Aloin a

Aloin A, aloin B, aloe emodin, emodin, and danthron were purchased from Sigma-Aldrich (Milan, Italy). LC-grade acetonitrile, formic acid, and methanol were obtained from Merck KGaA (Darmstadt, Germany). Ultrapure water (18.2 MΩ·cm) was produced using a Milli-Q water purification system from Millipore (Milford, MA, USA). Dry Cassia senna L. leaf and fruit extracts (dry extracts A–C), tablets containing extracts of C. senna L. and Aloe, and liquid products (Aloe juices A–C and hydroalcoholic solutions in the form of oral spray and single-dose bottles) with Aloe and C. senna L. were obtained from external companies. The latter were used to assess the robustness (i.e., the capacity to remain unaffected by small, deliberate variations in method parameters) and sensitivity of the analytical method.

Aloin A and Aloein A (phyproof^® Reference Substance) were obtained from Sigma-Aldrich (Poznan, Poland), as well as all reagents for activity assays: (Sigma-Aldrich). 2,2-Diphenyl-1-picrylhydrazyl (DPPH), neocuproine, acetate buffer, copper(II) chloride (CuCl₂·H₂O), kaempferol, sodium chloride, bovine serum albumin, hexadecyltrimethylammonium bromide (CTAB), hyaluronic acid (HA), hyaluronidase, sodium hydroxide, tyrosinase, L-DOPA, hydroquinone, Tris-HCl buffer, galantamine, acetylocholinesterase (AChE) and butyrylcholinesterase (BChE), 5,5-dithio-bis-(2-nitrobenzoic acid (DTNB), and phosphate buffer. The hydration solution and acceptor Prisma™ buffer were obtained from Pion Inc. (Billerica, MA, USA), whereas HPLC grade methanol and water were obtained from Merck. High-quality pure water and ultra-high quality pure water were prepared using a Direct-Q 3 UV Merck Millipore purification system.

The aloin A content of UP and UV-C irradiated samples was determined by high resolution liquid chromatography (UHPLC) according to Bozzi et al. [23 (link)], with some modifications. A Thermo Scientific Dionex Ultimate 300 (Sunnyvale, CA, USA) equipped with a quaternary pump, autosampler, and diode array detector (DAD) model ProStar 410 (Varian, Palo Alto, CA) was used. Samples were filtered through 0.45 µm nylon filters. The separation was performed by adding 0.1% v/v acetic acid to the mobile phase. The injection volume was 25 µL, the flow rate was 1.0 mL/min at 50 °C and a column AcclaimTM 120-C18 (120 Å, 4.6 × 150 mm) and a wavelength of 297 nm were used. High-purity aloin A (Sigma-Aldrich, St. Louis, MO, USA) was applied as the standard. aloin A contents were presented as the mean of triplicate analyses with standard deviation and expressed as mg/L of blend.