Encapsulação de ativos naturais com atividade antimicrobiana em materiais de parede proteicos e lipídicos

Abstract

With increasing of the resistance of microorganisms to commercial drugs, the search for new natural alternative antimicrobials, such as essential oils, has become im-portant. This research aims to test these essential oils against cutaneous pathogenic organisms that affect both humans and domestic animals, such as dogs and cats. Through the association with nanotechnology, this work proposes the encapsula-tion of these natural actives for the development of new formulations. Five natural active substances were selected: essential oil of Lippia alba, Lippia origanoides and Syzygium aromaticum; fixed oil of Dipteryx odorata and synthetic timol. The selected microorganisms were Sthaphylococcus aureus, Aspergillus fumigatus, Cryptococcus gattii, Candida albicans, Candida parapsilosis, Microsporum canis, Trichophyton mentalogrophytes, Trichophyton rubrum and Trichophyton tonsurans. For the devel-opment of new carrier materials, wall materials based on whey isolates, gums and phospholipids were selected to evaluate the interaction between the wall material and the active substances. The systems were submitted to the characterization techniques by NMR, UV-vis, DLS, FTIR, GC/MS and physico-chemical analysis. Among the tested substances, the essential oil of the specimens L. origanoides and S. aromaticum showed higher activity against the fungi and bacteria tested. The ac-tion can be attributed to the major constituents of oils, carvacrol, thymol and euge-nol, which are classified as phenolic compounds. Phenolic compounds have the activity of enzymatic catalysis of polyphenoloxidase, which is capable of oxidizing quinones, causing a toxic effect on microorganisms. Among the wall materials, whey isolates and phospholipid (soybean asolecitina) showed better interaction with the essential oils of the species S. aromaticum and L. origanoides when encapsu-lated. Both the protein and lipid wall materials exhibited satisfactory encapsulation efficiency. The systems that demonstrated better interaction and stability were WPI and Aso containing the thymol and MI conservants. This research may be consid-ered as the beginning of a developing process of a nanotecnological product based on natural actives for the control of the tested fungi and bacterium.