Screening of the Supercritical Impregnation of Olea europaea Leaves Extract into Filaments of Thermoplastic Polyurethane (TPU) and Polylactic Acid (PLA) Intended for Biomedical Applications.

The leaves of Olea europaea as agricultural waste represent a convenient source of antioxidants. In combination with supercritical CO2 (scCO2), assisted impregnation is an interesting strategy for the preparation of biomedical devices with specific bioactivity. For this purpose, 3D-printable filaments of thermoplastic polyurethane (TPU) and polylactic acid (PLA) were employed for the supercritical impregnation of ethanolic olive leaves extract (OLE) for biomedical application. The extraction of OLE was performed using pressurized liquids. The effect of pressure (100-400 bar), temperature (35-55 °C), and the polymer type on the OLE impregnation and the swelling degree were studied including a morphological analysis and the measurement of the final antioxidant activity. All the studied variables as well as their interactions showed significant effects on the OLE loading. Higher temperatures favored the OLE loading while the pressure presented opposite effects at values higher than 250 bar. Thus, the highest OLE loadings were achieved at 250 bar and 55 °C for both polymers. However, TPU showed c.a. 4 times higher OLE loading and antioxidant activity in comparison with PLA at the optimal conditions. To the best of our knowledge, this is the first report using TPU for the supercritical impregnation of a natural extract with bioactivity.

Possible protective effect of olive leaves extract on paracetamol induced hepatotoxicity in male albino rats / Possível efeito protetor do extrato de folhas de oliveira na hepatotoxicidade induzida por paracetamol em ratos albinos machos

Paracetamol (PCM) overdose can cause hepatotoxicity with oxidative stress; the present study was carried out to establish the possible protective effect of olive leaves extract (OLE) on toxicity induced by paracetamol in adult male rats. Twenty four adult male rats were divided into four equal groups; control, olive leaves extract group, paracetamol group and olive leaves extract plus paracetamol group. Some biochemical parameters and liver histopathology were evaluated. PCM treatment significantly increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, gamma-glutamyltransferase (GGT), lactate dehydrogenase (LDH), urea, creatinine and alpha-fetoprotein. Paracetamol was found to significantly increase malonaldehyde (MDA) and decrease glutathione reductase (GR) activity in tissue and significantly decrease total antioxidant capacity (TAC) and superoxide dismutase (SOD) in serum. Administration of OLE caused a significant decrease serum AST, ALT enzyme, total bilirubin, GGT, LDH, creatinine, urea, alpha-fetoprotein. Also, amelioration of oxidant ­ antioxidant status with olive leaves extract was observed in addition to a significant decrease in MDA and a significant increase in TAC in liver tissue with a significant increase in glutathione reductase (GR) and SOD in serum compared to paracetamol treated group The chemical pathological changes were in step with histopathological observation suggesting marked hepatoprotective result of olive leaves extract. It could be concluded that olive leaves extract (OLE) treatment may be effective in decreasing hepatic injury and oxidative stress induced by paracetamol overdose in male albino rats

A sobredosagem de paracetamol (PCM) pode causar hepatotoxicidade com estresse oxidativo; o presente estudo foi realizado para estabelecer o possível efeito protetor do extrato de folhas de oliveira (OLE) na toxicidade induzida pelo paracetamol em ratos machos adultos. Vinte e quatro ratos machos adultos foram divididos em quatro grupos iguais: controle, grupo extrato de folhas de oliveira, grupo paracetamol e extrato de folhas de oliveira mais grupo paracetamol. Alguns parâmetros bioquímicos e histopatologia hepática foram avaliados. O tratamento com PCM aumentou significativamente aspartato aminotransferase sérica (AST), alanina aminotransferase (ALT), bilirrubina total, gama-glutamiltransferase (GGT), lactato desidrogenase (LDH), uréia, creatinina e alfa-fetoproteína. Verificou-se que o paracetamol aumenta significativamente o malonaldeído (MDA) e diminui a atividade da glutationa redutase (GR) no tecido e diminui significativamente a capacidade antioxidante total (TAC) e a superóxido dismutase (SOD) no soro. A administração de OLE causou uma diminuição significativa de AST, enzima ALT, bilirrubina total, GGT, LDH, creatinina, uréia, alfa-fetoproteína. Também foi observada melhora do status oxidante - antioxidante com extrato de folhas de oliveira, além de uma diminuição significativa no MDA e um aumento significativo no TAC no tecido hepático, com um aumento significativo na glutationa redutase (GR) e SOD no soro em comparação ao grupo tratado com paracetamol. As alterações patológicas químicas acompanharam a observação histopatológica, sugerindo resultado hepatoprotetor acentuado do extrato de folhas de oliveira. Pode-se concluir que o tratamento com extrato de folhas de oliveira (OLE) pode ser eficaz na diminuição da lesão hepática e do estresse oxidativo induzido pela overdose de paracetamol em ratos albinos machos

Role of maltodextrin and inulin as encapsulating agents on the protection of oleuropein during in vitro gastrointestinal digestion.

Olive leaves extract (OLE) was spray-dried with maltodextrin (MD) or inulin (IN) to study the evolution of oleuropein (OE) during in vitro gastrointestinal digestion, its bioaccessibility and potential bioavailability. In the case of OLE-MD, OE was partially degraded in gastric and intestinal conditions; whereas in OLE-IN, OE was released under gastric conditions and partially degraded under intestinal conditions. In both cases, the encapsulation of OLE led to higher OE contents at the end of digestion, compared with non-encapsulated OLE, suggesting a protective role of the polysaccharides by the formation of non-covalent polysaccharides-OE complexes. OE bioaccessibility was ten times higher (p ≤ 0.05) in OLE-MD and OLE-IN than in non-encapsulated OLE. However, OE potential bioavailability, evaluated by tangential filtration, was not detected. Encapsulation technology and the encapsulant agent used may determine the release of the encapsulated compounds at a specific-site and their effect on health.

Double emulsions with olive leaves extract as fat replacers in meat systems with high oxidative stability.

Double emulsions (DE) with a healthy oil blend as lipid phase and an olive leave extract (OLE) encapsulated in the internal aqueous phase (DE/OLE) were incorporated as fat replacers in meat systems, in order to improve both the lipid profile and the oxidative stability. After 14 days of storage at 4 °C, DE/OLE showed good physical stability (90% of globule population was still below 10 µm diameter), and high antioxidant capacity (over 80%), longer than time required for this type of food ingredients. A high correlation was found between the remaining oleuropein content and the antioxidant capacity in both meat systems with DE/OLE (MS-DE/OLE) and meat systems with the oil blend as liquid oil and non-encapsulated OLE (MS-L/OLE). MS-DE/OLE were technologically feasible and showed higher retention of oleuropein (69%), oxidative stability and antioxidant capacity at 60 °C for 7 days than MS-L/OLE, where oleuropein was almost depleted. The encapsulation of OLE in DE could be a suitable strategy to avoid lipid oxidation in meat systems with healthier lipid profile.