Background: There are a substantial number of papers in the scientific literature reporting on the chemical composition of the Aloe vera plant. None of these investigations are truly comprehensive nor address the differences in composition that occur through processing variations in fresh leaves and commercially available product forms. Objectives: This work was to analytically examine a range of these forms and compile the findings. Methods: Fresh A. vera leaves and a number of commercial aloe juice powders were investigated for their major chemical constituents. Samples included fresh leaves from China and Mexico, plus commercial powders from different manufacturers made from different plant parts and/or manufacturing processes. The test results include moisture, ash, fiber, protein, lipids, minerals, organic acids, free sugars, and polysaccharides. The analytical methods employed comprise inductively coupled plasma-optical emission spectroscopy for minerals, high-performance anion-exchange chromatography equipped with pulsed amperometric detection for free sugars, HPLC for organic acids, and size exclusion chromatography (SEC)–multi-angle laser light scattering (MALS)–differential refractive index (dRI) for polysaccharide analyses. The absolute MW and MW distribution were determined using MALS measurement. Results: The major constituents of A. vera fresh leaf are fibers, proteins, organic acids, minerals, monosaccharides, and polysaccharides, which accounted for 85–95% of the total composition determined. In the commercial powdered aloe juice samples, four major components—organic acids, minerals, monosaccharides, and polysaccharides—accounted for 78–84% of the total composition. Apart from the four major components, products manufactured by ethanol precipitation contained high amounts of fiber and protein, while the free sugars were removed. In ethanol-precipitated products, the polysaccharide MW was less affected by manufacturing conditions and the concentration of aloe polysaccharides was higher than in products made in the nonethanol manufacturing processes. The overall chemical profiles were found to be consistent, except for the MW and content of polysaccharides in the commercial aloe samples analyzed, which were largely dependent on the types of manufacturing processes employed. Conclusions: This present study provides a comprehensive investigation of the major chemical composition of A. vera leaf and commercially derived products. The use of the SEC combined with MALS and differential RI detectors has proved to be an improved tool for the accurate determination of polysaccharide MW and contents of the various commercially available A. vera products in this study.
For in vivo extraction of trace and polar components in tissues, extraction materials should be biocompatible, highly permeable to matrix and have high extraction capacity for polar and ionic compounds. In this study, nanofibers (∼200 nm) with rough polyaniline (PAn) sheath were prepared successfully for the first time by coaxial electrospinning and coelectrospun polymer sacrificing method. The nanofibers (0.5 mg) were then compressed into tiny bar ( Φ 1 mm × 2 mm) and inserted directly into the aloe leaf for in vivo extraction of trace phytohormones. Due to the large surface area (13.97 m 2 /g) of nanofibers and large through pores formed between fibers, high extraction capacity (up to 10 μg/bar) and permeability to tissue matrix of the tiny bar can be obtained. Moreover, PAn sheath has high adsorption equilibrium constants (10 7 –10 8 mL/mol) for acidic phytohormones in aloe leaf. Four phytohormones were detected by in vivo extraction with a spatial resolution of 3–8 mm 3 , temporal resolution of 20 min, and limit of detection down to 60 pg/g. The quantification results were well met with that by traditional in vitro organic solvent extraction.
Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous aloe leaf extracts as both the reducing and capping agent. Transmission electron microscopy analysis revealed the average size of silver nanoparticles approximately 18.05 nm. Fourier transform infrared spectroscopy observation showed the estimation of two kinds of binding sites between aqueous aloe leaf and aqueous aloe leaf with silver nanoparticles. In addition, the critical roles of the concentration of silver nitrate, temperature, and reaction time in the formation of silver nanoparticles had been illustrated. Furthermore, silver nanoparticles were deposited on egg membrane bandage, forming a new egg membrane bandage that contained silver nanoparticles that exhibiting excellent antibacterial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus , which was 2.5 times stronger than the commercially available bandage.
危险品化学品经营许可证（带存储）