produtos nĆ£o enxaguĆ”veis aumentou drasticamente e, por consequĆŖncia, houve a necessidade de reforƧar a produĆ§Ć£o de agentes antimicrobianos, a fim de responder Ć s necessidades adicionais no contexto da atual pandemia. Neste cenĆ”rio, os compostos fitoquĆmicos que possuem diversos efeitos biolĆ³gicos, sĆ£o vistos como promissores para a criaĆ§Ć£o de agentes antimicrobianos e fĆ”rmacos alternativos aos de uso convencional. Estes compostos tĆŖm demonstrado ser uma mais-valia oferecendo uma proposta inovadora e com grande potencial para formulaĆ§Ć£o de produtos com capacidades antibacterianas, antifĆŗngicas e antioxidantes, alĆ©m da sua atividade quimiopreventiva, perante alguns tipos de cancro. Nesta dissertaĆ§Ć£o efetuou-se uma revisĆ£o bibliogrĆ”fica sobre a obtenĆ§Ć£o de compostos da famĆlia dos isotiocianatos a partir de produtos naturais e por sĆntese, bem como a apresentaĆ§Ć£o das suas propriedades antimicrobianas e quimiopreventivas. Foi tambĆ©m realizado o estudo da fotorreatividade e da complexaĆ§Ć£o com Ī²-ciclodextrinas do isotiocianato de benzilo (BITC), um dos compostos da famĆlia dos isotiocianatos mais citados em publicaƧƵes devido Ć sua atividade anticancerĆgena perante diferentes tipos de cancro, como o da mama e do pulmĆ£o. O estudo da fotorreatividade foi efetuado com intuito de avaliar a possĆvel fototoxicidade atribuĆda a este composto, o que pode limitar a sua aplicaĆ§Ć£o industrial. No entanto, de acordo com as anĆ”lises realizadas, o BITC nĆ£o Ć© fotorreativo, indicando que a possibilidade de expressar alguma fototoxicidade quando exposto a luz visĆvel Ć© baixa. O BITC apresenta elevada volatilidade e hidrofobia que pode igualmente inviabilizar a sua ampla utilizaĆ§Ć£o. A microencapsulaĆ§Ć£o deste composto, poderĆ” contribuir para o aumento da sua solubilidade em Ć”gua e impedir que o composto volatilize rapidamente. O estudo de complexaĆ§Ć£o foi realizado usando hidroxipropil-Ī²-ciclodextrina (HP-Ī²-CD) e metil-Ī²-ciclodextrina (M-Ī²-CD), com o objetivo de determinar e comparar as constantes de estabilidade obtidas atravĆ©s do uso de cada uma das ciclodextrinas. Nos dois casos, verificou-se uma relaĆ§Ć£o linear entre o aumento da solubilidade do BITC e o aumento da concentraĆ§Ć£o das ciclodextrinas utilizadas, com declives inferiores a 1, o que indica a formaĆ§Ć£o de complexos na proporĆ§Ć£o estequiomĆ©trica 1:1. Os resultados alcanƧados para as constantes de estabilidade foram de 250 Ā± 4 Mā1 para HP-Ī²-CD e 565 Ā± 10 Mā1 para a M-Ī²-CD. Foi possĆvel verificar um aumento na solubilidade do BITC de oito vezes quando se utilizou a HP-Ī²CD e de doze vezes com a utilizaĆ§Ć£o da M-Ī²-CD como agente encapsulante. Os resultados obtidos indicam que a microencapsulaĆ§Ć£o do isotiocianato de benzilo com CDs poderĆ” contribuir para melhorar o potencial de aplicaĆ§Ć£o desta substĆ¢ncia em fĆ”rmacos e agentes antibacterianos.
