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Technological stability of solid lipid nanoparticles loaded with phenolic compounds: drying process and stability along storage

Publication . Campos, Débora A.; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Maria Manuela; Gomes, Ana Maria

Solid lipid nanoparticles (SLNs) have been widely studied and tested as vehicles for natural compounds. Recently, Witepsol and Carnauba SLNs were shown to be effective systems for the entrapment of rosmarinic acid (RA) and herbal extracts. In the present work, the improvement of stability and bioactivity of these systems was studied. Thus, the freeze-drying of SLNs produced with Witepsol and Carnauba waxes loaded with RA and herbal extracts (sage and savory) were tested. The use of three different cryoprotectants (glucose, mannitol and trehalose) at two different concentrations (5 and 10%, w/v) were evaluated. Furthermore, the prepared SLNs were stored under different conditions (atmosphere, temperature, absence or presence of light) and in different packaging materials, over 365 days. The effect on the SLNs physical stability and bioactivity was assessed. The most suitable cryoprotectant was mannitol at 10% (w/v) for all formulations tested. The solid state of SLNs, with storage at room temperature, in glass flasks, protected from light and under N2 controlled atmosphere were the best storage conditions in which the SLNs bioactivity was maintained during 365 days.

2017Journal article

Restricted access

Stability of bioactive solid lipid nanoparticles loaded with herbal extracts when exposed to simulated gastrointestinal tract conditions

Publication . Campos, Débora A.; Madureira, Ana Raquel; Sarmento, Bruno; Gomes, Ana Maria; Pintado, Maria Manuela

Solid lipid nanoparticles (SLN) can be used as vehicles for phenolic compounds rich extracts. In the presentwork two types of waxes — witepsol and carnauba were tested for the first time in the production of solid lipid nanoparticles (WSLN and CSLN, respectively) loaded with sage and savoury extracts. Physical characterization and association efficiencies calculation were performed. Discrimination of loaded phenolic compounds from each extract was made using HPLC assays. Antioxidant activities of SLN were characterized using two different methods— ABTS and ORAC. Finally, the phenolic compound release profile from SLN and stabilitywhen exposed to simulated gastrointestinal tract (GIT) conditionswere also evaluated. Different phenolic compounds fromsage and savoury extracts were entrapped in SLN. The highest antioxidant activity was obtained for the SLN loaded with savoury extract. Stomach simulated condition provokes a partial release of rosmarinic acid from SLN, whereas at small intestine simulation step, all SLN showed a release of ca. 100%. Witepsol SLN were the ones that best maintained their physical integrity during digestion, showing to be the most stable vehicles for sage and savoury extracts. These SLN show to be suitable for the production of food functional ingredients bearing antioxidant activity.

2015Journal article

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Fermentation of bioactive solid lipid nanoparticles by human gut microflora

Publication . Madureira, Ana Raquel; Campos, Débora; Gullon, Beatriz; Marques, Cláudia; Rodríguez-Alcalá, Luís M.; Calhau, Conceição; Alonso, Jose Luis; Sarmento, Bruno; Gomes, Ana M.; Pintado, M. E.

Solid lipid nanoparticles (SLNs) can be used for oral delivery of phenolic compounds in order to protect them from the harsh conditions of digestion and improve their bioavailability in the intestinal epithelium. Recently, the production and characterization of SLNs loaded with rosmarinic acid (RA) and herbal extracts was performed for future use as functional food ingredients. Diet components have been shown to have a huge impact on gut microbiota viability and metabolic activity. Hence, SLNs loaded with RA, sage and savoury extracts have been evaluated for their effect on intestinal microbiota growth and the metabolic products generated. Fermentations in anaerobic batch cultures using volunteer human faeces were performed during 24 h. Dynamic bacterial population changes were analysed using PCR-real time, as well as the generation of fatty acids and the quantification of phenolic compounds by analytical methods. Solid lipid nanoparticles released phenolic compounds at non-inhibitory bacterial growth concentrations. Released herbal extract phenolic compounds showed a beneficial effect on gut microbiota growth (e.g. bifidogenic effects) and were used as substrates. Acetate, formate, lactate and butyrate were produced in higher concentrations. The released phenolic compounds also induced PUFA and trans fatty acids metabolic activity, the production of saturated fatty acids, as well of potential beneficial conjugated linoleic acid isomers. Solid lipid nanoparticles modulate gut microbiota and metabolic activities.

2016-01Journal article

Restricted access

Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches

Publication . Reis, Flávio; Madureira, Ana Raquel; Nunes, Sara; Campos, Débora; Fernandes, João; Marques, Cláudia; Zuzarte, Monica; Gullón, Beatriz; Rodríguez-Alcalá, Luis M.; Calhau, Conceição; Sarmento, Bruno; Gomes, Ana M.; Pintado, M. E.

Rosmarinic acid (RA) possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe) delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL) were evaluated for cell (lymphocytes) viability, necrosis and apoptosis, and antioxidant/prooxidant effects upon DNA. Wistar rats were orally treated for 14 days with vehicle (control) and with Witepsol or Carnauba nanoparticles loaded with RA at 1 and 10 mg/kg body weight/d. Blood, urine, feces, and several tissues were collected for analysis. Free and loaded RA, at 0.15 mg/mL, presented a safe profile, while genotoxic potential was found for the higher dose (1.5 mg/mL), mainly by necrosis. Our data suggest that both types of nanoparticles are safe when loaded with moderate concentrations of RA, without in vitro genotoxicity and cytotoxicity and with an in vivo safety profile in rats orally treated, thus opening new avenues for use in nutraceutical applications.

2016Journal article

Open access