Chitosan-based Pickering emulsion: A comprehensive review on their stabilizers, bioavailability, applications and regulations

BACKGROUND

Chitosan-based particles are one of the most promising Pickering emulsions stabilizers due to its cationic properties, cost-effective, biocompatibility, biodegradability. However, there are currently no comprehensive reviews analyzing the role of chitosan to develop Pickering emulsions, and the bioavailability and multiple uses of these emulsions.

SCOPE AND APPROACH

This review firstly summarizes the types, preparation and functional properties of chitosan-based Pickering emulsion stabilizers, followed by in vivo and in vitro bioavailability, main regulations, and future application and trends.

KEY FINDINGS AND CONCLUSIONS

Stabilizers used in chitosan-based Pickering emulsions include 6 categories: chitosan self-aggregating particles and 5 types of composites (chitosan-protein, chitosan-polysaccharide, chitosan-fatty acid, chitosan-polyphenol, and chitosan-inorganic). Chitosan-based Pickering emulsions improved the bioavailability of different compounds compared to traditional emulsions. Current applications include hydrogels, microcapsules, food ingredients, bio-based films, cosmeceuticals, porous scaffolds, environmental protection agents, and interfacial catalysis systems. However, due to current limitations, more research and development are needed to be extensively explored to meet consumer demand, industrial manufacturing, and regulatory requirements. Thus, optimization of stabilizers, bioavailability studies, 3D4D printing, fat substitutes, and double emulsions are the main potential development trends or research gaps in the field which would contribute to increase adoption of these promising emulsions at industrial level.

Terpenes and terpenoids as main bioactive compounds of essential oils, their roles in human health and potential application as natural food preservatives

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Terpenes and terpenoids are the main bioactive compounds of essential oils (EOs).

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EOs and their major constituents confer several biological activities.

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EOs are potential as natural food preservatives.

Essential oils (EOs) are volatile and concentrated liquids extracted from different parts of plants. Bioactive compounds found in EOs, especially terpenes and terpenoids possess a wide range of biological activities including anticancer, antimicrobial, anti-inflammatory, antioxidant, and antiallergic. Available literature confirms that EOs exhibit antimicrobial and food preservative properties that are considered as a real potential application in food industry. Hence, the purpose of this review is to present an overview of current knowledge of EOs for application in pharmaceutical and medical industries as well as their potential as food preservatives in food industry.

Effect of innovative technology using staves and micro-oxygenation on the odorant and sensory profile of aged wine spirit

The aged wine spirit is a beverage with great aromatic complexity. Their volatile compounds with odorant power coming from the distillate and from the wood used in its ageing, and the interactions that take place in the process, enhanced by oxygen, all contribute to this complexity. Due to time and cost inherent of ageing wine spirits in wooden barrels, research has sought to develop more sustainable alternatives to do it. In this context, the present study compares, the effect of traditional (wooden barrel) and alternative system (stainless steel tank with dipped staves and micro-oxygenation), on the odorant and sensory profile of a wine spirit, using Limousin oak and chestnut wood, after 12 months of ageing. The results suggest that the ageing process is accelerated by the alternative ageing technology and the chestnut wood, and the corresponding wine spirits presented characteristics of greater sensory evolution and strong wood compounds extraction.

Essential oils of basil chemotypes: Major compounds, binary mixtures, and antioxidant activity

The antioxidant potential of the essential oils (EO) of 24 basil genotypes was assessed by 4 distinct in vitro evaluation methods. Different combinations of the major compounds found in the EO were also tested to identify those combinations responsible for the antioxidant activity of the volatile oils and verify the occurrence of synergism or antagonism between them. Results indicate that 9 EO exhibited promising antioxidant potential, with at least 52.68% of inhibition of the linoleic acid peroxidation at 10 µL/mL and 76.34% of inhibition of the DPPH radical at 1 µL/mL. The major compound eugenol had the highest antioxidant activity. The antioxidant activity of these EO cannot be explained solely by the presence of the major compounds. Despite the influence of eugenol, the antioxidant activity is also related to the synergism between other minor compounds found in the EO. This fact confers a potent antioxidant activity to some basil EO.

