The effect of postharvest ripening on strawberry bioactive composition and antioxidant potential

BACKGROUND: The aim of the present work was to evaluate the phytochemical profile and the antioxidant activity of strawberry fruit (cv. Camarosa) upon postharvest ripening at room temperature (20 °C) and to correlate them with qualitative attributes. RESULTS: ‘Camarosa’ fruit retained an appreciable postharvest performance for up to 1 day shelf life; thereafter substantial quality deterioration was observed. An increased phenolic content, mainly attributed to hydroxycinnamic acids, flavonols and anthocyanins, was monitored after 3 days maintenance at 20 °C. The chromatographic fingerprint of athocyanins showed that pelargonidin‐3‐glucoside was the major anthocyanin, which increased with the increase of shelf life period, while cyanidin‐3‐glucoside and pelargonidin‐3‐rutinoside were found at lower concentrations. The potent radical scavenging activity, evaluated with four in vitro assays, showed a higher antioxidant capacity after 3 and 1 days of shelf life. In addition, the antioxidant effect of strawberry fruit extracts on lipid substrates and on an emulsion system showed a significant inhibition in the formation of conjugated diene hyperoxides. Interestingly, no direct correlation between the phytochemical profile and the quality attributes exist. CONCLUSION: ‘Camarosa’ fruit had acceptable quality attributes for fresh consumption and at the same time a high phytochemical content up to 1 day shelf life. The over‐ripe fruit continued to be an excellent reservoir of natural antioxidants, pointing to its potential use as food antioxidant and nutritional supplement. Copyright © 2011 Society of Chemical Industry     

Characterization,Stability, and In Vitro Release Evaluation of Carboxymethyl Chitosan Coated Liposomes Containing Fish Oil

Fish oil was extracted and refined from Nile tilapia viscera. Uncoated liposomes (un‐L) and carboxymethylchitosan (CMCS)‐coated liposomes (CM‐L) containing fish oil were prepared, and their characteristics, stability, and release in vitro were studied. The CMCS coating increased the mean diameter of liposomes but there was no effect on entrapment efficiency. The surface structure and characteristics of liposomes were determined. The Fourier transform infrared spectroscopy showed that the hydrogen bonding formed between the CMCS and the carbonyl region of the liposomes’ bilayer. The transition temperature of CM‐L was higher than un‐L. The stabilities of un‐L and CM‐L stored at 4 °C were better than 25 °C. Moreover, the CM‐L was significantly more stable than un‐L when stored at 25 °C. The release behaviors of un‐L and CM‐L were governed by 2 distinct stages and the first‐order model was the most suitable model for the whole release procedure. The diffusion and erosion may be the main release mechanisms for the full controlled release of fish oil from the liposomes. This study can provide theories and practice information for further applications of fish oil from tilapia viscera.     

Improved assay of coenzyme Q10 from liposomes by Tween 80 solubilisation and UV spectrophotometry

The encapsulated coenzyme Q₁₀ (CoQ₁₀) level is an important index in evaluating the quality of CoQ₁₀ liposomes. This study demonstrates a simple method to release encapsulated CoQ₁₀ from liposomal suspension using moderate amounts of the non‐ionic surfactant Tween 80 to form mixed micelles containing phospholipids, Tween 80 and CoQ₁₀. The encapsulated CoQ₁₀ level was detected by means of Tween 80 solubilisation and ultraviolet (UV) spectrophotometry, in which 1 mL of the reducing agent NaBH₄ (7 mg mL^?1) was added. The proposed method had a good linear correlation with ethanol solubilisation and reverse phase high‐performance liquid chromatography (RP‐HPLC) and with ethanol solubilisation and UV spectrophotometry over a CoQ₁₀ concentration range of 2.5–50 µg mL^?1 (R² > 0.999). The average recovery rate of CoQ₁₀ from blank liposomes was estimated as 99.46 ± 1.54%. The difference in results between the organic solvent extraction method and the Tween 80 solubilisation method was not statistically significant (P > 0.05). When the latter method was applied to determine the total and the encapsulated CoQ₁₀ content quantitatively, the relative standard deviation was lower than 5%. Therefore this method has proved to be convenient, sensitive, accurate and reproducible compared with conventional RP‐HPLC analysis and UV spectrophotometry with organic solvent extraction. Copyright © 2006 Society of Chemical Industry     

