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The major polyphenol components from Stevia rebaudiana (Bertoni) leaves (PPS) are chlorogenic acids, a polyphenol family of esters, including hydroxycinnamic acids with quinic acid, which possesses excellent hydrophilic antioxidant activity and other therapeutic properties. As an abundant byproduct during production of steviol glycosides, the PPS would be a new antioxidantive food resource or additives applied in foods and drugs with antidiabetic function. Extracting PPS from S. rebaudiana (Bertoni) leaves together with steviol glycosides would be an economic process, which will change most operation process in current Stevia factories. The quantification of PPS needs to be unified for regulation. In view of the current regulation status of polyphenols and extracts from Stevia, the PPS would be ready to go to the market with few regulation barriers in the near future. This review will summarize the analysis, extraction, and some functional properties of PPS, such as antioxidant, antidiabetic, antimicrobial, anti-inflammatory, and anticancer.

N and S co-doped carbon dots (N,S-CDs) synthesized from biomass can be used as multicolor probes for cell imaging. The N,S-CDs can selectively and sensitively detect Cr(vi) in real lake water, human serum and living cells.

Multicolor carbon dots (MCDs) have been receiving great attention because of their controllable fluorescence, which can be applied as novel optical sources. However, the preparation of MCDs is complex and the corresponding mechanism is still unclear. Here, using o-phenylenediamine and l-tryptophan as precursors, a facile one-step synthesis of MCDs (green, yellow, orange) is proposed through a reaction time engineering strategy. The structural and optical analyses combined with theoretical calculations are performed to disclose the synthetic and fluorescence mechanisms of MCDs. The result shows that increasing the reaction time improves the graphitization degree and surface states, making the emission wavelength red-shifted. In addition, the white-emissive CDs (w-CDs) are easily obtained using the same precursors. The structure and optical properties of w-CDs further confirm the importance of the graphitization degree and surface states in controlling the emissive color of CDs. Based on the optical properties, the MCDs are explored for water detection in organic solvents and multiple anticounterfeiting/information encryption. Moreover, multicolor light-emitting devices (LEDs) are successfully fabricated based on the MCD/PVP composition coated with 365 nm chips. In particular, high-performance white light-emitting devices (WLEDs) directly from w-CDs are obtained with Commission on Illumination (CIE) coordinates of (0.32 and 0.35) and a CRI of 87.2, similar to the standard w-LEDs.

With increasing health consciousness, Y 2 O 3 -based rare earth nanophosphors are considered as promising luminescent complexes for bio-applications. In the present study, an atmospheric pressure plasma-electrochemical technique is demonstrated for the synthesis of Eu 3 + /Tb 3 + single-doped or co-doped Y 2 O 3 nanophosphors from merely an aqueous solution of the corresponding rare earth nitrite salts. Systematic experiments were performed to prepare (Y 1-x-y Eu x Tb y ) 2 O 3 nanophosphors of various Tb 3 + and Eu 3 + ratios (x:y = 1:0, 2:1, 1:1, 1:2, and 0:1), with the ultimate goal to achieve the colour tunability by simply adjusting the dopant compositions. Results indicated successfulness synthesis of crystalline Eu/Tb single-doped and co-doped Y 2 O 3 nanophosphors with Tb 3 + and Eu 3 + ions being uniformly incorporated into the Y 2 O 3 host matrix. The generated products showed apparent downshift behaviour under ultraviolet irradiation, and characteristic spectral excitation and emission bands were detected by the photoluminescence measurement. Furthermore, by adjusting the relative composition ratios of the terbium and europium ions, the emission colours were shown to be regulated to a large extent. The demonstrated process can be characterized as simple, versatile and environmentally-friendly, featuring great flexibility in colour tunability, and therefore can present a considerable interest for emerging nanofabrication applications.

Botanic bioactive substances have issues with their solubility, stability, and oral bioavailability in the application, which could be improved by nanotechnologies. In another hands, green synthesis of nanoparticles (NPs) with plant extract is also a promising technology for preparation of NPs due to its safety advantage, yet the bioactive botanic substances that could be more than the assistant of the green synthesis of NPs. Based on the above concerns, this review summarized the preparation of botanic NPs with various plant extract, their solubility, stability, and oral bioavailability; specific attention has been paid to the botanic Ag/Au NPs, their capacity of antioxidant, bioavailability, antimicrobial, anti‐inflammatory, and anticancer.