Determination of kinetic parameters of the enzymatic reaction between soybean peroxidase and natural antioxidants using chemometric tools

The oxidation of eugenol, isoeugenol and vanillin natural antioxidants catalyzed by the soybean peroxidase enzyme was studied using uv-vis spectroscopy. An experimental design was used to optimize the different variables. The multivariate curve resolution method was used to obtain the profiles of antioxidant absorbance's as a function of time due to uv-vis absorption bands of both antioxidants and the enzymatic reaction product/s show a strong overlap. From these results, apparent Michaelis-Menten constants as well as the kinetic parameters k1 and k3 involved in the catalytic cycle of peroxidases were calculated. The antioxidant apparent acidity constants were also determined at different pH's from uv-vis spectrophotometric measurements. Values of k1 were (0.6 ± 0.1) × 105 M-1 s-1, (2.0 ± 0.2) × 105 M-1 s-1 and (7.0 ± 0.5) × 106 M-1 s-1 and k3 (4.0 ± 0.2) × 105 M-1 s-1, (6.0 ± 0.6) × 105 M-1 s-1 and (6.0 ± 0.9) × 106 M-1 s-1 for eugenol, isoeugenol and vanillin, respectively.

Antimicrobial, antioxidant and sensory features of eugenol, carvacrol and trans-anethole in active packaging for organic ready-to-eat iceberg lettuce

In this study, bio-based emitting sachets containing eugenol (EUG), carvacrol (CAR) and trans-anethole (ANT) were inserted into cellulose (CE) and polypropylene (PP) pillow packages of organic ready-to-eat (RTE) iceberg lettuce to investigate their functional features. EUG, CAR and ANT sachets in CE; and CAR in PP packages showed antimicrobial activities against coliforms (Δlog CFU g-1 of -1.38, -0.91, -0.93 and -0.93, respectively). EUG and ANT sachets in both packages reduced discoloration (ΔE of 9.5, 1.8, 9.4 and 5.6, respectively). ANT in both, and EUG only in PP packages induced biosynthesis of caffeoyl derivatives (CaTA, DiCaTA, DiCaQA), total phenolics and antioxidant activity (FRAP). Also, ANT and EUG in both packages improved overall freshness and odor. Principal component analysis separated ANT and EUG from CAR in both packages. The Pearson correlation confirmed that overall quality improvements were more pronounced by ANT inside the packages in comparison to EUG and CAR.

A review of the traditional and modern uses of Salvadora persica L. (Miswak): Toothbrush tree of Prophet Muhammad

ETHNOPHARMACOLOGICAL RELEVANCE

Salvadora persica L., also known as Arak (in Arabic) and Peelu (in Urdu), is the most common traditional source of tooth or chewing stick (miswak) highly recommended by Prophet Muhammad. To date, extensive studies have probed primarily into the validation of its traditional uses in oral care. Nonetheless, there is still a dearth of updated compilation and critical analysis of other potential ethnopharmacological properties of S. persica. This review therefore aims to provide an up-to-date detailed structured description of the traditional uses of S. persica and a critical analysis of its modern uses, highlighting its phytochemistry, pharmacological properties, and bioapplications.

MATERIALS AND METHODS

Various databases (Science Direct, PubMed, Wiley Online Library, and Google Scholar), books, and relevant primary sources were probed, surveyed, analysed, and included in this review. The literature cited in this review dated from 1979 to 2017.

RESULTS

S. persica was found to possess a plethora of bioactive compounds and broad pharmacological properties, including antimicrobial, antioxidant, enzyme inhibitory activity, antiulcer, anticonvulsant, sedative, analgesic, anti-inflammatory, hypoglycemic, hypolipidemic, antiosteoporosis, and antitumor activities. Studies also revealed the potential use of S. persica as a natural food preservative and a novel functional food ingredient. In addition, improvement in growth and reproductive performances have been observed by the introduction of S. persica in animal feed. Lastly, S. persica has also been used in the green synthesis of nanoparticles showing potential biotechnological applications.

CONCLUSION

S. persica showed a wide scope of application and its uses have been extended far beyond the initial traditional uses of its roots, stems, and twigs in oral care. We found a number of other ethnopharmacological uses and potential bioapplications of different parts of S. persica that warrants further investigations. Though widely studied using several in vitro and in vivo models, and tested clinically for oral hygiene mainly, several gaps and research priorities have been identified which needs to be addressed in future.

