TABLE 2.
Effects of tocotrienol on UV-damaged skin.
| Studies | Study design | Changes with tocotrienol |
|---|---|---|
| Pedrelli et al. (2012) | Subjects: 30 humans aged 27–70 with a clinical history of photosensitivity | ↓ Lesion, edema, itch, vesiculation |
| Treatment: Topical combination containing active agents, tocopherols (at concentration of 10%) and tocotrienols (at concentration of 0.3%) for 30 min. The areas were irradiated with a 2-fold MED | ↔ Erythema | |
| Weber et al. (1997) | Animals: Female hairless mice | ↑ α-tocotrienol, γ- tocotrienol after treatment |
| Treatment: 20 µl 5% TRF in polyethylene glycol-400 (PEG), 20 µl PEG for 2 h. Half of the sites were exposed to UV-irradiation | ↓ Total vitamin E after UV-irradiation | |
| ↑ Vitamin E in TRF-treated compared to non-irradiated control | ||
| Yamada et al. (2008) | Animals: 5-week-old female hairless mice (n = 32 and n = 36) | ↓ Sunburn in T-mix and T-mix + sesamin group |
| Treatment: Experimental diet 50 mg/kg α-tocopherol, 229 mg/kg T-mix, 229 mg/kg T-mix & 2 g/kg sesamin for 6 weeks. Half of the mice were exposed to UVB light once daily for 7 days | ||
| Traber et al. (1997) | Animals: Female hairless mice 8–12 weeks old | ↑ Tocotrienols in skin tissue |
| Treatment: Commercial chow diet containing α-tocopherol (30 ± 6 mg/kg, γ- tocopherol (10 ± 1 mg/kg diet), α-tocotrienol (3.1 ± 0.7 mg/kg diet), and γ-tocotrienol. 20 µl 5% TRF in polyethylene glycol-400 (PEG) for 2 h (Topical). The sites were exposed to UV-irradiation | ↓ Total vitamin E after UV-irradiation | |
| ↑ Vitamin E in TRF-treated compared to control | ||
| Brownlow et al. (2015) | Cells: Murine subcutaneous connective tissue fibroblasts | ↑ Cell viability after UVB exposure |
| Treatment: incubated for 24 and 48 h in non-emulsified propylenegycol based controls (Gen-PG and non-emulsified Tocomin-PG), empty vehicle and Gen-loaded prototype Tocomin NE | ↓ Cutaneous irritation potential (with cosurfactant TPGS and LF68) | |
| Shibata et al. (2010) | Cells: HaCaT cells were exposed to UVB | HaCaT cells: ↓ UVB-induced PGE2 (γ-T3), cyclooxgenase-2 (COX-2), interleukin (IL)-1β, IL-6, and monocyte chemotactic protein-1 |
| Treatment: cultured in test medium containing either γ-T3 or α-Toc for 2–24 h. UVB untreated cells were set as negative control | HR-1 hairless mice: ↓UVB-induced changes in skin thickness, COX-2 protein expression, and hyperplasia | |
| Animal: Female HR-1 hairless mice (10 weeks) | ||
| Treatment: divided into 4 groups: UVB-untreated/vehicle fed (Toc-stripped corn oil), UVB-irradiated/vehicle fed, UVB-irradiated/fed with 2.5 mg of α-Toc/day and UVB-irradiated/fed with 2.57 mg of RBT3 (0.09 mg of α-T3, 2.31 mg of γ-T3, 0.1 mg of δ-T3, 0.04 mg of γ-Toc, and 0.02 mg of δ-Toc)/day |
Abbreviation: ↑ increase, upregulate; ↓ decrease, inhibit or downregulate; ↔ no change; TRF, tocotrienol-rich fraction; UV-irradiation, ultraviolet-irradiation; UVB-induced PGE2, ultraviolet B-induced prostaglandin E2; COX-2, cyclooxygenase-2; IL-1β, interleukin-1β; IL-6, interleukin-6; RBT3, rice bran tocotrienol; α-Toc, alpha-tocopherol; α-T3, alpha-tocotrienol; γ-T3, gamma-tocotrienol; γ-Toc, gamma-tocopherol; δ-Toc, delta-tocopherol.