Incorporation of white tea extract in nano-liposomes: optimization, characterization, and stability

Herbal Extracts Encapsulated Nanoliposomes as Potential Glucose-lowering Agents: An in Vitro and in Vivo Approach Using Three Herbal Extracts

Encapsulation of polyphenol-rich herbal extracts into nanoliposomes is a promising strategy for the development of novel therapeutic agents against type 2 diabetes mellitus. An attempt was made to encapsulate aqueous, ethanol, and aqueous ethanol (70% v/v) extracts of Senna auriculata (L.) Roxb., Murraya koenigii (L.) Spreng,. and Coccinia grandis (L.) Voigt into nanoliposomes and to screen acute bioactivities in vitro and in vivo. A wide spectrum of bioactivity was observed of which aqueous extracts encapsulated nanoliposomes of all three plants showed high bioactivity in terms of in vivo glucose-lowering activity in high-fat diet-fed streptozotocin induced Wistar rats, compared to respective free extracts. The particle size, polydispersity index, and zeta potential of the aforementioned nanoliposomes ranged from 179-494 nm, 0.362-0.483, and (-22) to (-17) mV, respectively. The atomic force microscopy (AFM) imaging reflected that the nanoparticles have desired morphological characteristics and Fourier-transform infrared (FTIR) spectroscopy analysis revealed successful encapsulation of plant extracts into nanoparticles. However, only the S. auriculata aqueous extract encapsulated nanoliposome, despite the slow release (9% by 30 hours), showed significant (p < 0.05) in vitro α-glucosidase inhibitory activity and in vivo glucose-lowering activity compared to free extract, proving worthy for future investigations.

Liposomes Loaded with Green Tea Polyphenols-Optimization, Characterization, and Release Kinetics Under Conventional Heating and Pulsed Electric Fields

This study aimed to increase the encapsulation efficiency (EE%) of liposomes loaded with green tea polyphenols (GTP), by optimizing with response surface methodology (RSM), characterizing the obtained particles, and modeling their release under conventional heating and pulsed electric fields. GTP-loaded liposomes were prepared under conditions of Lecithin/Tween 80 (4:1, 1:1, and 1:4), cholesterol (0, 30, and 50%), and chitosan as coating (0, 0.05, and 0.1%). Particles were characterized by size, polydispersity index, ζ-potential, electrical conductivity, and optical microscopy. The release kinetics was modeled at a temperature of 60 °C and an electric field of 5.88 kV/cm. The optimal manufacturing conditions of GTP liposomes (ratio of lecithin/Tween 80 of 1:1, cholesterol 50%, and chitosan 0.1%) showed an EE% of 60.89% with a particle diameter of 513.75 nm, polydispersity index of 0.21, ζ-potential of 33.67 mV, and electrical conductivity of 0.14 mS/cm. Optical microscopy verified layering in the liposomes. The kinetic study revealed that the samples with chitosan were more stable to conventional heating, and those with higher cholesterol content were more stable to pulsed electric fields. However, in both treatments, the model with the best fit was the Peppas model. The results of the study allow us to give an indication of the knowledge of the behavior of liposomes under conditions of thermal and non-thermal treatments, helping the development of new functional ingredients based on liposomes for processed foods.

A comprehensive review of nano-delivery system for tea polyphenols: Construction, applications, and challenges

Tea polyphenols (TPs) are important bioactive compounds in tea and have excellent physiological regulation functions. However, the extraction and purification of TPs are key technologies affecting their further application, and the chemical instability, poor bioavailability of TPs are major challenges for researchers. In the past decade, therefore, research and development of advanced carrier systems for the delivery of TPs has been greatly promoted to improve their poor stability and poor bioavailability. In this review, the properties and function of TPs are introduced, and the recent advances in the extraction and purification technologies are systematically summarized. Particularly, the intelligent delivery of TPs via novel nano-carriers is critically reviewed, and the application of TPs nano-delivery system in medical field and food industry is also described. Finally, the main limitations, current challenges and future perspectives are highlighted in order to provide research ideas for exploiting nano-delivery carriers and their application in TPs.

Synthesis and application of near-infrared dyes based on sulfur-substituted dicyanomethylene-4H-chromene and diarylethene

Four novel compounds (S-DCM-1O, S-DCM-2O, S-DCM-3O, and S-DCM-4O) based on sulfur-substituted dicyanomethylene-4H-chromene (S-DCM) and diarylethene were synthesized. The detailed investigations on the fluorescence spectra, absorption spectra, time-dependent density functional theory...