Protecting HaCaT cells from ionizing radiation using persimmon tannin-Aloe gel composite.

Context: Persimmon tannin (extract of Diospyros kaki L.f [Ebenaceae]) and Aloe gel (extract of Aloe vera (L.) Burm.f. [Asphodelaceae]) are known as anti-radiation agents. However, radiation resistance of the persimmon tannin-Aloe gel composite remains inconclusive.Objective: To investigate the capacity of the persimmon tannin-Aloe gel composite to protect against ionising radiation at the cellular level.Materials and methods: HaCaT (human epidermal keratinocytes) cells were pre-treated with PT-A-1 (the mass ratio of persimmon tannin and Aloe gel was 2:1) or the single component (persimmon tannin or Aloe gel) at various concentrations (0, 50, 100, 200, 400, 800 µg/mL. Control group: medium with no HaCaT cells), and then radiated with X-rays (radiation dose: 4, 8, 12, 16, and 20 Gy). Cell viability, cell apoptosis, and radiation-induced intracellular reactive oxygen species (ROS) generation were analysed by CCK-8, Hoechst 33258 staining/flow cytometry, and 2',7'-dichlorfluorescein diacetate (DCFH-DA) assay, respectively, for 12 or 24 h incubation after radiation.Results: The optimal radiation dose and post-radiation incubation period were determined to be 8 Gy and 12 h. CCK-8 activity detection showed that the cell activity was 77.85% (p < 0.05, IC50 = 55.67 µg/mL). The apoptotic rate was the lowest (4.32%) at 200 µg/mL of PT-A-1 towards HaCaT cells. ROS production was the most effectively suppressed by 200 µg/mL PT-A-1 towards HaCaT cells.Discussion and conclusions: The persimmon tannin-Aloe gel composite has good radioprotective effect, and which will facilitate its clinic application as a potential natural anti-radiation agent in future.

Formulation optimization of chelerythrine loaded O-carboxymethylchitosan microspheres using response surface methodology.

The aims of this investigation were to develop a procedure to prepare chelerythrine (CHE) loaded O-carboxymethylchitosan (O-CMCS) microspheres by emulsion cross-linking method and optimize the process and formulation variables using response surface methodology (RSM) with a three-level, three-factor Box-Behnken design (BBD). The independent variables studied were O-CMCS/CHE ratio, O/W phase ratio, and O-CMCS concentration, dependent variables (responses) were drug loading content and encapsulation efficiency. Mathematical equations and response surface plots were used to relate the dependent and independent variables. The process and formulation variables were optimized to achieve maximum drug loading content and entrapment efficiency by the desirability function. The optimized microsphere formulation was characterized for particle size, shape, morphology and in vitro drug release. Results for mean particle size, drug loading content, entrapment efficiency, and in vitro drug release of CHE-loaded O-CMCS microspheres were found to be of 12.18 µm, 4.16 ± 3.36%, 57.40 ± 2.30%, and 54.5% at pH 7.4 after 70 h, respectively. The combination use of RSM, BBD and desirability function could provide a promising application for O-CMCS as controlled drug delivery carrier and help to develop procedures for a lab-scale microemulsion process.