Effects of clove essential oil and eugenol on quality and browning control of fresh-cut lettuce

This study confirmed the inhibitory effects of clove essential oil (CEO) and eugenol (EUG) on the browning and relevant enzymes of fresh-cut lettuce, and examined associated mechanisms by inhibition kinetics and computational docking analysis. Fresh-cut lettuce was treated with 0.05% CEO and 0.05% EUG solutions, resulting in inhibition of the deterioration of texture quality and browning of the lettuce surface and interior. Compared with the controls, CEO and EUG significantly inhibited the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD, all p<0.05). EUG suppressed PAL, PPO, and POD in vitro in a dose-dependent manner, with IC50 values of 5.4±0.9, 29.5±3.5, and 61.9±6.7mM, respectively. The binding and inhibition effects of EUG on PAL, PPO, and POD, determined by inhibition kinetics and computational docking analysis, established EUG as a competitive inhibitor of these browning-relevant enzymes.

Ethnobotanical investigations on plants used in folk medicine in the regions of Constantine and Mila (North-East of Algeria)

ETHNO-PHARMACOLOGICAL RELEVANCE

Constantine and Mila regions have been investigated in an ethnobotanical study for the first time. A total of 102 medicinal plants have been cited to treat human ailments. Twenty-eight new species of 31 common plants with 151 new therapeutic applications and 12 new cited species including one endemic specie Zygophyllum cornutum Coss were found as compared to other Algerian regions. In addition, to the best of our knowledge, 369 new medicinal uses of 75 known plants, were reported for the first time in the Mediterranean basin.

AIM OF THE STUDY

This study is aimed at contributing to safeguard world cultural heritage and document ethnomedicinal uses of plants in Algeria and the Mediterranean basin; data on the national and global uses in the world were obtained to extract new potential species for further phytochemical and clinical investigations.

MATERIALS AND METHODS

The survey was carried out in two cities in the northeast of Algeria: Constantine and Mila. It was based on semi-structured interviews of 79 local informants. Data were analyzed using quantitative indices, namely, informant consensus factor, fidelity level (FL), use value (UV), and relative frequency citation (RFC), to evaluate the reliability and richness of herbal knowledge in the region.

RESULTS

The interviewed persons used 102 plant species belonging to 90 genera and distributed among 53 families, represented mainly by Lamiaceae, Apiaceae, and Asteraceae (30%, 13%, and 10%, respectively), which were used to treat 14 ailment categories. The category of most frequent ailments (16%) was digestive disorders (diarrhea, constipation, and stomach bloating). The highest RFC was found for Origanum glandulosum Desf. With regard to the fidelity level, a higher FL was found for Tilia cordata Mill. (100%), followed by Artemisia herba alba Asso. with an FL of 95.74% and Punica granatum L. with an FL of 93.09%) to treat gastrointestinal system diseases, and Aloe sp. L. with an FL of 96.67% for skin diseases. The highest UV was found for Origanum glandulosum Desf. (2.280). Moreover, new medicinal uses were recorded for the first time in Algeria and Mediterranean regions.

CONCLUSION

The present study has highlighted the rich herbal knowledge about newfound medicinal plants and their new uses in the Mediterranean region, which could be useful not only in facilitating other studies such as phytochemical and pharmacological investigations and upgrading the sources of biomolecules beneficial to people but also in reopening discussion on pharmacovigilance in herbal medicine as an imperative requirement for local authorities.

Intra-laboratory study to determine the reproducibility of LLNA:BrdU-ELISA for the prediction of the skin sensitizing potential of chemicals

INTRODUCTION

The Local Lymph Node Assay (LLNA) has been designated as the first-choice in vivo assay for identification the skin sensitization potential of new chemicals. The LLNA:BrdU-ELISA is a validated non-radioactive modification to the LLNA. An intra-laboratory reproducibility study for the LLNA:BrdU-ELISA was conducted to demonstrate its adequate performance in our laboratory.

METHODS

Ten independent LLNA:BrdU-ELISAs with the preferred positive controls (PCs), i.e., 25% hexyl cinnamic aldehyde (HCA) and 25% eugenol, were conducted within a period of less than one year. In addition, different concentrations of 2,4-dinitrochlorobenzene (DNCB, an extreme sensitizer) (0.01, 0.1 and 0.3%), HCA (10, 25 and 50%) and eugenol (10, 25 and 50%), were tested to determine the EC1.6 values. Special Pathogen Free female CBA/J mice of 8-10weeks old were randomly allocated to the groups, each group having 4 mice. 25μl of AOO (vehicle, acetone: olive oil=4:1, v/v) or HCA, eugenol, DNCB at the needed concentration was applied to the dorsum of each ear of the mice, daily for 3 consecutive days. A single intraperitoneal injection of 0.5ml of BrdU solution (10mg/ml) was given on day 5. On day 6, a pair of auricular lymph nodes from each mouse was excised, and BrdU ELISA analysis was conducted.

