Incorporation of Different Metal Ion for Tuning Color and Enhancing Antioxidant Activity of Curcumin/Palygorskite Hybrid Materials

Development of konjac glucomannan-based active-intelligent emulsion films loaded with different curcumin-metal chelates: Stability, antioxidant, fresh-keeping and freshness detection properties

The aim of this study was to develop konjac glucomannan (KGM)-based active-intelligent emulsion films loaded with different curcumin-metal chelates, where six types of films were prepared and their corresponding properties were investigated. The FTIR and XRD results showed that curcumin chelated with metal ions successfully. Moreover, curcumin-Ca chelate had the best thermal stability and antioxidant activity with the DPPH and ABTS radical-scavenging activity values of 38.28 % and 22.79 %, respectively. Furthermore, the results of microstructure and contact angle showed that chelation with metal ions improved the interfacial interactions between curcumin-metal chelates and film matrix. Interestingly, KGM-based active-intelligent emulsion films loaded with curcumin-Ca chelate (Type IV film) displayed the best thermal stability with the highest temperature of maximum weight loss at 380 °C, the best mechanical property, the highest total phenol content (17.31 mg gallic acid/g film), as well as the best antioxidant activity with DPPH and ABTS radical-scavenging activity values of 69.24 % and 58.66 %, respectively, and the best antibacterial activity. Consequently, Type IV film was used for the fresh-keeping and freshness detection of pork. The results showed that the pork packaged with Type IV film displayed excellent fresh-keeping properties, including reducing the increase rate of volatile basic nitrogen (TVB-N) and pH values and the decrease rate of hardness and elasticity of pork during storage time. Meanwhile, the color of Type IV film gradually changed from yellow to red. Therefore, this study suggested that KGM-based active-intelligent emulsion films have great potential application in the fresh-keeping and freshness detection of fresh meat.

An Effective Method to Prepare Curcumin-Loaded Soy Protein Isolate Nanoparticles Co-Stabilized by Carrageenan and Fucoidan

In this study, a novel and simple strategy is proposed based on 3D network formed by easily blending polysaccharide carrageenan (Car) and fucoidan (Fuc) without a crosslinker. The Fuc/Car dual coating effectively assists the self-assembly of soy protein-isolated (SPI)/curcumin (Cur, C) composite microcapsules (SPI/C) and achieves an excellent curcumin encapsulation efficiency (EE) up to 95.28% with a 4.16% loading capacity (LC) under optimal conditions. The resulting nanocomposites achieved a satisfying redispersibility in aqueous solution and enhanced the water solubility with a lower size dispersity index (PDI) of 0.12 and a larger zeta potential of -29.67 mV. The Fuc/Car double-layer network not only dramatically improved its thermal stability and photostability, but also provided controlled release and enhanced antioxidant activity in in vitro conditions. The underlying mechanism of the self-assembly of the curcumin-loaded nanoparticles was also addressed. The results proved the feasibility of the encapsulation of unstable hydrophobic bioactive substances (curcumin) with the dual anionic polysaccharide Fuc/Car co-stabilized SPI nanoparticles. This study paves the way for an alternative way of developing novel curcumin delivery systems and will have broad prospects in the pharmaceutical industries.

Enemies or Allies? Hormetic and Apparent Non-Dose-Dependent Effects of Natural Bioactive Antioxidants in the Treatment of Inflammation

This review aims to analyze the emerging number of studies on biological media that describe the unexpected effects of different natural bioactive antioxidants. Hormetic effects, with a biphasic response depending on the dose, or activities that are apparently non-dose-dependent, have been described for compounds such as resveratrol, curcumin, ferulic acid or linoleic acid, among others. The analysis of the reported studies confirms the incidence of these types of effects, which should be taken into account by researchers, discarding initial interpretations of imprecise methodologies or measurements. The incidence of these types of effects should enhance research into the different mechanisms of action, particularly those studied in the field of basic research, that will help us understand the causes of these unusual behaviors, depending on the dose, such as the inactivation of the signaling pathways of the immune defense system. Antioxidative and anti-inflammatory activities in biological media should be addressed in ways that go beyond a mere statistical approach. In this work, some of the research pathways that may explain the understanding of these activities are revised, paying special attention to the ability of the selected bioactive compounds (curcumin, resveratrol, ferulic acid and linoleic acid) to form metal complexes and the activity of these complexes in biological media.

Fibrous Clays in Dermopharmaceutical and Cosmetic Applications: Traditional and Emerging Perspectives

Functionalization of natural clay minerals for high value-added pharmaceutical and cosmetic applications receives significant research attention worldwide attributable to a rising demand and ongoing search for green, efficient, economically sustainable and ecofriendly geomaterials. Fibrous clays, i.e. palygorskite and sepiolite, are naturally-occurring hydrated magnesium aluminum silicate clay minerals with 2:1 layer-chain microstructure and one-dimensional nanofibrous morphology. Due to their unique structural, textural and compatibility features, over the past decade, fibrous clays and their organic modified derivatives are increasingly used in the dermopharmaceutical and cosmetic fields as excipients, active agents or nanocarriers to develop novel skin delivery systems or to modify drug release profile for enhanced health effects. This comprehensive review presents the up-to-date information on fibrous clays used in topically-applied products for therapeutic and cosmetic purposes with the focus on their performance-related structural characteristics and the underlying mechanisms. The recent advancement of fibrous clay-based skin delivery systems was summarized in wide range of applications including pelotherapy, wound healing, antimicrobial action, coloration and UV protection. An overview of the commonly used topically-applied dosage forms (powders, hydrogels, films, peloids and Pickering emulsion) as well as the toxicological aspects was also included, which might provide guidance to the design and development of fibrous clay-based skin delivery systems.