Fabrication, characterization, and bioactivity of self-assembled carrier-free colloidal dispersions from Citrus × Limon 'Rosso' essential oil and tea polyphenols.

Carrier-free nanodelivery systems are fully self-assembled from active ingredients through interactions, offering the advantages of green, safe, and large-scale manufacturing. To improve the dispersion of Citrus × limon 'Rosso' peel essential oil (CEO) in water and boost the biological activity of CEO and tea polyphenols (TP), self-assembled CEO-TP colloidal dispersions (CEO-TP Colloids) were fabricated through sonication without surfactants or carriers. The optimal CEO and TP concentrations in the CEO-TP Colloids were determined to be 10.0 and 20.0 mg/mL by particle size and stability analyzer, respectively. The CEO self-assembled with TP to form spherical nanoparticles through hydrophobic and hydrogen-bonding interactions, whereas the CEO in CEO-TP Colloids weakened TP intramolecular aggregation. Meanwhile, the CEO-TP Colloids showed synergistic effects with better antibacterial, cellular antioxidant, and anti-inflammatory activities than single components. This study opens up the possibility of carrier-free co-delivery of hydrophobic and hydrophilic active components developed into food-grade formulations with multiple bioactivities.

A highly efficient nanoscale tapioca starch prepared by high-speed jet for Cu2+ removal in simulated industrial effluent.

BACKGROUND: Nanoscale tapioca starch (NTS) was successfully developed by high-speed jet in our previous study. In this study, the adsorption capacity of Cu2+ onto NTS was further discussed. The optimal adsorption conditions (pH, contact time, contact temperature, initial Cu2+ concentration, and adsorbent concentration), adsorption kinetics, isotherms, and thermodynamic were also evaluated. RESULTS: The results showed that NTS exhibited excellent performance in adsorption of Cu2+ , with adsorption capacities of 122.31 mg g-1 for Cu2+ (pH 7, 0.04 g L-1 , 0.2 g L-1 , 313.15 K and 10 min). The pseudo-second-order and Langmuir isotherms models could be used to explain the adsorption kinetics and adsorption equilibrium, respectively. The thermodynamic results showed that the adsorption process was spontaneous and endothermic with an increase in entropy. Cu2+ was adsorbed onto NTS, which was confirmed by energy dispersive spectrometry analysis. CONCLUSION: These findings indicated that NTS might be an effective, environment-friendly and renewable bio-resource adsorbent for removing heavy metals in industrial effluent. © 2021 Society of Chemical Industry.

Chemical composition and evaluation of antioxidant activities, antimicrobial, and anti-melanogenesis effect of the essential oils extracted from Dalbergia pinnata (Lour.) Prain.

ETHNOPHARMACOLOGICAL RELEVANCE: Dalbergia pinnata (Lour.) Prain (D. pinnata) is a plant widely distributed in tropical and subtropical regions of Asia, Africa, and the Americas. In humans, it is used in the prevention and treatment of diseases such as respiratory system, digestive system, cardiovascular and cerebrovascular diseases. AIM OF THE STUDY: This study was aim to evaluate chemical composition, antioxidant activities, antimicrobial, and anti-melanogenesis properties of Essential oils (EO) from D. pinnata. MATERIALS AND METHODS: In this paper, the EO of D. pinnata were extracted using the supercritical CO2 extraction method and purified by molecular distillation. The volatile compounds of EO were characterized using Gas Chromatography-Mass Spectrometer (GC-MS). The antioxidant activities were evaluated by the methods of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays. And two Gram-positive bacteria, three Gram-negative bacteria and a fungus were employed to evaluate the antimicrobial activity. The zebrafish was used as experimental model to evaluate the anti-melanogenesis effect of the EO from D. pinnata. RESULTS: The EO of D. pinnata were obtained in a yield of 4.75% (v/w) calculated on dry weight basis. 14 volatile compounds could be detected and the predominant components include elemicin (91.06%), methyl eugenol (3.69%), 4-allyl-2,6-dimethoxyphenol (1.16%), and whiskey lactone (0.55%). The antioxidant assay showed that the EO could scavenge DPPH (IC50 values of 0.038 mg/mL) and ABTS (IC50 value of 0.032 mg/mL) free radical, indicating that the EO had strong antioxidant activity. The results of antimicrobial test showed that Staphylococcus aureus was most sensitive to EO with minimal inhibitory concentration (MIC) of 0.78 µL/mL, followed by Streptococcus pyogenes (6.25 µL/mL) and Candida albicans (12.5 µL/mL). Gram-negative strains, including Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium, were slightly affected by the EO. Additionally, EO from D. pinnata could reduce tyrosinase activity and melanin synthesis of zebrafish embryos in dose-dependent manner. And EO exhibited the more obvious anti-melanogenic effect compared with the positive control arbutin at the same dose (30 mg/L). CONCLUSIONS: Our results validated the main activities attributed to D. pinnata for its antimicrobial and antioxidant. In addition, the potent inhibitory impacts of EO on the pigmentation provides a theoretical basis for the in-depth study of the EO from D. pinnata and their application in pharmaceutical and cosmetic industries.

Effects of temperature on cellulose hydrogen bonds during dissolution in ionic liquid.

Ionic liquids have been powerful solvents for cellulose. Mechanistic investigations of the dissolution processes have been extensively studied. In this paper, an experimental study has revealed that temperature also comes into play in cellulose dissolution. The supramolecular stuctrure of cellulose has been measured by X-ray diffraction, Fourier transform infrared spectroscopy, Solid-state CP/MAS 13C NMR, X-ray photoelectron spectroscopy and Gel permeation chromatography analysis, and the effects of temperature on hydrogen bonds of cellulose in ILs were investigated. These results indicated that hydrogen bonds of cellulose might be cracked by different ways at different temperature: The disruption of intramolecular hydrogen bonds (O(3) H-O (5)) could promote the dissolution process at lower temperature. And the disruption of intramolecular hydrogen bonds (O(2) H-O (6)) might be responsible for cellulose dissolution at higher temperature. It was suggested that higher dissolving temperature might be a way to avoid cellulose degradation with a high cellulose yield.

[Analysis of soluble Ca content in banana pulp based on pretreatment of digestion model in vitro].

In the present paper, soluble Ca content in banana pulp was analyzed with pretreatment of digestion model in vitro. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio) and determined by AA700 flame atomic absorption spectrophotometry (FAAS). Meanwhile, the reproducibility of the analytical method was investigated. The results showed that (1) Content of Ca was 1.479 mg x g(-1) x DW in eighty percent maturity banana pulp. And the relative standard deviation was 4.12%. (2) Contents of Ca in the soluble and insoluble fractions were 1.108 and 0.412 mg x g(-1) x DW, respectively in eighty percent maturity banana pulp with pretreatment of digestion model in vitro. The extraction rate was 74.9% and the residue rate was 27.8%. (3) The relative standard deviations of the analytical results of Ca contents in those two fractions were 2.56% and 9.10%, respectively, in the reproducibility tests. It was showed that the digestion model in vitro did not affect the reproduction quality significantly. Moreover, the deviation between the theoretical value and the summation value of the extraction and the residue rates was only 2.7%, which showed good availability of the digestion model in vitro to be used as a pretreatment method in mineral element analysis process. (4) Relative standard deviation and recovery yield in the determination procedure were 0.11% (n = 9) and 99.2%, respectively.