RESULTS

The result for each group is expressed as the mean Stimulation Index (SI). The mean of the 10 mean SIs for 25% HCA (2.58±0.95) and 25% eugenol (3.51±1.25) was not significantly different to that from the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) (i.e., the data on the formal validation study for the LLNA:BrdU-ELISA by the ICCVAM) (3.03±2.00 for 25% HCA, 6.13±6.06 for 25% eugenol) (P>0.05), with even smaller Coefficient of Variations (CV) (36.8% for 25% HCA, 35.6% for 25% eugenol) than that from the ICCVAM (66.0% for 25% HCA, 98.8% for 25% eugenol). In addition, the EC1.6 values for HCA, eugenol and DNCB (15.2, 12.5 and 0.25%, respectively) were consistent with that from the ICCVAM (12.92, 8.85 and 0.34%, respectively).

DISCUSSION

The results indicate that the reliability for our laboratory to conduct the LLNA:BrdU-ELISA is successfully determined.

Synergism between carvacrol or thymol increases the antimicrobial efficacy of soy sauce with no sensory impact

Here, we examined the antimicrobial effects of soy sauce containing essential oils (EOs) against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes at 22°C and 4°C. To screen a variety of combined effects, soy sauce was mixed with six different EOs (carvacrol, thymol, eugenol, trans-cinnamaldehyde, β-resorcylic acid, and vanillin), each at a concentration of 1mM for 10 min. None of the oils showed bactericidal activity when used alone. Soy sauce combined with carvacrol and thymol induced the greatest antibacterial activity against all tested bacteria; therefore, these oils were further tested at 0.25, 0.5, and 1mM (0.0039%, 0.0078%, and 0.0157%) for 1, 5, and 10 min at 4°C and 22°C. In addition, sensory evaluation of soy sauce containing each EO at 0.25, 0.5, 1, and 2mM was performed using the nine point hedonic test. Carvacrol or thymol (1mM) eliminated all the test bacteria (initial population, 7.0-7.5logCFU/ml) in 1-5 min at 22°C and within 10 min at 4°C. L. monocytogenes was slightly more tolerant at 4°C, which may be attributable to the ability of the cell membrane to adapt to low temperatures. The sensory scores for soy sauce containing EOs were not significantly different from that of soy sauce without EOs (P>0.05). The stability of EO efficacy in soy sauce was also verified. These results suggest that carvacrol and thymol act synergistically with other factors present in soy sauce to increase antimicrobial activity against major foodborne pathogens at both 4°C and 22°C. The synergism may be attributable to the combination of factors (mainly high salt concentration and low pH imparted by organic acids) present in soy sauce and the membrane attacking properties of carvacrol and thymol. This method will facilitate the production of microbiologically safe soy sauce, soy sauce-based marinades, and various marinated foods.

Free radicals quenching potential, protective properties against oxidative mediated ion toxicity and HPLC phenolic profile of a Cameroonian spice: Piper guineensis

Considerations on antioxidants derived from plants have continuously increased during this decade because of their beneficial effects on human health. In the present study we investigated the free radical scavenging properties of extracts from Piper guineense (P. guineense) and their inhibitory potentials against oxidative mediated ion toxicity. The free radical quenching properties of the extracts against [1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS•), hydroxyl radical (HO•), nitric oxide (NO•)] radical and their antioxidant potentials by FRAP and phosphomolybdenum were determined as well as their protective properties on liver enzymes. The phenolic profile was also investigated by HPLC. The results obtained, revealed that the extracts significantly inhibited the DPPH, NO, HO and ABTS radicals in a concentration depending manner. They also showed a significant ferrous ion chelating ability through FRAP and phosphomolybdenum antioxidant potential. Their polyphenol contents varied depending on the type of extracts and the solvent used. The hydroethanolic extracts (FFH) and the ethanolic extracts (FFE) of P. guineense leaves showed the higher level of phenolic compounds respectively of 21.62 ± 0.06 mg caffeic acid/g dried extract (CAE/g DE) and 19.01 ± 0.03 CAE/g DE. The HPLC phenolic compounds profile revealed a higher quantity of Eugenol, quercetin, rutin and catechin in the stem than in the leaves. The presence of these molecules could be responsible of the protective potentials of P. guineense extracts against lipid peroxidation and SOD, catalase and peroxidase. In conclusion, P. guineense extracts demonstrated significant antioxidant property and may be used as a prospective protector against metal related toxicity.