The demand for and development of new antimicrobial agents is a result of growing concern about the impact of the use of commercially available agents on the environment and the increasing threat to ecosystems from their unwanted effects. Furthermore, in recent years, with the spread of the SARS-CoV-2 coronavirus (COVID-19), the use of hand cleaners and disinfectants in the form of gels, wet wipes or other non-rinse-off products has increased dramatically and, consequently, there has been a need to strengthen the production of antimicrobial agents in order to meet the additional needs in the context of the current pandemic. In this scenario, phytochemical compounds that possess diverse biological effects, are seen as promising for the creation of alternative antimicrobial agents and drugs to those in conventional use. These compounds have demonstrated to be an added value offering an innovative proposal and with great potential for formulation of products with antibacterial, antifungal and antioxidant capacities, besides its chemopreventive activity, facing some types of cancer. In this dissertation a bibliographical revision on the obtainment of compounds of the family of the isothiocyanates from natural products and by synthesis was made as well as the presentation of its antimicrobial and chemopreventive properties. The study of photoreactivity and complexation with Ī²-cyclodextrins of benzyl isothiocyanate (BITC), one of the compounds of the isothiocyanate family most cited in publications due to its anticancer activity against different types of cancer, such as breast and lung cancer, was also performed. The photoreactivity study was carried out in order to evaluate the possible phototoxicity attributed to this compound, which may limit its industrial application. However, according to the analyses performed, BITC is not photoreactive, indicating that the possibility of expressing some phototoxicity when exposed to visible light is low. BITC presents high volatility and hydrophobicity that may also make its wide use unfeasible. The microencapsulation of this compound could contribute to the increase of its solubility in water and prevent that the compound volatilizes quickly. The complexation study was performed using hydroxypropyl-Ī²-cyclodextrin (HP-Ī²-CD) and methyl-Ī²-cyclodextrin (M-Ī²-CD), in order to determine and compare the stability constants obtained by using each of the cyclodextrins. In both cases, a linear relationship was found between the increase in the solubility of BITC and the increase in the concentration of the cyclodextrins used, with slopes lower than 1, indicating the formation of complexes in the stoichiometric 1:1 ratio. The results achieved for the stability constants were 250 Ā± 4 M-1 for HP-Ī²-CD and 565 Ā± 10 M-1 for M-Ī²-CD. An eight times increase in BITC solubility could be verified when HP-Ī²-CD was used and twelve times increase with the use of M-Ī²-CD as encapsulating agent. The results obtained indicate that the microencapsulation of benzyl isothiocyanate with CDs could contribute to improve the potential application of this substance in drugs and antibacterial agents.
The demand for and development of new antimicrobial agents is a result of growing concern about the impact of the use of commercially available agents on the environment and the increasing threat to ecosystems from their unwanted effects. Furthermore, in recent years, with the spread of the SARS-CoV-2 coronavirus (COVID-19), the use of hand cleaners and disinfectants in the form of gels, wet wipes or other non-rinse-off products has increased dramatically and, consequently, there has been a need to strengthen the production of antimicrobial agents in order to meet the additional needs in the context of the current pandemic. In this scenario, phytochemical compounds that possess diverse biological effects, are seen as promising for the creation of alternative antimicrobial agents and drugs to those in conventional use. These compounds have demonstrated to be an added value offering an innovative proposal and with great potential for formulation of products with antibacterial, antifungal and antioxidant capacities, besides its chemopreventive activity, facing some types of cancer. In this dissertation a bibliographical revision on the obtainment of compounds of the family of the isothiocyanates from natural products and by synthesis was made as well as the presentation of its antimicrobial and chemopreventive properties. The study of photoreactivity and complexation with Ī²-cyclodextrins of benzyl isothiocyanate (BITC), one of the compounds of the isothiocyanate family most cited in publications due to its anticancer activity against different types of cancer, such as breast and lung cancer, was also performed. The photoreactivity study was carried out in order to evaluate the possible phototoxicity attributed to this compound, which may limit its industrial application. However, according to the analyses performed, BITC is not photoreactive, indicating that the possibility of expressing some phototoxicity when exposed to visible light is low. BITC presents high volatility and hydrophobicity that may also make its wide use unfeasible. The microencapsulation of this compound could contribute to the increase of its solubility in water and prevent that the compound volatilizes quickly. The complexation study was performed using hydroxypropyl-Ī²-cyclodextrin (HP-Ī²-CD) and methyl-Ī²-cyclodextrin (M-Ī²-CD), in order to determine and compare the stability constants obtained by using each of the cyclodextrins. In both cases, a linear relationship was found between the increase in the solubility of BITC and the increase in the concentration of the cyclodextrins used, with slopes lower than 1, indicating the formation of complexes in the stoichiometric 1:1 ratio. The results achieved for the stability constants were 250 Ā± 4 M-1 for HP-Ī²-CD and 565 Ā± 10 M-1 for M-Ī²-CD. An eight times increase in BITC solubility could be verified when HP-Ī²-CD was used and twelve times increase with the use of M-Ī²-CD as encapsulating agent. The results obtained indicate that the microencapsulation of benzyl isothiocyanate with CDs could contribute to improve the potential application of this substance in drugs and antibacterial agents.
Description
Keywords
FitoquĆmicos Isotiocianatos MicroencapsulaĆ§Ć£o Ciclodextrinas Fotorreatividade Phytochemicals Isothiocyanates Microencapsulation Cyclodextrins Photoreactivity