Enhanced in vivo absorption and biodistribution of curcumin loaded into emulsions with high medium-chain triglyceride content.

The health benefits of curcumin have been demonstrated by several clinical studies, but its low bioavailability compromises its functionality. In this regard, emulsions have proven to be effective encapsulation systems for curcumin. Nevertheless, emulsions with a high oil content (50%) may offer some advantages due to the large amount of compound they can incorporate. Therefore, the aim of this work was to study the pharmacokinetics and biodistribution of curcumin when carried in optimized emulsions containing 50% MCT oil and a plant-based emulsifier (soybean lecithin) at 2 h or 4 h post-oral administration to rats. The most stable emulsion was obtained using 50% of oil and a surfactant-oil-ratio 0.1, through a microfluidization process. After the oral administration of the systems (150 mg curcumin/kg body weight), curcumin glucuronide was the main compound present in plasma (AUC0-t = 1556.3 ng·h·ml-1), especially at 2-4 h post-administration. The total curcuminoid bioavailability was increased by 10.6-fold when rats were fed with the curcumin emulsion rather than with a control suspension. Moreover, rats fed with the emulsion showed the highest accumulation of free curcuminoids, which present the highest biological activity, in the liver (129 ng curcumin/g tissue) and brown adipose tissue (193 ng curcumin/g tissue). The obtained results are of great interest since the presence of curcumin in the brown adipose tissue has been shown to play a relevant role in the prevention of obesity and its related metabolic disorders.

Emulsion-Based Delivery Systems to Enhance the Functionality of Bioactive Compounds: Towards the Use of Ingredients from Natural, Sustainable Sources.

In recent years, the trend in the population towards consuming more natural and sustainable foods has increased significantly. This claim has led to the search for new sources of bioactive compounds and extraction methods that have less impact on the environment. Moreover, the formulation of systems to protect these compounds is also focusing on the use of ingredients of natural origin. This article reviews novel, natural alternative sources of bioactive compounds with a positive impact on sustainability. In addition, it also contains information on the most recent studies based on the use of natural (especially from plants) emulsifiers in the design of emulsion-based delivery systems to protect bioactive compounds. The properties of these natural-based emulsion-delivery systems, as well as their functionality, including in vitro and in vivo studies, are also discussed. This review provides relevant information on the latest advances in the development of emulsion delivery systems based on ingredients from sustainable natural sources.

Enhancing in vivo retinol bioavailability by incorporating ß-carotene from alga Dunaliella salina into nanoemulsions containing natural-based emulsifiers.

The use of microalgae as a source of bioactive compounds has gained interest since they present advantages vs higher plants. Among them, Dunaliella salina is one of the best sources of natural ß-carotene, which is the precursor of vitamin A. However, ß-carotene shows reduced oral bioavailability due to its chemical degradation and poor absorption. The work aimed to evaluate the influence of the emulsifier and oil concentration on the digestive stability of Dunaliella Salina-based nanoemulsions and study their influence on the digestibility and the ß-carotene bioaccessibility. In addition, the effect of the emulsifier nature on the absorption of ß-carotene and its conversion to retinol in vivo was also investigated. Results showed that the coalescence observed in soybean lecithin nanoemulsion during the gastrointestinal digestion reduced the digestibility and ß-carotene bioaccessibility. In contrast, whey protein nanoemulsion that showed aggregation in the gastric phase could be redispersed in the intestinal phase facilitating the digestibility and bioaccessibility of the compound. In vivo results confirmed that whey protein nanoemulsion increased the bioavailability of retinol to a higher extent (Cmax 685 ng/mL) than soybean lecithin nanoemulsion (Cmax 394 ng/mL), because of an enhanced ß-carotene absorption.

Effect of the Emulsifier Used in Dunaliella salina-Based Nanoemulsions Formulation on the ß-Carotene Absorption and Metabolism in Rats.

SCOPE: Microalgae such as Dunaliella salina are a potential sustainable source of natural ß-carotene due to their fast growth and high adaptability to environmental conditions. This work aims to evaluate the effect of the incorporation of ß-carotene from this alga into different emulsifier-type nanoemulsions (soybean lecithin [SBL], whey protein isolate [WPI], sodium caseinate [SDC]) on its absorption, metabolization, and biodistribution in rats. METHODS AND RESULTS: Nanoemulsions formulated with different emulsifiers at 8% concentration are obtained by five cycles of microfluidization at 130 mPa, then expose to an in vitro digestion or orally administer to rats. Feeding rats with nanoemulsions improves ß-carotene uptake compared to control suspension, especially using SDC and WPI as emulsifiers. A greater presence of ß-carotene and retinol in the intestine, plasma, and liver is observed, being the liver the tissue that shows the highest accumulation. This fact can be a consequence of the smaller droplets that protein-nanoemulsions present compared to that with SBL in the intestine of rats, which promote faster digestibility and higher ß-carotene bioaccessibility (35%-50% more) according to the in vitro observations. CONCLUSIONS: Nanoemulsions, especially those formulated with protein emulsifiers, are effective systems for increasing ß-carotene absorption, as well as retinol concentration in different rat tissues.

Enhancing the Gastrointestinal Stability of Curcumin by Using Sodium Alginate-Based Nanoemulsions Containing Natural Emulsifiers.

Curcumin presents interesting biological activities but low chemical stability, so it has been incorporated into different emulsion-based systems in order to increase its bioaccessibility. Many strategies are being investigated to increase the stability of these systems. Among them, the use of polysaccharides has been seen to highly improve the emulsion stability but also to modulate their digestibility and the release of the encapsulated compounds. However, the effect of these polysaccharides on nanoemulsions depends on the presence of other components. Then, this work aimed to study the effect of alginate addition at different concentrations (0-1.5%) on the gastrointestinal fate and stability of curcumin-loaded nanoemulsions formulated using soybean lecithin or whey protein as emulsifiers. Results showed that, in the absence of polysaccharides, whey protein was more effective than lecithin in preventing curcumin degradation during digestion and its use also provided greater lipid digestibility and higher curcumin bioaccessibility. The addition of alginate, especially at ≥1%, greatly prevented curcumin degradation during digestion up to 23% and improved the stability of nanoemulsions over time. However, it reduced lipid digestibility and curcumin bioaccessibility. Our results provide relevant information on the use of alginate on different emulsifier-based nanoemulsions to act as carriers of curcumin.

Improving the In Vitro Bioaccessibility of ß-Carotene Using Pectin Added Nanoemulsions.

The intestinal absorption of lipophilic compounds such as ß-carotene has been reported to increase when they are incorporated in emulsion-based delivery systems. Moreover, the reduction of emulsions particle size and the addition of biopolymers in the systems seems to play an important role in the emulsion properties but also in their behavior under gastrointestinal conditions and the absorption of the encapsulated compound in the intestine. Hence, the present study aimed to evaluate the effect of pectin addition (0%, 1%, and 2%) on the physicochemical stability of oil-in-water nanoemulsions containing ß-carotene during 35 days at 4 °C, the oil digestibility and the compound bioaccessibility. The results showed that nanoemulsions presented greater stability and lower ß-carotene degradation over time in comparison with coarse emulsion, which was further reduced with the addition of pectin. Moreover, nanoemulsions presented a faster digestibility irrespective of the pectin concentration used and a higher ß-carotene bioaccessibility as the pectin concentration increased, being the maximum of ≈36% in nanoemulsion with 2% of pectin. These results highlight the potential of adding pectin to ß-carotene nanoemulsions to enhance their functionality by efficiently preventing the compound degradation and increasing the in vitro bioaccessibility.