Entrapment of Rosmarinus officinalis polyphenols in redispersible lipid-based systems

• Ano de defesa: 2020
• Autor(a) principal: Bankole, Victor Oloruntoba
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Antimicrobial activity; Antioxidant activity; Atividade antimicrobiana; Atividade antioxidante; Estudos de estabilidade; Polifenois de alecrim; Proliposomes; Prolipossomas; Rosemary polyphenols; Spray drying; Stability studies
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/60/60137/tde-22092021-091844/

Rosmarinus officinalis L. (rosemary) comprise polyphenolic compounds, principally phenolic acids and diterpenes which possess excellent antioxidant and antimicrobial properties. However, deriving maximum benefits from this material is limited by several drawbacks; including low solubility, bioavailability, and stability among others issues. Encapsulation of plant extracts in different materials is a credible way to improve their physicochemical properties and circumvent these challenges. Encapsulation in proliposomes is particularly interesting, having further advantages of incorporating multiple components of varying polarity with relatively higher stability compared to liquid formulations. Hence, this study aims at preparing proliposomes of rosemary polyphenols with a view to encapsulating bioactive compounds of varying polarity, thus enhancing the scope of their applicability. Polyphenolrich extract from dried and milled rosemary leaves was obtained by dynamic maceration, filtered, concentrated and freeze-dried. Following preliminary studies, liposomal compositions (using hydrogenated soyphosphatidylcholine and cholesterol) encapsulating rosemary polyphenols (caffeic, rosmarinic and carnosic acids, and carnosol as markers) were prepared by a modified solvent replacement method. The compositions were dried in a lab-scale spray dryer at flow rate of 4.0 g/min and temperature of 100 °C, using lactose as the drying aid to obtain proliposomes. The proliposome formulations were optimized by experimental design, using the Central Composite Design, and validated by correlating experimental values of critical quality attributes with the predicted. Spray dried proliposomes (SDP) were characterized by moisture content, water activity, retention and total content of marker polyphenols, density and flow properties, crystallinity, morphology, infrared spectroscopy, and redispersibility - including vesicle size and zeta potential on hydration. The spray drying performance was characterized by determination of the powder recovery. The optimal SDP and lyophilized extract (LE) were evaluated for antioxidant (DPPH· method) and antimicrobial (antibacterial and antifungal) properties. Stability study was carried out to evaluate the effect of relative humidity and temperature on SDP and LE. Storage samples were similarly analysed for changes in physicochemical properties. Results of experimental runs showed that SDP exhibited polyphenol retention, ranging from 62.0 - 100.0% w/w; showing dependence on composition variables and polyphenol lipophilicity. SDP recovery ranged from 20.1 to 45.8 %, with moisture content and water activity of 1.7±0.14 - 2.5±0.23 %w/w and 0.30±0.004 - 0.47±0.003, respectively. Composition variables influenced proliposome properties with optimal combinations being 4.26% w/w, 4.48% w/w, and 7.55% w/w for lipid concentration, LE concentration, and drying aid:(lipid+extract) ratio, respectively on wet basis. Results showed concurrence between predicted and experimental values except carnosol retention, being 22 % lower. Optimal SDP showed high antioxidant activity with IC50 of 9.2±0.2 µg/mL, superior to results obtained for LE (10.8 µg/mL) and Butylated Hydroxytoluene, a synthetic antioxidant (12.5 µg/mL). MIC and MFC against Candida albicans (ATCC1023) were 312.5 μg/mL and 1,250 μg/mL, respectively; lower than values obtained for bacteria strains used. The product stability was more affected by storage humidity (compared to temperature), indicating need for waterproof packaging. SDP is shown as a veritable tool to encapsulate hydrophilic and lipophilic rosemary polyphenols generating a product with improved physicochemical and biological properties.