In vitro and in vivo antioxidant properties of the plant-based supplement greens+™

Dietary antioxidants play an important role against oxidation, an underlying mechanism in the incidence of chronic diseases. Greens+ is a commercially available preparation containing a variety of plant-derived ingredients. The aim of the current study was to evaluate the antioxidant potential of the methanolic extract of greens+ powder using in vitro and in vivo techniques. In vitro studies were conducted using a liposome model system to simulate biological cell membranes. Total antioxidant potential and polyphenol content of the herbal preparation was measured. For in vivo analysis, 10 healthy human subjects consumed either three or six teaspoons of greens+ per day for four weeks. Blood samples were analyzed at baseline and at the conclusion of the treatment period for total antioxidant capacity, polyphenol content, protein, lipid and LDL oxidation, and the level of glutathione peroxidase. Results showed that greens+ supplementation was well tolerated and increased serum antioxidant potential at higher levels of intake in a dose-dependent manner. HPLC analysis showed the presence of quercetin, apigenin, kaempferol and luteolin in the supplement. Plasma analysis indicated the presence of kaempferol only. A statistically significant (p < 0.05) reduction in protein and lipid oxidation was observed. Based on its antioxidant properties, the results suggest that greens+ might play a role in reducing the risk of chronic diseases involving a burden of oxidative damage.     

维生素C和水杨酸复合脂质体制备及影响因素的研究

以大豆磷脂为膜材,采用复乳-超声法制备同时含有脂溶性水杨酸和水溶性维生素C的复合脂质体。研究配方中不同成分的质量比、维生素C水溶液的pH、乳化温度、包衣等对脂质体包封率和稳定性的影响。结果表明,在m(大豆磷脂)∶m(胆固醇)∶m(水杨酸)∶m(维生素C)=4∶1∶0.75∶1,维生素C水溶液的pH为5,初乳和复乳化温度分别为25、45℃时制备的复合脂质体中维生素C和水杨酸的包封率分别为48.2%和55.4%;包衣处理使水杨酸/维生素C复合脂质体稳定性提高。     

血红素铁脂质体的制备

目的：制备血红素铁脂质体。方法：采用乙醇注入法及旋转薄膜- 超声法制备,再经过不同孔径的滤膜得到不同粒径的血红素铁脂质体,在原有技术的基础上优化血红素铁脂质体各组分的制备工艺,应用紫外分光光度计测定血红素铁的含量,计算出血红素铁脂质体的包封率,用差示扫描量热法检测血红素铁脂质体各组成物质的相变过程。结果：两种方法都能够得到较为理想的脂质体,血红素铁:胆固醇:卵磷脂质量比范围为(0.1～200):(1～10):(10～100)。结论：所得血红素铁脂质体呈均一大单室型,通过0.8μm 的滤膜后有效粒径为0.804μm,最大包封率36%。     

Overcoming Biological Barriers in Neuroblastoma Therapy: The Vascular Targeting Approach with Liposomal Drug Nanocarriers

Neuroblastoma is a rare pediatric cancer characterized by a wide clinical behavior and adverse outcome despite aggressive therapies. New approaches based on targeted drug delivery may improve efficacy and decrease toxicity of cancer therapy. Furthermore, nanotechnology offers additional potential developments for cancer imaging, diagnosis, and treatment. Following these lines, in the past years, innovative therapies based on the use of liposomes loaded with anticancer agents and functionalized with peptides capable of recognizing neuroblastoma cells and/or tumor‐associated endothelial cells have been developed. Studies performed in experimental orthotopic models of human neuroblastoma have shown that targeted nanocarriers can be exploited for not only decreasing the systemic toxicity of the encapsulated anticancer drugs, but also increasing their tumor homing properties, enhancing tumor vascular permeability and perfusion (and, consequently, drug penetration), inducing tumor apoptosis, inhibiting angiogenesis, and reducing tumor glucose consumption. Furthermore, peptide‐tagged liposomal formulations are proved to be more efficacious in inhibiting tumor growth and metastatic spreading of neuroblastoma than nontargeted liposomes. These findings, herein reviewed, pave the way for the design of novel targeted liposomal nanocarriers useful for multitargeting treatment of neuroblastoma.