Table 1.
Main characteristics and key ingredients of different red raspberry seed oils (ROs) as the main components of the low-energy nanoemulsion oil phase.
Table 2.
Final composition (wt%) of the RO2-loaded gel-like phases and low-energy nanoemulsions investigated in the formulation studies.
Fig 1.
PTPD study of different red raspberry seed oils (RO1 – RO4)/ Polysorbate 80/ ultra-purified water (80 wt%) systems with the visual appearance of low-energy nanoemulsions (LE-NEs), microemulsions (MEs) and the characteristic transient LC phases.
The numbers representing the LC phases are: (3) semi-transparent, semi-solid isotropic LC gel-like phase, (4) transparent, semi-solid anisotropic LC gel-like phase, (5A, 5B) turbid, liquid, anisotropic LC phase, (6) semi-transparent, liquid, anisotropic LC phase. The numbers representing liquid emulsions are: (1) W/O transparent emulsion, (2) opalescent or turbid W/O emulsion, (7) milky white, liquid O/W emulsion, (8) semi-transparent, liquid O/W emulsion, (9) low viscosity, milky white O/W LE-NE, (10) low viscosity, transparent or slightly opalescent O/W LE-NE, (11) low viscosity, transparent O/W MEs of red raspberry seed oil.
Table 3.
Visual appearance of the SO mixtures and the main characteristics of the resulting low-energy nanoemulsions/microemulsions prepared with different red raspberry seed oils (RO1 – RO4) during the PTPD study of RO/P80/Water system.
Fig 2.
The influence of Tocopheryl acetate concentration (TA wt%), on mean droplet size (Z-average size) and mean polydispersity index of RO-loaded low-energy nanoemulsions, 24 h after preparation.
Fig 3.
A. Raman spectra of different red raspberry seed oils (ROs): RO1 –cold-pressed, refined, non-organic oil; RO2 –cold-pressed, unrefined, organic oil; RO3 –CO2-extracted, unrefined, non-organic oil; RO4 –CO2-extracted, unrefined, organic oil. B. The intensity ratios of the bands due to stretch deformation vibration in = C-H and band of in-phase methylene twisting (I 1266/I 1305) in the Raman spectra of different red raspberry seed oils. C. The intensity ratios of the bands of C = C to C = O stretch (I1659/ I1749) in the Raman spectra of different red raspberry seed oils. D. Raman spectra of P80, glycerol and LE-NEs prepared with different ROs 48 h after preparation (LE-NE composition: P80 10 wt%, RO1/RO2/RO3/RO4 9 wt%, tocopheryl acetate 1 wt%, glycerol 8 wt%, water 72 wt%).
Fig 4.
Optical microscopy study of LE-NEs prepared with RO2 –the cold-pressed, organic, unrefined seed oil: (A-D) after 7 days of storage at room temperature (RT); (E-H) after 45 days of storage at RT. All micrographs were taken at 400x magnification.
Table 4.
Physicochemical stability of the selected RO2-loaded LE-Nes.
Fig 5.
Atomic force microscopy of a representative stable LE-NE formulation (F1) prepared with RO2 –the cold-pressed, organic, unrefined red raspberry seed oil: (A) 2D error signal, (B) 2D topography, (C) 3D topography. The micrographs were taken 7 days after preparation.
Fig 6.
Electrical conductivity curves as a function of water phase content (wt%) along the PIC LE-NE formation pathway (of formulations F1−F4), or in a binary mixture (sample F control − P80/ 10 v/v% glycerol aqueous solution).
Fig 7.
Oscillatory rheological measurements of the gel-like phases: (A) complex viscosity as a function of frequency; (B) G'–elastic modulus (filled symbols) and G''− viscous modulus (empty symbols) as a function of frequency; Textural analysis of the gel-like phases: (C) Firmness (g), (D) Consistency (g*sec).
Table 5.
Flow characteristics of the selected RO2-loaded low-energy nanoemulsions: K-index and n-index 7 days after preparation.
Table 6.
Antioxidant activity of low-energy nanoemulsions and raw materials used in this study: ABTS assay in PCS buffer, and DPPH assay in methanol.
Fig 8.
Safety assessment by MTT test: (A) Effect of the raw materials and the LE-NE formulations on MRC-5 cell line, (B) Effect of the placebo NE on MRC-5 cells. Obtained data show cell viability % depending on the sample concentration. Each experiment was repeated three times and the results were presented as the mean value ± SD.
Fig 9.
Anti-proliferative effect on HeLa cells by MTT test: (A) Effect of the raw materials and the LE-NE formulations on HeLa cell line, (B) Effect of the placebo NE on HeLa cells. Obtained data show cell viability % depending on the sample concentration. Each experiment was repeated three times and the results were presented as the mean value ± SD.
Table 7.
MTT assay results: Concentrations of red raspberry seed oil or red raspberry seed oil with the addition of RE/ FE extract applied in the form of nanoemulsions that induced 50% decrease in the cell survival (IC50).