Topical treatment with coenzyme Q10-containing formulas improves skin's Q10 level and provides antioxidative effects

Abstract

Ubiquinone (coenzyme Q10, Q10) represents an endogenously synthesized lipid-soluble antioxidant which is crucial for cellular energy production but is diminished with age and under the influence of external stress factors in human skin. Here, it is shown that topical Q10 treatment is beneficial with regard to effective Q10 replenishment, augmentation of cellular energy metabolism, and antioxidant effects. Application of Q10-containing formulas significantly increased the levels of this quinone on the skin surface. In the deeper layers of the epidermis the ubiquinone level was significantly augmented indicating effective supplementation. Concurrent elevation of ubiquinol levels suggested metabolic transformation of ubiquinone resulting from increased energy metabolism. Incubation of cultured human keratinocytes with Q10 concentrations equivalent to treated skin showed a significant augmentation of energy metabolism. Moreover, the results demonstrated that stressed skin benefits from the topical Q10 treatment by reduction of free radicals and an increase in antioxidant capacity.

Keywords: antioxidant; coenzyme Q10; energy metabolism; mitochondrial activity; skin; skin aging; topical Q10 treatment.

Figure 1

Schematic illustration of collection of skin samples (not shown to scale). Samples from the skin surface (I) were obtained using adhesive sampling discs (D‐Squames^®). After raising suction blisters, the blister fluid (II) was collected using a sterile syringe. In the last step, suction blister epidermis (III) was harvested using sterile forceps and scissors (III).

Figure 2

Age‐dependent decline of quinone levels within human epidermis. Quinone concentrations of young (20–25 years; n = 28) and aged (60–66 years; n = 28) volunteers measured in suction blister epidermis obtained from untreated forearm skin. Data are depicted as mean ± SEM. Significant differences are marked with an asterisk [*P < 0.05 for comparison between young and aged subjects (Student's t‐test)].

Figure 3

Increase in quinone levels after treatment with Q10‐containing formulas. Following a 14‐day treatment with Q10‐containing formulas 1 and 2, quinone levels were assessed on the skin surface using samples obtained from D‐Squames^® (A) and within the epidermis using suction blister material (B). Results are shown as mean ± SEM (20–66 years; n = 73). Significant differences are marked with an asterisk [*P < 0.05 with respect to the untreated control (repeated measures analysis of variance, Dunnett's post hoc test)].

Figure 4

Increase in ubiquinone and ubiquinol content within the epidermis after treatment with Q10‐containing formulas. Following a 14‐day treatment with formula 1 and formula 2 ubiquinone (A) and ubiquinol (B) levels were determined within the epidermis obtained from treated forearm skin compared with untreated control skin. Results are depicted as mean ± SEM (20–66 years; n = 73). Significant differences are marked with an asterisk [*P < 0.05 with respect to the untreated control (repeated measures analysis of variance, Dunnett's post hoc test)].

Figure 5

Energy metabolism of cultured human keratinocytes is increased after treatment with Q10. Cultured human keratinocytes were supplemented with 18 µM ubiquinone (representing the amount of Q10 which was determined in the tissue after topical treatment) and the oxygen consumption rate (OCR) was determined. Results are depicted as mean ± SEM (n = 6 donors). Significant differences are marked with an asterisk [*P < 0.05 with respect to the untreated control (paired t‐test)].

Figure 6

Antioxidant properties of stressed skin are improved after treatment with Q10‐containing formulas. Volunteers displaying elevated oxidative stress (≥250 FORT units) in untreated skin, were analyzed following a 14‐day treatment with formula 1 and formula 2. The level of free oxygen radicals (A) and the free oxygen radical defense (B) were determined in suction blister fluid obtained from treated compared with untreated control samples. Results are depicted as mean ± SEM (n = 16). Significant differences are marked with an asterisk [*P < 0.05 with respect to the untreated control (repeated measures analysis of variance, Dunnett's post hoc test)].